TRIMMING MACHINE FOR FOOTWEAR SOLES MADE OF LEATHER OR THE LIKE

TRIMMING MACHINE FOR FOOTWEAR SOLES MADE OF LEATHER OR THE LIKE

DESCRIPTION

The invention relates to a trimming machine for footwear soles, made of leather or the like, and for equivalent uses, having various objects, including automatic trimming, an operation which does not require particular skills by the operator, and other objects and advantages, which will be apparent to those skilled in the art, from the text hereunder.

In the trimming machine in question - comprising a clamp to engage the sole or soles (or the like) to be machined and a rotating tool to carry out trimming - the clamp to engage the sole or soles is held in constant or approximately constant orientation, and means are provided to carry out a relative movement between the clamp and the tool according to two Cartesian axes lying on a plane orthogonal to the axis of rotation of the tool, to make them travel along an annular trajectory with respect to each other.

In practice, the following are provided: an element with a first supporting arm supported transversely by a tubular hub which can carry out angular movements, and a second tightening arm supported by tightening means provided at the ends of said two arms, and a member provided with pressers to engage the sole or soles (S) to be machined and to hold the soles according to a constant orientation, while said two arms are subjected to cyclic angular orientations to avoid collision with the trimming tool.

The member provided with the pressers for the sole can be limitedly orientable independently but coaxially with said tubular hub, as a function of the orientation required by the soles to be machined.

In a possible embodiment, the trimming tool has a fixed axis, and said member provided with the pressers engaging the sole or soles can move according to two Cartesian axes of a geometrical plane orthogonal to the axis of rotation of the tool. In this embodiment, the trimming machine comprises: - on a fixed structure, guides for a carriage movable according to a

Cartesian axis (X) approximately parallel to the approximately constant orientation of the sole or soles;

- on said carriage guides for a slide movable according to the Cartesian axis (Z) of a geometrical plane containing the axis (X) and orthogonal to the - Z - axis or axes of rotation of the tool or tools and to the axis of orientation of said element engaging the soles; said element is mounted on said slide, while the tool is supported by said fixed structure. In another possible embodiment, on the fixed structure the carriage movable according to a direction (X) supports guides for the slide sliding according to a direction (Z) orthogonal to the direction (X) and provided on said slide is at least one element for trimming tool according to an axis orthogonal to the geometrical plane containing said axes (X and Z); the element supporting the sole or soles to be machined is provided on the fixed structure. In this embodiment, it is the trimming tool that moves annularly around the sole.

In any case, the machine is provided with means to coordinate the movements according to the Cartesian axes (X and Z) of said slide, and the angular movements for orientation of said element surrounding the member provided with the pressers, to avoid collision with said tool or tools.

Advantageously, the trimming machine can comprise two elements supporting adjacent trimming tools, utilizable selectively through relative movements between said clamp and said tools. The invention will be better understood by following the description and accompanying drawing, which shows a non-limiting practical example of the finding. In the drawing:

Figures 1 and 2 are overall plan views of a machine according to the invention, in two positions of a horizontally sliding carriage; Figure 3 is a view of the line Ill-Ill in Figure 2, in a different orientation;

Figures 4 and 5 show a view from the line IV-V in Figure 1 in two different positions;

Figures 6 and 7 show a view from the line VI-VII in Figure 1 , in two positions relative to replacing the soles in the machine; Figure 8 shows a section according to VIII-VIII in Figure 7, greatly enlarged, of a detail indicated by the arrow f8 in Figure 7;

Figures 9 and 10 show diagrams of subsequent positions of the soles and of the clamp that engages them for machining thereof;

Figure 11 shows a plan view of a variant of embodiment of the machine forming the object of the invention;

Figures 12 and 13 show views from the lines XII-XII and XIII-XIII in Figure 11 ; and

Figures 14 and 15 show diagrams equivalent to those in Figures 8 and 9 but relative to the variant in Figures 11 to 13.

