Permanent-magnetically held closure cap for writing instruments

• US 4,168,129 A
• Filed: 02/22/1977
• Issued: 09/18/1979
• Est. Priority Date: 02/19/1976
• Status: Expired due to Term

• Current Assignee: Gunther Herrnring
• Original Assignee: Montblanc-Simplo GMBH (Compagnie Financiere Richemont SA)
• Inventors: Herrnring, Gunther
• Primary Examiner(s): Crowder, Clifford D.
• Application Number:
  US05/770,829
• Time in Patent Office: 938 Days
• Field of Search: 401/243, 401/244, 401/202, 401/100, 401/245, 401/246, 401/247, 401/62, 401/124, 401/213, 401/262, 206/818, 220/230, 24/73 MS, 24/201 B, 211/69.1, 292/251.5, 335/296, 335/297, 335/302, 335/303, 335/306
• US Class Current: 401/243
• CPC Class Codes: B43K 23/126 with clips
• CPC Class Codes: Y10T 292/11 Magnetic

Abstract

A closure cap which is held on writing instruments by a permanent magnet connected to the cap. The permanent magnet is arranged near the closed end of the cap, has a nearly cylindrical cross section, and has pole shoes on its pole faces, the free ends of the pole faces engaging ferro-magnetic annular parts of the writing instrument when the cap is placed on the latter.

Claims

1. For use in connection with a writing instrument having ferro-magnetic means on at least a portion of the writing end of said writing instrument, a closure cap having a normally closed end and an open end and an inner contour capable of being placed over said writing end of said writing instrument, said cap comprising in combination:

a permanent magnet having pole faces and being located within said cap, and

pole shoes located on at least a part of said pole faces of said permanent magnet, at least a portion of said pole shoes being engageable with said ferro-magnet means, said permanent magnet and said pole shoes together forming a permanent magnet system connected to said cap urged and held in completely seated closure positioning by mainly axially directed magnetic forces, said permanent magnet being magnetized in the longitudinal direction of said cap and having an axial bore corresponding in shape to the shape of said writing end of said writing instrument, said pole shoes comprising a first annular disc located on that pole face of said magnet directed towards said closed end of said cap and a second annular disc located on that pole face of said magnet directed towards said open end of said cap, said pole shoes extending radially with regard to said axial bore, said first annular disc having a contact surface for axially engaging said ferro-magnetic means, and said second annular disc having a contact surface for radially engaging said ferro-magnetic means.

2. A closure cap in combination according to claim 1, in which the permanent magnet system has an outer contour that conforms to the inner contour of said cap.

3. A closure cap in combination according to claim 1, in which the inner wall surface of said permanent magnet forming said axial bore defines a truncated cone.

4. A closure cap in combination according to claim 1, in which said pole shoes comprising two sections are spaced from each other and form a mirror image of each other while being mounted on said permanent magnet so as to be symmetrical to each other with regard to said cap, said pole shoe sections projecting from said permanent magnet towards said open end of said cap.

5. A closure cap in combination according to claim 4, in which said permanent magnet, on that end face thereof directed towards said open end of said cap, has a recess extending in the longitudinal direction of said cap.

6. A closure cap in combination according to claim 4, in which said pole shoe sections have a contact surface for axially engaging said ferro-magnetic means.

7. A closure cap in combination according to claim 1, in which said permanent magnet comprises barium ferrite crystals embedded in synthetic material.

8. A closure cap in combination according to claim 1, in which said pole shoes comprise a vanadium, cobalt, iron alloy.

9. A closure cap in combination according to claim 8, in which said alloy comprises about 2% vanadium, 49% cobalt, and 49% iron.

10. In combination:

a writing instrument having a writing end and also having ferro-magnetic means on at least a portion of said writing end, and a closure cap with an open end and an oppositely located closed end, said cap extending and fitting over said writing end and including;

a permanent magnetic having pole faces and being within said cap, pole shoes located on at least a part of said pole faces of said permanent magnet, at least a portion of said pole shoes engaging said ferro-magnetic means, said permanent magnet and said pole shoes together forming a permanent magnet system connected to said cap and with said ferro-magnetic means forming a closed magnetic circuit, said cap being urged and held in completely sealed closure positioning by mainly axially directed magnetic forces, said permanent magnet being magnetized in the longitudinal direction of said cap and having an axial bore corresponding in shape to the shape of said writing end of said writing instrument, said pole shoes comprising a first annular disc located on that pole face of said magnet directed towards said closed end of said cap and a second annular disc located on that pole face of said magnet directed towards said open end of said cap, said pole shoes extending radially with regard to said axial bore, said first annular disc having a contact surface for axially engaging said ferro-magnetic means, and said second annular disc having a contact surface for radially engaging said ferro-magnetic means.