Print hammer mechanism

A hammer mechanism for a printer comprising:

• an elongated magnetic circuit structure including permanent magnet means extending along the length of the magnetic circuit structure, the length of the magnetic circuit structure being divided into a succession of hammer element positions of generally uniform size, there being a dummy hammer element position adjacent each end of the magnetic circuit structure and a plurality of intermediate hammer element positions therebetween;
• a different resilient magnetic hammer element coupled to the magnetic circuit structure in each of the intermediate hammer element positions and only in the intermediate hammer element positions, the permanent magnet means establishing a magnetic field normally maintaining each hammer element in a spring-loaded retracted position;
• and
• different means associated with each of the magnetic hammer elements and coupled to the magnetic circuit structure for substantially cancelling the magnetic field in a portion of the magnetic circuit structure adjacent the associated hammer element to release the associated hammer element from the retracted position for a selected period of time.

A hammer mechanism for a printer comprising:

• a magnetic circuit structure including permanent magnet means;
• a plurality of resilient magnetic hammer elements coupled to the magnetic circuit structure, the permanent magnet means establishing a magnetic field normally maintaining each hammer element in a spring-loaded retracted position;
• different means associated with each of the magnetic hammer elements and coupled to the magnetic circuit structure for substantially cancelling the magnetic field in a portion of the magnetic circuit structure adjacent the associated hammer element to release the associated hammer element from the retracted position for a selected period of time;
• and
• a relatively thin, generally planar barrier element of magnetic material mounted on the magnetic circuit structure and disposed adjacent and spaced-apart from the magnetic hammer elements and the different means for substantially cancelling the barrier element providing a magnetic path in parallel with a magnetic path defined by each magnetic hammer element, the barrier element comprising part of a housing enclosing the hammer mechanism;
• each of the hammer elements having a printing tip mounted thereon and a barrier element being generally parallel to the hammer elements and having a plurality of holes therein through which the printing tips extend to the outside of the housing when the hammer elements mounting the printing tips are released from the retracted position for the selected period of time.

A hammer mechanism for a printer comprising:

• a magnetic circuit structure including permanent magnet means;
• a plurality of resilient magnetic hammer elements coupled to the magnetic circuit structure, the permanent magnet means establishing a magnetic field normally maintaining each hammer element in a spring-loaded retracted position;
• different means associated with each of the magentic hammer elements and coupled to the magnetic circuit structure for substantially cancelling the magnetic field in a portion of the magnetic circuit structure adjacent the associated hammer element to release the associated hammer element from the retracted position for a selected period of time;
• and
• a relatively thin, generally planar barrier element of magnetic material mounted on the magnetic circuit structure and disposed adjacent and spaced-apart from the magnetic hammer elements and the different means for substantially cancelling the barrier element providing a magnetic path in parallel with a magnetic path defined by each magnetic hammer element, the barrier element comprising part of a housing enclosing the hammer mechanism;
• the means for substantially cancelling the magnetic field comprising a plurality of electrical coils and means for selectively energizing the electrical coils, and further including means for introducing air under pressure into the inside of the housing to cool the hammer mechanism including the electrical coils.

A hammer mechanism for a printer comprising:

• a housing having a hollow interior and a plurality of openings therein;
• a magnetic circuit structure mounted within the interior of the housing;
• electrical coil means mounted on and forming a part of the magnetic circuit structure;
• a plurality of hammer elements having one portion thereof coupled to the magnetic circuit structure at a location thereon away from the electrical coil means and normally maintained in and temporarily releasable from a spring-loaded retracted position in which a portion thereof opposite said one portion is held against the electrical coil means by a magnetic force, each of the hammer elements including print means which extends through a different one of the plurality of openings in the housing to the outside of the housing when the hammer element is temporarily released from the retracted position;
• means for selectively energizing the electrical coil means to overcome said magnetic force and temporarily release the hammer elements from the retracted position;
• and
• means for introducing air under pressure into the interior of the housing to cool the hammer mechanism including the electrical coil means.

A hammer mechanism for a printer comprising:

• a magnetic circuit structure having a hammer element mounted portion and an opposite hammer element holding portion;
• a plurality of resilient magnetic hammer elements, each having a first end mounted on the mounting portion of the magnetic circuit structure and an opposite second end normally in contact with the holding portion of the magnetic circuit structure when the hammer element is in a retracted position to complete a magnetic circuit through the magnetic circuit structure;
• permanent magnet means forming a part of the magnetic circuit structure and operative to provide magnetic flux in the magnetic circuit structure to normally hold the hammer elements in the retracted position;
• a plurality of flux cancelling means forming a part of the magnetic circuit structure and each being associated with a different one of the hammer elements and operative when energized to generate a magnetic flux in the region of the associated hammer element which overcomes the magnetic flux from the permanent magnet means and momentarily releases the associated hammer element from the retracted position;
• and
• a housing having the magnetic circuit structure and the included hammer elements, permanent magnet means and flux cancelling means mounted therein, said housing having a portion of magnetic material coupled to the magnetic circuit structure adjacent the hammer element mounting portion and extending generally parallel to and spaced-apart from the hammer elements to a region adjacent the holding portion of the magnetic circuit structure to form auxiliary flux paths parallel with the hammer elements and thereby increase the flux density in the region of the holding portion of the magnetic circuit structure, said portion of magnetic material having at least one aperture therein to provide access to the outside of the housing for the hammer elements.

A hammer mechanism for a printer comprising:

• a magnetic circuit structure having a generally U-shaped cross-section defined by a pair of opposite end portions extending from an intermediate portion, one of the opposite end portions defining a hammer element mounting region and the other one of the opposite end portions defining a hammer element holding region;
• a permanent magnet included in and forming a part of the magnetic circuit structure;
• a plurality of coils mounted on the other one of the opposite end portions and spaced apart along the length of the magnetic circuit structure;
• a plurality of elongated hammer elements mounted in spaced-apart relation at first ends thereof along the length of the magnetic circuit structure at the mounting region and having opposite second ends thereof disposed adjacent different respective ones of the coils, each of the hammer elements being held in a retracted position against the holding region by the permanent magnet except when an adjacent one of the coils is energized;
• and
• a generally rectangular housing having a bottom on which said one of the opposite end portions of the magnetic circuit structure is mounted, a top adjacent said other one of the opposite end portions of the magnetic circuit structure, a first side adjacent the intermediate portion of the magnetic circuit structure, and a second side adjacent the hammer elements, the second side being made of magnetic material and contacting the mounting region of the magnetic circuit structure and extending along the length of the hammer elements in generally parallel, spaced-apart relation thereto past the holding region of the magnetic circuit structure to form a plurality of magnetic paths parallel to the hammer elements as well as a portion of the housing enclosing the magnetic circuit structure, the permanent magnet, the coils and the hammer elements, the second side having at last one hole therein to provide access to the outside of the housing for the hammer elements.