| WO/2011/045731 | A SYSTEM FOR SUPPORTING AND ORIENTATING FOR A CURVED - NEEDLE SEWING MACHINE |
| JP06121887 | CLOTH END NOTCH DETECTOR FOR SEWING MACHINE |
| JP05293277 | SEWING MACHINE |
| 1. | A machine for sewing various kinds of articles, in particular made of leather, characterised in that it includes: a longitudinal guiding plate (7), a part of which defines two opposite flat side surfaces (7a,7b), with a first article to be sewn (8) and a second article to be sewn (9) positioned each one against a respective surface (7a,7b), with said guide (7) being formed at the lower end of a substantially vertical support arm (12); an arclike needle (6), which reciprocates on a plate that is transversal to said guiding plate (7), between a retracted position, in which the needle is located beside one of said flat side surfaces (7b) and a piercing position, in which the needle pierces said articles (8,9), said needle being moved forward and backward according to a predetermined step; a rotary hook assembly (10) and a thread spool located beside the other end of said flat side surface (7a) for cooperation with said needle (6) to form the stitches. |
| 2. | A machine as in claim 1 , characterised in that said flat surfaces (7a,7b) of said guiding plate (7) are substantially vertical and define respective working surfaces, on which edges of said articles (8,9) to be sewn together rest. |
| 3. | A machine as in claim 1 , characterised in that over said guiding plate (7), said support arm (12) carries a rim presser, including two elements (14,15) situated over said flat surfaces (7a,7b), respectively and acting on the edges of said articles (8,9). |
| 4. | A machine as in claim 3, characterised in that said presser elements (14,15) are adjustable independently from each other, through respective vertical slots (17,19), so as to define mutual position of said articles (8,9). |
| 5. | A machine as in claim 1 , characterised in that it includes a crumpling group (23) situated beside the flat surface (7b) and equipped with a head that reciprocates, upon suitable commands, backward and forward in direction transversal to the guiding plate (7), so as to clamp an edge of said second article (9), and in direction longitudinal to the guiding plate (7), to make a crumpling in said edge of said article (9). |
| 6. | A machine as in claim 1 , characterised in that it includes a presser foot (20) located beside said flat surface (7a) and moved in direction transversal to said guiding plate (7) so as to clamp said article (8) while the needle (6) is piercing it, said presser foot (20) featuring a through hole (21), through which the same needle (6) passes freely. |
| 7. | A machine as in claim 1 , characterised in that it includes a leather pressing element (22), situated beside said flat surface (7b) and moved in direction transversal to said guiding plate (7) so as to clamp said article (9) after each stitch has been performed, while the needle (6) is being extracted. |
TECHNICAL FIELD
The present invention concerns sewing articles made of leather or the like, in particular for production of footwear, bags and the like.
BACKGROUND ART
Known automatic machines for sewing leather articles usually feature a head, cantilevered on the front of the base structure and equipped with means for supporting the needle and related operating means. The needle is moved toward an arm, situated below, that acts as a horizontal support, on which the leather articles to be sewn rest.
The needle moves also in direction parallel to the support arm.
The above mentioned machines are equipped also with transport means that move the overlapped edges of the leather articles to be sewn. A machine of this type is disclosed n the US Patent No. 4.848.252 of the same
Applicant. This machine includes a guide that longitudinally defines two flat inclined surfaces, upwardly convergent to form respective work tops, on which the leather articles to be sewn are moved.
Over the guide, there is a longitudinal shaft, with an arm keyed thereto and provided at its free end with a curved needle.
The shaft is oscillated so as to alternatively move the needle between a raised position and a lowered position, in order to pierce the edges of the leather articles.
The needle operates in combination with a rotary hook provided with a thread. The above described machine is designed to sew edges of two leather articles e.g. shoe uppers and toe caps.
However, this machine cannot be used for sewing together bottom and upper, in case the shoe is of open type and a strip is to be joined to the bottom.
Figure 8 shows, as an example, a shoe with an upper sewn along its edge to a bottom. It is to be noted that in this case the sewing is visible both along the edge of the upper and along the edge of the bottom, thus forming a kind of decorative motif.
At present, the sewing of the bottom to the upper is often hand-made, that requires a specialised staff thus increasing manpower cost and subsequently, the final cost of the product, and moreover, the productivity is reduced. Another problem deriving from the hand-made sewing lies in the necessity of a camber that is made in front part of the shoe by previously shaping the front part of the upper like a dome.
