Coating implements with material supply – With means to attach or conform to body of user
Reexamination Certificate
2002-07-10
2004-10-12
Walczak, David J. (Department: 3751)
Coating implements with material supply
With means to attach or conform to body of user
C264S241000, C264S267000, C264S271100
Reexamination Certificate
active
06802664
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates among others to the production of a front portion of a housing or for a housing of a writing instrument having a refilling device (refill), said front portion comprising a sleeve body made of a shape-retaining material (preform) and a jacket covering a surface of said sleeve body along a substantial part of a length thereof, said jacket being made of a material having elastic gripping properties. When said writing instrument is used, said jacket serves as a gripping zone which is adapted to give a good hold to a user's fingers. For this purpose, the outer surface of said jacket can also have a conical extension. Said jacket can be adapted to have an elastic ductility appropriate to the purpose.
In writing instruments comprising a front part that, for a better handling, is mostly adapted to have a conical extension, sprue portions of elastic materials cause problems, since the material tears off uncontrolledly when being separated or detached from a mold. Therefore, efforts are made to hide said sprue portions. When hiding said sprue portions and when covering a front part of a writing instrument at an outside thereof from an inside and through walls thereof with a material that has elastic gripping properties, a conducting channel for a thermoplastic melt cannot be adapted to extend through a refill opening (refilling device opening or guiding and penetration opening), since said opening is adapted to usual refilling devices, thus having a diameter which is too small for sufficiently economically providing a guiding channel with cores. Therefore, it is necessary to adapt a front portion of a front part of a writing instrument to have a larger diameter for initially applying a circumferential jacket made of a material that has elastic gripping properties around said front portion, and for subsequently, in a further working step, applying a tip portion by ultrasonic welding or friction welding. Only then, said subsequently provided tip portion can be adapted to have a diameter at a front end thereof which is small enough to laterally support the refilling device.
Therefore, a one-piece sleeve body cannot be used, on the contrary, due to production processes, a two-piece sleeve body is inevitably required, said sleeve body comprising a first portion and a tip portion applied subsequently. An object of the invention is to reduce the cost for producing such front parts of writing instruments, and further to keep sprue portions of soft parts hidden, even if a one-piece sleeve body is used as a blank for receiving a portion which is applied circumferentially (said portion having elastic gripping properties).
SUMMARY OF THE INVENTION
In order to simplify production and to reduce production cost, the invention provides a penetration and guiding portion at the tip of a sleeve body (refill opening), said portion being adapted as a portion of an injection channel for a material of an outer jacket, said material having elastic gripping properties, at least partly circumferentially in a radially outward direction, without a metallic support of a ram-shaped core which is (relatively) moved into said sleeve body in front of a rear end thereof. Said core either starts only behind said channel segment of said blank, at or from a diameter allowing a practical application of a material conduct in said core, or has a channel conduct that is open towards an outside.
Said sleeve body has at least one aperture in a jacket portion thereof through which a material forming a gripping zone is conducted from an inside towards an outside, from said injection channel segment to an outer circumferential portion of said sleeve body. One of said penetration and guiding opening at said tip of said sleeve body and an adjoining portion of said inside of said sleeve body can be adapted as a portion enlarging towards said inside of said sleeve body or as a portion having an undercut.
Due to said properties and to the ability of injecting a material supplied as a second material, particularly a thermoplastic elastomer, by using a two-component injection molding technology through a refill opening provided in said sleeve body to a circumferentially limited extent, said sleeve body itself can be provided in one piece—without a weld or a connecting seam—, thereby substantially simplifying and accelerating the production of a front part of a writing instrument, and thus reducing production cost.
For obtaining a better attachment by complementary shapes between said jacket and said sleeve body, said sleeve body can be provided with at least two apertures distributed over a circumference thereof, said apertures being filled in when forming (injection molding) said surface-covering jacket. For improving said connection, at least one of said apertures can be provided with a contour enlarging from and outside towards an inside thereof; since there is no material bond between the two materials of said two-component injection molding technology (the materials do not stuck together), a better support of said circumferential jacket at said—inside located—shape-retaining sleeve body is obtained by said mechanical arrangement, said support also having a surface effect.
A production in two-component injection molding technology comprises a first component for producing a shape-retaining sleeve body of a relatively brittle plastic material, such as ABS; a second component serves for producing a jacket and uses a thermoplastic elastomer (TPE). Initially, a shape-retaining sleeve-body is produced, said sleeve body comprising a penetration and guiding opening (for a refilling device inserted later) and at least one, preferably two apertures in a circumferential wall thereof. An elastomer forming an outer jacket is applied along a considerable length—a multiple of the diameter of said refill opening—of said circumferential wall, far into a tip portion, said elastomer being injected through a penetration and guiding opening of said sleeve body into an inner space thereof, particularly being contactingly supported and conducted, for being guided from said inner space through said aperture(s) towards an outside onto a circumferential wall of said sleeve body, and for being shaped on said circumferential wall to obtain a continuous circumferential jacket.
It is not disturbing that, after penetrating into the penetration and guiding opening inside said sleeve-body, the stream of said second material, when being injected, is initially enlarged in cross-section, said second material being only subsequently conducted to an outside through an aperture of said preform. During production, said penetration and guiding opening (refill opening), which has one of a cross-section enlarging towards an inside of said sleeve body and an undercut, is blocked by an inserted core as of an axial position, said position being located behind, particularly markedly behind a front end of said refill opening. Thus, said refill opening (tip opening) forms part of an “injection channel” conducting a melt of said second material, and can therefore be small in diameter—corresponding to a refilling device inserted later—without opposing a too high flow resistance to said injection process in a post pressure phase. Inserting a core extending to a front end for guiding said melt is dispensable.
A particular embodiment of a top portion of said core can result in said core still extending further into said tip portion, up to said refill opening, nevertheless maintaining the inventive idea. However, in said portion, no inside guiding channel of said core is required, said core having a metallic outside cover, on the contrary, at least one portion of a circumference (in case of laterally open channels) or the entire circumference (in case of a core having a conical top portion) of said inside surface of said sleeve body is used for closing the guiding channels left open by said top portion of the core. Said guiding channel can have an annular shape. A plurality of combinations are possible, starting from a shorter core
Gantlert Erich
Vial Siegbert
Duane Morris LLP
Merz & Krell GmbH & Co. KGaA
Walczak David J.
LandOfFree
Production of a front portion of a writing instrument,... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Production of a front portion of a writing instrument,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Production of a front portion of a writing instrument,... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3315604