A DEVICE FOR DRIVING TOOLS FOR CUTTING FLAT ARTICLES, IN PARTICULAR LEATHER

TECHNICAL FIELD

The invention relates to a device for driving tools for cutting flat articles, in particular leather.

BACKGROUND ART

In the sector of production of shoes and leather articles, a well-known requirement is cutting the leather rapidly and precisely. In particular, the need to cut through-holes is very frequent, for example in order to enable insertion of laces or in order to perform subsequent work operations.

To satisfy this requirement, various devices have been provided which enable through-holes to be made in leather articles by use of automatic machines comprising a cutting device, known as a cutting head, borne mobile by a special support means. The support means, in broad terms, enables a rotation motion about an axis thereof and an alternating translation motion along a vertical axis. The composition of these motions enables through-holes and the like to be performed rapidly and with good precision.

For example, European patent application EP 0 674 010 describes a device for performing holes in leather articles, comprising a holding means which is brought into contact with the leather at the point where a through-hole is to be made, and a cutting organ which projects from the holding means. The device further comprises a first actuator means,

destined to move the cutting organ along a perpendicular direction to the leather surface, and a second actuator means for impressing a rotary motion on the cutting organ. The composition of the vertical translation motion and the rotary motion enables the cutting organ to exert an effective cutting action on the leather in order t o realise through-holes and the like.

Cutting devices of the above-described type enable effective cutting of leather articles. However, the devices generally include the presence of one or more actuator organs, external of the main body of the cutting device, which actuator organs are relative large. This type of architecture requires the presence of suitable drive transmission means, usually a belt-drive, between the actuators and the cutting organ. The presence of these drive transmission means further increases the size and reduces the versatility of the device. Beyond this, the drive transmission means are subject to wear, and require specific maintenance, incurring extra costs.

By way of example, a known device for moving tools for cutting flat articles, illustrated in figure 1 , comprises a motor 201 projectingly borne with respect to the body 202 of the device by means of a transversal support arm 203. The drive shaft 204 exiting from the motor 201 is connected to the rotating organ 205 of the device bearing the cutting head 206 by means of a cogged-belt-driven mechanical transmission 207.

DISCLOSURE OF INVENTION

The aim of the present invention is to solve the above-described problem, by providing a device which can optimally realise the

movennents of the tools for cutting leather articles and the like, but which is of limited dimensions.

In the ambit of the above aim, a further aim of the present invention is to provide a device which does not require the use of actuators and drive transmission means which are external of the body of the device.

A further aim of the invention is to provide a device of simple conception, which is functionally very reliable and which is versatile to use, has a long working life and requires no maintenance.

The above aims are obtained in accordance with what is set out in the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics of the invention are set out herein below, with particular reference to the accompanying figures of the tables of drawings, in which:

figure 1 is a front view of a device for driving cutting tools of known type;

figure 2 is a section view of a device for driving cutting tools according to the invention;

figure 3 is a section view of a detail of the device for driving cutting tools of the invention;

figures 4 and 5 illustrate an axonometric view of the device, respectively in an exploded configuration and in a mounted configuration.

- A -

BEST MODE FOR CARRYING OUT THE INVENTION

With particular reference to the figures of the drawings, 1 denotes in its entirety a device for driving tools for cutting flat articles, in particular leather articles.

The device 1 comprises a rotating organ 10, better illustrated in figure 3, destined to rotate a cutting organ 5. The rotating organ 10 comprises, in the upper part thereof, a motor group 2, for example constituted by an electric micromotor, preferably cylindhcally shaped. The motor group 2 is provided with a fixed stator 21 and a drive axis 22 which is substantially vertical and destined to be activated to produce a rotary motion. The motor axis 22 exhibits, at a lower end thereof, a hub 23 which functions as a connecting means for transmitting the rotary drive produced by the motor group 2.

The hub 23 is destined to be housed in a seating 3 of a stem 4, coaxial to the drive axis 22 of the motor group 2. The hub 23 is blocked in the seating and solidly constrained to the stem 4 by means of a suitable screw, which for reasons of simplicity is not shown in the figures.

At a lower end thereof, the stem 4 axially bears the cutting organ 5, comprising, in a known way, a cutting head 6 having a hollow tip, suitable for performing through-holes in materials such as leather.

