US 4,759,650 AGranted

Retractable marking pen with tip protection mechanism

AssigneeDennison Manufacturing Company

InventorRichard Granoff

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Abstract

A retractable marking pen having a tip guard to protect the writing tip (nib) from contact with external material when the ink cartridge to which the tip is connected is retracted into the pen casing. The tip guard is composed of a pair of guard flaps which open allowing the writing tip to pass therethrough when the pen is placed in writing mode and close over the tip when the pen is in retracted mode. The guard flaps are a pair of continuous panels which extend from the inside wall of the pen casing and are integrally molded with the casing. Each guard flap has a rear section which is essentially parallel to the pen casing wall surface and a forward section which slopes towards the axis of symmetry of the pen casing at the writing end of the pen. A major bend line in the surface of each flap separates the forward section from the rear section of the flap and forms an abutment wall. As the cartridge is pushed forward the pressure exerted by the cartridge against the abutment wall causes the guard flaps to open. Upon retraction of the ink cartridge the guard flaps automatically reclose to protect the tip.

A marking instrument of the type having a casing and an ink cartridge insertable in the casing and a marking tip in communication with the cartridge at the writing end of the marking instrument, the marking tip being retractable into the instrument casing when the instrument is in nonuse;

the improvement comprising:
a guard for said marking tip comprising a pair of flaps each joined at one end to the inside surface of the casing and being integrally molded with the casing, each of said flaps being a single continuous panel extending from the inside wall of the casing, neither of said panels having an elastomeric band in contact with any portion of said panels, each of said continuous panels being divided by a major bend in its surface to form a forward section (33) and a rear section (36), the rear section of each of said panels lying approximately parallel to the casing inside wall surface, said forward section (33) of each panel being divided further into a far forward section (32) and a mid forward section (34) by a minor bend in the surface of the forward section so that in the normal closed position of the flaps the plane of each of the far forward section and mid forward section slopes towards the writing end of the casing and the far forward section has a greater slope towards the axis of symmetry of the casing at the writing end than does the mid forward section and in said normal closed position the mid forward section has a greater slope towards the axis of symmetry of the casing at the writing end than does the rear section;
the far forward section, the mid forward section and rear section each being substantially flat, wherein said forward section of each of said panels opens as the cartridge containing the marker tip is manually pushed forward allowing the marker tip to pass therethrough without contacting any portion of said panels, and said forward section of each panel automatically returns to its normal closed position as the marker tip is retracted, the panels forming a shield around the marker tip preventing external material from contacting the marker tip when the marker tip is retracted.

Abstract

Claims9