DESCRIPTION OF THE PRIOR ART Basically, known shoe sewing machines each one includes a horn-like support turned upwards, driven into rotation with respect to a vertical axis.

A disc is fastened to the upper part of this support and rotates with respect to the above mentioned axis, it being driven by gears mounted on the support.

The disc features an axial hole and another hole, eccentric with respect to the axis, from which a stitching thread goes out.

During stitching, the support is introduced into the upper.

A needle, coaxial with the support axis and located outside the shoe upper, cooperates with the support and passes through the shoe upper, thus piercing it, until it enters the axial hole of the disc, so as to hitch the thread guided by the eccentric hole.

During its upward stroke, the needle pulls a thread slipknot, which is then latched by a looper or crochet external to the upper.

The holes made by the needle in the upper must be large enough to allow passage of a double thread.

To perform such a stitch, the operator moves manually the stitching member with respect to the shoe introduced on the support, so as to follow substantially the sole peripheral edge.

It is obvious that the quality of shoe produced by the above mentioned machines basically depends on the operator's ability, which influences also the production throughput.

Moreover, because the operator must work while seeing the process, it is very difficult to comply with all safety requirements.

Another disadvantage of shoe stitching with the above mentioned machines results from their high noisiness, which considerably affects the working conditions in negative way.

SUMMARY OF THE INVENTION It is an object of the present invention to solve this problem by proposing a method which allows automatic stitching of a shoe upper to a related sole, guaranteeing constant production quality and high throughput.

Another object of the present invention is to propose a machine which carries out this method by a simple, safe,

practical and reliable technical solution which can be widely used and complies with safety requirements.

The above mentioned objects are obtained, in accordance with the content of the claims, by means of a method for stitching a shoe upper to a related sole, according to which a stitching member inside the shoe upper associated to the sole of the shoe to be stitched, and a needle is operated while being slidingly guided through the end of said stitching member. The needle cooperates with a crochet situated outside the shoe for making a stitching.

The above mentioned method is performed by means of a shoe sewing machine that it includes: a stitching member which is introduced into the shoe upper associated to the sole of the shoe being stitched, with a needle guided slidingly at the end of said stitching member; a crochet, situated outside the shoe and cooperating with said needle to make a stitching; driving means for moving the upper together with the sole joined thereto; a first frame of said driving means, that rotates about a vertical axis substantially coincident with the axis of the needle while stitching; a second frame of said driving means, carried by said first frame and operated to move along a horizontal direction crosswise to said vertical axis; a cradle of said driving means, for supporting said shoe upper and said sole, said cradle being carried by said second frame and moved along a path orthogonal to said advancement direction of said second frame, with a variable attitude.

DESCRIPTION ON THE DRAWINGS The characteristics of the invention have been pointed out in the following, with a particular reference to the enclosed drawings, in which: -Figure 1 shows a front view of the machine for stitching a shoe upper to a related sole according to the subject method; -Figure 2 shows a corresponding lateral view of this machine, in cross-section taken along the line II-II of Figure 1; -Figure 3 shows a corresponding plan view of this machine, in cross-section taken along the line III-III of Figure 1; -Figure 4 shows a fragmentary lateral view of this machine, with a partial cross-section taken along a vertical plane, so as to point out internal parts of the machine; -Figure 5 shows a longitudinal section view of a stitching member of the subject machine; -Figure 6 shows a perspective view of a looper or crochet of the subject machine; -Figure 7 shows a perspective view of the crochet during a stitching step, seen at a different angle; -Figures 8a and 8b show an enlarged view of particular T of Figure 5, in different working steps; -Figures 8c and 8d show the same view of the particular T, in different embodiments;

-Figure 9 shows a partial front view of the machine, in an initial step of the stitching cycle; -Figure 9a shows a corresponding plan view of the shoe being stitched in this last mentioned step; -Figure 10 shows the same front view of the machine, during a subsequent stitching step; -Figure 10a shows a corresponding plan view of the shoe being stitched in this last mentioned step; -Figure 10b shows an enlarged particular Kl of Figure 10; -Figures 11 and 12 show plan views of the machine, in subsequent working cycle steps, respectively; -Figure 13 shows the same front view of the machine, in another stitching cycle step; -Figures 13a and 13c show corresponding plan views of the shoe being stitched in this last mentioned step; -Figure 13b shows an enlarged view of particular K2 of Figure 13.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the above described figures, reference numeral 1 indicates a machine for stitching a shoe upper to a related sole for manufacturing e. g. a moccasin type shoe.

The machine 1 includes a stitching member 10, situated over a bed 2. The stitching member 10 is to be introduced into a shoe upper 3 associated to a related sole 4 forming the shoe to be stitched. For sake of clarity,

this shoe will be indicated with numeral 5 in the following description.

