Liberato M Rizzi

US Patent:

6364064, Apr 2, 2002

Filed:

Mar 8, 2000

Appl. No.:

09/521062

Inventors:

Liberato Rizzi - Clinton NJ

Assignee:

Inventio AG - Hergiswil

International Classification:

B66B 134

US Classification:

187292

Abstract:

An apparatus for actively controlling transmission of vibration energy to a movable platform, such as an elevator floor, attached to a carriage for transporting the movable platform. The apparatus includes a passive vibration attenuator for passively absorbing vibration energy transmitted through the carriage. Also included is a vibration sensor having a first piezoelectric material and connected in series with the passive vibration attenuator. The vibration sensor is configured to generate an electrical signal in response to deformation of the vibration sensor caused by vibration energy transmitted through the passive vibration attenuator. An inverter for inverting the electrical signal from the vibration sensor and outputting an inverted electrical signal that is equal in magnitude and opposite in polarity to the electrical signal from the vibration sensor. A vibration generator, responsive to the inverted electrical signal and connected in series with the vibration sensor, is comprised of a second piezoelectric material for transmitting a vibration force to substantially cancel the vibration energy transmitted through the passive vibration attenuator.