TECHNICAL FIELD

The present invention relates to machines for footwear production.

BACKGROUND ART

The Applicant has already constructed machines for sewing leather, e.g. toe caps and uppers that form a kind of shoe called moccasin (see Italian Patent No. 1.192.031) .

This known machine is extremely versatile and particularly suitable for producing the so called tubular moccasins . As it is known, this type of moccasin includes a close-bottomed upper. During manufacturing, the edge of the upper and the edge of the toe cap are placed on upwardly convergent work tops, close to each ohter, and sewn together. The just mentioned machine includes a feed dog, situated beside the first work top, and reciprocating longitudinally in phase relation with the movement of the needle and a first presser foot, but in the opposite direction. When the edges of the leather articles are being sewn, the feed dog crimps the edge of the upper so as to allow shaping of the moccasin.

The tubular moccasin, obtained in this way, partially covers the support arm of the sewing equipment that must have a suitable shape so as not to interfere with the operator' s movements and the

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shoe making parts.

The necessity exists of a machine that features the same quality as the machine briefly described above, but that is simpler under the manufacturing point of view and that is particularly suitable for sewing moccasins only with open-bottomed upper.

DISCLOSURE OF THE INVENTION

The object of the present invention is to propose an automatic machine for sewing leather that meets the above mentioned necessity, i.e. a machine of simple construction, easy to use, reliable and functional.

Another object of the present invention is to make it possible to use the machine in its simplified form, even with a rectilinear needle. The above mentioned objects are obtained, in accordance with the claims, by means of an automatic machine for sewing different kinds of articles, especially leather articles such as a upper and a toe cap for producing a so-called open moccasin, that includes: a longitudinal guide that is removably mounted on an underlying fixed support and that defines two longitudinal work tops, first and second, respectively formed by flat sloping surfaces mutually and upwardly convergent; hold down means that are located above said guide and that, in conjunction with said work tops, guide the edges of articles resting on said work tops; a needle situated beside the second work top, and movable so as to define two extreme positions, in one of which the said needle pierces juxtaposed

edges of the articles resting on the above mentioned work tops, by passing through a slot made in the upper part of said work tops, said needle being also given a reciprocating longitudinal motion with an outward and return stroke, so as to make the leather articles move forward; a rotary hook device, located beside the first work top and working in conjunction with said needle to sew a stitch when the needle is in its lowermost position, in which it pierces the leather articles, said rotary hook device being also reciprocated, together with the needle.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be fully understood from the following detailed description thereof, in connection with accompanying drawings which form a part of this application and in which:

- Figs. 1, 2 are perspective views of the working zone of the subject machine;

- Fig. 3 is a perspective view of the working zone of the subject machine, seen from a different point of view;

Fig. 4 is a perspective view of the machine working zone with the leather edges in sewing position;

- Figs. 5, 6 and 7 are prospective views of the machine working zone, during three subsequent sewing steps;

- Fig. 8 shows the toe cap and the upper, sewn one to the other.

BEST MODE OF CARRYING OUT THE INVENTION

With reference to the above mentioned

Figures, the reference number 1 indicates a stationary support (that is an integral part of the machine support frame) , on which a longitudinal guide 3 is removably fastened.

In particular, the stationary support 1 is formed by an arm 2, extending from the machine support frame, and a prismatic element 4, that is fastened to the arm 2. The vertical position of the prismatic element can be adjusted with respect to the arm 2.

The prismatic element 4 holds the guide 3, and the horizontal position of the guide 3 can be changed with respect to the prismatic element. These adjustment possibilities allow the guide 3 to be suitably positioned with respect to the needle.

The sides of the guide 3 are formed by corresponding flat sloping surfaces 3a, 3b, mutually and upwardly convergent, that form longitudinal work tops PI, P2, on opposite sides, first and second work top, respectively.

Over the guide 3 , there are hold down means 8,9, cooperating with the work tops PI, P2 in guiding the edges 30a, 30b of the articles 30, 40 that rest on the same work tops PI, P2.

The hold down means 8, 9 are fastened to a small fin 7 that is integral with the guide 3. The hold down means 8 is formed by a blunted plate, and the blunting faces the work top P2. The hold down means 9 includes a protrusion of the fin 7, nearly parallel to the correspondent work top PI.

The curved needle 14, with thread 14a, is mounted on an arm 13 that has a length equal to the radius of the curvature of the needle and is situated on the side of the second work top P2.

