CUTTING DEVICE

Abstract: A cutting device comprising an ultrasonic vibrating device (12) and a cutting blade (18) mounted on the device so as to be vibrated thereby/therewith, the blade (18) lying in a plane extending transversely to the longitudinal axis (E-F) of vibration and a method of cutting an article involving mounting a cutting blade (18) on an ultrasonic vibrating device (12) in a manner such that the blade (18) lies in a plane extending transverse to the longitudinal axis (E-F) of vibrations, and moving said blade (18) in said plane through said article (18).

Description: This invention is concerned with improvements relating to cutting, particularly by a method involving the use of high frequency (ultrasonic) vibration devices. The conventional method of ultrasonic cutting involves the use of a cutting blade which is mounted on an ultrasonic vibrating device with the blade lying in a plane containing the longitudinal axis of vibrations, and moving the blade through the article to be cut in said plane, e.g. DE-A1-2625636. Difficulty is experienced using conventional methods in that the depth of cut which is attainable is limited. For this reason ultrasonic cutting has in general been limited to thin articles, such as paper, cloth and thin plastic sheets. A significant problem exists in cutting blocks of substantial depth, and/or in providing a number of parallel cuts simultaneously. Difficulty is also experienced in cutting materials which are brittle, e.g. honeycomb or crystalline materials. According to this invention there is provided a method of cutting an article involving mounting a cutting blade on an ultrasonic vibrating device in a manner such that the blade lies in a plane extending transverse to the longitudinal axis of vibrations, and moving said blade in said plane through said article. In this manner the blade moves back and forth transverse to the plane in which it moves through the article, effecting a removal of the material of the article along the line of cut. Preferably the plane lies at right angles to the longitudinal axis of vibrations. If desired the device may be rotated about its longitudinal axis, effecting rotation on the blade in the plane within which it lies. According to this invention there is also provided a cutting device comprising an ultrasonic vibrating device and a cutting blade mounted on the device so as to be vibrated thereby/therewith, the blade lying in a plane extending transvserse (preferably at right angles to) the longitudinal axis of vibration. In use, the cutting device will be moved relative to an article to be cut, in a plane containing the blade. If desired, the device may comprise means by which the vibrating device, and hence the blade, is rotated in said plane, i.e. about the longitudinal axis of a vibration, as it is moved in said plane to cut the article. Conveniently the vibrating device comprises a support member which is vibrated by the device, and the support member comprises a plurality of blades, each lying in one of a plurality of parallel planes, desirable the blades being located at anti-nodes of the support member. Preferably the vibrating device comprises a plurality of support members, each supporting a plurality of blades, some at least of the support members being secured to the vibrating device through the intermediary of node/anti-node displacement devices. Preferably the device comprises vibrating mechanism to which the support member or support members are secured, the vibrating mechanism being in the form of a horn, one surface of which is caused to vibrate at ultrasonic frequency. There will now be given detailed descriptions, to be read with reference to the accompanying drawings, of embodiments of this invention which have been selected for the purposes of illustrating the invention by way of example. In the accompanying drawings: FIGURE 1 is a schematic view showing a conventional ultrasonic cutting device in use in cutting an article; FIGURE 2 is a plane view of the cutting device which is the preferred embodiment of this invention; FIGURE 3 is a schematic view showing the preferred embodiment in use in cutting an article; FIGURE 4 is a side view of the preferred embodiment; FIGURE 5 is a view of an alternative form of execution of the invention. In a conventional ultrasonic cutting operation, a blade 6 is vibrated at ultrasonic frequency in the plane containing the blade, and the blade is moved within said plane in the direction X towards the article 8 to be cut. As the blade penetrates the article, a cut 10 is opened, which subjects the article to compressive vibrations in the directions A and B. Where the article is of a friable or brittle material, this can result in the production of a fractured cut. The device which is the preferred embodiment of this invention (Figures 2 and 4) comprises a vibrating device 12 in the form of a mother horn, and front face 14 of which is vibrated at ultrasonic frequency in the longitudinal direction E-F, the face 14 representing an anti-node of the device. Connected to the front face 14 are a plurality of supporting devices 16 a , 16 b , 16 c and 16 d , the supporting devices extending in the longitudinal direction E-F. Mounted at spaced intervals on the supporting member 16 a are cutting blades 18 a , the cutting blades lying in a plane extending at right angles to the longitudinal axis of the support member, and being located on the support member at spaced anti-nodes. Thus in use, the blades 18 will vibrate in a complicated mode, primarily in the direction E-F, and on passage through the article 8 to be cut, will excavate a cut 10 a from the article, as the blade passes through the article in the direction X, while removing fine dust material C and D from the cut slot, see Figure 3. The support members 16 b and 16 c are mounted on the front face 14 through the intermediary of node/anti-node displacement members 20 b , 20 c , of the type having reduce mass, whereby the anti-node succeeding the front face 14 is removed in a direction towards the front face 14. Similarly, the support member 16 d is connected to the face 14 through the intermediary of a node/anti-node displacement device 20 d of the type having added mass, whereby the succeeding anti-node is displaced in a direction away from the face 14. Thus when blades 18 are mounted on the support members 16 b , 16 c and 16 d at anti-nodes thereof, a blade assembly is produced in which the blades are uniformly staggered in a direction away from the front face 14 (see Figure 4). In this manner, when the device is moved relative to the article 8 to be cut, relative movement taking place in a direction at right angles to the longitudinal axis E-F, with the blades 18 moving in the planes in which they lay, the article 8 may be cut simultaneously by a plurality of cut lines. The present invention may also be put into practice as is shown schematically in Figure 5, by simultaneous rotation of the blade about the longitudinal axis of vibration of the device, the cutting operation being effected by movement of the blade in the plane in which it is mounted, i.e. extending at right angles to the longitudinal axis E-F. Thus the invention may be applied, to a machine tool (particularly of the kind disclosed in EP-A-0287374, published after the date of filing of the present application Art. 54(3) EPC, in which an ultrasonic vibrating support member is simultaneously rotated, whilst being capable of multi-axis orientation relative to a workpiece, and capable of movement relative to the workpiece in a plurality of orthogonal axes, such as a robotic arm. Thus there is shown in Figure 5 a high frequency machining tool comprising a housing 34 of generally cross-circular cross-section, having at one end a tapered mounting format ion 36 of a shape similar to that provided in a conventional tool holding chuck. Mounted in the housing is an ultrasonic sub-assembly 38 comprising a transducer 40, and a booster device 42, the booster device carrying a horn 44, at an end portion of which, corresponding to a vibrational anti-node, a blade 48 is mounted, the blade 48, in accordance with this invention, lying in a plane extending at right angles to the longitudinal axis of vibration. The device illustrated in Figure 5 is specifically for use in conjunction with a conventional machine tool comprising a housing 58 in which a rotatable drive spindle 60 is mounted, the spindle 60 carrying at its leading end portion a chuck mounting device 62 provided with a conventional chuck-receiving aperture 64, the machining device being capable of being mounted in the chuck-receiving aperture 64. Thus, the spindle 60 and the housing 34 may be rotated about the longitudinal axis of the spindle 60, i.e. about the longitudinal vibrational axis, whilst the cutting blade 48 may be moved in any desired manner in relation to an article to be cut.