Other known automatic machines, so-called "Rapid", can sew the bottom to the shoe upper. However, the use of these machines requires former joining of the bottom and the upper by means of glue; moreover, the shoe must be mounted on a suitable last during sewing.
Obviously, this results in considerable working complexity and consequently, affects the cost of the product and the productivity. The Patent Application No. BO95A 000392 owned by the same Applicant, proposes a sewing method that includes positioning edges of the articles to be sewn together against respective flat side surfaces of a longitudinal guiding plate formed at the top of a ring-like block.
The ring-like block rotates on a pin that is supported, with horizontal axis and perpendicular to said guiding plate, by a free end of an arm that swings with respect to a stationary frame.
The edges of the articles are sewn by means of an arc-shaped needle which is reciprocated on a plane transversal to the guiding plate between a retracted position and a piercing position, in which the needle pierces the articles to be sewn.
Sewing of the articles is followed by swinging the arm together so that spatial attitude of the guiding plate is kept unchanged as the sewing progresses.
DISCLOSURE OF THE INVENTION
The object of the present invention is to propose a machine for simplified sewing of leather articles, in particular the bottom and the upper of a shoe, without preliminary operations. The above mentioned object is obtained by means of a machine for sewing various kinds of articles, in particular made of leather, which includes: a longitudinal guiding plate, a part of which defines two opposite flat side surfaces, with a first article and a second article to be sewn positioned each one against a respective surface, with the guide being formed at the lower end of a support arm substantially vertical; an arc-like needle, which reciprocates on a plate that is transversal to the guiding plate, between a retracted position, in which the needle is located beside one of the flat side surfaces and a piercing position, in which the needle pierces the articles, said needle being moved forward and backward according to a predetermined step; a rotary hook assembly and a thread spool located beside the other end of the flat side surface for co-operation with the needle to form the stitches.
BRIEF DESCRIPTION OF THE DRAWINGS
The characteristic features of the invention are pointed out in the following description, with particular reference to the enclosed drawings, in which:
• fig. 1 is a front view of the present machine for sewing leather articles;
• fig. 2 is an enlarged view of a particular of this machine, in the stitching area;
• fig. 3 is a prospective view of the above mentioned stitching area; • fig. 4, is a back view and figs. 5, 6 are side views of a longitudinal plate guiding the articles to be sewn;
• fig. 7 is a prospective view of the bottom and upper of a shoe to be sewn with this machine;
• fig. 8 is a perspective view of a shoe sewn by the present machine.
BEST MODE OF CARRYING OUT THE INVENTION
With reference to the above mentioned figures, numeral 1 indicates the head of the sewing machine, that carries means for operating sewing means.
The head 1 is an integral part of a stationary support frame 2 of the machine; in particular, the head 1 is cantilevered on the front of a body 3 of the frame 2, whose axis is suitably inclined with respect to the vertical. The head 1 supports, in known way, a longitudinal shaft 4 provided with a transversal arm 5. A curved needle 6 is mounted to a free end of the transversal arm 5 and is in coaxial relation with the arc described by the free end. The needle 6 oscillates between a retracted position, beside the work surfaces of the guiding plate 7, as specified in the following, and a piercing position, in which the needle passes through the articles 8 and 9 to be sewn. These articles 8 and 9 in particular include bottom and upper of a shoe, in the case illustrated in fig. 7, the upper is open, i.e. forms a strip, which is to be joined with the bottom 8 along an edge.
The needle 6 oscillates in a suitable time relation with the advancement movement of the leather articles to be sewn.
The shaft 4 of the needle 6 is reciprocated axially so as to move forward and backward according to a predetermined step, and impart a forwarding motion to the articles 8,9 1 be sewn.
A rotary hook 10, provided with a thread spool, works in co-operation with the needle 6. The rotary hook 10 is situated beside the work surfaces of the guiding plate 7 on the side opposite to the side where the needle rests when in retracted position. As seen in detail in fig. 2, the guiding plate 7 is laterally delimited by flat surfaces 7a,7b which are substantially vertical.
The flat surfaces 7a, 7b form respective working surfaces for positioning and guiding the articles 8 and 9 to be sewn.
Below the working surface 7a, the guiding plate 7 forms a shoulder 7c, on which the internal edge of the article 8 abuts. The guiding plate 7 features a longitudinal slot 11 , open at the back, through which the needle 6 passes.
