Ball holder for ball point pen

• US 4,384,800 A
• Filed: 07/15/1980
• Issued: 05/24/1983
• Est. Priority Date: 07/14/1979
• Status: Expired due to Term

• Current Assignee: Pentel Kabushiki Kaisha
• Original Assignee: Pentel Kabushiki Kaisha
• Inventors: Dyama, Hirosi
• Primary Examiner(s): Coughenour, Clyde I.
• Application Number:
  US06/169,184
• Time in Patent Office: 1,043 Days
• Field of Search: 401/215, 401/216, 401/197, 401/200, 401/209
• US Class Current: 401/216
• CPC Class Codes: B43K 1/08 with ball points; Balls or ball beds B43M11/085 takes precedence

Abstract

A tip for a ball point pen utilizing a water soluble ink is provided, and comprises a ball holder which rotatably supports a ball in a tip end thereof, a ball abutment defined within the ball holder, and an ink passageway providing a communication between the ball abutment and an ink supply path. The ink passage is elongate in cross section. The ball abutment is defined by four flat bearing surfaces which are inclined toward the center of the passageway, two of the bearing surfaces being disposed on each side of the passageway and being directly joined with each other with an angle therebetween, the ball being supported by contact with a point on each of the four bearing surfaces, the joining portions between the bearing surfaces defining an ink reservoir which communicates with the passageway.

Claims

1. A ball holder for a ball point pen comprising:

an elongate hollow ball holder body formed of a synthetic resin material,

a ball trap socket for holding a ball in one end of the holder body in a rotatable manner and against removal, the socket being formed integrally with the holder body and having a cavity defined therein which holds the ball in a manner such that the ball partly projects through a tip end of the holder body,

and an elongate ink guide passageway providing communication between the other end of the holder body and the bottom of the cavity, the passageway having an elongate configuration in cross section perpendicular to the axis of the passageway, said elongate cross section having a longitudinal length at least slightly less than the diameter of the ball and a width in the direction perpendicular to the length thereof which increases from its opposite longitudinal ends toward the center of the length, the bottom of the cavity being formed with four flat bearing surfaces all of which are inclined in a direction away from said one end of the holder body toward the center of the passageway, two of the four bearing surfaces being disposed on each side of the passageway and being directly joined with each other and being inclined toward each other, the ball being supported by contact with a point on each of the four bearing surfaces, the joining portions between the bearing surfaces defining an ink reservoir which communicates with the guide passageway.

2. A ball holder for a ball point type pen comprising:

an elongate ball holder body having means therein defining a ball-retaining socket for rotatably retaining a ball in such manner that the ball partly portrudes from one end of the ball holder body;

ball-supporting means disposed at the base of the socket for rotatably supporting the ball within the ball-retaining socket at a plurality of discrete point contact sites, the ball-supporting means comprising a plurality of discrete, substantially flat bearing surfaces each one of which makes point contact with the ball at one point contact site; and

means defining an elongate ink passageway providing communication between the other end of the ball holder body and the ball-retaining socket, the ink passageway having an elongate cross section perpendicular to the longitudinal axis of the passageway, the elongate cross section having a length dimension approximately equal to the diameter of the ball and a width dimension which increases from a minimal value at the two opposite longitudinal ends of the elongate cross section to a maximal value at the center thereof, the plurality of bearing surfaces being arranged in two groups with one group on each side of the passageway, each of the bearing surfaces sloping in a direction away from the one end of the ball holder body toward the passageway and each two adjoining bearing surfaces on each side of the passageway sloping toward one another.

3. A ball holder according to claim 2;

wherein the width dimension varies uniformly and progressively from the two opposite longitudinal ends to the center of the elongate cross section.

4. A ball holder according to claim 2;

wherein the maximal value of the width of the elongate cross section is no greater than twice the minimal value.

5. A ball holder according to claim 2;

wherein the plurality of flat bearing surfaces are arranged in two sets, one set of flat bearing surfaces being disposed on one side of the elongate cross section along the length thereof and the other set being disposed on the other side of the elongate cross section along the length thereof.

6. A ball holder according to claim 5;

wherein the flat bearing surfaces of each set are all inclined toward the center of the elongate cross section.