Actuator mechanism for a printer or the like using dual magnets

A hammer mechanism for a device such as a printer comprising

• a magnetic hammer element comprising an elongated relatively flat beam of resilient material having a relatively small uniform thickness between first and second opposite surfaces and having a fixed end and an opposite deflectable free end and including an impact element extending from said first surface of said beam in the vicinity of said free end,
• said beam being mounted at the fixed end so as to assume a relatively straight configuration defining a neutral position when not flexed,
• magnetic circuit means including permanent magnet means and a magnetic core means disposed adjacent said second surface of said beam in the vicinity of said free end thereof so as to be coupled in magnetic circuit with an end portion of said beam immediately adjacent said free end,
• said magnetic core means includes first, second, and third pole pieces spaced from each other along said end portion of said beam, said third pole piece being located between said first and second pole pieces,
• said permanent magnet means comprises first and second permanent magnets supported by said first and second pole pieces adjacent said end portion of said beam with said third pole therebetween,
• said first and second permanent magnets having the same polarity and establishing first and second magnetic fields in the vicinity of said end portion of said beam whereby flux from said first and second permanent magnets flows through said end portion of said beam and returns through said third pole piece,
• said first and second magnetic fields retracting and holding said beam from said neutral to a retracted position, and
• means coupled to said third pole piece for counteracting said flux from said first and second permanent magnets in said third pole piece whereby said beam is released for movement from said retracted position toward said neutral position.