Claims: 1. A method of cutting an article (8) involving mounting a cutting blade (18, 48) on an ultrasonic vibrating device (12, 38) characterised in that the blade (18, 48) lies in a plane extending transverse to the longitudinal axis (E-F) of vibrations, and moving said blade (18, 48) in said plane through said article (8). 2. A method according to claim 1 in which the plane lies at right angles to the longitudinal axis (E-F) of vibrations. 3. A method according to claim 1 in which the device (12, 38) is rotated about its longitudinal axis (E-F), effecting rotation on the blade (18, 48) in the plane within which it lies. 4. A cutting device comprising an ultrasonic vibrating device (12, 38) and a cutting blade (18, 48) mounted on the device so as to be vibrated thereby/therewith, characterised in that the blade (18, 48) lies in a plane extending transversely to the longitudinal axis (E-F) of vibration. 5. A cutting device according to claim 4 in which the blade (18, 48) lies in a plane at right angles to the longitudinal axis (E-F) of vibration. 6. A cutting device according to claim 4 which comprises means by which the vibrating device (38), and hence the blade (48), is rotated about the longitudinal axis (E-F) of vibration, as it is moved in said plane to cut the article (8). 7. A cutting device according to claim 4 wherein the vibrating device (12) comprises a support member (16) which is vibrated by the device (12), and the support member (16) comprises a plurality of blades (18), each lying in one of a plurality of parallel planes. 8. A cutting device according to claim 7 wherein the blades (18) are located at anti-nodes of the support member (16). 9. A cutting device according to claim 4 wherein the vibrating device (12) comprises a plurality of support members (16), each supporting a plurality of blades (18), some at least of the support members (16) being secured to the vibrating device (12) through the intermediary of node/anti-node displacement devices (20). 10. A cutting device according to claim 7 which comprises a vibrating mechanism to which the support member or support members (16) are secured, the vibrating mechanism being in the form of a horn (12), one surface (14) of which is caused to vibrate at ultrasonic frequency.

Inventors: MORRIS, PAUL STEVEN, RAWSON, FRANCIS FREDERICK HAMILTON
Applicants: SOCIETE DES PRODUITS NESTLE S.A.
Application year: 1989
Main classification: B26D1
IPC codes: B23D33, B06B3, B23Q5, B26D7, B28D5