Stimulator

Claim 2

Apparatus for generating a sound field comprising: a support, an elongated elastic column constructed to maintain its structural integrity when subjected to vibrational stresses, a constraint structure constraining said column against transverse motion relative to said support while permitting longitudinal motion of portions of said column, an electromagnetic motor arranged to provide periodic longitudinal forces acting on an end of said column, the period of said forces being equal to the period of the longitudinal resonant vibrational mode of said column, a control system for controlling the amplitude of said longitudinal motion of said column, and a piston affixed to an end of said column and having an extended gas-interacting surface transverse to said column, wherein said column is bilaterally symmetric about a transverse plane, a movable part of said motor is affixed to an end of said column opposed to said end at which said piston is affixed, and said part has a mass equal to the mass of said piston.

Claim 3

The device of claim 1 wherein said column is arranged with its longitudinal axis vertical, and is supported on said support near said transverse plane.

Claim 4

Apparatus for generating a sound field comprising an elongated oscillating assembly for longitudinal vibration at a predetermined frequency including an elastic column, a mass having a gas-interacting surface affixed to one end of said column and a second mass affixed to the other end of said column, said assembly being supported at a minimum velocity region between said masses by a flexible structure permitting longitudinal motion of said minimum velocity region, and motive means operatively connected to said assembly to apply periodic forces to said second mass at said frequency.

Claim 5

Apparatus for generating a sound field comprising an elongated oscillating assembly for longitudinal vibration at a predetermined frequency including an elastic column, a mass having a gas-interacting surface affixed to one end of said column and a second mass affixed to the other end of said column, said assembly being supported at a minimum velocity region between said masses by a flexible structure permitting longitudinal motion of said minimum velocity region, and motive means operatively connected to said assembly to apply periodic forces to said second mass at said frequency.

Claim 6

The apparatus of claim 3 wherein said motive means is an electromagnetic motor and said second mass is the armature thereof.

Claim 7

The apparatus of claim 4 including a resonant acoustic chamber, and wherein said gas-interacting surface is arranged to form a wall of said chamber for generating a sound field therein.

Claim 8

The apparatus of claim 5 wherein said frequency is about 400 HZ.

Claim 9

An acoustic stimulator for feeding sound power to a resonant acoustic chamber and maintaining a sound field therein at a frequency approximately 400 HZ and at a level exceeding 0.5 psi peak pressure comprising in combination: a support an oscillating assembly having an elongated elastically extensible central column, a motor armature mass attached to one end of said elongated Column, and a piston mass with a laterally extended gas-interacting surface attached to the other end of said column, said gas-interacting surface being arranged to form a wall of said acoustic chamber, said assembly having a resonant vibration mode wherein said masses move in linear opposition to alternatively compress and extend said elongated central column at a predetermined resonant frequency, an electric motor including said armature mass operatively connected to drive said assembly in said vibration mode, a flexing support to support said assembly at a region of velocity minimum while permitting movement of said region, a constraint structure to maintain the lateral position of said armature mass, and a constraint structure to maintain the lateral position of said piston mass.

Claim 10

An acoustic stimulator for feeding sound power to a resonant acoustic chamber and maintaining a sound field therein at a frequency approximately 400 HZ and at a level exceeding 0.5 psi peak pressure comprising in combination: a support an oscillating assembly having an elongated elastically extensible central column, a motor armature mass attached to one end of said elongated Column, and a piston mass with a laterally extended gas-interacting surface attached to the other end of said column, said gas-interacting surface being arranged to form a wall of said acoustic chamber, said assembly having a resonant vibration mode wherein said masses move in linear opposition to alternatively compress and extend said elongated central column at a predetermined resonant frequency, an electric motor including said armature mass operatively connected to drive said assembly in said vibration mode, a flexing support to support said assembly at a region of velocity minimum while permitting movement of said region, a constraint structure to maintain the lateral position of said armature mass, and a constraint structure to maintain the lateral position of said piston mass.

Claim 11

The device of claim 7 wherein said motor comprises an armature affixed to an end of said column with a winding running circumferentially around an axis longitudinal to said column, and a magnet providing a magnetic field radial in said winding, and said winding is electrically connected to a source of alternating current, whereby said armature is axially oscillated.

Claim 12

The device of claim 8 wherein said constraint structure comprises a flexible electrically conductive member extending between said support and one end of said column and electrically connected to said armature for connecting said armature to said alternating current source.

Claim 13

The device of claim 8 wherein said magnet is of annular construction encircling said column, and is secured to said support.

Claim 14

The device of claim 10 wherein said magnet has a magnetic flux conducting portion in regions adjacent to said armature winding formed of a plurality of lamina, arranged with their short dimensions substantially circumferential to said axis, whereby interfering circumferential fields are prevented adjacent said armature.

Claim 15

The device of claim 11 wherein said plurality of lamina are disposed in a multitude of segmented bundles.

Claim 16

The device of claim 9 wherein said magnet comprises a winding connected to a source of electrical current running circumferential to said axis.

Claim 17

The device of claim 10 wherein said magnet includes spaced annular portions defining an annular slot therebetween, said magnetic field is radial in said slot between said annular portions, and said armature is located for axial movement in said slot.

Claim 18

The device of claim 7 in which said constraint structure comprises a flexible member affixed to said column and to said support.

Claim 19

The device of claim 15 in which said flexible member is connected to an end of said column.

Claim 20

The device of claim 7 wherein said constraint structure comprises a plurality of flexible straps arranged in a rectangular grid, each strap having its ends secured to said support and an intermediate portion connected to an end of said column.