Traveling cylinder imprinter with over center platen cylinder activating mechanism

Claim 1

In a hand-operated imprinting mechanism for causing impressions to be made on a sheet held over appropriate printing means, such as a credit card or the like, and which includes a base defining supporting top surface for said sheet and said printing means, and having elongated side portions extending downwardly from said top surface, one of said side portions having a slot therein extending from one end of the base to the other; and a carriage reciprocally movable along the top surface of said base; the combination of: a shaft, bearing means mounted on the underside of said carriage and eccentrically supporting said shaft in a transverse position with respect to said base; roller means rotatably mounted on said shaft; and overcenter operating means coupled to said shaft effectively to turn said shaft in said bearing means between first and second angular positions so as to move said roller means between an operative position with respect to said top surface of said base as said carriage is moved in one direction along said base, and to an inoperative position displaced up from said top surface as said carriage is moved in the opposite direction along said base, said overcenter operating means including a shaft actuator member mounted on said shaft and keyed thereto and having a projection extending axially therefrom, and a pair of pivotally mounted spring-biased slide members, one of said slide members having an opening therein for receiving said projection of said actuator and said opening having oppositely inclined edges meeting at an apex and engaging said projection at said apex, and said slide members being slidable with said carriage along said base, the other of said slide members having a projection extending into the aforesaid slot in said one of said side portions of said base and engaging the respective ends of said slot to stop the sliding movement of said slide members and to produce relative movement between said slide members and said carriage so as to cause said actuator to turn said shaft between said first and second angular positions each time the carriage is moved across the top surface of said base to a limiting position at each end thereof.