Fastening device for print head

A releasable fastening device for fastening a unitary print head to a projecting mounting post provided with first indexing means, an abutment surface and a circumferential groove comprising:

• said print head having a plurality of type characters embossed on its periphery and an axial hole formed therein for slidable positioning on said mounting post;
• second indexing means formed on said head to mate with said first indexing means on said mounting post for predetermined relative angular positioning of said print head with respect to said mounting post;
• an annular shoulder formed on said print head to mate with said abutment surface of said mounting post to limit the axial position of said print head in a first direction;
• manually-controllable locking means operatively associated with said print head for cooperating with said circumferential groove in said mounting post to limit the axial position of said print head in a second direction, comprising locking members in the form of one or more bent levers, each of said bent levers being capable of pivotal movement between an unlocked position out of said groove in which each of said bent levers is unstressed, and a locked position in which each of said bent levers is deflected into a stressed position within said groove, and control lever means capable of pivotal movement between corresponding unlocked and locked positions, said control lever means being provided with journal bearing means intersecting its effective pivot axis at an acute angle for moving said locking means between the unlocked and the locked positions.