The arm 13 is keyed onto a longitudinal shaft

12, that is made to oscillate with rotary motion in such a manner as to define the needle lowermost and uppermost positions, respectively raised and lowered.

The arm 13 performs also axial back and forth motion, so that the needle 14 reciprocates in directions parallel to the work tops P1,P2.

In its lowered position, the needle pierces the juxtaposed edges 30a,40a of the articles 30,40 located on work tops PI, P2, passing through a slot 27 made in the upper part of the work tops P1,P2.

Beside the second work top P2, there is a needle protecting element 16, rotatably mounted to the shaft 12, and connected to the arm 13 by elastic means 22 constituted by a spring.

The element 16 is pulled by the needle 14, during its downward movement, until it touches the edge 30 of the articles placed on the second work top P2.

In its lower end, the element 16 features a hollow 17 through which the needle 14 passes.

The element 16 remains in this position until the needle has left the edges of the articles 30,40, located on the work tops P1,P2, and then, while going upwards, the needle picks it up with a stopping means 24 and brings it back to the raised position.

Two presser feet 15a, 15b are located on opposite sides of the two work tops PI, P2 and are made to reciprocate so as to act, in predetermined time, on the edges 30a, 40a of the articles situated on the rear part of the work tops.

The presser feet keep pressed the edges 30a, 40a of the leather articles 30,40 when the needle passes through and goes out of them.

A crochet 19, also known as rotary hook device, with a not shown bobbin of thread, is situated at the side of the first work top PI, and cooperates with the needle 14 when it is in its lowermost position, to make the stitches.

As shown in Fig. 5, while the protection element 16 is in idle position, the needle 14 (in raised position) is moved in to the direction indicated by the arrow M, thus beginning its descending stroke.

At the same time, due to their motion according to the arrows Rl and R2, the presser feet 15a, 15b clamp the edges 30a, 40a of the leather articles. After having reached the descent lowermost point (see Fig. 6) , the needle pierces the edges of the articles 30,40 and drives the protection element 16, by the spring 22, to the working position, in which the said element 16 contacts the piercing zone, so as to protect the needle 14.

Afterwards, the presser feet 15a, 15b are moved in opposite directions Ql and Q2, thus being opened, and subsequently, the needle together with the crochet 19 translate in direction T, toward the machine support frame.

Due to these movements, the leather articles 30,40 are moved one step forward.

Fig. 7 shows the next step, in which the pressure feet are moved in opposite directions Rl, R2, thus clamping the edges 30a, 40a, while the needle moves in direction N to its raised position.

Finally, the needle 14 and the crochet 19 are moved away from the machine frame, brought back to their initial position, so that a new sewing cycle can begin.

Fig. 8 shows the final effect of sewing the

toe cap 40 to the upper 30, in order to form a open-bottomed moccasin.

Since only this type of footwear is to be sewn, the machine can be simplified in the above described way, because the upper of an open-bottomed moccasin does not have to be crimped in order to follow the toe cap shape during the stitching step.

As an alternative, the particular shape of the guide 3 and of the hold down means 8 and 9 allows to use a straight needle instead of the conventional curved needle.

A straight needle 25, in a position suitable for its best working, is shown with a broken line in

Fig. 5. Obviously, the straight needle 25 will be moved by other means, different from the shaft 12 operating the curved needle.

The fact that the upper of an ^" open moccasin remains almost flat, as shown in Fig. 8, even after the toe cap has been sewn thereto, allows to mount a simpler arm with respect to the more versatile version of the machine described in the previous Italian Patent, mentioned in the introductory note.

The pitch of the stitch (i.e. the length of the stroke of the needle and crochet) can be adjusted, in known way, by using the means that act on the drive of the needle 14 and crochet 19.

The present machine, although in a simplified version, allows to obtain the same advantages as by the machine disclosed and claimed in the Italian Patent No. 1.192.031, nevertheless limited to sewing toe caps and uppers for open moccasins.

In particular, the machine is equipped with two work tops PI and P2; this makes it possible orienting the edges 30a and 40a in any way desired, and the orientation is defined by the slope of the surfaces 3a, 3b in relation to each other.

It is understood that the description supplied herein is solely an unlimited example such that possible variations in the construction details will not affect the protective scope afforded to the invention as claimed hereinafter.