US3124107A - Reservoir seal - Google Patents

Reservoir seal Download PDF

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Publication number
US3124107A
US3124107A US3124107DA US3124107A US 3124107 A US3124107 A US 3124107A US 3124107D A US3124107D A US 3124107DA US 3124107 A US3124107 A US 3124107A
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United States
Prior art keywords
reservoir
conduit
liquid
follower
piston means
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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English (en)
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K7/00—Ball-point pens
    • B43K7/02—Ink reservoirs; Ink cartridges
    • B43K7/08—Preventing leakage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K7/00—Ball-point pens
    • B43K7/02—Ink reservoirs; Ink cartridges

Definitions

  • This invention relates to seals for liquid reservoirs in dispensing instruments lor the like and, more particularly, to a new and improved reservoir seal which is effective in all orientations of the reservoir.
  • the spring exerts on the piston, in all orientations of the reservoir, a force tending to urge the piston ⁇ out of the reservoir liquid.
  • the pressure in the reservoir is decreased by an amount corresponding to the capillary pressure set up by this force, thus tending to cancel the positive head of liquid in the reservoir.
  • This eifect is most pronounced when the reservoir is nearly empty, in Iwhich condition the spring is almost fully compressed and there then arises a limitation as to the extent to which the reservoir can be emptied under gravity.
  • a liquid reservoir for a writing instrument such as a ball-point pen
  • Another object of the present invention is to provide a liquid reservoir seal which is uniformly effective in all orientations of the reservoir.
  • a reservoir having a bore and a follower piston slidable in the bore along with an arrangement for urging the piston out of a liquid in the bore in all orientations of the reservoir, means for modifying the force applied by the urging arrangement when the reser- stall is in a vertical orientation.
  • the urging means is a compression spring within the reservoir
  • the means for modifying the force comprises a weight interposed between the spring and the piston.
  • FIGURE l is a view in longitudinal section through a ball point writing instrument having a reservoir seal ar- ICC ranged according to the invention and positioned with the writing point downward;
  • FIGURE 2 is a view in longitudinal section through the instrument of FIGURE l positioned With the writing point upward;
  • FIGURE 3 is .a fragmentary vieaw in section through the relevant part of the reservoir of FIGURES 1 and 2 showing the relative attitudes of the Weight and follower when the reservoir is horizontal.
  • While the invention is applicable to reservoirs 0f writing instruments such as fountain pens, stylographic pens, and ballpens and ball-point pens, it is also applicable to dispensing instruments or applicators (primarily those having a ball-tip or ball-valve discharge end) such as may be used for dispensing or applying deodorants, scent and other cosmetics. IIt is especially applicable to the reservoirs of ball-point writing instruments, for the diiliculties which the invention seeks to redu-ce have chielly arisen in connection with ball-point Writing instruments.
  • the reservoir of a ballpoint writing instrument is numbered 10, the column of ink or other reservoir liquid A1-1, and the piston follower 12.
  • the follower 12 is an easy sliding t in the bore and forms a capillary annular clearance with the wall of the bore. This clearance is occupied by the liquid 11 which present-s a meniscus at the rear end of the annular clearance and thus forms a seal. If desired, a different sealing liquid may be used. It is important that the follower 12 is slightly buoyant, i.e., its overall specific gravity or bulk density is slightly less than that of the Ireservoir liquid ⁇ 11 in order that it does not sink.
  • the interior of the reservoir constitutes the bore aforesaid; it is desirably of circular cross section and smooth.
  • one end or face of the follower 12 is immersed in the reservoir liquid 11 whilst the other end or face (usually subject to atmospheric pressure) emerges from the liquid with the result that at the latter end a small meniscus is formed at the surface of the thin annulus of liquid filling the clearance between the follower periphery and the reservoir wall.
  • the follower 12 will move into the liquid 11 and extrude the latter through the above-mentioned annular clearance.
  • This condition normally exists when the Writing instrument lies on its side. Movement of the follower into the liquid will continue until the concave meniscus changes its shape in such a way that the resulting capillary forces no longer reduce the hydrostatic pressure in the reservoir, i.e., when in effect the pressure difference between the two ends of the follower has vanished.
  • the capillary pressure can only decrease if the radius 0f the meniscus increases, i.e., if a strong, stable meniscus changes into a weak and usually unstable meniscus, whether slightly convex or slightly concave. When this happens there is danger of liquid seepage towards the rear end of the reservoir, especially if there already exists a film of liquid on the reservoir wall behind the follower (as may happen due to the liquid level being lowered by the dispensing of liquid).
  • a compression spring 20 is inserted in the bore of the reservoir to urge the piston 12 out of the liquid 11 with a force insufficient to expel the follower from the liquid, as described in the above-mentioned copending application.
  • the follower 12 is buoyant, however, the total force urging it out of the liquid 11 would be greater in the upright position shown in FIGURE 1 than in the inverted position shown in FIGURE 2 in the absence of any means for modifying the force and this obviously imposes a limitation on the range of forces which can be applied to the follower by the spring 20 without expelling it from the liquid.
  • a ball 21 made of heavy material, e.g. metal there is inserted between the compression spring 20 and the follower 12 a ball 21 made of heavy material, e.g. metal.
  • the weight of this ball 21 is preferably such as fully to compress the spring as shown in FIGURE l when the reservoir is vertical with the writing point downward.
  • the ball 21 has no effect on the follower 12 since its weight is carried by the lower portion of the reservoir wall.
  • the maximum outward thrust of spring and ball 21 on the follower 12 shall not be sufficient to eject the follower from the reservoir liquid, i.e., the maximum outward thrust on the follower must not exceed the value corresponding to the maximum permissible pressure differential across the liquid meniscus as set out in the copending patent application.
  • the maximum outward thrust occurs when the reservoir is almost empty and in the inverted attitude, that is to say when the weight of the ball 21 is added to the thrust of the spring 20 in its almost fully compressed condition. It will be understood that the forces acting on the follower must be insufficient to overcome the capillary forces in the narrow gap between the ball and its housing.
  • the (Po-Pi)max and (Po-Pi)min conditions are the conditions in which the pressure differential across the liquid meniscus surrounding the follower is at the maximum and the minimum permissible values, respectively.
  • a liquid reservoir including a seal comprising a conduit having a forward end and a rear end and having a bore of greater-than-capillary cross-sectional area which is subject to atmospheric pressure, piston means slidable within the conduit and having a peripheral shape similar to but slightly smaller than that of the inside surface of the conduit so as to provide a space of capillary dimensions between the adjacent surfaces of the piston means and the conduit, urging means effective when the reservoir conduit is in a first position between horizontal orientation and an orientation wherein one of said rear end and said forward end is lower than the other thereof for applying a component of force to the piston means directed in the longitudinal direction of the conduit in a manner tending to thrust the piston means out of a liquid in the conduit which is suicient to balance any capillary forces tending to draw the piston means into a liquid in the conduit, thereby preventing seepage of liquid through the space between the piston means and the conduit, and means for modifying the component of force applied by the urging means to the piston means when the reservoir conduit is in a second position wherein
  • a liquid reservoir according to claim 1 wherein the means for modifying the component of force applied by the urging means is responsive to gravity.
  • a liquid reservoir according to claim 4 wherein the 1 U TEP s TES AT N Si means for modifying the urging means component of 2,672,127 Albertmg u Mar- 15 1954 force comprises a member movable within the reservoir 5 conduit having a bulk Weight greater than that of a liquid FOREIGN PATENTS to be contained in the reservoir interposed between the 1,138,908 France Feb. 4, 1957 compression spring and the piston means.

