Patent ID: 7339857

Claim:
A vibrating device for a portable object, such as a wristwatch, the device including a moving mass formed in part of a magnetic structure connected to a fixed structure via a spring element, and a coil connected to the fixed structure without any mechanical contact with the moving mass and electro-magnetically coupled to the moving mass to enable said mass to oscillate in at least one direction of oscillation when it is powered by alternating electrical signals at a determined frequency, wherein one fixed part of the vibrating device is arranged so as to cooperate with one part of the moving mass to enable the moving mass to oscillate freely in a normal operating mode of the vibrating device at least to a determined maximum amplitude value, and to limit the movement amplitude of the moving mass in a determined manner in all directions in order to protect the vibrating device from mechanical shocks, wherein the spring element includes a base strip secured to the fixed structure, and two strip springs integral with the base strip and arranged substantially perpendiculary to the base strip on two opposite sides of said base strip, the mass being held between the two strip springs, wherein the fixed part of the vibrating device includes a part integral with the base strip which is arranged on one side of the base strip parallel to the direction of oscillation of the moving mass, and wherein the moving mass includes a projecting element on the side of the base strip positioned in guide means defined by said part or by a combination of the part and the fixed structure to enable the moving mass to oscillate freely during normal operation in a determined direction of oscillation and to limit the movement amplitude of the moving mass in a determined manner in each direction with respect to a central position of the projecting element of the moving mass at rest.