The guide 7 is formed at the lower end of a support arm 12, arranged substantially vertical and fastened to the front of the head 1 of the sewing machine by a screw 13. A rim presser, situated over the guide 7 and carried by the support arm 12, includes a pair of elements 14,15 pressing respective edges of the articles 8,9.
The first pressing element 14, that is substantially bracket-shaped, is mounted over the working surface 7a by a screw 16 that passes through a vertical slot 17
(fig. 5). The second pressing element 15 is mounted over the working surface 7b by a screw 18 that passes through a vertical slot 19 (fig. 6).
This second pressing element 15 features a panel 15a, folded downward so as to define a guiding channel for the edge of the article 9, in practice a shoe upper, with respect to the working surface 7b. Therefore, these pressing elements 14,15 can be adjusted independently from each other by the vertical slots 17,19, so as to adjust mutual position of the articles 8,9.
As has already been described in the above mentioned Patent Application No.
B095A 000392, a presser foot 20, drawn with broken line in fig. 2, is situated beside the working surface 7a of the guiding plate 7, and is carried by an arm which is moved by known means in direction transversal to the stitching line being formed.
The foot 20 features a hole 21 , through which the needle 6 passes.
During piercing of the needle 6, the articles 8,9 are held down by the foot 20.
A leather pressing element 22, situated beside the working surface 7b moves in direction transversal to the stitching line being formed and holds the articles 8, 9 after each stitch has been performed, when the needle 6 is being withdrawn.
A crumpling group 23, also situated beside the working surface 7b, reciprocates backward and forward in direction longitudinal with respect to the guiding plate 7 and in direction transversal thereto.
The group 23 supports a head 24, provided with a transversal peg 25 that engages the article 9, i.e. the shoe upper, so as to crumple the edge of the same upper being sewn, as it will be described in the following. In order to be sewn, the edges of the articles, in this case a shoe bottom 8 and upper 9, are positioned each one against a respective working surface 7a, 7b of the guiding plate 7.
In working configuration, the rim pressers 14, 15 abut on the upper part of the edges of the bottom 8 and the upper 9 (fig.2). In this arrangement, rotation of the needle 6 to the piercing position performs, in conjunction with the action of the rotary hook 10, a stitch on the above mentioned edges of the bottom 8 and the upper 9.
The needle 6 follows a circular path.
It is to be noted that, during the needle 6 piercing movement, the presser foot 20 engages the upper part of the peripheral groove 80, so as to abut on the same bottom 8.
After the needle 6 has passed through the edges of the bottom 8 and the upper
9, the articles 8,9 are moved forward on the guiding plate 7.
In fact, this movement is determined by the longitudinal translation of the needle 6, which makes the articles 8,9 slide on the guiding plate 7.
Afterwards, the leather pressing element 22 is imparted an oscillation on a plane transversal to the guiding plate 7 so as to clamp the edge of the upper 9 to the guiding plate, in a position adjacent to the just made stitch.
This allows to hold the stitched area of the articles 8 and 9 when the needle 6 goes up.
At this point, the needle 6 together with the rotary hook 10 are longitudinally translated in a direction opposite to the forward movement direction of the articles 8,9, so that the initial conditions are restored, in order to perform next stitch. The operator can also activate the group 23 that allows to perform crumpling of a sewing edge, in particular that of the upper 9.
This crumpling group 23 is moved first in direction transversal to the guiding plate 7, so as to bring the head 24, fitted with a transversal peg engaged with the upper 9, and then in longitudinal direction so as to determine crumpling of the upper edge.
The crumpled edge of the upper 9 remains clamped between the head 24 and the guiding plate 7 until the needle 6 is operated to perform next stitch. Consequently, the above described machine allows to automatically perform stitching of leather articles like the bottom and the upper of footwear. In particular, this operation does not need previous gluing of the edges to be sewn and mounting of the shoe on a suitable last during the sewing step. The machine allows to produce footwear of the type illustrated in fig.8, in which the sewing is seen both along the upper 9 edge and along the bottom 8 edge. Moreover, the machine allows to crumple a sewing edge, in particular the edge of the upper.
It is to be pointed out that the above mentioned operation is carried out in a simple way during a normal sewing cycle of the machine, without changing duration of the working steps and functionality of the cycle. It is understood that what above has been described as a mere, non limitative example, therefore possible constructive variants remain within the protective scope of the present technical solution, as described above and claimed in the following.
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