According to the illustrations in the accompanying drawing, a structure 2 is provided with horizontal sliding guides 1 for a carriage 3, which can be controlled to move in the direction of the double arrow X by means of a threaded bar (or preferably a recirculating ball screw) 5, which is controlled by a motor 7 to move in the two directions according to the direction X. Provided on this carriage 3 are vertical sliding guides 9 which allow sliding according to a vertical direction Z of a slide 12, the sliding of which is controlled by means of a threaded bar (or recirculating ball screw) 14 operated by a motor 16; a cylinder 18 is provided with counterweight and control functions for the movements of the slide 12. Mounted on the slide 12 is a core 20 which (see in particular Figure 8) forms seats with rotating bearings for a tubular hub 22 controlled through a transmission 24 by a motor 26, which can thus move the tubular hub 22 and an element 27 with a supporting arm 28 mounted transversely on the tubular hub 22. Provided inside the tubular hub 22 is the seat for a shaft 30 coaxial with said tubular hub 22 and controlled through a transmission 32 by a motor 34 to control rotation of a clamp indicated generically with 36, which must engage the sole or soles S to be machined with a trimming tool to be described.

The element 27, which is supported by the tubular hub 22, comprises the supporting arm 28, with which a second moving arm 38 is combined to tighten the clamp 36; the moving arm 38 is engaged with the arm 28 through two piston-cylinder tightening means 40, which are mounted between the corresponding ends of the arm 28 and of the arm 38; the moving arm 38 can be moved back - i.e. by means of reaction springs - and is tightened by the two tightening means 40 to move two pressers 42A and 42B of the clamp 36, supported respectively by the shaft 30 and by the moving arm 38, towards each other, the presser 42B being mounted idle on the arm 38 and coaxial with the shaft 30 through a supporting member 43.

On the same structure 2 that supports the guides 1 for sliding of the - A - carriage 3, an assembly 50 is provided to support the machining tools, in a single element or also, and advantageously, in two trimming elements 52, 60, independently intended to operate alternatively, being taken alternatively to the machining position with sliding according to the arrow fU. One of the two trimming elements 52 slides on guides 54 in the direction of the arrow fU and supports one or two trimming tools 58 on a tool-holder shaft 56. A second element 60, sliding on guides 62, is provided with a tool-holder 64 for two trimming tools 66 and 68 which can operate alternatively, when the element 60 is moved to position one or other of the two tools 66 and 68 for two subsequent operations usually on the same perimeter surface of the soles. Each of the tool-holders 56 and 64 is operated by its own motor, which is supported by the respective element 52 and 60. Positioning respectively in the machining position and in the idle position in the direction of the arrow fU and in opposite directions, is controlled by a program to bring the tools alternatively into alignment with the soles S - engaged by the pressers 42A and 42B - in order to carry out the two successive operations with the tools 66 and 68 when the carriage 3 is positioned at the level of the tool-holder 64 and of the element 60 of the two tools 66 and 68. When the carriage 3 is moved to operate with the tools 58, the tools 58 of the tool-holding element 56 are moved forwards to the machining position and the tools 66 and 68 are withdrawn to exclude them from the machining position.

