Sewing machine with two independent needles

Abstract

A sewing machine with two independent needles (10), comprising a base (12) to which a sewing structure is stabilized, comprising an upright (14) and a sewing arm 16 overhanging with respect to said upright 14, the sewing arm (16) comprising a first sewing head (18) and a second sewing head (20), mutually arranged side-by-side and supporting a first needle (22) and a second needle (24), respectively, arranged equally side-by-side with a vertical orientation and vertically moved along an outward / return travel and an associated first foot and second foot, the base (12) comprising a first unit (26) and a second unit (28) of the column type and arranged side-by-side and adjacent to each other and arranged at, and below the first needle (22) and second needle (24), respectively, and comprising a first crochet and a second crochet, respectively, for cooperating with the first needle (22) and second needle (24) to make the stitches and a first jaw (30) and second jaw (32), with said elements being mutually movable in synchrony for advancing an article to be sewn along a sewing direction in step relation with the vertical movement of the first needle (22) and second needle (24), the sewing machine comprising first movement means for actuating a mutual approaching / distancing between the first sewing head (18) and the second sewing head (20) completely independently of each other and second movement means for actuating a mutual approaching / distancing between the first unit (26) and the second unit (28) completely independently of each other and in agreement with the mutual approaching / distancing between the first sewing head (18) and the second sewing head (20).

Description

[0001] SEWING MACHINE WITH TWO INDEPENDENT NEEDLES

[0002] The present invention relates to a sewing machine with two independent needles .

[0003] More specifically, the present invention relates to a sewing machine with two needles used to obtain a double sewing line with two different threads on articles , such as leather goods , footwear, automotive and the like .

[0004] As known, a sewing machine with two needles is a type of sewing machine, in which two needles work simultaneously using two different threads , which are separate from each other in order to obtain sewing lines , parallel to each other, uniform and resistant .

[0005] Sewing machines with two needles are typically used in the textile and clothing industry or in types of sewing processes requiring high precision and resistance, such as the stitching of car seats in the automotive sector or armchair or sofa covers or the like in the sector of furnishing, for example .

[0006] Sewing machines with two needles allow obtaining precise and parallel stitching on a wide variety of fabrics or leathers , including thick or heavy leathers , as well as achieving the above stitching in a single operation with a consequent advantage in terms of time saving .

[0007] Sewing machines with two needles traditionally comprise a sewing head and a base arranged below said sewing head, comprising a pair of needles arranged with a vertical orientation at a predetermined distance from each other and vertically movable along outward / return travels and with the base comprising a pair of sewing units arranged side- by-side and adjacent to each other and in which each comprises a crochet actuated to cooperate with a single needle and a movement jaw for moving the article to be sewn along a sewing direction .

[0008] However, traditional sewing machines with two needles have significant drawbacks related to the fact that , in order to vary the type of sewing, understood in terms of distance between the sewing cords or the sewing style or other, it is necessary to vary the distance between the needles of the sewing head, as well as that between the sewing units of the base cooperating with said needles , and said operation is performed manually by a qualified expert who must change the pieces , for example, and vary the settings thereof with consequent lengthy machine downtimes , to which related high costs are associated .

[0009] In order to overcome said drawbacks , sewing machines with two needles have been developed, which require no intervention by a qualified expert to vary the distance between the sewing lines to be made .

[0010] More specifically and in this respect , sewing machines with two needles are known, in which movement means allow a mutual approaching of the two needles (and of the sewing units ) between two end positions and by means of a motor actuation, which translatably moves one of the two needles (and one of the two sewing units ) with respect to the other, the latter remaining fixed .

[0011] Examples of such types of sewing machines are described in EP3875653 , EP3875654 , US4043283 or CZ2013434 .

