The present invention relates to a machine for production
of footwear in accordance with the preamble of claim 1.
As is known, in the production of footwear the upper is
glued onto the insole. For this purpose, the upper is applied and stretched on a
footwear last, with the base of which an insole has previously been associated.
Subsequently, after having spread glue on the contour of the insole, the edges of
the upper are folded and pressed onto the insole, such as to obtain the required
gluing.
According to the known art, the above-described operations
are carried out in the footwear industry automatically by using pre-assembly machines
in which the operation of adding the glue is carried out using different methods.
The use of machines which can carry out these operations
automatically is advantageous from the points of view both of the high production
volumes which these machines make it possible to obtain, and the constant quality
of the products obtained, which these machines succeed in assuring.
The requirement which these machines must fulfil consists
of succeeding in adapting to the different shapes and dimensions of existing insoles.
In this respect it is necessary to take into consideration that for insoles of the
same size, there can be models which have different shapes and fittings (for example
narrow or wide).
In order to obtain satisfactory gluing of the upper to
the insole, the glue must be well supplied at the contour of the insole. Thus, it
is apparent that as the shape of the insole varies, the means provided for supplying
the glue must be able to supply the glue at the points required, independently of
the shape of the insole.
Account must also be taken of the fact that the glue supplying
must be limited only to the portions of the insole which are designed to be glued
onto the upper, i.e. along the contour of the insole. In fact, the presence of glue
outside these portions is undesirable in.the subsequent processing operations to
which the upper must be subjected.
A machine which can carry out the above-described operation
is known, for example, from patent application EP-A-1036516. In the machine according
to the known art, the glue is added in the front part of the insole by means of
a supplier plate which is provided with a plurality of suppliers at the rear part
of the insole, by means of two movable suppliers, in order to follow the contour
of the remaining part of the insole.
The patent also specifies that when the shape and dimension
of the insoles varies, the plate can adapt to the profile of the front part of the
insole, whereas the two suppliers follow the contour of the insole starting from
the plate.
Although the solution proposed in patent application EP-A-1036516
is designed for insoles which have different shapes and dimensions, it is not satisfactory
for applying the glue onto an insole when the front part of the insole has a pointed
or blunt shape, as it is known.
In order to eliminate this disadvantage, machines have
been proposed for production of footwear, wherein the glue is added by means of
two movable suppliers, in order to supply the glue along the contour of the insole,
as far as the front end of the insole itself.
However these machines also have problems relating to the
uniformity of glue supplying and the pressure of the insole against the sole of
the footwear last. In particular, when the footwear last is extremely pointed, the
movable suppliers cannot supply the glue regularly along the contour of the insole,
particularly at the edges of the tip of the insole. In addition, if the insole is
extremely thin, the pressure exerted by the suppliers is insufficient to maintain
the tip of the insole pressed firmly against the base of the footwear last, when
the suppliers are released from the insole in order to permit folding of the upper
onto the insole.
The problem on which the present invention is based consists
of devising a machine for production of footwear, which has characteristics such
as to fulfil the above-described requirements and simultaneously to eliminate the
disadvantages described with reference to the known art.
This problem is solved by a machine for production of footwear
according to claim 1.
Further characteristics and the advantages of the machine
according to the present invention will become apparent from the following description,
provided by way of non-limiting indication, with reference to the appended figures,
in which:
- figure 1 represents a schematic perspective view of a machine according to the
invention;
- figures 2-5 represent schematic perspective views of the glue supplier means
of the machine in figure 1, in different positions assumed during operation of the
machine;
- figure 6 represents a schematic view of the glue supplier plate of the machine
1 in different positions assumed during operation of the machine;
- figures 7-9 represent schematic views of the glue supplier means of the machine
in figure 1 according to a first operating mode of the machine;
- figures 10-12 represent schematic views of the glue supplier means of the machine
in figure 1 according to a second operating mode of the machine;
- figure 13 represents a perspective view of a footwear last with which the upper
and the insole are associated; and
- figures 14 to 18 represent plan views of an insole during different stages of
the operating cycle of the machine 1.
