3results about How to "Limit amplitude" patented technology

The present invention relates to the field of earphone technology, and in particular to a dual-magnetic noise reduction earphone and a control method thereof, comprising an earphone holder; both ends of the earphone holder are provided with a telescopic frame; one end of a fixed part is provided with a push rod for abutting against the earphone holder; the other end of the fixed part is provided with a body; the body is provided with a first diaphragm; a accommodating cavity is formed between the first diaphragm and the body; a driving unit is provided in the accommodating cavity; a lifting bracket is provided for lifting and lowering activities in the accommodating cavity; a permanent magnet is provided at the top of the lifting bracket; a second diaphragm is provided at the bottom of the first diaphragm; a magnetorheological fluid is provided between the first diaphragm and the second diaphragm; a transmission mechanism is provided between the push rod and the lifting bracket. The present invention adjusts the extension and retraction of the telescopic frame according to the size of the user's head, thereby driving the lifting bracket to drive the permanent magnet to move up and down, and uses the second permanent magnet to change the stiffness of the magnetorheological fluid, thereby limiting the amplitude of the first diaphragm, controlling the volume output, and preventing excessive volume from damaging the hearing of child users.

The utility model relates to reciprocating vibration screen technical field, concretely to a kind of super-silent reciprocating vibration screen, including base, the connecting frame being set at the top of base, vibration motor and connecting shaft being connected in the inside of vibration motor are distributed in the outer surface of the both ends of connecting frame, the inside of connecting frame is provided with connecting piece, the connecting piece includes second gasket, mounting plate, third gasket and fixed plate;Second gasket is fixed in the inner surface of connecting frame, second gasket is provided with eight groups, mounting plate is arranged at the outside of the both sides of any one group second gasket, third gasket is arranged at the inside of mounting plate top end, and fixed plate is fixed on the outer surface of third gasket.The utility model has simple structure, reasonable in design, by using connecting piece instead of transmission spring, avoid the collision between screen body and base, cause the situation of larger noise, maintain the advantages of silent work of device, solve the problem proposed in the above technical background.

The present disclosure relates to the field of ultrasonic deformation material control. Disclosed are an ultrasonic control device and an ultrasonic control testing system, applied to control or tests of deformation of a material in a human body or an animal body caused by ultrasonic waves. The ultrasonic control device comprises a fixed platform, movable supports, ultrasonic transmitters, and a controller. Due to the safety of ultrasonic waves, the present disclosure can be applied to aspects such as scientific research and treatment of biomedicine.