Ink pen cartridge and mounting arm for a recording instrument

An ink pen cartridge for attachment to a mounting arm comprising,

• a hollow body for holding ink,
• a nib adjacent one end of the body and extending from one side of the body,
• a cap insertable into the second end and into the interior of the cartridge body, said cap including a first end shaped and coacting with the interior of the body to normally seal against the inside of the body for holding ink in the body,
• said cap having a second end larger than the interior of the body for abutting the second end of the body when the cap is positioned in the body,
• said cap having a longitudinal recess on one side for receiving the mounting arm,
• the second end of the cap including an outwardly facing shoulder on each side of the recess for coacting with the mounting arm.

An ink pen cartridge for attachment to a mounting arm having an end with a notch and a stop shoulder on each edge, said cartridge comprising,

• a hollow body for holding ink,
• a nib adjacent one end of the body,
• an opening in the side of the body adjacent to but spaced from the second end of the body,
• a cap insertable into the second end and into the interior of the cartridge body, said cap including a first end shaped and coacting with the interior of the body to normally seal against the inside of the body for holding ink in the body,
• a post extending outwardly from one side of the cap between the ends of the cap for extending into the body opening for locking the cap in the cartridge body,
• said cap having a second end larger than the interior of the cartridge body for abutting the second end of the cartridge body when the cap is positioned in the body,
• said cap having a longitudinal recess on the side from which the post extends for receiving said one end of the mounting arm, said recess extending from the second end of the cap towards the first end of the cap,
• the second end of the cap including an outwardly facing shoulder on each side of the recess for coacting with shoulders on the mounting arm.

A mounting arm for supporting an ink pen cartridge which has a longitudinal recess in one end, a post positioned in the middle of the recess and a shoulder on either side of said recess at said one end, said arm comprising,

• an elongate arm having first and second ends,
• the first end shaped for attachment to a recorder,
• said second end being generally rectangular in cross section and sized for insertion in the recess in the cartridge, said second end including a notch for engagement with the post, and
• a stop shoulder on each edge spaced from the second end for coaction with the shoulder on the end of the cartridge.

An ink pen cartridge for attachment to a mounting arm having an end with a notch and a stop shoulder on each edge, said cartridge comprising,

• a hollow body for holding ink,
• a nib adjacent one end of the body and extending from one side of the body,
• an opening in opposite sides of the body adjacent to but spaced from the second end of the body, one of the sides being the one from which the nib extends,
• a cap insertable into the second end and into the interior of the cartridge body, said cap including a first end shaped and coacting with the interior of the body to normally seal against the inside of the body for holding ink in the body,
• said cap having a second end larger than the interior of the cartridge body for abutting the second end of the cartridge body when the cap is positioned in the body,
• said cap having a longitudinal recess on opposite sides for receiving one end of the mounting arm, said recess extending from the second end of the cap toward the first end of the cap and decreasing in thickness from the second end,
• a post extending outwardly from each recess of the cap for extending into one of the body openings for locking the cap in the cartridge body said post blocking only part of the openings, said posts positioned to engage the notch on a mounting arm when an arm is inserted into one of the recesses,
• the second end of the cap including an outwardly facing shoulder on each side of both recesses for coacting with the shoulders on the mounting arm.