With reference to the appended figures, 1 indicates as
a whole a machine for pre-assembly and assembly of an upper 21 on a footwear last
2. With the sole 15 of the last 2 there is associated a footwear insole 23 which
extends between a rear end 32 and a front end 31.
The machine 1 comprises a support frame 3, to which there
are secured positioning means 5 which are designed to support the last 2 at its
tip 6.
In the example, the positioning means 5 take the form of
a support element 4 which has a flat triangular surface with a limited size, on
which the last 2 is designed to be positioned in a supported manner.
The support element 4 is inclined such that the line Z-Z
perpendicular to its flat triangular surface coincides substantially with the line
of view of an operator who is observing the surface itself, and is standing in front
of the machine 1 (at the point indicated by 0 in figure 1) .
The machine 1 comprises an upper thruster 7, two lateral
thrusters, both of which are indicated by 8, and a rear thruster 9. These thrusters
are designed to engage respectively with the back 10, with the sides 11 and with
the heel 12 of the last 2, in order to maintain the last itself in pressure contact
against the triangular surface of the support element 4, in an operative working
position (Figures 3-5).
It should be noted that in the figures, for the sake of
simplicity, there are not shown the support element 4 or other elements which are
not essential for the purposes of understanding the operation of the machine according
to the present invention, but are necessary in order for it to operate.
A plurality of grippers, all of which are indicated by
13, are disposed around the support element 4, such as to face the contour of the
tip 6 of the footwear last 2. In a conventional known manner, the opening and closure
of the grippers 13 is controlled, and they are displaced individually as required
in order to obtain the desired tensioning of the upper 21 on the footwear last 2,
before the gluing is carried out.
The machine 1 also comprises means which are indicated
as 14 as a whole, in order to fold the edges of the upper 21 towards the sole 15
of the footwear last 2, after opening of the grippers 13, as well as means, not
shown in the_figures, to press the folded edges of the upper 21 from beneath, against
the insole 23, along its contour which is provided with glue 24.
In the example illustrated, the means 14 for folding the
edges of the upper 21 comprise two arched plates 17, which reproduce the profile
of the contour of the tip 6 of the footwear last 2 and are movable towards the last
itself.
The machine 1 comprises means for supplying the glue 24
onto the insole 23. These means comprise a glue supplier plate 19 which has a plurality
of nozzles 20 and one or more glue suppliers 22, of which there are two in the example.
The supplier plate 19 is positioned in the vicinity of
the support element 4, and is shaped specifically such as to follow the profile
of the front portion of a footwear last. According to a preferred embodiment, the
supplier plate 19 is associated with an underlying support plate 28, by means of
securing elements which are not shown in the figures.
Advantageously, but not necessarily, the supplier plate
19 can comprise a plurality of pieces which are connected to one another such as
to be articulated as described, for example, in European patent application EP-1036516.
With the nozzles 20 of the plate 19 there are associated
electrical resistors which make it possible to heat the glue such as to make it
fluid and facilitate its supplying.
By means of activation means 40, the supplier plate 19
is movable between a rest position which is spaced from the last 2, and an operative
position in which the plate 19 is in contact with the footwear last 2, and specifically
with the insole 23 applied to the sole 15, in order to supply the glue along the
contour 27 of the front portion of the insole 23. In other words, the supplier plate
19 makes it possible to supply the glue at the tip 6 of the footwear last 2. In
particular, the plate 19 has a surface portion 19a which can be associated with
the insole 23 during the glue supplying.
Preferably the said activation means 40 do not act directly
on the supplier plate 19, but on the support plate 28.
By means of activation means 41, the suppliers 22 are movable
between a rest position and an operative position in which they engage from beneath
with the footwear last 2, and in particular with the insole 23 applied to the sole
15, in order to supply the glue 24 along the contour 27 of the insole 23.