[0012] However, this type of machine also has significant drawbacks related to the fact that it allows the distance to be varied between the needles without the option of making complex stitching with reference to the type of stitches in esthetic terms ( for example, a first sewing cord with one shape and a second sewing cord with a different shape ) and moreover, it does not allow stitching on complex-shaped profiles and, in particular, on form or assembled profiles , which are not flat , such as materials for covering armchairs or seats or the like in the furnishing sector or coverings for seats or dashboards or other motor vehicle parts ; in the case of complex-shaped stitches or two sewing cords with a different development and shape to each other, traditional machines do not make the two sewing cords simultaneously, but separately, i . e . creating a first sewing cord and then a second sewing cord . It is the object of the present invention to obviate the drawbacks disclosed above .

[0013] More specifically, it is the object of the present invention to provide a sewing machine with two independent needles adapted to completely eliminate the intervention of a qualified expert to adjust the position of the sewing needles .

[0014] It is a further object of the present invention to provide a sewing machine with two needles , which does not require the replacement of mechanical parts in the case of varying the type of sewing .

[0015] It is a further object of the present invention to provide a sewing machine with two needles adapted to allow the execution of dif ferent types of sewing as regard to size and shape .

[0016] It is a further object of the present invention to provide a sewing machine with two needles adapted to allow the execution of different types of sewing on form or assembled products , but not on flat products .

[0017] It is a further object of the present invention to provide users with a sewing machine with two needles adapted to ensure great reliability and duration in time, which is also cheap and easy to produce .

[0018] These and other objects are achieved by the invention having the features outlined in claim 1 .

[0019] According to the invention, a sewing machine with two independent needles is provided and comprising a base to which a sewing structure is stabilized, comprising an upright and a sewing arm overhanging with respect to said upright , the sewing arm comprising a first sewing head and a second sewing head, mutually arranged side-by-side and supporting a first needle and a second needle, respectively, equally arranged side-by-side with a vertical orientation and vertically moved along an outward / return travel, the base comprising a first unit and a second unit arranged side-by-side and adjacent to each other and arranged at , and below the first needle and second needle, respectively, and comprising a first crochet and a second crochet , respectively, for cooperating with the first needle and the second needle to make the stitches , and a first jaw and second jaw, mutually movable, respectively, in synchrony for advancing an article to be sewn along a sewing direction in step relation with the vertical movement of the first needle and the second needle, the sewing machine also comprising first movement means for actuating a mutual approaching / distancing between the first sewing head and the second sewing head completely independently of each other and second movement means for actuating a mutual approaching / distancing between the first unit and the second unit completely independently of each other and in agreement with the mutual approaching / distancing between the first sewing head and the second sewing head .

[0020] Advantageous embodiments of the invention become apparent from the dependent claims .

[0021] The constructional and functional features of the sewing machine with two independent needles of the present invention can be better understood from the following detailed description, in which reference is made to the appended drawings , which show a preferred and non-limiting embodiment , and in which : figure 1 diagrammatically shows a partially sectioned axonometric view of the sewing machine with two needles of the invention; figure 2 diagrammatically shows a partially sectioned front view of the sewing machine with two needles of the invention; figure 3 diagrammatically shows a partially sectioned front view of a portion of the sewing machine with two needles of the invention and, in particular, of the portion corresponding to the sewing head; figure 4 diagrammatically shows a partially sectioned view from below of the sewing machine portion with two needles with reference to figure 3 ; figure 5 diagrammatically shows an enlarged detail indicated by the dotted circle denoted with "A" in figure 4 ; figure 6 diagrammatically shows a view from below of a portion of the sewing machine with two needles of the invention and, in particular, of the portion corresponding to the sewing base ; figure 7 diagrammatically shows a longitudinal sectional view according to a vertical plane ( section plane A-A in figure 6 ) of the base portion with reference to figure 6 ; figure 8 diagrammatically shows a view from above of the base portion of the sewing machine with reference to figures 6 and 7 ; figure 9 diagrammatically shows an enlarged detail seen from above of a component with reference to figures 7 and 8 ; figures 10 and 11 diagrammatically show two illustrative types of sewing obtainable with the sewing machine with two independent needles of the invention .

