MACHINE FOR STRETCHING SHOE UPPERS AND FOR ATTACHING THEM TO CORRESPONDING SOLES
BACKGROUND OF THE INVENTION
The present invention relates to production of footwear and, more precisely, it concerns a machine for stretching shoe uppers before joining them to relative bottom elements, e.g. soles made of plastic material or material like natural or synthetic rubber, or other like materials.
DESCRIPTION OF THE PRIOR ART
Generally m the art, the uppers are joined to the soles by suitable glues, applied previously to the parts to be joined and heat-activated by determining a suitable temperature when the joining is being performed.
At present, control of the above mentioned operations is performed only empirically, using single devices operated by authorized persons. Obviously, this not only requires skilled personnel, but also increases costs and reduces the production rate.
SUMMARY OF THE INVENTION
The object of the present invention is to propose a machine for automatically stretching shoe uppers and then joining them to corresponding bottom elements.
Another object of the present invention is to propose a machine, which stretches shoe uppers in a perfectly homogenous way.
A further object of the present invention is to propose a versatile machine, which can be used for stretching and joining the uppers to the corresponding soles and can be easily adjusted in accordance to different sizes of the shoes.
The above mentioned objects are obtained, in accordance with the contents of the claims, by means of a machine for stretching shoe uppers and attaching them to corresponding soles, which includes a carrousel, with a series of operative locations disposed along a peripheral border of the carrousel.
The operative locations are provided with respective lasts for supporting the uppers to be stretched and corresponding support members for supporting relative soles to be joined to said uppers .
The support members move between a position in which said soles are placed thereon, and which is far from the respective lasts, and a joining position in which said soles are brought to touch said uppers,
The carrousel is adapted to carry said operative locations, one by one, to a series of stations, namely:
a loading station, where uppers are placed on the lasts and soles are placed on the support members;
a joining station, in which the uppers are joined to corresponding soles;
a pressing station for pressing the lasted upper; and
a discharge station, where the uppers joined to corresponding soles are removed from the carrousel.
DESCRIPTION ON THE DRAWINGS
The characteristic features of the invention will be pointed out in the following description of a preferred, but not limitative embodiment, with reference to the enclosed drawings, in which:
- Figure 1 is a schematic plan view of the machine according to the present invention;
- Figures 2a and 2b are lateral views, taken along the section line II-II of Figure 1, showing a station, in which the uppers and corresponding soles are placed on the supports, in subsequent working steps;
- Figure 3 is a plan view of soles supporting and centering means, taken along the section line III-III of Figure 2a;
- Figures 4a and 4b are lateral views, taken along the section line IV-IV of Figure 1, showing a station, in which the upper tip, sides, heel and foot-strap are stretched, in subsequent working steps;
- Figure 5 is a front view, taken along the section line V-V of Figure 4b, illustrating steps in which the upper tip and sides are stretched;
- Figure 6a is a lateral view, taken along the section line VI-VI of Figure 1, of a station, in a moment in which the glue of the sole and the upper is heat-activated;
- Figure 6b is the same view as Figure 6a showing the step subsequent the one in which the glue is heated, i.e. the mutual joining of the sole to the upper;
- Figure 7 is a front view of the above mentioned joining station, taken along the section line VII-VII of Figure 6a, in
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which means for heating the glue of the sole and the upper are best shown;
- Figures 8a and 8b are lateral views, taken along the section line VIII-VIII of Figure 1, showing subsequent working steps of a pressing station in which the uppers together with corresponding soles are subjected to pressing step;
- Figures 9a and 9b show front views of different operative configurations of the above mentioned pressing station, taken along the section line IX-IX of Figure 8a;
- Figure 10 is a view, taken along the section line X-X of Figure 8b, showing a particular of the above mentioned pressing station.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the above mentioned figures, numeral 1 indicates the machine for stretching shoe uppers and then joining them to corresponding soles.
The machine 1 includes a round carrousel 2, driven into rotation about a vertical axis. Rotation of the carrousel takes place stepwise in the direction indicated with the arrow G in Figure 1.
The carrousel 2 is equipped, along its peripheral border, with a series of operative locations 10, regularly spaced apart, which receive respective uppers 3 and the relative soles 4.
In the case herein described, the carrousel 2 has twelve operative locations 10, which receive uppers 3 and soles 4 of six pairs of shoes, obviously formed each one by a right and a left shoe.
Naturally, the number of operative locations on the carrousel can vary according to various necessities.
Basically, each of these operative locations includes a last 11 for supporting the upper 3 to be stretched. The last cantilevers from a support structure 13 extending from the carrousel 2 (Figure 2a).
The last 11 is preferably constituted by modular units, so that the shoe upper can be mounted on and removed from the lasts m very quick and easy way. However, when the upper is mounted on the last, there are not portion of the uppers which are not supported by the last.
In particular, each last includes two portions 11a and lib, respectively a toe portion 11a fastened to the support structure 13 and a heel portion lib, hinged on a pm 12, which is eccentric to this support structure 13.
Therefore, the toe portion 11a is stationary with respect to the support structure 13.
