Tunable vibration absorber

• US 3,917,246 A
• Filed: 04/15/1974
• Issued: 11/04/1975
• Est. Priority Date: 04/15/1974
• Status: Expired due to Term

• Current Assignee: Harold M. Miller, Joseph R. Gartner
• Original Assignee: Harold M. Miller, Joseph R. Gartner
• Inventors: Gartner, Joseph R., Miller, Harold M.
• Primary Examiner(s): Marbert, James B.
• Application Number:
  US05/461,265
• Time in Patent Office: 568 Days
• Field of Search: 188/1B 74/574 267/136,137
• US Class Current: 267/136
• CPC Class Codes: B64C 2027/005 using suspended masses
• CPC Class Codes: B64C 27/001 Vibration damping devices
• CPC Class Codes: F16F 7/1017 by fluid means
• CPC Class Codes: F16F 9/22 with one or more cylinders each having a single working space closed by a piston or plunger

Abstract

A vibration absorber includes an inertia mass having oppositely directed spaced apart pistons, each being disposed within an independent pressurizable cylindrical chamber which is rigidly attached to a vibrating body. The inertia mass moves back and forth in response to vibrations of the vibrating body, alternately compressing the pressurizable fluid within each chamber. Automatic adjusting means in one embodiment keeps the inertia mass reciprocating substantially evenly about a central point whereby the restoring force on each piston face at the end of each stroke is always about the same. A pressure regulator keeps equal minimum pressures within the chambers. The magnitude of the pressure in conjunction with the mean volume of the pressurized chambers determines the natural period of the reciprocating motion. The pressure can be set so that the device may absorb a wide band of vibrating frequencies of the vibrating body.

Claims

1. A vibration absorber for attachment to a vibrating mass comprising:

housing means;

inertia mass means adapted to naturally reciprocate in response to vibrations of the vibrating mass, said inertia mass means comprising oppositely facing first and second piston faces disposed within said housing means along a common axis, said faces defining in combination with said housing means a first and a second pressurizable chamber each being independent of the other, said inertia mass means also including connecting means rigidly joining said piston faces;

pressure regulating means associated with said chambers for maintaining substantially equal minimum pressures therewithin;

control means associated with said pressure regulating means for setting the proper pressure in said chambers to cause said inertia mass means to naturally reciprocate with substantially the same period as the vibrations of the vibrating mass; and

adjusting means associated with said inertia mass means causing adjustment in the position of said inertia mass means to maintain approximately symmetric restoring forces on said first and second piston faces during reciprocating motion of said inertia mass means.

2. The vibration absorber according to claim 1 wherein said chambers have equal volumes when said inertia mass means is in a first position, and said adjusting means includes means for adjusting the position of said inertia mass means so that it always reciprocates substantially about said first position, thereby maintaining approximately symmetric restoring forces on said piston faces during operation of the absorber.

3. The vibration absorber according to claim 1 wherein said inertia mass means is a cylinder and said piston faces are end faces of said cylinder.

4. The vibration absorber according to claim 3 wherein said housing means defines a cylindrical chamber and said first and second pressurizable chambers are portions of said cylindrical chamber and said inertia mass means is disposed within said cylindrical chamber.

5. The vibration absorber according to claim 1 wherein said adjusting means includes means for temporarily creating a differential in pressure between said chambers.

6. The vibration absorber according to claim 1 wherein said chambers have equal volumes when said inertia mass means is in a first position, and said adjusting means includes means for sensing during reciprocal motion of said inertia mass means when the position of said inertia mass means is more than a predetermined distance from said first position, said adjusting means also including means responsive to said sensing means for temporarily creating a differential in pressure between said chambers when said predetermined distance is reached so as to cause said inertia mass means to shift in position so that it is less than said predetermined distance from said first position.

7. The vibration absorber according to claim 6 wherein when said inertia mass means is reciprocating evenly about said first position the minimum volume in either chamber is the means minimum volume and wherein when said inertia mass means is at said predetermined distance from said first position the volume in said chambers is within 25 percent of said mean minimum volume.