The rotary organ 10 is destined to be housed in a body 7 of the device having a tubular shape. The body 7 exhibits, in a central part thereof, an annulus 8 projecting externally in a radial direction. The annulus 8 affords an annular gully for a ring-type sealing organ 9. The body 7 axially exhibits, at a lower end thereof, an opening from which the cutting head 5 of the rotary organ 10 projects when operating. The rotary organ 10 is destined to be associated to the body 7 by means of

a threaded locking crown 15, which constrains the body 7 to the fixed stator 21 of the motor group 2.

The body 7 is destined to be inserted in a tubular jacket 17 internally defining a cylindrical chamber 11. The tubular jacket 17 is constituted by a central portion 12 locked between an upper head 13 and a lower head 14. The lower head 14 exhibits a sleeve 16 in which the body 7 of the device is slidably guided. The sleeve 16 exhibits a connecting hole

18 to pneumatic supply means of known type. The hole 18 is destined to be placed in communication at a certain operating stage which will be better defined herein below with a through-slot 19 in the body 7; the slot

19 in turn is destined to be placed in communication with an annular compartment 20 afforded internally of the lower head 14 and open on the chamber 11 of the tubular jacket 17.

The body 7 is destined to translate axially internally of the tubular jacket 17 with a run having an excursion defined by the stop position of the annulus 8 against the opposite heads 13, 14 of the jacket 17. In more detail, the run is alternatively defined between a raised position of the rotary organ 10, in which the rotary organ 10 is disengaged and in which the annulus 8 is in contact with the upper head 13, and a working lowered position of the rotary organ 10, in which the annulus 8 is in contact with the lower head 14. During the run of the body 7 in the jacket 17, the elastic ring 9 is kept in contact with the internal surface of the central portion 12, thus achieving the seal.

The operation of the device for moving tools of the invention is described herein below.

The device is predisposed in the vertical position with the cutting head above the article to be treated. In particular, the article to be treated, which for example consists of a piece of material such as leather, is

predisposed on a horizontal plane situated below the cutting organ 5, with the zone where the through-hole is to be realised located at the position of the cutting head 6.

The body 7 of the device is initially in the raised disengaged position, in which the annulus 8 is in contact with the surface of the upper head 13. In this configuration, the cutting head 6 is in the raised position with respect to the piece to be cut (not shown).

Thereafter, the rotary organ 10 is set in rotation by the motor group 2. In suitable phase relation, the body 7 is activated to translate axially via an appropriate pneumatic command which is realised in the chamber 11 of the tubular jacket 17, in which the annulus 8 of the body 7 sealedly slides. In practice, the tubular jacket 17 constitutes a pneumatic actuator which, supplied with compressed air, determines an axial translation of the body 7.

In this way, the body 7 is brought into the lowered operating position in which the annulus 8 comes into contact with the surface of the lower head 14. Consequently the cutting head 6 is activated to move, with a helical motion resulting from the composition of the rotary motion impressed by the rotary organ 10 and the axially translating motion of the body 7. The cutting head 6 intercepts the underlying article to be treated, efficiently performing the piercing at the desired point.

The body 7 is then returned to the disengaged raised position, by inverting the supply of compressed air to the tubular jacket 17, and the article in which the hole has been cut can be removed.

The device of the invention thus attains the aim of realising the movement of the cutting tools without using actuators which are external of the body, thus leading to a relevant reduction in the overall

size of the device. In particular, this is obtained thanks to the introduction of the motor group which controls the rotation of the cutting head internally of a body which performs as a pneumatic actuator for realising the axial cutting run of the cutting head.

In this way the device very reliably enables a helical cutting motion, which is a resultant of the composition of a rotary motion and an axial oscillating motion, destined to produce through-holes and the like in flat materials such as leather.

Worthy of note is the fact that there is a total absence of motor drive transmission of the belt type and cogwheel type, which enables further reductions in the overall dimensions of the device. Further, the device itself is more compact and less subject to wear, and thus enables a reduction in maintenance costs.

The above has been described purely by way of non-limiting example, such that any constructional variants thereto are intended as falling within the ambit of protection of the present technical solution, as described herein above and as claimed herein below.