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US 4,399,334 AGranted
Speaker unit for headphones
AssigneeSony Corporation
InventorsTsutomu Kakiuchi, Yoshiyuki Kamon
Life of this patent
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AssigneeSony Corporation
InventorsTsutomu Kakiuchi, Yoshiyuki Kamon
Estimating the term…
A speaker unit for headphones including a magnetic circuit which has a magnetic gap and including a diaphragm which is moveable to generate sound in response to energy applied to a coil wound on a bobbin which is connected to the diaphragm and mounted within the magnetic gap and including a frame for supporting the magnetic circuit and the diaphragm and a protecting means mounted at the front of the diaphragm and having projections so as to engage the diaphragm near the region where the bobbin is mounted so as to limit the maximum motion of the diaphragm and the protecting means formed with openings such that the protector prevents the bobbin from moving completely out of the magnetic gap. The invention is applicable to speaker units for open air type headphones, for example.
A speaker unit comprising,
A speaker unit comprising a cylindrical frame member, a diaphragm with its outer edges attached to said frame member, a cylindrical shaped bobbin of thickness "T" attached to the rear side of said diaphragm and a voice coil mounted thereon, a magnetic circuit with pole pieces attached to said frame adjacent said bobbin and magnetically coupled to said voice coil, a front protective cover attached to said frame and having at least one inwardly extending projection which extends toward said diaphragm and engageable therewith when said diaphragm is over driven, wherein said one inwardly extending projection is aligned with an edge of said cylindrical shaped bobbin so as to limit the movement of said bobbin, said voice coil and said diaphragm.
Dependencies are inferred from the claim text.