EP0088723A1 - Embroidery machine head - Google Patents

Abstract

The sewing head comprises at least one cylindrical sector (2) rotatably mounted in a cradle (1) and having tubular housings in each of which is guided a tool bar (3). The tools of this sewing head can be coupled to the mechanism of a conventional embroidery machine. It allows a simplification of the manipulations required when changing embroidery models to be made and for replacing damaged tools.

Description

The invention relates to a sewing head comprising a set of tool-holder bars, arranged parallel to one another and movable in the axial direction, intended in particular to be mounted on an embroidery machine.

Embroidery machines are already known comprising needles and piercers, fixed to movable supports, actuated by a separate mechanism ensuring a reciprocating movement of the needles and piercers, in the axial direction.

They are equipped, over their entire length, with a row of needles arranged side by side. The distance between each needle is 1 French inch, or 27.07 mm. This distance is defined, in business jargon, by 4/4. This is how the distance, between 3 needles placed side by side, will be 8/4, between 4 needles: 12/4 etc ... These machines work at an average speed of 200 points per minute.

When embroidering with different threads (either quality, size or color), the productivity is reduced in a proportional ratio to the quantities of different threads. Indeed, on traditional machines, it is necessary, after embroidery with the 1st thread, to stop the embroidery machine, to unthread all of the needles used and to re-thread them with the new thread. This operation is very tedious and long lasting. It will have to be repeated with each change of thread, thus reducing, in enormous proportions, productivity. When changing the pattern, it is necessary to replace needles according to the pattern and to remove needles that have become unnecessary.

If there are holes to be drilled in specific places of the fabric to be embroidered, piercers are mounted on suitable supports. When changing the pattern, it is necessary to replace the piercers on their support according to the new pattern, which also requires prolonged stops of the machine.

In order to increase productivity, some machines have been fitted with a second row of needles located halfway up the machine.

It should be taken into account that current machines can have from 340 to more than 700 needles per row depending on the size of the machine.

Several other attempts to improve this state of affairs inherent in the very complex construction of these embroidery machines have not produced the desired result. Indeed, the application of these, both during the manufacture of new machines and for the transformation of the fleet of existing machines, implies such modifications of the design and mechanisms of the embroidery machines, that none of those -this could not be applied in practice. The main causes are that these devices are much too bulky or require a force such that the power of the machines should be increased in significant proportions, since the different organs must be actuated, in many cases, against the effect of return springs.

The sewing head according to the invention which makes it possible to reduce the duration of most of these interventions is characterized in that needle-holder bars are guided in a cylindrical sector mounted rotatably in a cradle comprising at least a first member driving a needle bar in a reciprocating movement in the axial direction, actuable by the mechanism of an embroidery machine and a needle bar selector member allowing the selected bar to be coupled to the first drive member.

• La figure 1 en est une vue en élévation partiellement en coupe axiale.
• La figure 2 en est une vue en coupe transversale selon II-II de la fig. 1.
• La figure 3 en est une vue en bout de droite à gauche de la fig. 1.
• La figure 4 en est une vue semblable à la fig. 1 représentant la tête de couture, accouplée au mécanisme d'une machine à broder de la technique antérieure.
• La figure 5 est une vue partielle d'une machine à broder de la technique antérieure, montrant une aiguille et un perceur montés sur son mécanisme à titre comparatif.
• La figure 6 indique schématiquement la séquence d'opérations requises pour la broderie avec trois fils différents sur une machine telle que représentée à la figure 5.
• La figure 7 indique schématiquement la séquence d'opérations requises pour la broderie à trois fils différents sur une autre machine de la technique antérieure.
• La figure 8 indique schématiquement la séquence d'opérations requises pour la broderie à trois fils différents sur la machine représentée à la figure 4.

The accompanying drawing shows schematically and by way of example an embodiment of the sewing head according to the invention.

• Figure 1 is an elevational view partially in axial section.
• Figure 2 is a cross-sectional view along II-II of FIG. 1.
• Figure 3 is an end view from right to left of FIG. 1.
• Figure 4 is a view similar to FIG. 1 representing the sewing head, coupled to the mechanism of an embroidery machine of the prior art.
• Figure 5 is a partial view of an embroidery machine of the prior art, showing a needle and a piercer mounted on its mechanism for comparison.
• FIG. 6 schematically indicates the sequence of operations required for embroidery with three different threads on a machine as shown in FIG. 5.
• FIG. 7 schematically indicates the sequence of operations required for embroidery with three different threads on another machine of the prior art.
• FIG. 8 schematically indicates the sequence of operations required for embroidery with three different threads on the machine shown in FIG. 4.

