EP0464625A2

EP0464625A2 - Cutting head for sheet-like products, particularly fabrics for the clothing industry

Info

Publication number: EP0464625A2
Application number: EP91110543A
Authority: EP
Inventors: Alberto Peron
Original assignee: Tamiello Alessandro
Priority date: 1990-06-29
Filing date: 1991-06-26
Publication date: 1992-01-08
Anticipated expiration: 2011-06-26
Also published as: IT9085592A0; IT9085592A1; EP0464625A3; IT1243125B; EP0464625B1; DE69113138D1

Abstract

A cutting head for fabrics for the clothing industry, includes a body (4) which can move in a direction which is substantially parallel to the plane of arrangement of the products to be cut and supports a cutting blade (8) which oscillates transversely with respect to the plane; the head has electromagnetic means (A, B) which act directly on the blade to cause its controlled oscillation.

Description

The present invention relates to a cutting head for sheet-like products, particularly fabrics for the clothing industry.
Machines for cutting flexible sheet-like products with a mechanically actuated cutting head are known. The head supports a cutting blade which is subjected to a reciprocating motion by means of mechanical transmission means which are in turn connected to an electric motor of preset power.
Each type of machine has to be provided with an adapted motor having technical characteristics adequate to the physical and qualitative characteristics of the material to be cut, as well as to the thickness and number of layers of the products being processed.
These known types of machine are not free from disadvantages. For example, in order to vary the cutting characteristics of the head, such as the frequency, the extent and the power of the blade's motion, it is necessary to provide adjustment devices which are rather complicated and difficult to maintain.
The moving mechanical parts furthermore require frequent maintenance in order to prevent the failures and wear to which they are normally subject. These facts negatively affect the operating expenses of the machines as a whole, and contribute to increase the final cost of the product.
Finally, the damage which notoriously arises from the sound pollution and from the vibrations produced by mechanically actuated machines should not be underestimated.
The aim of the present invention is to eliminate the disadvantages described above by providing a cutting head which, by virtue of its peculiar characteristics, has considerable flexibility and readiness in use, reduced operating costs, limited power losses and, the greatest reliability and safety in use.
Within the scope of the above aim, a particular object of the invention is to reduce the number of mechanical moving parts to be subjected to adjustment.
A further object is to provide a cutting head having component parts that can be obtained easily and can furthermore be rapidly assembled without requiring constructive complications.
This aim, these objects and others which will become apparent hereinafter are achieved by a cutting head for sheet-like products, particularly fabrics for the clothing industry, which comprises a body which can move in a direction which is substantially parallel to the plane of arrangement of the products to be cut and supports a cutting blade which oscillates transversely with respect to said plane, characterized in that it comprises electromagnetic means which act directly on said blade to cause its controlled oscillation.
Further characteristics and advantages of the invention will become apparent from the description of a preferred but not exclusive embodiment of the cutting head, illustrated only by way of non-limitative example in the accompanying drawings, wherein the only Figure is a transverse sectional view of a cutting head which is movably supported parallel to a plane of arrangement of the products to be cut and is connected to an electronic control unit.
With reference to the above figure, the cutting head according to the invention, generally indicated by the reference numeral 1, is adapted to be associated with an element M of a per se known machine, which can move bidirectionally in a direction which is parallel to the plane of arrangement G of the products to be cut, following a path which is defined by the cutting plane. In particular, the head can be removably fixed to the element M by means of an anchoring head 2 which is fixed by means of bolts 3 or of other equivalent elements.
The head 1 furthermore comprises an upper fixed body 4 and a lower slider 5 which can move in a direction which is substantially perpendicular to the plane of arrangement G of the products P, along guides 6 which are rigidly associated with the plate 2.
Conveniently, a stop element 7 for a cutting blade 8 which protrudes beyond the anchoring plate 2 is provided at the free end of the slider 5. The blade 8 thus follows the movements of the slider 5 so as to interact with the products P to be cut.
Advantageously, according to the invention, there are electromagnetic means which act directly on the blade 8 to cause its controlled oscillation. Said electromagnetic means comprise a fixed element, which is rigidly associated with the body of the head and is generally indicated by A, and a movable element, which is mounted on the slider 5 and is generally indicated by B.
In particular, the fixed element A is enclosed within the upper body 4, which has a cylindrical symmetry, and comprises a central core 9, which also has a cylindrical shape and is provided with an axial through cavity 10. A substantially torus-like permanent magnet 11 is inserted between the body 4 and the core 9, and its constant internal diameter defines, together with the outer diameter of the core 9, an annular interspace 12. Advantageously, the permanent magnet 11 can be made of highly stable ferromagnetic materials, such as for example those belonging to the series of rare earths or lanthanoids.
The movable element B is formed by a support 13 made of insulating material having a substantially cylindrical shape, on which a certain number of turns n of a conductor made of copper or the like is wound so as to define a solenoid 14. The assembly constituted by the solenoid 14 wound on the support 13 has such dimensions as to slide freely and within the annular cavity 12 coaxially thereto. The support 13 is furthermore rigidly fixed to the end of the slider 5 which is opposite to the blade 8 in a position which is approximately coaxial to said blade.
The number of turns n, the diameter Φ of the conductor and the diameter D of the solenoid 14 can be determined as a function of the required power, by means of calculations which are within the capabilities of any expert in the field.
Conveniently, the terminals of the solenoids 14 are connected, by means of conductors 15, 16, to a source of electric current L. If the energization current is alternating, the magnetic field generated by the solenoid 14 varies in a cyclic manner in direction and intensity, causing an oscillation in the slider 5 which in turn causes a reciprocating motion of the blade 8 with a frequency which is equal to that of the current and an extent which is variable according to the frequency and the cutting resistance opposed by the products P.
In order to adjust the operating parameters of the head, there is an electronic control unit 17 which connects the movable electromagnet 10 to the electric power supply line L. The control unit 17 has, inside it, per se known circuits for adjusting the frequency and the current, as well as possible external indication elements, such as a digital display 18, and actuation means such as buttons or keys 19.
The electric parts of the head can of course be provided with the usual safety devices provided for the equipment of machine tools.
Elastic means, constituted by a spring 20 which is anchored to the slider 5 so as to support it in a position of equilibrium, can be interposed between the fixed part and the movable part of the electromagnetic means. Finally, in order to accurately guide the movable part with respect to the fixed part there is a central rod 21 which is rigidly associated with the slider and can slide within the axial cavity 10 of the core 9, with the optional interposition of a sliding sheath 22 made of antifriction material. Adjustable abutments, made of shock-absorbing material, can be provided in the wall of the core which faces the slider, in order to avoid unwanted overrunning strokes.
From what has been described above, the operation of a cutting head according to the invention is apparent and can be summarized as follows.
The element M of the cutting machine is moved by per se known motor means, pulling the head 1 along the plane of arrangement G along the contour of the products P to be cut. The control unit is adjusted beforehand so as to select the most appropriate values for the frequency and intensity of the solenoid's energization current. During the movement of the head, the blade oscillates about its equilibrium position, exploiting the principle of electromotive forces typical of electric motors.
From what has been described above, it is apparent that the invention achieves the intended aim and objects; in particular, the extreme constructive simplicity, as well as the great economy and the safety in operation of the device are stressed.
The cutting head according to the invention is susceptible to numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may furthermore be replaced with technically equivalent elements.
In practice, the materials employed, so long as compatible with the contingent use, as well as the dimensions, may be any according to the requirements and to the state of the art.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims

