Latching mechanism for printing machines

Claim 1

A data recorder for imprinting forms by means of printing devices in which forms of various thickness may be accepted, comprising; a base; a bed on the base for holding a printing device and a form to be imprinted; a print head, a pivot mount on the base for providing movement of said print head between an open position spaced from the bed and a closed printing position, means for providing an infinite number of possible closed positions within a range spaced from the Bed a distance less than the open position; a platen supported on the print head, means for moving said platen across the bed when the print head is in said closed position from a home position to an actuated position to perform a printing stroke; said means for providing the infinite number of closed positions including stop means carried by the print head separate from said platen and responsive to movement of the print head towards the closed position for striking the bed in the area which holds a form, said form lying between said stop means and said bed, said stop means terminating the closing action of the print head at a position wherein the platen is spaced from the bed in a printing relationship determined by the form thickness; a latching arm pivotally mounted on the base; a lock surface carried by said print head on the side of said pivot mount opposite the platen travel, said lock surface facing said bed and swingable away from said bed as a result of the pivot position as the print head closes, and movable toward said bed as the print head opens; said latching arm located to swing into the space between said lock surface and bed, said latching arm having a plurality of radial segment portions measured from its said pivot mount producing a generally curved top surface wherein each segment portion differs in length from all other portions, and wherein each segment portion surface serves as a blocking wedge to fit under the lock surface in one particular pivotal position of said print head; whereby, said print head may be pivoted towards said bed until the stop means abuts the top surface of said form and brings the head to a stop in one of a number of possible positions determined by the thickness of a form on said bed, and said latching arm is pivoted under the lock surface until a segment thereof that fits the space comes to rest between the lock surface and bed, the stop means serving to prevent further closing movement and the latching arm preventing opening movement until displaced from its locking position.