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  • Coating Apparatus (AREA)
  • Pens And Brushes (AREA)
US3124107D 1960-07-30 Reservoir seal Expired - Lifetime US3124107A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB26623/60A GB955260A (en) 1960-07-30 1960-07-30 Improvements in and relating to reservoirs of writing and other dispensing instruments

Publications (1)

Publication Number Publication Date
US3124107A true US3124107A (en) 1964-03-10

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ID=10246544

Family Applications (1)

Application Number Title Priority Date Filing Date
US3124107D Expired - Lifetime US3124107A (en) 1960-07-30 Reservoir seal

Country Status (4)

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US (1) US3124107A (en:Method)
CH (1) CH379329A (en:Method)
GB (1) GB955260A (en:Method)
NL (3) NL267542A (en:Method)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3282254A (en) * 1965-06-30 1966-11-01 Paper Mate Mfg Co Multi-purpose connector
US4498797A (en) * 1979-05-17 1985-02-12 The Gillette Company Pressurized cartridge for a writing instrument
USD406166S (en) * 1998-07-09 1999-02-23 Timothy Grannis Wallet pen
US6361234B1 (en) 2000-03-08 2002-03-26 Bic Corporation Pressurized writing instrument employing a compressible piston member

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2672127A (en) * 1948-07-15 1954-03-16 Compania Uruguaya De Fomento Industrial Sa Writing instrument
FR1138908A (fr) * 1954-11-10 1957-06-21 Caran D Ache Crayons Stylographe à réservoir

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2672127A (en) * 1948-07-15 1954-03-16 Compania Uruguaya De Fomento Industrial Sa Writing instrument
FR1138908A (fr) * 1954-11-10 1957-06-21 Caran D Ache Crayons Stylographe à réservoir

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3282254A (en) * 1965-06-30 1966-11-01 Paper Mate Mfg Co Multi-purpose connector
US4498797A (en) * 1979-05-17 1985-02-12 The Gillette Company Pressurized cartridge for a writing instrument
USD406166S (en) * 1998-07-09 1999-02-23 Timothy Grannis Wallet pen
US6361234B1 (en) 2000-03-08 2002-03-26 Bic Corporation Pressurized writing instrument employing a compressible piston member

Also Published As

Publication number Publication date
CH379329A (fr) 1964-06-30
NL267542A (en:Method)
GB955260A (en) 1964-04-15
NL266641A (en:Method)
NL113228C (en:Method)

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