The toe portion has a shape typically corresponding to the toe and central part of a shoe upper of a finished shoe.
The heel portion lib has a curved profile which defines a fragment of a cylinder in the part facing the toe portion. The axis of this cylinder coincides with the axis of the pin 12.
The portion lib is rotated via a lever mechanism 14 operated by an actuator 15. When the portion lib is oriented in a non-use configuration, the total length of the last is at the minimum value. With such configuration, it is extremely easy to mount an upper on the last.
When the heel portion lib is then rotated to the normal operation configuration, i.e. with the upper mounted and ready to undergo operations, the last 11 has the maximum length and generally has the shape of the shoe when finished.
This means that, rotation of the heel portion lib toward the normal operation configuration stretches the upper, without leaving any unsupported parts for the upper 3.
When the heel portion lib of the last 11 is rotated back to the non-use configuration, the upper 3 can be removed therefrom without any difficulties.
Each operative location 10 features also a plate 16 supporting the respective sole 4.
The plate 16 is carried oscillating by an angular arm 17, hinged to the support structure 13 on a pin 18 and operated by a relative actuator 19.
In fact, the plate 16 is preferably fastened to the arm 17 by a series of rear stems 16a, guided in corresponding holes made in the arm 17.
Spring means 26, mounted on the stems 16a, holds elastically the plate 16.
The plate 16 features a suitably adjustable stop 5 for the heel of the sole 4 and two pairs of centering means 6 acting on the opposite sides of the sole 4 (Figure 3) .
These centering means 6 have respective pads 7, operated by relative actuators 8, which are mounted in an adjustable position along slots 9 made on the plate 16 and which can rotate about relative pins 8a.
The carrousel 2 brings the above mentioned operative locations, one by one, first to a station 20, where the uppers
3 ana corresponding soles 4 are loaded; then to a station 30, where the toes and the sides of the uppers 3 mounted on the modular lasts 11, are stretched; afterwards, to a station 40, where the uppers are joined to the relative soles 4; then to a pressing station 50; and finally, to a station 60, where the uppers 30, stretched and joined to the corresponding soles 4 are removed from the carrousel 2.
The stretching station 30 features a suitably shaped roller 31, that is moved so as to touch the toe and the sides of the uppers 3 mounted on the lasts 11 (Figure 4a) .
The roller 31 is rotatably supported by a frame 32, that has a slider 33, operated by an actuator 34.
The slider 33 moves along guides 35, which extend in radial direction from a hub 36, operated to rotate.
The actuator 34 operating the frame 32 is fastened to the hub 36 m a radial direction and along an axis parallel to the above mentioned guides 35. The hub 36 is carried by a saddle
37, which is operated to slide, by not shown means, on a frame
38, which is stationary with respect to the carrousel 2.
The station 40, where the uppers 3 are joined to the soles 4, includes heating means 41, which activate the glue applied on the uppers 3 and the soles 4 (Figure 6a) .
The heating means 41 are fastened to a frame 43 pivoted on a pin 42 m an angular position, and driven to rotate, by means which are not shown, between a working position, interposed between the upper 3 and a related sole 4 (Figure 6a), and a disengaged position, partially shown with the broken line 43a in Figure 7.
A pusher 44, working in the joining station 40, is guided by shafts 45 and operated, by means which are not shown, so that is goes out of the frame 38.
The pusher acts on the back of the plate 16, supporting a sole 4, of a operative location 10 which is stopped in the station 40.
The action of the pusher 44 is contrasted by the elastic action of spring 26. Otherwise, a ack (not shown) can be used instead of the spring 26.
Due to the action of the pusher, the sole 4 is brought to touch the corresponding upper 3 mounted on the last 11 of this operative location 10 (Figure 6b) .
The pressing station 50 has a bowl 51 forming a recess delimited by a diaphragm 52 made of elastic material
A chamber 53 is delimited by the diaphragm 52 and the bottom of the bowl 51, and is fed with compressed air during pressing step (Figure 8a) .
The bowl 51, operated by not shown means, is guided by means of shafts 54 so that it goes out of the frame 38. Due to the motion of the bowl, the upper 3, disposed in the operative location 10 situated in this station 50, enters the recess of the bowl (Figure 8b) .
The front part of the bowl 51 is closed by a pair of wings 55, sliding along transversal walls 56, operated by an actuator 57 (Figure 9a) .
The wings 55 have respective indentations 55a, opposite to each other, which define, with the wings 55 closed, an aperture for the passage of the supports of the last 11 while the upper 3 is being pressed (Figure 9b) .
The wings 55 of the bowl 51 are locked in the above mentioned closed position, by respective locking means 70, formed substantially by a hook 71 pivoted to the bowl 51 on a pm 72 and rotated by an actuator 73 (see particularly Figure 10) .
Operation of the machine will be described in the following beginning from loading the uppers 3 to be stretched and the corresponding soles 4 in the loading station 20.
Two operative locations 10, arranged side by side, are present in the loading station 20, as well as in the discharging station 60.
