In the footwear processing sector, machines are known that automatically perform the various processing operations. In general terms, said processing operations comprise : arranging the upper on the shoe-making last after an insole has previously been associated with the sole of the last, gripping the edges of the upper by means of a multiplicity of grippers mounted around the last, stretching the upper on the last by means of a relative displacement between grippers and last, blocking the upper on the last by means of pressure members, applying an adhesive to the edge of the insole, gradually easing the grip of the grippers on the upper and turning the edge of the upper over the edge of the insole, resulting in the adhesive bonding of the edge of the upper to the insole.

In order for the assembly of the upper on the insole to be performed correctly, the grippers have to be positioned around the last in a manner such that their gripping tips, or more specifically the segments that

define the respective gripping portions of the tensioning grippers, are mutually aligned at a predetermined distance from the last, reproducing the profile of the latter and exercising a uniform traction along the entire edge of the upper.

The tensioning grippers comprise a central gripper positioned in alignment with the front part of the shoe-making last and two respective opposing pluralities of lateral grippers.

In order to permit the abovementioned positioning, adjusting members are associated with each gripper and make it possible to move the gripper closer to or away from the last. Subsequently, each of said pluralities of lateral grippers is borne by a respective support member which, relative to the bearing structure, is movable along a curved trajectory which encompasses the shoe-making last, so as better to adjust the positioning of the lateral grippers relative to the specific geometry of the last. This makes it possible to adjust the position of the lateral grippers rapidly to the varying geometries of shoe-making lasts which, as is obvious, vary in accordance with the type of footwear to be produced.

It is, however, necessary to point out that, as regards the central gripper, if the geometry of the width

of the tip of the last is varied, for example by changing to a shape of footwear having a square front end rather than a rounded one, it is necessary to use a gripper of different width. Therefore, when the geometry of the shoe-making last varies, while in the case of the lateral grippers it is sufficient to reposition the respective support member, in the case of the central gripper it becomes necessary to replace said gripper with one of appropriate width.

That having been said, the complexity of the abovementioned machines and the bulk of all the elements that form them result in a situation where there is insufficient space around the central gripper to be able to operate with a tool, such as a spanner, the use of which becomes necessary in order, to carry out operations of loosening and tightening the securing members that lock the central gripper on its support. As a result, before the central gripper can be replaced, it becomes necessary to remove the lateral grippers so as to create the necessary space around the central gripper to operate with the tool, it. being impossible to proceed manually without tools.

The removal of the lateral grippers, or even their mere loosening, entails a subsequent need to adjust the position of the lateral grippers relative to the

last. As may easily be deduced, this adjustment has to be performed by trained personnel and takes time, so that it has an adverse impact on the productivity of the machine, partly because it has to be repeated each time the footwear model to be assembled is changed.

From the above it is evident that, within the footwear sector, there is a greatly felt need to be able to undertake the replacement of the central gripper simply and quickly, without the need to use specialized personnel.

It is an object of the present invention to devise a machine for the preassembly and assembly of an upper on a shoe-making last which possesses structural and functional features such as to meet the above requirement and, at the same time, eliminates the disadvantages to which reference has been made.

This object is achieved by a machine for the preassembly and assembly of an'upper on a shoe-making last in accordance with Claim 1, which makes it possible to create rapidly a sufficient space around the central gripper to operate with a tool so as to permit easy replacement thereof, depending on the type of footwear.

Further features and the advantages of the machine according to the present invention will become apparent from the description given below of a preferred

example of embodiment thereof, given by way of indication and without implying limitation, with reference to the attached figures, in which : Figure 1 shows a diagrammatic perspective view of the working zone of a machine according to the invention for the preassembly and assembly of an upper on a shoe- making last ; Figure 2 shows a simplified plan view of Figure 1 ; Figure 3 shows a perspective view in partial section of a detail of the machine according to Figure 1 ; Figure 4 shows a lateral view in section of Figure 3 and Figure 5 shows a lateral view of a detail of the machine according to Figure 1.

. With reference to the attached figures, 1 globally designates a machine according to the invention for the preassembly and assembly of an upper on shoe- making last 3, with the sole of which an insole has been associated.

The machine 1 comprises a bearing structure 9 to which is fixed a support 4 having a triangular upper surface of limited extent on which the last 3 is intended to bear in alignment with its front part, in other words with its sole.

The last 3 is supported from below by the triangular surface of the support 4, in a manner such as to present the upper 2 facing upwards, and is positioned in a manner such as to extend from a rear part to a front part along a longitudinal axis The triangular surface of the support 4 is inclined so that its perpendicular, marked Z-Z, is subvertical and substantially coincides with the line of sight of an operator who, standing in front of the machine 1, is observing the upper surface of said support 4.

The machine 1 comprises an upper pushing device 7, two opposed lateral pushing devices, both marked 8, and a rear pushing device, not shown in the figures, which are intended to engage respectively with the back, the sides and the heel of the last 3, so as to keep said last in pressing contact against the triangular surface of the support 4 and substantially immobilized in the working position.

