Miniaturized extensible and retractable pen

Claim 1

A MINIATURIZED BALL POINT PEN STRUCTURALLY AND FUNCTIONALLY ADAPTED TO BE REMOVABLY POCKETED AND CONCEALED NEATLY IN THE USUAL FOLD OF AN ADULT-SIZE FOLDING WALLET COMPRISING: A RELATIVELY LONG OPEN-ENDED FORWARD BARREL SECTION HAVING A PREDETERMINED OUTSIDE DIAMETER NOT EXCEEDING 3/16" AND A UNIFORM OPEN-ENDED BORE, A THIMBLE TELESCOPINGLY PRESS-FITTED INTO THE FORWARD END OF SAID BORE, SAID THIMBLE HAVING AN OUTSTANDING SHOULDER ABUTTING THE COOPERATING END OF SAID FORWARD BARREL SECTION, THE BORE OF SAID THIMBLE CONSTITUTING A BUSHING FOR AN INK CARTRIDGE, AN INK CARTRIDGE DISPOSED AXIALLY IN THE BORE OF SAID FORWARD BARREL SECTION, SAID CARTRIDGE BEING OF A TRANSVERSE CROSS-SECTION LESS THAN THE CORRESPONDING CROSS-SECTION OF THE BORE OF SAID FORWARD BARREL SECTION, OF LENGTH LESS THAN THE LENGTH OF SAID FORWARD BARREL SECTION, HAVING ITS FORWARD END PORTION PRESS-FITTED AND FRICTIONALLY RETAINED IN THE BORE OF SAID THIMBLE, THE REARWARD END OF SAID CARTRIDGE BEING GRADUALLY INCREASED IN CROSS-SECTION AND THUS FLARED OUTWARDLY, TERMINATING SHORT OF THE REARWARD END OF SAID FORWARD BARREL SECTION AND SAID OUTWARDLY FLARED PORTION PROVIDING A STOP SHOULDER, A COMPLEMENTAL REARWARD BARREL SECTION OPEN AT ITS ENDS, SHORTER IN LENGTH THAN THE LENGTH OF SAID FORWARD BARREL SECTION AND ALSO HAVING A PREDETERMINED OUTSIDE DIAMETER NOT EXCEEDING 3/16", THE ADJACENT ENDS OF SAID BARREL SECTIONS BEING ADAPTED TO ABUT EACH OTHER WHEN THEY ARE DISPOSED IN END-TO-END ABUTTING RELATIONSHIP, AN ASSEMBLING AND RIGIDIFYING OPEN-ENDED SLEEVE OF A LENGTH GREATER THAN THE LENGTH OF SAID REARWARD BARREL SECTION AND SHORTER THAN SAID FORWARD BARREL SECTION, THE REARWARD END PORTION OF SAID SLEEVE BEING PRESS-FITTED IN THE BORE OF THE REARWARD BARREL SECTION AND HAVING ITS REARWARD END FLUSH WITH THE CORRESPONDING REARWARD END OF SAID REARWARD BARREL SECTION, THE MAJOR FORWARD PORTION OF SAID SLEEVE PROJECTING BEYOND THE FORWARD END OF SAID REARWARD BARREL SECTION, SAID PROJECTING FORWARD PORTION FITTING TELESCOPINGLY AND SLIDINGLY INTO THE BORE OF SAID FORWARD BARREL SECTION AND BEING CONCEALED NORMALLY THEREIN, THE LEADING TERMINAL END OF SAID SLEEVE BEING REDUCED IN CROSS-SECTION AND BEING ADAPTED TO SURROUND AND ABUT SAID STOP SHOULDER WHEN SAID SLEEVE IS WITHDRAWN FROM THE FORWARD BARREL SECTION AND IS ORIENTED TO ASSUME ITS EXPOSED USABLE POSITION AND RELATIONSHIP TO SAID BARREL SECTIONS, AND A VENTED HEADED PLUG HAVING ITS PLUG PORTION PRESS-FITTED INTO THE REARWARD END OF THE BORE OF SAID SLEEVE.