As shown in Figures 1 and 2, the sewing head includes a cradle 1 in which are rotatably mounted around a cylindrical support 23, two cylindrical sectors 2 for guiding the needle holder bars 3. Each of these cylindrical sectors has three tubular housings in each of which is engaged a needle holder bar 3 sliding in the axial direction.

Two piercing bars 4 are engaged and individually guided in the cradle 1 parallel to the needle bars 3. In the inactive retracted position bars 3 and 4 are retained in the cradle 1 by magnets 5.

The cylindrical sectors 2 have a peripheral toothing 6 which meshes with a rectilinear toothing of a push rod 7 intended to drive the cylindrical sector 2 in rotation within determined limits. Curved notches 8 are cut from a plate 9 closing the front end of the cradle 1. These semi-circular notches 8 provide a passage at the front end of the needle holder bars 3.

The needle holder bars are provided with pins 10 intended to couple them to a drive arm 11 slidably mounted on a guide bar 12 associated with the cradle 1. The drive arm 11 is itself provided with a stud 13 coupling to the mechanism of an embroidery machine. The end of the pins 10 opposite to that which is intended to be coupled to the drive arm 11 is engaged in a longitudinal groove of the cylindrical sector 2, in order to guide the needle holder bars 3 in the axial direction.

The push rod 7 also makes it possible to actuate a lever 15 pivoted on a slide 16 mounted on the bar 12, by means of a pin 17. The lever 15 in turn actuates a pin 18 which penetrates into a housing 19 of one of the piercing bars 4 for coupling it to the slide 16 which is provided with a stud 20 for coupling to the mechanism of the above-mentioned embroidery machine. However, it would also be possible to mount a piercer on a needle bar.

There is shown in Figure 4 the sewing head mounted, with minimal transformations, on a conventional embroidery machine as shown in Figure 5. It suffices to cut at the height of the pivots 21, 22 of the thread pullers supplying the needle, the needle holders and the piercing holders of the machine shown in FIG. 5 and to make therein housings for the pins 13 to 20 of the sewing head, as shown in FIG. 4.

The prior art embroidery machines are constructed so as to leave a gap of one French inch (27.07 mm) between adjacent needles. This same ratio was maintained in the sewing head according to the invention and it is thus possible to substitute a set of twice three needles fed, through the cylindrical support 23, in different threads, to two adjacent needles of a machine to embroider usual. The needles of each of these groups of three needles can be substituted for one another or deactivated by rotation of their cylindrical sector 2 under the action of their respective selection member 7.

By actuation of their respective lever 15 one or two piercers can be turned on.

In the embodiment shown in Figure 4, the needle holder bars are actuated by a connecting rod from an oscillating shaft 24 extending over the entire length of the embroidery machine. The same applies to the piercing bars, which are actuated from an oscillating shaft 25. They could however be actuated by any other pneumatic or electronic mechanical means.

As shown in phantom in Figure 4, the cradle 1 of the sewing heads aligned side by side can be pivotally mounted about a transverse axis. It is thus possible to easily turn off several sewing heads, in particular when a change of thread or needle is required.

Preferably, the transverse pivot axis of the cradle 1 is at the height of the cylindrical support 23 so that when the cradle is pivoted from one of its positions in the other the length of the threads between the eye of the needles and the thread puller remains unchanged.

It should also be noted that, by actuation of the corresponding push rod 7 upwards in FIG. 1, the pin 10 of the lower tool holder is detached from its drive arm 11 at the end of the stroke, which allows you to turn it off.

Conversely, at the end of the downward stroke, the push rod 7 actuates the lever 15 by means of its pin 17 and couples the piercer holder 4 to its drive slide 16.

When two pins 10 are simultaneously in contact with the same drive arm 11, the latter drives the corresponding tool bars 3 in contact with the magnets 5 where they remain out of function, owing to the fact that the shape of the member actuation of the arm 11 from left to right in FIG. 1 ensures the driving of a pin 10 only in the centered position of the latter.

By way of comparison, FIGS. 6 and 7 show the operations required to produce three-threaded embroidery patterns of different colors on machines of the prior art and in FIG. 8 the operations required to produce the same patterns on a machine. equipped with the sewing head according to the invention.