In particular, the suppliers 22 are movable, i.e. they
are supported by the frame 3 of the machine 1 such as to be able to move along the
contour 27 of the insole 23. In other words, the suppliers 22 make it possible to
follow the sides of the insole 23 in order to supply the glue 24 along the latter.
According to a preferred embodiment, the suppliers 22 are
associated with a support element 33, on which there act the activation means 41
which move the suppliers 22 such that the latter move along the contour 27 of the
insole 23, starting from the rear part of the insole 23.
Preferably, the suppliers 22 are supplied with a thermoplastic
thread of glue (not represented in the figures), and end in a roller which makes
it possible to spread the glue 24 supplied along the contour 27 of the front portion
of the insole 23.
Advantageously, with the suppliers 22 there are associated
electrical resistors which make it possible to heat the thermoplastic thread of
glue until it becomes an adhesive fluid.
The activation means 40, 41 can comprise for example hydraulic
actuators, step-by-step electric motors or other conventional means which are normally
used to automate the movement of two or more parts. In addition, the machine 1 can
be provided with command and control means in order to control the operation of
the said activation means 40, 41, i.e. in order to control the movement respectively
of the plate 19 and the suppliers 22 from the rest position to the operative position.
Advantageously, the rest position of the supplier plate
19 is such as to permit advance of the suppliers 22 as far as the front end 31 of
the insole 23, without giving rise to interference between the supplier plate 19
and the suppliers 22 themselves. In particular, the rest position of the supplier
plate 19 permits advance of the suppliers 22 as far as the front end 31 of the insole
23, such that the suppliers 22 are above the supplier plate 19.
Preferably, the plate 19 is displaced from the operative
position to the rest position spaced from the footwear last 2, by means of translation
movement parallel to the said direction Z-Z (figure 1).
Preferably, the support plate 28 is associated with a telescopic
guide 42 which is movable in order to obtain displacement of the plate 19 between
the rest position and the operative position and vice versa. In the example shown
in the figures, the guide 42 is extended according to a straight axis parallel to
the said direction Z-Z (figure 1), and is movable in this direction.
Activation means, not illustrated in the figures, are associated
with the telescopic guide 42.
Alternatively, the support plate 28 can be supported by
a sliding runner on a guide which extends in the direction Z-Z. The slide is then
activated by drive means in order to control the movement of the slide along the
guide.
In the rest position, the distance between the upper surface
19a of the plate 19 and the insole 23, measured along the axis Z-Z, is 10 cm or
more, preferably between 10 cm and 13 cm, for example 11,5 cm.
The aforementioned values are provided by way of example
with reference to a typical machine for production of footwear. It is apparent that
these values can vary according to the dimension of the plate 19, the size of the
suppliers 22, and the general dimension of the machine 1 for production of footwear.
According to a preferred embodiment, the plate 19 can stop
in an intermediate position (I) between the rest position (R) and the operative
position (O). At each actuation cycle of the machine, when use of the supplier plate
19 is required, this makes it possible to prevent long pause times which are necessary
in order to displace the plate 19 from the rest position spaced from the last 2,
to the operative position for supplying the glue, onto the insole 23.
In fact, since in the intermediate position (I) the distance
between the portion of surface 19a of the plate 19 and the insole 23, measured along
the axis Z-Z, is short (in the example concerned it is between 2 cm and 3 cm, preferably
2,5 cm), and is substantially shorter than the distance between the spaced rest
position and the operative position for supplying, the time taken by the supplier-plate
19 to go into the operative position for supplying (figure 11) is very short.
The supplier plate 19 is supplied with a thermoplastic
thread of glue (shown in a broken line in the figures). Advantageously, with the
supplier plate 19 there are associated electrical resistors which make it possible
to heat the thermoplastic thread of glue such as to transform it into a fluid which
can be supplied by means of the nozzles 20. The thread of thermoplastic material
can be of the same type as that used for the suppliers 22.