[0022] With reference to the above figures , the sewing machine with two independent needles of the invention, globally indicated with 10 in figures 1 and 2 , comprises a base 12 to which a sewing structure is stabilized comprising an upright 14 and a sewing arm 16, with the upright 14 stabilized at the base 12 and vertically developed and the sewing arm 16 overhanging with respect to said upright 14 and developed according to a horizontal direction perpendicular to the direction of the upright from one end of said upright 14 opposite to the constraining end with respect to the base 12 .

[0023] The sewing structure and, in particular, the sewing arm 16 comprises a pair of sewing heads defined by a first sewing head 18 and a second sewing head 20 , respectively, arranged side-by-side and supporting a first needle 22 and a second needle 24 , respectively, equally arranged side-by-side with a vertical orientation and vertically moved along an outward / return travel .

[0024] The base 12 , arranged below the sewing structure, comprises a first unit 26 and a second unit 28 arranged side-by-side and adjacent to each other, with the first unit 26 arranged at and below the first needle 22 and with the second unit 28 arranged at and below the second needle 24 ; said first unit 26 and said second unit 28 comprising a first crochet (not shown) and a second crochet (not shown) , respectively, for cooperating with the first needle 22 and with the second needle 24 to make the stitching, a first jaw 30 and a second jaw 32 , respectively, mutually movable in synchrony for determining the advancement of an article to be sewn along a sewing direction in step relation with the vertical movement of the first needle 22 and the second needle 24 .

[0025] According to the embodiment with reference to the figures , the first unit 26 and the second unit 28 are defined by a pair of columns extending vertically for a height of up to 600mm and, preferably, but not exclusively, equal to about 170mm (with the height of said columns , which, however, may differ from the value indicated as a function of the specific sewing needs ) .

[0026] According to an alternative embodiment or alternative use, the first unit 26 and the second unit 28 can be configured flat , corresponding to the base 12 ; the passage from a configuration with columns to a flat configuration can be carried out automatically or semi-automatically or manually .

[0027] The sewing structure comprises first movement means for actuating a mutual approaching / distancing between the first sewing head 18 and the second sewing head 20 completely independently of each other .

[0028] Said first movement means comprise a first sewing-motor 34 and a second sewing-motor 36 (preferably of the brushless type ) having the function of supplying the main rotation of shafts relative to the first needle 22 and the second needle 24 of the first sewing head 18 and the second sewing head 20 , respectively, and a third sewing-motor 38 and fourth sewing-motor 40 (preferably of the stepper type ) having the function of actuating the movement of a first carriage 42 , second carriage 44 , third carriage 46 and fourth carriage 48 , with the first carriage 42 and the third carriage 46 being actuated by the third sewing-motor 38 and with the second carriage 44 and the fourth carriage 48 being actuated by the fourth sewing-motor 40 .

[0029] According to an alternative embodiment , the sewing structure can comprise a further pair of motors , one for each sewing head 18 and 20 , functional for controlling and adjusting the length of the stitches , with said motors being independent of each other, but in step between the first sewing head 18 and the first unit 26 and between the second sewing head 20 and the second unit 28 .

[0030] The first sewing head 18 and the second sewing head 20 comprise a first bar 50 and a second bar 52 , respectively, actuated by the first motor 34 and by the second motor 36 (preferably of the brushless type ) and a corresponding pair of feet defined by a first foot 51 (associated with the first sewing head) and by a second foot 53 (associated with the second sewing head) , respectively, which are coupled in step to the first jaw 30 and to the second jaw 32 of the first unit 26 and second unit 28 of the base 12 . The base 12 comprises , in turn, second movement means for actuating a mutual approaching / distancing between the first unit 26 and the second unit 28 completely independently of each other and in agreement with the mutual approaching / distancing between the first sewing head 18 and the second sewing head 20 .

[0031] Said second movement means comprise a pair of motors (of the brushless type ) defined by a first base-motor 54 and a second base-motor 56, supplying a first main shaft 58 and a second main shaft 58 ' , respectively, which are independent of each other and actuate and control the main rotation of the crochet sewing element with reference to the first and second unit of the base 12 , a pair of further motors (of the stepper type ) defined by a third base-motor 60 and a fourth base-motor 62 for moving base-carriages 64 and 66 and base carriages 68 and 70 , respectively, which act to linearly move the first 26 and the second 28 units , allowing the variation in the sewing distance between said two units , with said distance being, preferably, but not exclusively, from 4 to 25 mm; possibly further motors (not shown) are used for adjusting the length of the stitch .