Cutting head for sheet-like products, particularly fabrics for the clothing industry, comprising a body (4) which can move parallel to the plane of arrangement of said products and a cutting blade (8) which oscillates transversely with respect to said plane, characterized in that it comprises electromagnetic means (A, B) which act directly on said blade so as to cause its controlled oscillation.
Cutting head according to claim 1, wherein said body (4) is rigidly associated with an anchoring plate (2) which supports sliding means for said blade which extend in a direction which is perpendicular to the plane of arrangement (G) of the products to be cut (P).
Cutting head according to claim 2, wherein said sliding means comprise a slider (5) which can move along guides (6) which are rigidly associated with said plate (2).
Cutting head according to claim 3, wherein said slider (5) comprises means (7) for rigidly associating said blade (8) so that it can be released.
Cutting head according to claim 3, wherein it comprises elastic means (20) for keeping said slider (5) in a position of equilibrium with respect to said plate.
Cutting head according to claim 3, wherein said electromagnetic means comprise a fixed element (A) which is rigidly associated with said anchoring plate (2) and a movable element (B) which is rigidly associated with said slider (5).
Cutting head according to claim 6, wherein said fixed element (A) comprises a permanent magnet (11) which has a substantially torus-like shape and an essentially cylindrical ferromagnetic core (9) which is arranged inside said permanent magnet (11) so as to define an annular interspace (12).
Cutting head according to claim 6, wherein said movable element (B) comprises an electromagnet (14) which has a substantially cylindrical shape, can move coaxially and freely within said annular interspace (12) and is fixed to the end of said slider (5) which is opposite to said blade.
Cutting head according to claim 8, wherein said electromagnet (14) is formed by an insulating support (13) on which a conductor is wound so as to define a substantially cylindrical solenoid (14).
Cutting head according to claim 8, wherein said solenoid (14) is connected to a source of alternating current (L) by means of an electronic control unit (17) which is suitable for varying the intensity and the frequency of the energization current.
Cutting head according to claim 8, wherein said permanent magnet (11) is made of highly stable ferromagnetic material.
Cutting head according to claim 11, wherein said ferromagnetic material belongs to the rare-earth series.