The electrical resistors of the plate 19 are supplied by
a supply cable which extends inside the telescopic guide 42. The supplier plate
19 comprises a temperature sensor which is connected by means of an electric wire
to a control unit.
The supply cable and the electric wire of the sensor are
slack, i.e. slightly longer than necessary, in order to be able to follow the plate
19 in its movement between the rest position and the operative position. As far
as the thread of thermoplastic glue is concerned, there are no problems in following
the movement of the supplier plate 19 and support 28, since this thread is supplied
continuously.
Advantageously, the telescopic guide 42 consists of tubular
elements inside which there pass the supply cable for the resistors of the plate
19, the electric wire of the temperature sensor, and the thread of thermoplastic
glue.
When the machine 1 is operating, the footwear last 2 is
supported in the support element 4. Subsequently, the thrusters 7, 8 and 9 fix the
last 2 in its work position. By means of the grippers 13, tensioning of the upper
21 is pulled on the footwear last 2.
The operation of the supplying means is described starting
with an initial situation in which the supplier plate 19 and the suppliers 22 are
in the rest position and are ready to receive the commands from the command and
control means.
In particular, the following description relates to operation
of the machine 1 for gluing the upper to insoles which have medium to high rigidity
and/or a tapered tip. In this case, the glue can advantageously be supplied solely
by using the suppliers 22.
Figures 2 and 6 show the plate 19 and the suppliers 22
in a rest position (R).
If on the other hand the supplier plate 19 is in the intermediate
position (I) between the rest position and the operative position (O) (fig. , the
supplier plate 19 must be moved downwards, taking it from the intermediate position
(I) to the rest position (O), such as to permit advance of the suppliers 22.
At this point, by means of the activation means 41, which
are controlled by the command and control means, the suppliers 22 are advanced from
the rest position to the operative position, such as to carry out glue supplying
along respective portions of the contour of the insole 23 (figures 14-18).
Figure 3 and figures 7 to 9 show the movement of the suppliers
22 in the operative position and the plate 19 in the rest position (R).
The suppliers 22 are able to move along the said portions
of the contour of the insole 23 such as to follow a path previously stored, and
to remain constantly pressed against the insole 23. By this means, the suppliers
22 keep the insole 23 pressed against the sole 15 of the last 2.
In particular, the rest position assumed by the plate 19
allows the suppliers 22 to advance towards the front end 31 of the insole 23, without
interference occurring between the supplier plate 19 and the suppliers 22. If this
were not the case, i.e. if the plate 19 were in the intermediate position or in
the operative position, the suppliers 22 could supply the glue along the contour
27 of the insole 23 only as far as in the vicinity of the plate 19, the presence
of which would prevent further advance of the suppliers 22 towards the front end
31 of the insole 23.
On completion of the phase of supplying the glue 24, a
supplier 22 is released from the insole 23 at a detachment point 29 which is positioned
in the vicinity of the front end 31 of the insole 23, thus allowing only the remaining
supplier 22 to continue as far as the front end of the tip of the insole (figures
14-18). Once the remaining supplier 22 also reaches the front end of the tip of
the insole, the latter is released from the insole 23, and both the suppliers 22
return to the rest position.
There are preferably at least two suppliers 22, such -that
each supplier can supply the glue 24 along a respective and distinct portion 26
of the insole 23.
In particular-, the portions 26 determine the contour 27
of the insole 23 along which the glue 24 is applied.
The suppliers 22 are thus movable along respective portions
26 of the contour 27 of the insole 23 which determine the said predetermined path.
The path, which is variable according to the shape of the insole 23, is stored in
order to control automatically the movement of the suppliers themselves.
Supplying the glue 24 onto the insole 23 is advantageously
carried out starting from the rear part of the insole 23 towards the front end 31
of the insole 23, as shown in figure 3.
