This invention involves methods and apparatus relating to the assembly and structure of a dot matrix print head. The invention includes a single unit, coil assembly of a bobbin, coil, and clapper which can be removeably placed as a unit among fixed pole pieces and yoke members in the print head. The print head also includes a supporting arrangement for the coil assemblies which automatically aligns the clapper of each coil assembly with the impact end of one of the print wires during the assembly of the print head. Other disclosed features of the invention are novel designs for the wire guide members, a heat sink member, and mounting structure by which the print head is attached to the main guide and rail guide bearings of the printing mechanism. The invention also includes novel assembly aids and procedures which simplify and hasten the assembly of the print head including the use of assembly aids for inserting the print wires into the wire guide members and a grinding technique whereby all of the print wires can be easily and quickly ground to the proper length. With the novel print head design of this invention, the mounting plate, heat sink member, and coil assemblies can all be slideably assembled together and retained in place by snap-in, mating recess-detent arrangements between each bobbin and pole piece. In this manner, the print head can be easily and quickly assembled for operation and easily and quickly disassembled for repairs.
This application is a division of U.S. patent application Ser. No. 499,208 filed May 31, 1983, now abandoned, which is a division of U.S. patent application Ser. No. 425,255 filed Sept. 28, 1982, now U.S. Pat. No. 4,401,392, which is a continuation of U.S. patent application Ser. No. 256,032 filed on Apr. 21, 1981, now abandoned, which is a division of U.S. patent application Ser. No. 38,724 filed May 14, 1979, now U.S. Pat. No. 4,279,518.
