Drafting pen

Claim 2

A drafting pen comprising a cylindrical barrel having an open upper end and a lower end constituting an ink storage portion closed by a portion of reduced diameter provided with a tubular pen point having a bore communicating with the ink storage portion of the barrel, means closing said open end and including vent means movable between open and closed positions, control means in the barrel above the ink storage portion having a portion, the outer diameter of which is slightly smaller than the inner diameter of the cooperating barrel portion, one of said portions being cylindrical and the other having a helical thread on the surface to receive and retain a film of ink between the crest of the threads and the cylindrical portion with the roots of the thread forming a venting passage, said venting means in open position permitting ink to flow from said pen point during a writing operation.

Claim 3

The invention as defined in claim 1 wherein the barrel has a smooth inner portion and the control means has the helical thread on the surface to cooperate therewith.

Claim 4

A pen comprising a cylindrical barrel having an open upper end and a lower end constituting an ink storage portion closed by a portiOn of reduced diameter provided with a tubular pen point having a bore communicating with the ink storage portion of the barrel, a control means above said ink storage portion, said control means including an inner member carried by the barrel comprising a bushing closing said open end and slidably supporting a stem having a vent passage, said vent passage being opened and closed in response to sliding of said stem, said stem having on an intermediate portion a member having a helical thread on the outer surface, the outer diameter of said member being slightly smaller than the inner diameter of the barrel to receive a film of ink between the crest of threads and the barrel with the roots of the thread forming a venting passage therethrough, the forward end of said stem having a needle extending through said tubular pen point, movement of the stem to open the vent causing the needle to be withdrawn within the pen point whereby ink is free to flow from the pen point during a writing operation.

Claim 5

A pen comprising a cylindrical barrel having an open upper end and a lower end constituting an ink storage portion closed by a portiOn of reduced diameter provided with a tubular pen point having a bore communicating with the ink storage portion of the barrel, a control means above said ink storage portion, said control means including an inner member carried by the barrel comprising a bushing closing said open end and slidably supporting a stem having a vent passage, said vent passage being opened and closed in response to sliding of said stem, said stem having on an intermediate portion a member having a helical thread on the outer surface, the outer diameter of said member being slightly smaller than the inner diameter of the barrel to receive a film of ink between the crest of threads and the barrel with the roots of the thread forming a venting passage therethrough, the forward end of said stem having a needle extending through said tubular pen point, movement of the stem to open the vent causing the needle to be withdrawn within the pen point whereby ink is free to flow from the pen point during a writing operation.

Claim 6

The invention as defined in claim 3 wherein said bushing has a bore closed by an apertured wall at the inner end, said bore has threads at the outer end, and said stem has a reduced end portion slidable in said apertured wall and provided with said vent passage, the end of the stem being secured to a button having an end flange and having threads to be threaded into the threads in the bore of the bushing, a sealing washer on said button to engage the end of the bushing when the button is threaded into the bushing and seals the vent passage, and a spring in said bore normally urging the stem and button to projected unsealing position when the button is unthreaded from said bore in the bushing.

Claim 7

A pen comprising a cylindrical barrel having an open upper end and a lower end constituting an ink storage portion closed by a portion of reduced diameter provided with a tubular pen point having a bore communicating with the ink storage portion of the barrel, a control means above said ink storage portion, said control means including an inner member carried by the barrel comprising a bushing disposed in said open upper end with a right fit and having a bore closed by an apertured wall at the inner end, said bore having threads at the outer end, a stem having a reduced end portion slidable in said apertured wall and provided with a vent passage, the end of the stem being secured to a button having an end flange and having threads to be threaded into the threads in the bore of the bushing, a sealing washer on said button to engage the end of the bushing when the button is threaded into the bushing and seals the vent passage, a spring in said bore normally urging the stem and button to projected unsealing position, said stem having a member on an intermediate portion provided with a helical thread on the outer surface, the outer diameter of said portion being slightly smaller than the inner diameter of the barrel to receive and retain a film of ink between the crest of the threads and the barrel with the roots of the thread forming a venting passage, the forward end of said stem having a needle extending through said tubular pen point, the unthreading of the button from the threaded portion of the bushing releasing the stem for movement under said spring to remove the seal, vent the upper end of the stem and partially withdraw the needle within the pen point whereby the ink is free to flow from the pen point during a writing operation.

Claim 8

A pen comprising a cylindrical barrel having an open upper end and a lower end constituting an ink storage portion closed by a portion of reduced diameter provided with a tubular pen point having a bore communicating with the ink storage portion of the barrel, a control means above said ink storage portion, said control means including an inner member carried by the barrel comprising a bushing disposed in said open upper end with a right fit and having a bore closed by an apertured wall at the inner end, said bore having threads at the outer end, a stem having a reduced end portion slidable in said apertured wall and provided with a vent passage, the end of the stem being secured to a button having an end flange and having threads to be threaded into the threads in the bore of the bushing, a sealing washer on said button to engage the end of the bushing when the button is threaded into the bushing and seals the vent passage, a spring in said bore normally urging the stem and button to projected unsealing position, said stem having a member on an intermediate portion provided with a helical thread on the outer surface, the outer diameter of said portion being slightly smaller than the inner diameter of the barrel to receive and retain a film of ink between the crest of the threads and the barrel with the roots of the thread forming a venting passage, the forward end of said stem having a needle extending through said tubular pen point, the unthreading of the button from the threaded portion of the bushing releasing the stem for movement under said spring to remove the seal, vent the upper end of the stem and partially withdraw the needle within the pen point whereby the ink is free to flow from the pen point during a writing operation.

Claim 9

The invention as defined in claim 3 wherein the needle has helical grooves in its outer surface to permit free flow of ink to said tubular pen point and the edges of the grooves clean dry ink from said pen point during a cleaning operation.