Ink cartridge selection control mechanism of a multi-ink cartridge writing apparatus

An ink cartridge selection control mechanism for a writing apparatus having an elongated barrel with a lower, writing end and an upper end, and a plurality of ink cartridges each having a writing end portion and movable between retracted and extended positions, the control mechanism comprising:

• a) a locating board mounted in the elongated barrel adjacent to the lower, writing end of the barrel, the locating board having a plurality of through holes each having a writing end portion of an ink cartridge extending therethrough, the through holes located so as to form the writing end portion of each cartridge into a curved configuration;
• b) a plurality of slots in the elongated barrel adjacent to the lower, writing end of the barrel, each slot having a lower end terminating with an enlarged, tapered hole;
• c) a slide fixedly attached to each ink cartridge at the curved end portion, each slide having spaced apart tapered upper and tapered lower lugs facing a longitudinal axis of the elongated barrel, a driving arm extending through one of the plurality of slots, each driving arm having an enlarged end disposed externally of the elongated barrel;
• and,
• d) a spring mounted around each of the plurality of ink cartridges and extending between the locating board and the associated slide so as to bias the cartridge toward its retracted position;
• wherein when a first ink cartridge is moved to the extended position by the respective first slide, the respective spring is compressed, and the enlarged end of the associated driving arm of the respective slide is forced into engagement with the enlarged, tapered hole of the respective slot by the curvature of the writing end portion of the ink cartridge to lock the first ink cartridge in the extended position;
• and, when a second ink cartridge is moved by the respective second slide toward the extended position, the first slide of the extended first ink cartridge is forced outwards by contact between the tapered lugs of the first and second slides to release the enlarged end of the respective driving arm from the enlarged, tapered hole of the respective slot, thereby enabling the respective spring to push the first slide and first cartridge to the retracted position.