Vibration device

• US 20080106223A1
• Filed: 12/27/2007
• Published: 05/08/2008
• Est. Priority Date: 01/04/2005
• Status: Active Grant

• Current Assignee: General Vibration Corporation
• Original Assignee: Coactive Drive Corporation
• Inventors: Delson, Nathan
• Granted Patent: US 7,994,741 B2
• Time in Patent Office: Days
• US Class Current: 318/114
• CPC Class Codes: H01F 7/1615 Armatures or stationary parts of magnetic circuit having permanent magnet
• CPC Class Codes: H02K 33/02 with armatures moved one way by energisation of a single coil system and returned by mechanical force, e.g. by springs

Abstract

The present invention pertains to vibration devices that do not require a rotating mass. In accordance with aspects of the invention, a coil causes a plunger to move linearly. A spring device is coupled to one end of the plunger. Activation of the coil causes the plunger to move in a first direction relative to a body and coil deactivation enables the spring device to move the plunger in an opposite direction relative to the body. Activating the coil at a predetermined frequency causes vibration of the plunger. Vibratory forces are transferred via the spring device and coil onto the body at predetermined locations. Opposing spring devices may be affixed to either end of the plunger. Spring devices may be linear or non-linear. Such spring devices may be used in conjunction with magnetic spring devices. A controller and a driver circuit may be used to control system operation.

Claims

1. A method of controlling a vibration device having a coil for generating an electromagnetic field and affixed to a body, a moveable mass of magnetic material at least partly encircled by the coil, a nonlinear spring device coupled at a first end thereof to the moveable mass and affixed at a second end thereof to the body, and a driving circuit coupled to the coil and operable to generate a modulation signal for directing operation of the coil, wherein the nonlinear spring device has an effective stiffness, the method comprising:

selecting an activation frequency of the coil to approximate a natural frequency of the moveable mass;

generating a control signal;

supplying the control signal to the driving circuit; and

varying current in the coil with the driving circuit to modulate the activation frequency and to modulate the effective stiffness of the nonlinear spring device.

2. The method of claim 1, wherein the natural frequency varies based on an amplitude of vibration.