The stitching member 10 includes a shaped arm 11 extending substantially on a vertical plane and having a two curved points, so as to define two consecutive terminal and intermediate sections lla, llb curved in opposite directions.

In particular, the terminal section lla is curved downwards (Figure 5).

The shape of the arm 11 facilitates its introduction into the upper 3 to be stitched to the related sole 4, so as to bring the terminal section lla up to the toe of the shoe 5.

A channel 12, extending along the shaped arm 11, houses in its terminal part a needle 13, whose curving corresponds to the curving of the above mentioned terminal section lla of the arm 11.

The needle 13 moves the stitching thread 6 and cooperates, during the stitching step, with a looper or crochet 7, situated under the sole 4 to be stitched, outside the shoe; the crochet 7 can be rotary or oscillating, in accordance to well known techniques.

As seen in detail in Figure 6, the upper part of the crochet 7 features a plate 77, which presses the leather, during the stitching and is operated, by a suitable cam (not shown), to move vertically in time relation with the crochet 7 movements.

In its central part, the plate 77 has a hole 77a, through which the needle 13 passes.

The plate 77 is brought to a raised position, so as to press the material when the stitches are made, while when

the needle 13 returns inside the arm 11, the plate is lowered to a release position, in which the material is released and allowed to advance.

Moreover, the crochet 7 has an element 17, so called thread preserver, which keeps the thread unwinding from the bobbin at a suitable distance, thus preventing it from being caught by the crochet latch or by the needle tip.

The needle 13 is reciprocated by a flexible member 14, which is introduced into the channel 12 of the arm 11.

The flexible member 14 is moved by a piston 15 controlled by a suitable mechanism 16 formed by a connecting rod and a crank.

In the case illustrated in Figures 8a, 8b, the flexible member 14 is formed by a roller chain 14a. Nevertheless, the flexible member 14 can be otherwise formed by a series of balls with diametrical holes through which a metallic wire 14c passes, so as to pull the needle 13 (see Figure 8c).

Figure 8d shows another embodiment of the flexible member 14, which includes a band 14d of plastic material, like e. g. teflon, whose opposite surfaces feature each one a series of transversal notches 14e, regularly spaced apart.

These notches 14e allow the band 14d to bend, since they get larger to compensate the extension of the dilatation of the side becoming longer and get narrower along the side which is compressed.

The terminal section lla of the arm 11 has a holed part llc, that features a hole for precisely guiding the needle 13.

This holed part llc can be formed by a removable bushing, so as to be easily substituted for e. g. changing the diameter of the needle to be used.

The shaped arm 11 of the stitching member 10 is fastened to a head 60, which cantilevers from a column 61.

The column 61 is slidably guided in a tube 62 fastened to the bed 2.

The head 60 is moved between a lowered operative position and a raised inoperative position, indicated with broken line 60a in Figure 4. When the head 60 is in the inoperative position, a shoe to be stitched is introduced and removed after stitching.

The head 60 is driven in this motion between the two positions by a motor 63 carried by the column 61.

For performing its task, the motor 63 drives, via transmission means 64, a screw 65 which is supported inside the column 61 with possibility of rotation about a vertical axis. The screw 65 is coupled with a corresponding nut screw 66 fastened to the tube 62 and crossing a slot made in the column 61.

During sliding, the column 61 is guided by a pair of vertical guides, situated on both sides thereof, which engage corresponding idle rollers 69 carried by the tube 62 (Figure 3).

Inside the head 60, there is supported rotatably a driving shaft for operation of the mechanism 16 which activates a plunger 15.

The driving shaft 70 is operated with continuous motion by a motor 71, that is carried by the column 61, via transmission means 72 (Figure 2).

The driving shaft 70 transmits this continuous motion by means of a pair of bevel gears 73, to a vertical shaft 74. The vertical shaft 74 has a splined portion 74a, which is coupled with a tubular shaft 74b.

This tubular shaft 74b transmits the motion, via other transmission means 75, to another pair of bevel gears 76, one of which is keyed onto a driven shaft 78, which is carried rotatably inside the bed 2.

This driven shaft 78 operates, by a transmission member 79, the crochet 7 and the cam for movement of the plate 77.

In its front part, the head 60 carries also a device 18, so called thread puller and widely known in the art, which holds the thread 6 and is operated by the driving shaft 70.

The thread 6 is guided externally with respect to the arm 11 of the stitching member 10 and is introduced in the terminal section lla of the arm 11 in the region of an aperture 19 (Figure 7).

The shoe upper 3 and sole 4 to be stitched thereto, are carried, associated to one another, by driving means 20 located on the bed 2, under the stitching member 10.

These driving means 20 include a first frame 30, a second frame 40 and a shoe supporting cradle 50.

