Coating implements with material supply – Including ball – roller or endless-belt tool – Ball
Reexamination Certificate
1999-05-07
2001-10-30
Walczak, David J. (Department: 3751)
Coating implements with material supply
Including ball, roller or endless-belt tool
Ball
C401S243000
Reexamination Certificate
active
06309127
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to caps for writing instruments, e.g., caps for ball point pens.
Writing instruments that contain liquid ink often include caps to prevent the ink from drying out. Such caps are sometimes provided with vent holes at the closed end. These vent holes reduce the pressure exerted on the ink within the writing instrument when the cap is applied, reducing the likelihood that ink will leak from the pen due to the pressure differential caused by applying and removing the cap in a normal manner. Also, if the cap is swallowed by a small child the vent holes may allow the child to breathe with the cap lodged in the child's throat. These vent holes may allow air to flow past the pen tip and cause the ink at the tip to dry out.
One problem that is sometimes encountered with pen caps is “cap pump”. This is a phenomenon that occurs when a user of the pen repeatedly pumps the cap on and off of the pen tip. This pumping forces air into the pen through an air vent that is normally provided on the side of the pen tip. The air then travels into the ink reservoir of the pen, displacing ink which then travels up to the tip and out through the air vent. Thus, ink may undesirably “burp” out of the tip and into the cap.
SUMMARY OF THE INVENTION
The invention provides caps for writing instruments that provide a close seal against the pen tip to prevent the ink at the tip from drying out. Preferred caps also minimize pressure build-up when the cap is pumped on and off of a pen, preventing cap pump under most circumstances. Preferred caps include a sealing member having a portion that is fixed axially relative to the cap body. Because the sealing member as a whole does not move axially between two positions, the caps are relatively simple and economical to manufacture, and are resistant to failure. In preferred caps, the cap is vented and the sealing member is constructed so that an air passageway is provided along the long axis of the cap at all times, to allow a child to breathe if the cap is swallowed.
The invention features caps for covering the writing end of a writing instrument containing a non-solid writing material.
In one aspect, the caps include a cap body having an open end for receiving the writing end, a closed end for covering the writing end, and a long axis extending from the open end to the closed end. The cap further includes a sealing member, disposed within the cap body, a portion of which is fixed axially relative to the long axis of the cap body.
Preferred caps include one or more of the following features. The cap body defines an air flow passage extending from the open end to the closed end. The sealing member includes a cushioning portion constructed to resiliently deflect in response to pressure exerted by the tip of the writing instrument when the cap is applied. The cushioning portion includes a thermoplastic elastomer. The sealing member further includes a sealing cap for receiving the tip of the writing instrument in sealing engagement. The sealing cap has a volume of less than 50 mm
3
. The sealing cap includes a frustroconical or hemispherical portion at its closed end, to closely surround the tip of the writing instrument. The diameter of the open end of the sealing cap is substantially equal to the diameter of a rim portion of the writing instrument. The sealing member includes one or more air vents to allow passage of air through the sealing member along the air flow passage. The sealing member is fixed by an interference fit with a portion of the inner wall of the cap body. The closed end of the cap body includes one or more air vents which remain open when the cap is in place on a writing instrument.
In another aspect, the caps include a cap body having an open end for receiving the writing end, a closed end for covering the writing end, and a long axis extending from the open end to the closed end, the cap body defining an air flow passage extending from the open end to the closed end. The cap further includes a sealing member disposed within the cap body, the sealing member being constructed to resiliently deflect towards the closed end during insertion of the writing end into the open end without closing or blocking the air flow passage.
In another aspect, the caps include a cap body having an open end for receiving the writing end, a closed end for covering the writing end, and a long axis extending from the open end to the closed end. The cap further includes a sealing member, disposed within the cap body, that is constructed to resiliently deflect axially towards the closed end, during insertion of the writing end into the open end, to limit compression of the air within the sealing member, and to return to its normal position when the cap is removed from the pen. Preferably, compression of the air is sufficiently limited so that cap pump is substantially prevented even after repeated pumping of the cap on and off.
Preferred implementations of these caps include one or more of the preferred features discussed above.
The invention also features methods of covering the writing end of a writing instrument using caps of the invention, and writing instruments that include caps of the invention.
Other features and advantages will become apparent from the following Description of the Preferred Embodiments, the drawings and the claims.
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Berol Corporation
Marshall Gerstein & Borun
Walczak David J.
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