Tubular writting pen with superposed pressure equalization chambers
AssigneeKoh-I-Noor Rapidograph, Inc.
InventorGerold Anderka
Life of this patent
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Abstract
Tubular writing pens of the stylographic type, as used by artists and technical draftsmen. Particularly a tubular writing pen having superposed inner and outer ink pressure equalization chambers defined in the cylindrical pen body. A removable outer sleeve complementally engages the cylindrical body of the pen, to cover the outer pressure equalization chamber. A locking surface is defined in the removable sleeve rear edge, so that the sleeve may not be removed accidently with consequent ink loss and damage.
Claims9
In a tubular writing pen of the type having a soft plastic writing fluid reservoir cartridge (6) with a front end which is adapted to be pushed from the rear and forwardly onto the outer surface of a hard plastic cylindrical body (1) which has an inner bore to communicate ink from said reservoir cartridge to a writing capillary tube carried at the front end of said cylindrical body (1), the improvement which comprises a front wall region on said reservoir cartridge (6) that is configured to cooperate with said cylindrical body (1) and a surrounding cylindrical sleeve (9) so as to define an equalizing chamber means comprised of axially extending, interconnected helical passages, that is replaced with replacement of said reservoir cartridge, said equalizing chamber means further comprising an outer equalization chamber (12) and an inner equalization chamber (14), wherein the outer equalization chamber (12) further comprises outwardly open channels defined within an outer surface of said cartridge front wall region that are adapted to be covered by a smooth inner surface portion of a surrounding cylindrical sleeve (9), to define a first axially extending helical passage, said outer equalization chamber further having a rear end that terminates proximate to a connecting bore (13) that extends transversely through said front wall region in order to interconnect with said inner equalization chamber and a front end that communicates with surrounding air through an aperture defined between a front end of the cylindrical sleeve (9) and a portion of the outer surface of said cylindrical body (1), wherein further said inner equalizing chamber 14 comprises inwardly open channels defined within an inner surface of said reservoir cartridge front wall region, that are adapted to be covered by a smooth outer surface portion of said cylindrical body (1) to define a second axially extending helical passage, said inner equalization chamber further having a rear end which communicates with said connecting bore (13) and a front end that communicates with said cylindrical body inner bore through a transverse bore (7), means to mount said cylindrical sleeve (9) from the front and rearwardly into a surrounding relationship to the soft plastic reservoir cartridge front wall region, so as to cause a first sealing engagement between an inner surface of said sleeve and an outer surface of said reservoir cartridge and a second sealing engagement between a soft plastic inner equalization chamber front end and a hard plastic cylindrical body annular shoulder (18) proximate the front end of the cylindrical body (1), said cylindrical sleeve mounting means further comprising a reservoir cartridge intermediate wall region, posterior to the outer equalization chamber (12), which comprises an outer surface defined with a first external thread (16), and said cylindrical sleeve (9) has a first internal thread proximate its the rear end of said cylindrical sleeve (9) that is adapted to engage with said first external thread (16), whereby said cylindrical sleeve is adapted to surround and cover said reservoir cartridge front wall region, and axially urge the hard plastic cylindrical body annular shoulder (18) against the soft plastic inner equalization chamber front end upon an axial engagement of said cylindrical sleeve first internal thread rearwardly onto the first external thread (16) of the reservoir cartridge.
In a tubular writing pen writing fluid reservoir cartridge (6) of the type having a front end which is adapted to be pushed from the rear and forwardly onto the outer surface of a hard plastic cylindrical body (1) which has an inner bore to communicate ink from said reservoir cartridge to a writing capillary tube carried at the front end of said cylindrical body (1), the improvement in said reservoir cartridge which comprises a soft plastic front wall region on said reservoir cartridge (6) comprises portions adapted so as to be able to cooperate with a smooth outer surface of a hard plastic cylindrical body (1) and a smooth inner surface of a cylindrical sleeve (9), and thereby define an equalizing chamber means comprised of axially extending interconnected helical passages for a tubular writing pen that will be replaced upon replacement of said reservoir cartridge, said reservoir cartridge equalizing chamber means further a soft plastic front wall region being structurally adapted to define an outer equalizing chamber (12) and an inner equalization chamber (14) wherein an outer equalizing chamber (12) cartridge portion further comprises an outwardly open channel defined within an outer surface of said cartridge front wall region that is adapted to be covered by a smooth inner surface portion of a surrounding cylindrical sleeve (9), said outer equalization chamber cartridge portion further having a rear end that terminates proximate to a connecting bore (13) that extends transversely through said front wall region in order to interconnect with an inner equalization chamber cartridge portion, and a front end adapted to communicate surrounding air into the front end of said outer equalization chamber cartridge portion, wherein further said inner equalizing chamber cartridge portion (14) further comprises an inwardly open channel defined within an inner surface of said cartridge front wall region that is adapted to be covered by a smooth outer surface of a cylindrical body (1) said inner equalization chamber cartridge portion having a rear end which communicates with said connecting bore (13) and a front end that structurally is adapted so as to be able to communicate with a transverse bore (7) in any adjacent cylindrical body (1), wherein said cartridge further comprises a cartridge mounting means that structurally is adapted to permit a first sealing engagement between the inner equalization chamber front end portion of said cartridge and a hard plastic shoulder (18) proximate the front end of any cylindrical body (1) when any cylindrical sleeve (9) is mounted from the front and rearwardly into a surrounding relationship to the soft plastic cartridge front wall region and further comprises a soft plastic reservoir cartridge intermediate wall region, posterior to the outer equalizing chamber cartridge portion (12), which comprises an outer surface defined with an external thread (16), that structurally is adapted so as to be able to engage with an internal thread proximate a rear end of said any cylindrical sleeve (9) whereby, when said reservoir cartridge is employed according to its intended use, an inner bore of a technical pen will be communicated with surrounding air through an equalizing chamber means which will be exposed each time a cylindrical sleeve is removed forwardly from the reservoir cartridge and then the reservoir cartridge is removed rearwardly, from said any cylindrical body.
Dependencies are inferred from the claim text.