The first frame 30 rotates about a vertical axis, substantially coinciding with the axis of the needle 13, during stitching of the shoe.

The second frame 40 is carried by the first frame 30 and is operated to move in horizontal direction crosswise to the last mentioned vertical axis.

The shoe supporting cradle 50 is carried by the second frame 40 and moves along a variable path, basically along a direction longitudinal to the shoe 5 to be stitched and orthogonal to the second frame 40 movement direction.

More precisely, the first frame 30, substantially quadrilateral, is equipped, in its central part, with an internally toothed crown 31, carried rotatably by means of a roll-bearing fifth wheel 8 fastened to the bed 2.

Roll-bearings 9 are interposed between the fifth wheel and the bed 2.

The crown 31 is in a gear meshing with a vertical pinion 32, operated by a motor which is not shown.

The second frame 40 includes a pair of parallel side panels 41, joined by cross bars 42.

In their lower parts, the side panels 41 are equipped with respective pairs of nut screws 43. The first frame 30 supports rotatably a pair of parallel horizontal screws 33, which engage the nut screws 43 of the second frame 40.

The screws 33 are operated, in counter-rotating directions, by a motor 34 carried by the frame 30, via a driving belt 35 mounted on pulleys 36 which are keyed onto these screws 33.

On their sides facing the inside of the frame 40, the side panels 41 have respective grooved guides 44.

Pairs of rollers 51a, 51b, fore and rear, respectively, protruding from opposite sides of the cradle 50, run in the grooved guides 44.

The grooved guides 44 define a part of the path of related transmission means 45, basically constituted by a chain trained around toothed wheels 46 mounted inside the

side panels 41 and operated in alternate rotation by a related motor 47.

More precisely, the grooved guides 44 include an arc-like section 44a, which is located in intermediate position and is engaged by the fore rollers 51a of the cradle 50.

The intermediate arc-like section determines inclination of the cradle 50 with respect to the second frame 40 of the driving means 20.

This allows the terminal section lla of the arm 11 to reach the shoe toe area, as better described in the following.

The grooved guides feature also, in their rear part, a sloping section 44b, along which the rear rollers 51b of the cradle 50 run.

Otherwise, the cradle 50 can be inclined by a pair of step motors, fastened to relative screws carried by a horizontal slide.

A support means 55 for supporting the shoe being stitched is fastened to the cradle 50.

This support means 55 is substantially formed by a jig made from a slotted sheet material, thus featuring an opening which is shaped in accordance to the profile and dimensions of the shoe 5 to be stitched. Therefore, the jig is replaced with another when the shape or dimension of the shoe 5 are changed.

The slotted opening features a flange 55a, that supports the edge of the sole 4 of the shoe 5 (see Figure lOb).

The height of the flange 55a varies to compensate diverse thickness of the sole and diverse length of the path through the upper and sole where the needle enters. The

flange 55a is interrupted in the region of the heel 4a of the sole 4 (Figure 13b).

The edge of the sole 4 is advantageously kept firmly by locking means, which stabilize the position of the shoe, with the sole resting on the flange 55a.

These locking means are formed by e. g. two or more square elements 155. One wing of each square element is pivoted to the support means 55, with possibility to rotate with respect to the wing axis, so that the other wing holds down the sole edge.

Operation of the machine, in accordance to the subject method, will be now described beginning from the moment when the shoe 5 to be stitched is arranged on the support jig 55 fastened to the cradle 50 of the driving means 20.

To do so, the motor 63 must be operated so as to bring the head 60 to the raised position 60a, thus raising the stitching member 10 (Figure 4).

Subsequently, the head 60 is lowered again, so as to introduce the arm 11 of the stitching member 1 into the upper 3 of the shoe 5, as indicated with broken line la in Figure 9.

The shoe 5 is arranged in such a way as to align the holed portion llc of the terminal section lla of the arm 11, that supports the needle 13, with a stitching start, point, also called zero point, indicated with A in Figure 9a.

This point A is preferably situated in the region of the median area and at the internal side of the shoe profile.

Needle 13 operation, together with the coordinated operation of the crochet 7 and movement of the shoe 5 carried by the driving means 20, determine the stitching

of the upper 3 to sole 4, by e. g. double thread knotted stitch.

The needle 13, guided by the holed part llc of the terminal section lla of the arm 11, follows a circumferential arc path extending from inside toward outside of the shoe to be stitched, with the rotation center C coinciding with the needle 13 curving center.

In particular, the flexible member 14 operates the needle 13 with alternate movements, so as to make it go in and out of the terminal section lla of the arm 11.

The needle 13, protruding from the arm 11, passes through the plate 77, which clamps the material during stitching and engages the crochet 7, so as to form a slipknot into which the crochet latch enters, thus forming a stitch point (Figure 8a).