If the front end 31 of the insole 23 is tapered, on completion
of the phase of supplying the glue 24, the two suppliers 22 are both released from
the insole 23 at a detachment point 29 which is located in the vicinity of the front
end 31 of the insole 23. In particular, each supplier will pass via this point 29
at successive temporal moments, such as to prevent interference with the other supplier.
Alternatively, on completion of the phase of supplying
the glue 24, a first supplier is released from the insole 23 at a first point 29
which is located in the vicinity of the front end 31, whereas the other supplier
is released at a second point 30 which is located at a predetermined distance from
the first point 32, so as not to interfere with the first supplier.
According to the said embodiment, the detachment points
29 and 30 -are disposed aligned with one another according to a longitudinal axis
A-A of the insole 23, which passes via the front end 31 of the insole 23.
The points 29 and 30 are indicated in the figures by way
of non-limiting example, thus allowing for the possibility of modifying the position
of release of the suppliers 22 according to the different design requirements and
the different shapes of the insole 23.
If the glue must be applied onto a footwear last which
has an extremely pointed front profile and/or the insole is not very rigid, it is
necessary to intervene with an appropriately-shaped supplier plate 19. In fact,
in this case, the use of the suppliers 22 alone is not satisfactory in terms of
uniformity of glue supplying at the edges of the front end 31 of the insole 23.
Furthermore, the pressure exerted by the suppliers 22 alone is not sufficient to
keep the insole 23 firmly pressed against the sole 15 of the footwear last 2 in
the interval of time which elapses between release of the suppliers 22 from the
insole 23 and the intervention of the means for folding of the upper 21.
In this case, the suppliers 22 are positioned in the vicinity
of the supplier plate 19 (figure 10) and supply the glue 24 onto the insole 23 by
moving from the plate 19 towards the rear end 32 of the insole 23 (figures 11 and
12).
Figure 4 and figure 11 show the suppliers 22 in the operative
position in the vicinity of the plate 19 and the plate in the intermediate position.
Simultaneously with the movement of positioning of the
suppliers 22 in the vicinity of the supplier plate 19, or when the suppliers 22
are in this position, by means of the activation means 40 which are controlled by
the command and control means, the supplier plate 19 is moved from - the rest position
(R), or, more advantageously, from the intermediate position (I), to the operative
position (O), where glue is supplied onto the insole 23 via the nozzles 20.
Subsequently, the suppliers 22 and the plate 19 are returned
(figure 12) to the respective rest or intermediate positions. Figure 5 shows the
plate 19 and the suppliers 22 in the operative position.
The glue is applied along the contour 27 of the front portion
of the insole 23, in particular at the front end 31 of the insole 23.
When the operation of supplying the glue by the plate 19
is completed, the activation means 40 are controlled in order to return the plate
19 to the rest position.
Subsequently, the means 14 for folding the edges of the
upper 21 towards the insole 23 are activated, and then the means for pressing the
edges themselves against the insole 23 are activated, such as to assure correct
gluing of the upper 21 to the insole 23.
At each operating cycle of the machine 1, the command and
control means make it possible to command and control the means for activation 40
and 41 according to the type of insole 23 onto which the upper is to be glued. For
example, the operator may decide to use only the suppliers 22, and not to use the
supplier plate 19, or to use the said means for supplying the glue 19, 22 in succession,
as described in the example previously given.
As can be appreciated from the foregoing description, the
machine for production of footwear according to the present invention has structural
and functional characteristics which can meet the above-described requirements,
at the same time eliminating the disadvantages presented and described with reference
to the machines according to the known art for production of footwear.
In particular, the machine can be used in two different
operative modes. According to a first operative mode, only movable suppliers are
used, in particular for footwear lasts which have a tapered profile and for insoles
which have medium to high rigidity. According to a second operative mode, the supplier
plate is also used, in particular for footwear lasts which have a profile with an
extremely pointed tip, and for insoles with low rigidity.