[0032] The first jaw 30 and the second jaw 32 with reference to the columns of the first unit 26 and second unit 28 of the base 12 can be moved independently of each other and synchronously with the corresponding first needle 22 and second needle 24 of the first sewing head 18 and second sewing head 20 for transporting the sewing and crochet material underlying said jaws .

[0033] The first sewing head 18 and the first unit 26 are actuated in a mutual synchronous movement ( so that the first needle 22 of the first sewing head 18 , with the relative first needle 22 and the relative foot 51 , can cooperate with the first jaw 30 and the relative crochet of the first unit 26 ) and, likewise, the second sewing head 20 and the second unit 28 are actuated in a mutual synchronous movement ( so that the second sewing head 20 with the relative second needle 24 and the relative second foot 53 can cooperate with the second jaw 32 and the relative crochet of the second unit 28 ) , with the first sewing head 18 and the first unit 26 being actuated and movable completely independently of the second sewing head 20 and the second unit 28 .

[0034] The variation in the distance between the first needle 22 and the second needle 24 is actuated by means of the stepper motors with reference to the sewing heads and, correspondingly, by means of the stepper motors of the columns defining the movable base units .

[0035] More specifically, with reference to the first needle 22 , the third sewing-motor 38 of the first sewing head 18 moves the first carriage 42 and the third carriage 46 of the first sewing head 18 and the third base-motor 60 of the first unit 26 moves the base-carriages 64 and 66 of the first unit 26 .

[0036] With reference to the second needle 24 , the fourth sewingmotor 40 of the second sewing head 20 moves the second carriage 44 and the fourth carriage 48 and the fourth basemotor 62 of the second unit 28 moves the base-carriages 68 and 70 of the second unit 28 .

[0037] Motors 34 and 36 manage the rotation of shafts relative to the first needle 22 and the second needle 24 and, by means of a combination of the longitudinal translation movement of the first 18 and second 20 sewing heads with the movement of the first unit 26 and the second unit 28 , as well as the advancement of the product being sewn given by the movement of the first 30 and second jaw 32 , it is possible to make zig-zag or wavy stitches of the type shown in figures 10 and 11 .

[0038] The motors described are connected to a control unit (not shown) , which manages the actuations thereof as a function of the specific sewing needs ; the definition of the sewing specifications ( in terms of the shape of the sewing cords , the distance, the color and the type of thread and similar) are defined by an operator and communicated to the control unit by means of a user interface on board the sewing machine or arranged remotely with respect thereto .

[0039] The independent movement of the two needles 22 and 24 and, correspondingly, the movement of the corresponding units 26 and 28 of the base 12 (with the cooperation of the independent movement of the jaws and feet with which each unit of the base and each sewing head) is allowed not only to manage the distance between the sewing cords , but also to manage and make different types of stitching, with the first needle making stitches of a different type / shape and completely independently of those made by the second needle or vice versa and with said different types of stitches , which are not only made on flat products , but also and especially on shaped or assembled and preformed products , such as covers for motor-vehicle seats or covers for dashboards and the like ; for example, while the first needle 22 makes a rectilinear sewing cord, the second needle 24 can make a zig-zag or wavy sewing cord or another type of sewing cord as a function of the specific sewing needs .

[0040] As regards and with reference to figures 10 and 11 , two different types of sewing are shown diagrammatically and by way of example, obtained by means of the above sewing machine with two independent needles .

[0041] Figure 10 shows an example of sewing 80 comprising a first sewing cord 80 ' with a wavy development and a second sewing cord 80 ' ' with a rectilinear development , substantially parallel to the first cord 80 ' .

[0042] Figure 11 shows a further example of sewing 81 comprising a first sewing cord 81 ' with a wavy development and a second sewing cord 81 ' ' with an equally wavy development , parallel to the first cord . In both types of sewing with reference to the example, by means of the sewing machine of the invention, while a first needle makes a sewing cord, the second needle makes the second sewing cord with movement entirely independent of that of the first needle .