The upper 3 is mounted onto the stationary toe portion 11a of the modular last 11 disposed in the a operative location 10 which is situated at the loading station 20 (Figure 2a) .
The heel of the upper 3 is put onto the heel portion lib of the last 11, which is rotated to a position aimed at facilitating this operation.
Then, the heel portion lib of the last 11 is rotated on the pm 12, so as to stretch the upper 3, though maintaining a substantially continuous the shape of the last 11 (Figure 2b).
The corresponding sole 4 is put onto the supporting plate 16, arranged in a position far from the last 11 (see again Figure 2a) and locked by centering means 8, which have been previously adjusted in a position suiting the size of the shoes being stretched (Figure 3) .
Then, due to the rotation of the carrousel 2, the operative location 10 with the upper 3 and the sole 4 previously loaded, is brought to the upper stretching station 30.
In the beginning, the shaped roller 31 of this station is situated far from the last 11 (Figure 4a) .
It is to be noted that the previously described working stations are alternated with inoperative stations, so as to optimize duration of the working steps.
The roller 31 of the stretching station 30 is brought to touch the toe of the upper 3 put on the last 11 first by an approaching stroke determined by the actuator 34, and then by operating the saddle 37 (Figure 3) .
A pressure sensor stores in a memory the stop position of the roller 31 while it is touching the upper 3 toe, thus supplying a reference for subsequent moving steps of the roller 31.
As shown in Figure 5, after the approaching (arrow A), the roller 31 performs the following movements:
a movement following the side of the upper 3 (arrow B) , up to the stop position 31a;
a return stroke along the same side (arrow C) ;
a movement following the opposite side of the upper (arrow D) , up to the stop position 31b;
a return stroke (arrow E) ; and
finally, a stroke moving away from the stretched upper 3 (arrow F) .
These movements are obtained by combination of rotation of the hub 36 and shifting of the saddle 37.
It is to be pointed out that any size of the upper can be stretched without need of any kind of adjustment; in fact, contact of the roller 31 with the upper toe is detected by the pressure sensor and stored.
This constitutes a reference signal (zero signal), which is detected automatically without any adjustment; m other words,
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the station 30 performs a self-adjusting operation in accordance with the size of the upper.
Due to heating of the front and heel portions of the last, also the heel and the foot-strap of the upper are indirectly stretched, and wrinkling of the foot-strap near the stitching is thus eliminated.
Then the carrousel 2 brings the operative location 10 with the stretched upper 3 and the corresponding sole 4 to the station 40, where the upper 3 is joined to the sole 4.
In the joining station 40, the heating means 41 are rotated m the working position between the upper 3 and the sole 4, which is brought to the raised position by rotation of the arm 17 fastened to the plate 16 (Figures 6 and 7) .
The heating means 41 activate the glue applied to the upper 3 and sole 4.
At this point, the frame 43 is rotated to the disengaged position 43a, which allows operation of the pusher 44.
The pusher 44 is operated and goes out of the frame 38, thus acting on the back of the plate 16 supporting the sole 4, in contrast with elastic action of the spring 26.
The sole 4 is thus brought to touch the corresponding upper 3 mounted on the last 11 (Figure 6b) .
The lasts 11 can be heated or cooled by circulation of a suitable heating or cooling liquid.
The lasts 11 are heated in the stretching station 30, so as to make the upper 3 sufficiently soft and facilitate stretching thereof .
The lasts are cooled in the joining station 40 to avoid formation of condense during glue activation and to stabilize
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the shape imposed to the leather during the previous stretching .
Afterwards, the operative location 10 with the upper 3 joined to the corresponding sole 4, supported by the last 11, is brought to the station 50, in front of the bowl 51 (Figure 8a) .
In the beginning the wings 55 of the bowl 51 are open (Figure 9a) .
Subsequently, the advancement of the bowl 51 is operated, so that the upper 3 present in the station 50 is inserted in the recess of the bowl (Figure 8b) .
Then, the wings 55 of the bowl 51 are closed and locked by respective locking means 70 (Figure 9b) .
Compressed air is fed into the chamber 53 defined by the diaphragm 52, so that the diaphragm 52 wraps the upper 3 joined to the sole 4 and presses it uniformly, so as to complete the stretching of the upper 3 on the last 11 (see again Figure 8b) .
During this pressing step, the last 11 is kept cooled by circulating of cooling liquid, so as to stabilize the shape assumed by the upper 3 on the last 11.
Then, the bowl 51 is opened and the stretched upper 3 is extracted and subsequently brought to the discharge station 60, where the stretched uppers 3 joined to the corresponding soles 4 are removed from the lasts 11.
The disclosed machine allows to stretch automatically the shoe uppers and subsequently join them to corresponding soles, which results in cost reduction and productivity increase.
The machine is versatile, because it can be used for stitching shoes of different shapes and sizes by changing the upper carrying lasts 11 and adjusting the stop means 5 and the means 6 for centering the soles 4 on the plates 16. In particular, the upper stretching and pressing steps, as well as the step in which the uppers are joined to the soles, are not affected negatively by different shape or size of the shoes .
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 .