Ball type marker construction which eliminates stick-slip phenomena

Claim 2

In a ball-type marking instrument, wherein a writing ball is rotatably held in a socket of a metallic writing tip element carried by a forward end portion of a thermoplastic composition barrel member, including a rearwardly disposed chamber including a porous reservoir containing ink having an aqueous solution base, the provision of: means for modifying the stick-slip friction relationships between the ball and its seat while writing and of the provision of means to prevent interruption of writing ability by reason of discontinuity of ink feeding when the instrument is subject to shock, said means including a feeder rod composed of a bundle of virtually parallel polymeric filaments lightly bonded together, the rear end portion of said rod extending into the ink of said reservoir and a front end face adjacent the rear of the writing ball, the filaments of said feeder rod being adapted to expand in the presence of ink from the reservoir and to flex and exert a yielding and opposing pressure on the rear of said ball during writing with the frontal surface of said ball, and means connecting and holding at least the rear portion of said rod in normally fixed and axially immovable relation with respect to the barrel member and ball.

Claim 3

A ball point writing instrument as stated in claim 1, wherein the means includes an axial ink-conducting channel in communication with the socket for the ball, said channel having a length of between 0.5 and 0.7 of the ball diameter and a diameter not smaller than 0.3 of the ball diameter, the forward end of the feeder rod having a diameter adapted to be slidably received within such channel.

Claim 6

In a ball-type marking instrument, wherein a writing ball is rotatably held in a socket of a metallic writing tip element carried by a forward end portion of a thermoplastic composition barrel member, including a rearwardly disposed chamber including a porous reservoir containing ink having an aqueous solution base, the provision of: means for modifying the stick-slip friction relationships between the ball and its seat while writing and of the provision of means to prevent interruption of writing ability by reason of discontinuity of ink feeding when the instrument is subject to shock, said means including a feeder rod composed of a bundle of virtually parallel polymeric filaments lightly bonded together, the rear end portion of said rod extending into the ink of said reservoir and a front end face adjacent the rear of the writing ball, a movable disk of thin fluorocarbon film trapped between the front face of the feeder rod and back of said ball, the filaments of said feeder rod being adapted to expand in the presence of ink from the reservoir and to flex and exert a yielding and opposing pressure on the rear of said ball through said disk during writing with the frontal surface of said ball, and means connecting and holding at least the rear portion of said rod in normally fixed and axially immovable relation with respect to the barrel member and ball.

Claim 7

In a ball-type marking instrument, wherein a writing ball is rotatably held in a socket of a metallic writing tip element carried by a forward end portion of a thermoplastic composition barrel member, including a rearwardly disposed chamber including a porous reservoir containing ink having an aqueous solution base, the provision of: means for modifying the stick-slip friction relationships between the ball and its seat while writing and of the provision of means to prevent interruption of writing ability by reason of discontinuity of ink feeding when the instrument is subject to shock, said means including a feeder rod composed of a bundle of virtually parallel polymeric filaments lightly bonded together, the rear end portion of said rod extending into the ink of said reservoir and a front end face adjacent the rear of the writing ball, a movable disk of thin fluorocarbon film trapped between the front face of the feeder rod and back of said ball, the filaments of said feeder rod being adapted to expand in the presence of ink from the reservoir and to flex and exert a yielding and opposing pressure on the rear of said ball through said disk during writing with the frontal surface of said ball, and means connecting and holding at least the rear portion of said rod in normally fixed and axially immovable relation with respect to the barrel member and ball.

Claim 8

In a ball point writing instrument including a plastic composition body portion having a rearward ink reservoir and a forwardly extending tapering hollow portion carrying a metallic writing tip, said writing tip being provided with a socket having a writing ball rotatably held therein upon a spherical zone ball seat, the provision of an axial inkconducting channel in communication with said socket, said channel having a diameter not less than 0.3 of the ball diameter and a length not exceeding said channel diameter, said channel extending rearwardly to an enlarged counterbore, and means for modifying frictional relationships of the writing ball with respect to its seat with the ball subjected to writing pressure, said means including a porous inkconducting feeder rod composed of filamentary material lightly bonded together, said rod having a rear portion extending into contact with ink having an aqueous solution base in said rearward ink reservoir and a front portion of reduced diameter extending into said axial channel and terminating in a substantially flat transverse end face, said reduced diameter axial portion slidably fitting said axial channel, said feeder rod including a stop surface adapted to cooperate with a shoulder of said metallic tip to position the end face of the rod in desired proximity to the ball in said socket, a movable disk of fluorocarbon film trapped in said channel between the ball and the front face of said feeder rod, the filamentary material of said feeder rod being adapted to expand in the presence of ink from said reservoir and exerting yielding, compliant pressure against the writing ball during writing, and means connecting and holding at least the rear portion of said rod immovable axially with respect to said body portion.

Claim 9

In a ball point writing instrument including a plastic composition body portion having a rearward ink reservoir and a forwardly extending tapering hollow portion carrying a metallic writing tip, said writing tip being provided with a socket having a writing ball rotatably held therein upon a spherical zone ball seat, the provision of an axial inkconducting channel in communication with said socket, said channel having a diameter not less than 0.3 of the ball diameter and a length not exceeding said channel diameter, said channel extending rearwardly to an enlarged counterbore, and means for modifying frictional relationships of the writing ball with respect to its seat with the ball subjected to writing pressure, said means including a porous inkconducting feeder rod composed of filamentary material lightly bonded together, said rod having a rear portion extending into contact with ink having an aqueous solution base in said rearward ink reservoir and a front portion of reduced diameter extending into said axial channel and terminating in a substantially flat transverse end face, said reduced diameter axial portion slidably fitting said axial channel, said feeder rod including a stop surface adapted to cooperate with a shoulder of said metallic tip to position the end face of the rod in desired proximity to the ball in said socket, a movable disk of fluorocarbon film trapped in said channel between the ball and the front face of said feeder rod, the filamentary material of said feeder rod being adapted to expand in the presence of ink from said reservoir and exerting yielding, compliant pressure against the writing ball during writing, and means connecting and holding at least the rear portion of said rod immovable axially with respect to said body portion.