[0043] Additional multiple sewing shapes can be obtained by means of the sewing machine of the invention, besides those shown with reference to figures 10 and 11 , as a function of the specific needs of production and style ; for example , a first sewing cord with a rectilinear development and a second sewing cord with a zig-zag development , a first sewing cord with a wavy development and a second sewing cord with a zig-zag development , both cords with a zig-zag development , a first sewing cord with a wavy development and a second sewing cord with a wavy development and the same step as the first sewing cord, but with different width dimensions of the "waves" with respect to those of the first sewing cord, sewing cords with a similar development (wavy or zig-zag or Greek key pattern) but with different steps , sewing cords in which sections are present with different developments within a single sewing cord (e . g . rectilinear section followed by a wavy section and / or by a zig-zag or Greek key section) , etc . , with the distance between the two sewing cords that can vary (also in the sewing step) and with said sewing cords that can be made both on a flat product and on already in form or assembled or preassembled product ( such as seats , headrests , dashboards , etc . in the sector of motor vehicles ) , with said sewing machining being made possible by virtue of the fact that the sewing machine with two independent needles of the invention comprises a first 26 and a second 28 units in a column-type configuration (as in the embodiment shown in the figures ) , allowing the shape of the product already in form to be followed during the sewing process . The control unit will manage the actuations of the movement means of the sewing heads and the base units to adjust the movements of the needles and feet and of said base units and the relative jaws as a function of the specific sewing types defined by the operator .

[0044] The advantages achieved by the improved sewing machine of the invention are apparent from the above description .

[0045] Advantageously, the sewing machine with two independent needles of the present invention allows managing the variation of the distance between the sewing cords completely automatically, eliminating the intervention of a qualified expert to adjust the position of said sewing needles .

[0046] A further advantage of the sewing machine of the invention is represented by the fact that it allows obtaining a completely independent movement of one needle with respect to the other, and therefore, it substantially configures two sewing machines working in pairs and synchronously (i . e . at the same time ) .

[0047] A further advantage of the sewing machine of the invention is represented by the fact that the completely independent movement between the two needles also allows adjusting the distance between the sewing cords while work is in progress .

[0048] A further advantage of the sewing machine of the invention is represented by the fact that the completely independent movement of the two sewing needles allows obtaining types of sewing, which can differ between the first and the second needle both in terms of distance between the sewing cords and in terms of shapes of the sewing cords (e . g . zigzag, wavy, etc . ) .

[0049] A further advantage of the sewing machine of the invention is represented by the fact that the development in height of the columns defining the first unit 26 and the second unit 28 of the base (together with the movement of the jaws and feet ) also allows managing the sewing of already in form or shaped products , e . g . covers for motor-vehicle seats for which finishing stitches must be made around the two needles also with different sewing paths (machining not possible with a flat sewing machine or a column sewing machine, which, at most , allows making only one pair of linear sewing cords on flat elements ) .

[0050] A further advantage is the fact that the sewing machine with two independent needles of the invention allows a drastic reduction in the adjustment and variation of the distance between the needles and, consequently, in the related costs .

[0051] Although the invention has been described above with particular reference to an embodiment thereof , given by way of non-limiting example, several modifications and variations will be apparent to those skilled in the art in the light of the above description . Therefore, the present invention intends to include all the modifications and variations lying within the scope of the following claims .