The machine 1 is equipped with tensioning grippers, marked 5,10 and 11, able to engage the edge of the upper 2 and to pull said upper 2, causing it to adhere to the last 3. The abovementioned tensioning grippers are positioned around the support 4 in a manner such as to be substantially facing the contour of the

front part of the sole of the last 3, positioned on the support 4.

The grippers 5, 10 and} 1 are of the type described and illustrated in'the same applicant's document EP 0 582 027-B1, the content of which is explicitly incorporated here by way of reference. Each gripper comprises a body which is provided at the upper end with two jaws 33 and is fixed at the lower end to a manipulating rod 12 by means of two arms (not shown) which define a parallelogram linkage system making it possible to cause the opening and closing movements of the jaws 33. Each gripper is selectively controlled for opening and closing, and can be selectively displaced in the direction Z-Z by means of appropriate actuating means, so as to obtain the desired tensioning of the leather of the upper 2 on the last 3.

The tensioning grippers comprise a central gripper 5 positioned along the longitudinal axis L-L in alignment with the front part of the shoe-making last 3 and a first plurality and a second plurality of lateral grippers, respectively marked 10 and 11, opposite one another relative to the longitudinal axis L-L. As stated above, the grippers 5,10 and 11 are positioned in a manner such as to surround the contour of the front part of the sole of the shoe-making last 3.

The lateral grippers 10 of the first plurality (that on the left in Figure 2) and the lateral grippers 11 of the second plurality (that on the right in Figure 2) are mounted on the support member, respectively marked 13 and 14 and movable relative to the bearing structure along a curved trajectory T which encompasses the support 4 on which the shoe-making. last 3 is positioned. This makes it possible to adjust the positioning of the lateral grippers 10 and 11 of each plurality to the geometry of the shoe-making last 3. In substance, by moving each support member 13 and 14, it is possible to obtain a simultaneous displacement ot all the lateral grippers, 10 and 11 respectively, associated therewith.

In the example, each support member 13,14 takes the specific form of a substantially flat and rectangular supporting base 15, from the central portion of which extends a vertical wall 16. From the upper end of the vertical wall 16, a bracket 18 extends substantially parallel to a portion of the underlying supporting base 15. The bracket 18, the vertical wall 16 and the supporting base portion covered by the bracket IS define a C-shaped structure. The two support members 13,14 are disposed in a manner such as to present the respective C- shaped structures facing one another and extending in the direction of the longitudinal axis L-L of the machine 1

In substance, the C formed by each support member 13, 14 is facing the support 4 on which the last 3 is positioned.

The bracket 18 and the underlying portion of the supporting base 15 of each support member 13,14 are provided with appropriate respective pluralities of through-holes, one above the other, through which extend the rods 12 on whose upper ends the tensioning grippers 10 and 11 are fixed. Connected to the lower end of each rod 12 is a pneumatic cylinder 19 whereby the vertical movement of said grippers is obtained, intended to ensure the correct tensioning of the upper 2.

As is apparent from Figure 3, in which only the support member 13 (that on the left in Figure 2) is shown, the support member 13 provides operational support for four lateral grippers 10, and an equal number of lateral grippers 11 are supported by the support member 14 Each support unit 13,14 bears, with its base 15, on a working level 6 of the bearing structure 9 disposed perpendicularly to the abovementioned direction Z-Z. The working level 6 is thus substantially parallel to the sole of the shoe-making last 3. Alternatively, the working level 6 may be replaced by a plurality of cross- pieces.

According to an advantageous feature, at least one support member 13, 14, and both in the example shown, is or are mounted on a respective trolley or slide 20, 21, which is movable from and to a remote position in which the respective pluralities of lateral grippers 10, 11 is at a distance from the central gripper 5.

When the two trolleys 20,21 are in the remote position, a sufficient space is created around the central gripper 5 to manipulate a tool, such as for example a manipulating spanner for loosening the bolts which provide the tightening of the central gripper 5 on the rod 12.

The machine 1 comprises means for actuating the two trolleys 20,21 from and to the remote position, in other words from an advanced operating position, in which the lateral grippers 10, 11 are positioned close to the last 3 to a remote position and vice-versa. Preferably, the movement oE the two trolleys 20,21 takes place simultaneously. In this respect, it must be specified that Figure 2 refers to a plan view of the zone of the machine 1 in which the grippers 5,10,11, the support members 13, 1 and the two trolleys 20,21 are present.

However, simply for purposes of illustration, the right- hand half of Figure 2 refers to a situation in which the trolley 21 associated with the support member 13 is in

the remote position, while in the left-hand half of the same Figure 2 the trolley 20 associated with the support member 14 is shown in the advanced, operating position.

Each trolley 20,21 performs the displacement from the advanced, operating position (shown in the left- hand half of Fig. 2) to the remote position (shown in the right-hand half of Fig. 2) with a movement having a displacement component transverse to the longitudinal axis L-L. Preferably, this displacement consists of a translatory movement of each of the two trolleys 20,21 in a direction X-X perpendicular to the longitudinal axis L-L. In substance, the two trolleys 20,21, during the movement, move away from or towards one another.

