Method and apparatus for surface treating and prestressing the inside wall of a cavity
First Claim
1. An ultrasound shot-blasting method for treating and putting under compression prestress an inside wall of a cavity within a workpiece having a longitudinal cavity dimension much greater than a transverse dimension thereof, the cavity having at least one orifice, said method comprising:
- exciting a high frequency vibration within a high frequency exciter coupled to a closed end radially enlarged portion of a hollow bulb integral with a coaxial, reduced diameter tubular element terminating in an open, free end adapted to contact said at least one orifice of said workpiece cavity upon alignment therewith,setting balls of determined diameter within said hollow bulb-shaped vibrator into vibration at a resonant frequency of said bulb-shaped vibrator, andcausing vibrating balls to move from said hollow bulb-shaped vibrator through said free end of said tubular element and said at least one orifice into said cavity for shot-blasting the cavity inside wall of said workpiece by radial impingement.
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Accused Products
Abstract
The present invention relates to a method and apparatus for surface treating and putting under compression prestress the inside wall of a cavity, in particular a cylindrical cavity of circular section. The apparatus comprises a bulb-shaped vibrator provided with a tubular portion designed to be engaged in an orifice of a cavity to be treated. It is associated with a vibration exciter designed to excite the vibrator at its resonant frequency. The treatment is obtained by shot in the form of balls being projected against the walls of the cavity and returned into the treatment field by a reflector. The method is particularly applicable to treating holes that are designed to receive the fixing pins of turbine blades.
25 Citations
13 Claims
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1. An ultrasound shot-blasting method for treating and putting under compression prestress an inside wall of a cavity within a workpiece having a longitudinal cavity dimension much greater than a transverse dimension thereof, the cavity having at least one orifice, said method comprising:
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exciting a high frequency vibration within a high frequency exciter coupled to a closed end radially enlarged portion of a hollow bulb integral with a coaxial, reduced diameter tubular element terminating in an open, free end adapted to contact said at least one orifice of said workpiece cavity upon alignment therewith, setting balls of determined diameter within said hollow bulb-shaped vibrator into vibration at a resonant frequency of said bulb-shaped vibrator, and causing vibrating balls to move from said hollow bulb-shaped vibrator through said free end of said tubular element and said at least one orifice into said cavity for shot-blasting the cavity inside wall of said workpiece by radial impingement. - View Dependent Claims (2, 3, 4, 5, 6)
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- 7. An apparatus for treating and putting under compression prestress an inside wall of a cavity within a workpiece having a longitudinal cavity dimension much greater than a transverse dimension thereof, the cavity having at least one orifice, said apparatus comprising a hollow bulb-shaped vibrator coupled to a high frequency vibration exciter, said hollow bulb-shaped vibrator having a radially enlarged portion opening to and extended by a tubular portion forming a tubular neck, said tubular neck having a free open end opposite to said radially enlarged portion, and a set of balls of a predetermined diameter within said hollow bulb-shaped vibrator, whereby upon subjecting said hollow bulb-shaped vibrator to high frequency vibration, said hollow bulb-shaped vibrator may be set into vibratory resonance to cause said balls under vibration to move from said hollow bulb-shaped vibrator through said free end of said tubular element and said at least one orifice into said cavity for shot-blasting the cavity inside wall of said workpiece.
Specification