As shown in Figure 6, to make embroidery patterns on a traditional machine, with 3 threads of different color superimposed or juxtaposed inside the pattern, it is necessary, in a first operation A1 to embroider using of the first color, all the dots to appear in this pattern; then the machine is stopped and the wires are replaced by those of a second color. The machine is then restarted, to embroider in a second operation A2 of the second color. These operations are repeated in A3 to embroider the dots of the third color.

As shown in FIG. 7, it is possible to eliminate these multiple stops, by threading the juxtaposed needles, of the different threads, in a well-defined sequence, these needles being put into operation successively, in order to embroider the dots of different colors in one after the other.

The pattern is embroidered in a color in the first operation, with needle No. 1. The stitches practiced with the second shade will be made in a second operation, with needle No. 2. The stitches embroidered with the next shade will be made in a third operation using needle No. 3. On examination of this figure, it clearly appears that, for a pattern, 3 juxtaposed needles (1, 2, 3) are used.

The following pattern will be embroidered with the following 3 needles (4, 5, 6), which implies a decrease in productivity of 1/3. Indeed, when the first patterns are made in phase A, there is necessarily, between them, the free space of 2 patterns which must be embroidered afterwards, one after the other, in phases B and C , in order to use the full surface of the fabric. Between each phase, the fabric must be moved laterally by the value of a pattern, that is to say that the entire fabric can only be embroidered in 3 phases, each representing 3 operations.

As shown in FIG. 8, the present invention makes it possible to respond, in a simple and rational manner, to the desired goal, that is to say to increase the productivity of the machines, while being able to be applied both for the manufacture of new machines as well as for the transformation of the existing machine park.

It is noted that at each location of needles, there is the possibility of using 3 different threads and the passage from one thread to another can be done, by appropriate control means, without stopping the machine and embroidered patterns can be made at each needle location, i.e. all the patterns in a row can be executed in a single phase, which increases productivity by 3 times, while practically eliminating time necessary to change the thread. If more than 3 wires are used, the increase in productivity is proportional to the number of wires.

In addition, for making openwork embroidery, each embroidery location is equipped with a piercer which, according to a pre-established program will be activated at the desired locations.

Consequently, it is no longer necessary to stop the machine in order to eliminate or add piercers, as is the case with the machines of the prior art.

The sewing heads according to the invention can be mounted as well in embroidery machines with vertical working plane as in embroidery machines with horizontal working plane, these machines can be either of the shuttle or hook type.

These sewing heads can also be adapted to industrial, artisanal or household sewing machines.

Claims (10)

1. Sewing head comprising a set of tool-holder bars arranged parallel to one another and displaceable in the axial direction, characterized in that needle-holder bars (3) are guided in a cylindrical sector (2) mounted so rotatable in a cradle (1) comprising at least a first drive member (11) of a needle bar (3) in a back-and-forth movement in the axial direction, actuable by the mechanism of a machine to be embroidered and a needle bar selection member (7) (3) allowing the selected bar to be coupled to the first drive member (11). 2. Sewing head according to claim 1, particularly intended to be mounted on an embroidery machine, characterized in that piercing bars (4) are arranged parallel to the needle bars (3) in the cradle (1 ) which is associated with a coupling device (15, 19) of at least one piercing bar (4) to a second drive member (16). 3. Sewing head according to claims 1 and 2, characterized in that the cradle (1) is mounted on the machine movably between an active position and an inactive position. 4. Sewing head according to claim 1, characterized in that the selection member (7) of the needle holder bars (3) is a push rod having a toothing meshing with a peripheral toothing (6) of the cylindrical sector (2). 5. Sewing head according to claim 1, characterized in that the needle holder bars (3) are guided in axial direction along the cylindrical sector (2) by a projection of one engaged in a longitudinal groove of the 'other. 6. Sewing head according to claims 1 and 4, characterized in that the needle holder bars (3) each have a transverse connecting member (10) intended to couple them to the first drive member (11). 7. Sewing head according to claims 1, 5 and 6, characterized in that the end of the connecting member (10) opposite to that which is intended to be coupled to the first drive member is engaged in a longitudinal groove presented by the cylindrical sector (2). 8. Sewing head according to claims 1 and 2, characterized in that the device for coupling the piercer holder (4) to the second drive member (16) is controlled by the selector member (7) of the bars needle holder (3). 9. Sewing head according to claim 1, characterized in that in at least one position of the selection member (7) the needle holder bars (3) are deactivated in the inactive position. 10. Use of sewing heads according to claim 1, by replacing the sewing heads of the prior art, mounted on existing embroidery machines.

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