Ribbon fork actuating mechanism for typewriters and the like

Claim 2

In a mechanism for typewriters, particularly power-driven typewriters and the like for effecting a positive lifting and lowering of a ribbon fork thereof between a rest position and either one of two operating positions, the combination of a drive lever, rigidly mounted on a drive shaft, pivotal through a predetermined arcuate range, a pair of intermediate levers operatively connected to the drive lever for pivotal movement relative thereto, first means for selectively establishing a rigid connection between the two intermediate levers, and second means for establishing a rigid connection between the drive lever and one of said intermediate levers when said first means is inoperative, said intermediate levers operatively connecting the drive lever to said ribbon fork.

Claim 3

A mechanism according to claim 1, wherein said second means is disposed to selectively establish a connection of said one intermediate lever with said drive shaft whereby movement of said one intermediate lever is limited to pivoting about the axis of said drive shaft.

Claim 4

A mechanism accorDing to claim 2, wherein said second means includes an extension provided on said one intermediate lever engageable with said drive shaft at one side thereof, and a blocking lever, pivotal to selectively engage the drive shaft at the opposite side thereof.

Claim 5

A mechanism according to claim 1 wherein said first means includes a pair of pivotal coupling links which connect said intermediate levers and are spring biased in an overcenter position in engagement with a stop disposed on one of said intermediate levers, whereby said coupling links may act as a single rigid member connecting said intermediate levers in rigid relation, and a control member selectively engageable with said coupling links to enable movement of said coupling links out of said overcenter position for relative pivotal movement therebetween.

Claim 6

A mechanism according to claim 1, wherein said one intermediate lever is pivotally connected at one end thereof with the free end of said drive lever and at its opposite end to the other intermediate lever intermediate the ends thereof, said first means including a pair of coupling links having their adjacent ends pivotally connected, the free end of one of said coupling links being pivotally connected to one end of said other intermediate lever and the free end of the other of said coupling links being pivotally connected to said one intermediate lever intermediate the ends thereof, a stop member carried by said one of said intermediate members, spring means biasing said coupling links into engagement with said stop member with the coupling links in overcenter positions whereby they may act as a single rigid link connecting said intermediate levers in a rigid relation, a control member selectively engageable with said coupling links to enable movement of said coupling links out of said overcenter position, said second means including an extension provided on said one intermediate lever engageable with said drive shaft at one side thereof, and a blocking lever pivotally connected to said one intermediate lever disposed for pivotal movement to selectively engage said drive shaft at the opposite side thereof to rigidly connect said one intermediate lever thereto, said blocking lever being engageable with means associated with said other intermediate lever when said coupling links are in overcenter position operative to dispose said blocking lever in a nonblocking position.