Printer with removable print carriage

Claim 1

A band-type data printer comprising a main frame releasably supporting a print carriage, A. said main frame being cooperable with said print carriage for defining a path for passage of a recording medium therebetween and containing a plurality of actuable hammers mounted adjacent said path and cooperable with said print carriage to imprint information on the recording medium, and further including: (1) carriage supporting means for supporting said print carriage, and (2) carriage latch means cooperable with said print carriage for releasably securing said print carriage to said frame, said carriage latch means comprising: i. a cam pivotally mounted on said frame and having a head cooperable with a notch in said print carriage, ii. a trunnion pivotally mounted on said frame, iii. a connecting rod having first and second rod heads, means for preventing said rod heads from separating by more than a predetermined distance, and a spring coaxial with said connecting rod for urging said rod heads apart to tend to keep said rod heads separated by said predetermined distance, said first and second rod heads being pivotally connected to said cam and said trunnion, respectively, at pivot points thereon separated from said cam and trunnion axes, respectively, to tend to keep the pivot points separated by the predetermined distance so that said cam tends to rotate with rotation of said trunnion and there is a range of angular positions of said trunnion in which the axis of said connecting rod passes from one side of the trunnion axis through the trunnion axis to the other side thereof, and iv. an arm on said trunnion extending outward of said frame for rotation of said trunnion through said range of angular positions from a first position, in which the connecting-rod axis is disposed on one side of the trunnion axis, to a second position, in which the connecting rod is disposed on the other side of the trunnion axis, the spring thereby applying torque to the trunnion in one direction when said arm is in the first position and in the opposite direction when said arm is in the second position, and B. said print carriage further comprising: (1) means defining a printing anvil adjacent said path, and (2) means for rotatably mounting a printing band on said print carriage for cooperation with said anvil and said hammers when said print carriage is secured to said print frame to enable information to be printed on the recording medium.