It is clear that the trimming tools such as those 58 and those 66 and 68 all operate about respective fixed axes, with the only movement according to the double arrow fU to be transferred to the machining position in alignment with the soles S and in conditions of exclusion to leave way for the other tool. Movement of the carriage 3 allows the soles S (engaged by the clamp 27 and by the pressers 42A and 42B) to be placed in conditions to be machined by the tools 58, or by the tools 66 or 68, which can be moved by a short distance to position one or other in machining conditions. With the machine as described above, soles S are machined with fixed axis tools and with movement of the clamp 27 (composed of the assembly 28, 38, 42A, 42B) which moves according to a plane perpendicular to the axes of the trimming tools such as those 58, 66, 68, according to the Cartesian axes X and Y defined respectively by horizontal and vertical movements of the carriage 3 on the guides 1 and of the slide 12 on the guides 9. The progressive machining conditions in this case are shown in Figures 9 and 10, where A, B, C, D, E, F, G show successively the position taken by the clamp 27 (28, 38) during a machining cycle of a trimming tool, such as the tool 68, around the soles 9 engaged by the element composed of the components 28, 38 with respect to the fixed axis tool 68. It can be seen how the soles S and the pressers 42A, 42B remain in a position with constant angular orientation, while the element 27 of the arms 28 and 38 takes progressively angled orientations from A to G to allow machining by the tool 68, without collision with said element 27, 28, 38, as in fact can be seen in the sequence A, B, C, D₁ E, F, G in Figure 10. Figure 9 shows the sequence of the positions taken successively by the soles S around the fixed axis tool 66 that machines the periphery of the soles. These successive positions are obtained through the combined operating program of the motors that control the carriage 3 in the horizontal direction X and the slide 12 in the vertical direction Z, and the element 27 about the axis of the tubular support 22. Progressive angular orientation of the element 27 of the arms 28 and 38 makes it possible to exclude collision of the assembly of the arms 28 and 38 with respect to the fixed axis of the tools in the fixed machining position. Figure 9 indicates, again with A to G, the successive positions of the soles and consequently of the pressers with respect to the trimming tool, and Figure 10, again with A to G, indicates the corresponding position of the assembly 27 of arms 28, 38, with progressive rotation through 180°. All this is synchronized with the movements of the carriage 3 and of the slide 9 and by the movements imparted to the element 27 of the arms 28, 38 by the motor 26, which controls rotation of the tubular hub 22.

In the embodiment in Figures 11 to 15 - in alternative to the solution described above - the sole or soles are held in a fixed position with the relative pressers, and a cyclic movement about the soles is imparted by the assemblies 150 and 152 of the trimming tools. This solution is shown in the diagrams in Figures 14 and 15 (equivalent to the diagrams in Figures 9 and 10). In this case the assemblies 150 and 152 of the trimming tools are mounted on a slide 112 moving on guides 109 of a carriage 103 moving on guides 101 (equivalent to those 12 and 3) while the element 127 of the presser and of the arms 128 and 138 (equivalent to those 27, 28, 38) in this embodiment rotates on an assembly 120 positioned fixed on the structure (in the same way as the assembly of the groups of tools of the previous example). Also in this case collision is avoided between the element 128, 138 with respect to the machining trimming tools, said tools rotating around the soles, which remain in an approximately horizontal position.

To replace the soles automatically, the element of the arms 28, 38 can be oriented as shown in Figures 6 and 7. On the basis of the program, a slightly inclined orientation is imparted to the assembly of pressers 42A, 42B through the motor 34, while the assembly 27, 28, 38 is controlled to promptly take approximately vertical and approximately horizontal positions, to allow the assemblies 65 and 65A to carry out movements according to the double arrow f65 to be inserted inside the space offered by the arms 28 and 38, in order to receive the machined soles dropped into a seat specifically provided in said element 65 and to subsequently insert, from the assembly 65A, a new sole or pair of soles or group of soles between the opened pressers 42A and 42B, according to an inclined line L to guarantee specific positioning of the soles to be machined in a position established to correspond exactly with the one to be taken by the soles - engaged between the two pressers 42A and 42B - to be machined. The pressers with the soles to be machined are rotated to obtain the required positioning to carry out a machining cycle by trimming as indicated in the diagrams in Figures 14 and 15, the soles S' being in a fixed position while the trimming tools, such as the one 166, move around the soles, and in the same way when operating with the machine as shown in Figures 1 to 10.

The tools can be replaced with movements according to Y. It is understood that the drawing only shows an example provided by way of a practical arrangement of the invention, which may vary in forms and arrangement without however departing from the scope of the concept on which said invention is based. For example, more than two elements supporting trimming members, also of the drum type, can be provided. Moreover, it would also be possible, in a trimming machine according to the invention as a whole, for the axes of the tools to be vertical or inclined, and correspondingly for the soles to lie in a horizontal (or inclined) position.