Afterwards, the needle 13 returns inside the arm 11 (Figure 8b).

The driving means 20, controlled by an electronic unit, move the shoe 5, thus determining stitching advancement along the internal edge of the shoe from the point A up to the point B in the region of the shoe toe (Figure 10a).

In particular, the stitching advancement is determined by the backward movement of the cradle 50 with respect to the second frame 40 of the driving means 20, in combination with a translation of the second frame 40 with respect to the first frame 30.

During this step, also the first frame 30 of the driving means 20 performs a limited rotation to allow a better penetration of the terminal section lla of the arm 11 in the region of the upper tip.

It is to be noted that, during this stitching step, the position of the cradle 50, supporting the shoe 5, changes because its lower part slopes downward due to the movement of the fore rollers 51a of the cradle 50 in the arc-like median section 44a of the grooved guides 44.

This downward sloping allows the terminal section lla of the arm 11 to reach the shoe tip, as seen in Figure 10.

At the same time, the rear rollers 51b of the cradle 50 run the rear sloping part 44b of the grooved guides 44.

As seen in detail in the enlarged particular of Figure lOb, inclination of the shoe 5 during the toe stitching increases the length of the path of the needle 13 through the upper and sole, and therefore this would also increase the distance between the terminal section lla and the plate 77.

Increase of both upper-sole through path and terminal section-plate distance is eliminated by a decrease of the thickness of the flange 55a. In this way, the part of the needle which protrude beyond the hole of the plate 77 during the stitching, is more or less constant, thus performing a batter stitching.

It is also to be noted that the upper surface of the plate 77 is rounded, so as to fit any cradle 50 inclination.

Then, the cradle 50 is moved in the opposite direction and this, together with a suitable translation of the second frame 40, determine stitching of the shoe outer edge, up to a point D, substantially symmetrical to the zero point A (Figure 11).

At this moment, the first frame 30 of the driving means 20 is to rotated a bit less than half a turn (Figure 12).

It is to be noted that the frame 30, driven by the pinion 32 acting on the toothed crown 31, rotates about a vertical axis coinciding with the piercing axis of the needle 13.

Upon completion of this rotation, the shoe 5 carried by the driving means 20 takes a reversed position with respect to the arm 11, which now faces the rear part of the upper 3 (Figure 13).

Due to the subsequent movement of the cradle 50, together with a transversal translation of the second frame 40, the stitching starts again from the external point D, reaching the point E situated on the extreme rear area of the heel (Figure 13a). Then, the stitching is completes by returning to the zero point A (Figure 13c).

As seen in detail in the enlarged particular of Figure 13b, during the heel 4a stitching, the cradle 50 is arranged horizontal, so that the needle 13 passes through the sole 4 following a path almost perpendicular thereto.

According to an advantageous variant, during the heel stitching, the cradle 50 attitude is changed, so as to bring the stitching line still nearer to the heel outer profile in the region where the needle goes out.

The method and machine according to the present invention fulfill the objects of the present invention to automatically sew a shoe upper to a related sole, thus guaranteeing a constant working quality and high production throughput.

In fact, the working quality no longer depends on the operator's ability, since the stitching is performed by automatic motion of the shoe being stitched with respect to the stitching member, along a predetermined path.

This allows also to comply with very strict safety requirements.

It is to be pointed out that the described method overcomes the conventional technique according to which the stitching of the upper to the hole is necessarily performed from outside toward inside of the shoe.

The particular shape of the stitching member introduced inside the upper and the change of the shoe attitude during the stitching allow to perform the stitching from inside toward outside also in the region of the shoe tip.

The machine operation is controlled by electronic means, which command different working steps in the best way.

It is to be pointed out that these electronic control means have stored data selected in relation to the shoe model, as well as to its size.

These data can be acquired by e. g. learning technique; in this case the operator manually imposes the machine movements, so as to optimize the stitching line. These movements are detected and corresponding date are stored to be used subsequently for stitching shoes of the same model and size.

Advantageously, these control means can be equipped with sensor means (e. g. video cameras) which scan the profile of each single shoe, so as to control the electronic, means in relation to the detected data.

In this case, the size differences between single shoes become irrelevant, since the data relative to each of them must be detected to drive the electronic control means.

These electronic control means allow also to manage automatically the thread use, thus avoiding wastes.

In fact, it is possible to register the quantity of stored thread and subsequently, control in real time the thread use.

If the remaining quantity of thread is not sufficient to complete the stitching, the machine is stopped, so as to substitute the thread bobbin before starting.

It is important to point out that this result is obtained with a simple, functional, safe and reliable technical solution, that is also versatile in its use.

In particular, the machine is very silent.

Another advantage of the present invention derives from the fact that it guarantees a perfect water-tight stitching.

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.