As will be more clearly apparent from the continuation of the description, the translatory movement proves to be advantageous to implement from the standpoint of the structural simplicity of the machine 1, though it is possible to impose a rotational or rotational/translatory movement on the two trolleys 20, Z1 or, more specifically, on the support members 13 and 14 of the lateral grippers 10, 11. In a further alternative embodiment, it is possible to provide a movement of the support members 13,14 of the lateral grippers 10, 11 in a vertical direction or in the abovementioned direction Z-Z.

In the example shown, each trolley takes the specific form of a plate supported by and shape engaged with sliding guides 22, which extend in the abovementioned direction X-x below the working level 6 and are supported by the bearing structure 9. of the machine 1.

Each support member 13, 14 is connected to the respective trolley 20,21 by means of two bolts 23 having the threaded shank extending in the direction Z-Z. In order to permit movement of the support member 13,14 relative to the trolley 20, 21 along the curved trajectory T encompassing the support 4 and the last 3, slots 24 are provided in the base 15 of each support member 13, 14, extending along the abovementioned trajectory T, through which slots the shank of a respective bolt 23 extends, Alternatively, the slots 24 may be replaced by a slit of greater length.

By analogy with what has been described above, slots 25 are made in alignment with the bolts 23 in the working level 6, through which slots the shanks of the bolts 23 extend. The slots 35 extend in the transverse direction X-X. Clearly, the length of the slots and their positioning is such as to allow each trolley 20,21 the possibility of movement in the manner described above between the advanced, operating position and the remote

position, and vice-versa, without the shanks of the bolts 23 interfering with the working level 6.

In the example, the means for actuating the trolleys 20,21 comprise a threaded bar 26 extending in said transverse direction X-X and pivotably supported in rotation by the bearing structure 9. This threaded bar 26 is kinematically associated with an electric motor (not shown) for the rotational actuation thereof and is in screw/nut engagement with a portion, or appendage 27, of each of said trolleys 20, 21. Consequently, one rotation of the threaded bar 26 produces to a translatory movement of the trolleys 20,21 along the sliding guides 22.

It is appropriate to point out that, in order to obtain simultaneous movement together or apart of the two trolleys 20,21, it is necessary for the threaded bar 26 to have two threaded lengths with opposing threads (right-hand and left-hand), the first of these threaded lengths being in screw/nut engagement with the threaded appendage 27 of the trolley 20 and the other threaded length being in screw/nut engagement with the threaded appendage 27 of the trolley 21.

The kinematic connection between the shaft of the electric motor and the threaded bar 26 is produced by means of a chain transmission comprising a chain 26 engaging with two pinions 2. 9, 30 respectively keyed on

the threaded bar 26 and on the shaft of the electric motor.

The actuation of the support members 13, 14 along the curved trajectory T is obtained by virtue of respective actuating cylinders, for example of the pneumatic type, which act directly on the base 15 of the support members 13, 14 by means of a manipulating rod 31.

The machine 1 further comprises-means for folding the edge of the upper 2 over onto the sole of the shoe- making last 3, and means for pressing the folded-over edge of the upper 2 from below against the insole, following application of adhesive along the edge of the insole.

In the example shown, the abovementioned means for folding over the edge of the upper 2 comprise two plates 17, curved so as to encompass the profile of the tip of the last 3 and movable towards said last 3, while the abovementioned means for pressing comprise a plurality of rod-like elements 32 that are movable towards the last 3 in a manner such as to engage it from below with a predetermined elastic force.

The machine l is equipped with means 34 for distributing the adhesive along the contour of the sole of the insole associated with the last 3.

The machine 1 is additionally equipped with

actuating means, regulating and monitoring means, control means and others also necessary to ensure the correct functioning thereof during its working cycle. Such means are known per se and are not described below or shown in the figures.

As may be appreciated from the above description, the machine according to the invention for the preaseembly and assembly of an upper on a shoe-making last makes it possible to meet the above requirement and, at the same time, to overcome the disadvantages to which reference was made in the introductory part of the present description.

Specifically, when it is, necessary to replace the central gripper of the machine, it is sufficient to reverse the two trolleys from the latter into the remote position in order to create the necessary space around the central gripper 5 to operate with a manipulating spanner on the bolts that ensure the tightening of the said gripper. It should be pointed out that the reversing movement and the subsequent placement of the abovementioned trolleys in the operating position, and hence also that of the respective lateral grippers associated therewith, does not in any way entail the loss of the position of said lateral grippers, any subsequent adjustment being unnecessary.

Yet a further advantage of the machine according to the invention lies in the structural simplicity of the structural solution adopted.

Clearly, a person skilled in the art, in order to meet contingent and specific requirements, will be able to introduce numerous modifications and variations into the machine described above for the preassembly and assembly of an upper on a shoe-making last, all of these, however, being contained within the scope of protection of the invention as defined by the claims that follow.