Claims

CLAIMS1. A sewing machine with two independent needles (10) for making a double sewing line with two different threads on articles, such as leather goods, footwear, automotive and the like, comprising a base (12) to which a sewing structure is stabilized, comprising an upright (14) and a sewing arm (16) overhanging with respect to said upright (14) , the sewing arm (16) comprising a first sewing head (18) and a second sewing head (20) , mutually set side-by- side and supporting a first needle (22) and a second needle (24) , respectively, arranged equally side-by-side with a vertical orientation and vertically movable along an outward / return travel and an associated first foot (51) and second foot (53) , the base (12) comprising a first unit (26) and a second unit (28) set side-by-side and adjacent to each other and arranged at, and below the first needle (22) and second needle (24) , respectively, and comprising a first crochet and a second crochet, respectively, for cooperating with the first needle (22) and second needle (24) to make the stitches and a first jaw (30) and second jaw (32) , with said jaws being mutually movable in synchrony for advancing an article to be sewn along a sewing direction in step relation with the vertical movement of the first needle (22) and second needle (24) , respectively, the sewing machine characterized in that it comprises first movement means for actuating a mutual linear approaching / distancing movement between the first sewing head (18) and the second sewing head (20) completely independently of each other and second movement means for actuating a mutual approaching / distancing between the first unit (26) and the second unit (28) completely independently of each other and in agreement with the mutual approaching / distancing between the first sewing head (18) and the second sewing head (20) .

2. A sewing machine with two needles according to claim 1,characterized in that it comprises a control unit for managing first movement means and second movement means, in communication with a user interface on board the sewing machine or in a remote position.

3. A sewing machine with two needles according to claim 1, characterized in that the first movement means comprise a first sewing-motor (34) and a second sewing-motor (36) for supplying the main rotation of shafts relative to the first needle 22 and the second needle 24 of the first sewing head (18) and the second sewing head (20) , respectively, and a third sewing-motor (38) and a fourth sewing-motor (40) for actuating the movement of a first carriage (42) , second carriage (44) , third carriage (46) and fourth carriage (48) , the first carriage (42) and the third carriage (46) being actuated by the third sewing-motor (38) for the linear approaching / distancing movement of the first sewing head (18) and with the second carriage (44) and fourth carriage (48) being actuated by the fourth sewing-motor (40) for a linear approaching / distancing movement of the second sewing head (20) .

4. A sewing machine with two needles according to claim 3, characterized in that the first sewing-motor (34) and the second sewing-motor (36) are of the brushless type and that the third sewing-motor (38) and the fourth sewing-motor (40) are of the stepper type.

5. A sewing machine with two needles according to claim 1, characterized in that the second movement means for actuating a mutual linear approaching / distancing movement between the first unit (26) and the second unit (28) of the base (12) comprise a first base-motor (54) and a second base-motor (56) of the brushless type, which supply a first main shaft (58) and second main shaft (58' ) independently of each other and actuate and control the main rotation of the first crochet and the second crochet, a third basemotor (60) and a fourth base-motor (62) of the stepper typefor moving base-carriages (64, 66) and base-carriages (68, 70) of said first unit (26) and said second unit (28) , respectively .

6. A sewing machine with two needles according to claim 3, characterized in that it comprises a further pair of motors, one for the first sewing head (18) and one for the second sewing head (20) for controlling and adjusting the length of the stitches.

7. A sewing machine with two needles according to claim 5, characterized in that it comprises a further pair of motors, one for the first unit (26) and one for the second unit (28) , for adjusting the length of the stitch.

8. A sewing machine with two needles according to one or more of the preceding claims, characterized in that the first unit (26) and the second unit (28) comprise a configuration with columns extending vertically, functional for sewing form or assembled / pre-assembled products.

9. A sewing machine with two needles according to one or more of the claims 1 to 7, characterized in that the first unit (26) and the second unit (28) have a flat configuration corresponding to that of the base (12) .

10. A double sewing line with two different threads made by the sewing machine with two independent needles according to the preceding claims, characterized in that it comprises a first sewing cord and a second sewing cord, which are substantially parallel to each other and with shapes having an equal or different development to each other as regards the form, size and step of the single cords, with a constant development along the whole extension of the single sewing cord or with a varying development along the extension thereof and with a distance between said sewing cords, which is constant or varying, said sewing cords being formed on a flat product or on a form / assembled product, with a first sewing cord being obtained by means of a synchronous cooperation between a first needle and afirst foot of the first sewing head and a first base unit and a first jaw with linear approaching / distancing movement completely independent of a second needle and a second foot of the second sewing head in synchronous cooperation with a second base unit and a second jaw making the second sewing cord .

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