Cutting device

Abstract: A cutting device comprising an ultrasonic vibrating device and a cutting blade (14-17) mounted on the device so as to be vibrated thereby/therewith, the blade lying in a plane extending transversely to the longitudinal axis of vibration wherein the vibrating device comprises two or more support members (12,13), the cutting blade (14-17) being supported by two adjacent support members (12,13).

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. 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. In our co-pending EP-A 0 353 415 there is described and claimed a method and apparatus for 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 (preferably at right angles) 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. In one embodiment of the invention of EP-A 0 353 415, the vibrating device comprises one or more support members which are vibrated by the device, each support member supporting a plurality of blades. In the specific embodiments described in the detailed description as illustrated in the drawings of EP-A 0 353 415, each blade is secured to a single support member at its centre. We have now found that a cutting method and device falling within the claims of EP-A 0 353 415 where the blade is secured to adjacent support members, provides significantly more cutting power than where the blade is secured to a single support member. Accordingly the present invention provides 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 transversely to the longitudinal axis of vibration wherein the vibrating device comprises two or more support members, the cutting blade being supported by two adjacent support members. Advantageously, the blade is secured at its ends to the adjacent support members. Preferably the blade lies in a plane at right angles to the longitudinal axis of vibration. The support members are vibrated by the device, and each support member may comprise a plurality of blades, each lying in one of a plurality of parallel planes, desirably the blades being located at anti-nodes of the support member. The blades are conveniently made of steel e.g. graphite impregnated steel or tempered high tensile steel. They could be coated with chrome or polytetrafluoroethylene which may impart a non-stick surface. The cutting edge of the blade may be spark-eroded or otherwise cut to produce a hollow edge. The blades may be wide, narrow, thin or they may be wires. They may be round, triangular or roughly square in shape but preferably rectangular e.g. from 10 to 100 mm long and from 1 to 22 mm wide. When the blades are roughly square or rectangular in shape, they are advantageously profiled so that they are narrower along a portion of their lengths than at their ends. For example, from 40% to 90% and preferably from 50% to 70% of their length between the ends is narrower and the width may be up to 60% less than at the ends. The thickness of the blades may be from 0.25 to 1 mm and more usually from 0.3 to 0.6 mm, especially from 0.35 to 0.45 mm. Some at least of the support members may be secured to the vibrating device through the intermediary of node/anti-node displacement devices. Preferably the device comprises a vibrating mechanism to which the support member or support members are secured, the vibrating mechanism being in the form of a horn, preferably cylindrical or rectangular in shape, one surface of which is caused to vibrate at ultrasonic frequency. The number of support members is only limited by practical considerations and there may be, for instance, up to 20 support members The present invention also provides 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, wherein the vibrating device comprises two or more support members, the cutting blade being supported by two adjacent support members. The movement of the blade relating to the article to be cut may, if desired, be achieved by moving the article through the blade. However, it is also possible to move the blade through the article to be cut. The present invention will now be further illustrated by way of example only with reference to the accompanying drawings in which Figure 1 represents a diagrammatic side sectional view of a cutting device according to the invention, Figure 2 represents a view of a blade of Figure 1 looking in the direction of the arrows B-B, and Figure 3 represents an alternative shape of the blade of Figure 2. The device which is the preferred embodiment of this invention comprises a vibrating device 10 in the form of a cylindrical or rectangular shaped mother horn, the front face 11 of which is vibrated at ultrasonic frequency in the longitudinal direction E-F, the face 11 representing an anti-node of the device. Connected to the front face 11 are two or possibly several pairs of supporting devices 12 and 13 extending in the longitudinal direction E-F. Mounted at spaced intervals between the supporting members 12 and 13 are blades 14, 15, 16 and 17. Each blade is connected at each end to the support member by an internal stud fastening 18 which passes through the apertures 19. The blades are 0.38 mm thick, 15 mm wide and 90 mm long. The cutting blades lie in a plane extending at right angles to the longitudinal axis of the support member, and are located on the support members at spaced anti-nodes. Thus in use, the blades will vibrate in a complicated mode, primarily in the direction E-F, and on passage through the article to be cut, will excavate a cut from the article, as the blade passes through the article. When the device is moved relative to the article to be cut, relative movement taking place in a direction at right angle to the longitudinal axis E-F, with the blades moving in the planes in which they lie, the article may be cut simultaneously by a plurality of cut lines.

Claims: 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 transversely to the longitudinal axis of vibration wherein the vibrating device comprises two or more support members, the cutting blade being supported by two adjacent support members. A cutting device according to claim 1 wherein the blade is secured at its ends to the adjacent support members. A cutting device according to claim 1 in which the blade lies in a plane at right angles to the longitudinal axis of vibration. A cutting device according to claim 1 wherein the support members are vibrated by the device, and the support members comprise a plurality of blades, each lying in one of a plurality of parallel planes. A cutting device according to claim 1 wherein the blades are located at anti-nodes of the support members. A cutting device according to claim 1 wherein the blades are rectangular in shape having a length of from 10 to 100 mm and a width of from 1 to 22 mm. A cutting device according to claim 6 wherein the blades are narrower along a portion of their lengths then at their ends. A cutting device according to claim 1 wherein the thickness of the cutting blades is from 0.25 to 1 mm. A cutting device according to claim 1 wherein some at least of the support members are secured to the vibrating device through the intermediary of node/anti-node displacement devices. A cutting device according to claim 1 which comprises a vibrating mechanism to which the 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. 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, wherein the vibrating device comprises two or more support members, the cutting blade being supported by two adjacent support members.

Inventors: HARROP MARTIN, RAWSON FRANCIS F H, HARROP, MARTIN, RAWSON, FRANCIS F.H.
Applicants: NESTLE SA, SOCIETE DES PRODUITS NESTLE S.A.
Application year: 1991
Main classification: B26D7
IPC codes: B26D1, B26D7