Loading patent…
AssigneeSra Developments Limited
InventorsMichael John Radley Young, Stephen Michael Radley Young, James Anton Slipszenko, Michael James Ede
Estimating the term…
Apparatus (5,50) for generating torsional-mode ultrasonic vibrations comprises a stack of axially-polarized piezo-electric ceramic rings (10) having a torsional converter (1,51,53) mounted coaxially to either one face of the stack or to two opposite faces thereof. Each torsional converter (1,51,53) has a cross-sectional inhomogeneity comprising a plurality of helically-extending grooves (2,55) extending substantially from end to end of the converter. The grooves (2,55) each have a length, measured axially along the converter (1,51,53), of approximately half the wavelength of ultrasonic vibrations therein. When the stack is energized, the stack and the converter (1) or converters (51,53) resonate together in a purely torsional-mode vibration. The apparatus (5,50) is compact and axisymmetric, and is straightforward to incorporate into a simple tool handpiece. The ultrasonic vibrations may be transmitted along a conventional elongate waveguide (3) of a tool to a distal operative tip (35). A very high amplitude torsional oscillation may thus be induced at the operative tip (35) of the tool. Alternatively, a further converter element (32) may be located at a distal end of the waveguide (3) in order partially to convert torsional-mode to longitudinal-mode vibrations for tool operative tips requiring combined-mode oscillations.
Apparatus adapted to generate pure torsional-mode ultrasonic vibrations, comprising a co-axially aligned array of piezo-electric elements having a distal face, and a substantially co-axially extending first conversion element having a proximal end directly mounted to the distal face of the array, wherein said first conversion element comprises a cross-sectional inhomogeneity of generally helical symmetry extending from adjacent the proximal end of the first conversion element to adjacent a distal end of the first conversion element.
Apparatus adapted to generate pure torsional-mode ultrasonic vibrations, comprising a co-axially aligned array of piezo-electric elements having a substantially co-axially extending first conversion element mounted thereto, wherein said first conversion element comprises a cross-sectional inhomogeneity of generally helical symmetry having an axial length corresponding substantially to λT/2, where λT is the wavelength of ultrasonic vibrations within the first conversion element.
Apparatus adapted to generate pure torsional mode ultrasonic vibrations, comprising a co-axially aligned array of axially-polarised piezo-electric elements having a substantially co-axially extending first conversion element mounted thereto, wherein said first conversion element comprises a cross-sectional inhomogeneity of generally helical symmetry, and wherein energising the array of piezo-electric elements induces a pure torsional-mode ultrasonic vibration in both the first conversion element and the array of axially-polarised piezo-electric elements.
An ultrasonically vibratable tool comprising means to generate ultrasonic vibrations operatively connected to an elongate waveguide extending to an operative distal tip of the tool, wherein the waveguide comprises a cross-sectional inhomogeneity having a generally helical symmetry located adjacent said distal tip of the tool, said cross-sectional inhomogeneity being adapted to convert torsional-mode ultrasonic vibrations in the waveguide at least partially into longitudinal-mode ultrasonic vibrations at the operative distal tip of the tool.
Dependencies are inferred from the claim text.