Patent Application
20130287889
An aspect generally relates to (but is not limited to) a nozzle-tip apparatus including (and not limited to) a nozzle-tip body having a pressure-relief feature.
U.S. Pat. No. 5,695,793 appears to disclose an injection molding valve member with head and neck portions, in which the injection molding valve member has a smaller neck portion leading to a short head portion. This facilitates the backflow of melt around the head portion as the valve member is driven forwardly to the closed position. In one embodiment, the neck portion is formed by a number of flutes spaced around the valve member having lands between them.
The inventor has researched a problem associated with known molding systems that inadvertently manufacture bad-quality molded articles or parts. After much study, the inventor believes he has arrived at an understanding of the problem and its solution, which are stated below, and the inventor believes this understanding is not known to the public.
A valve pin, valve stem or valve member of a known valve gated injection molding apparatus has a cylindrical or tapered front end and reciprocates between a retracted open position and a forward closed position in which the front end is seated in a gate. As a valve pin is driven forward to the closed position, some of the melt displaced by the valve pin may flow backwards around the valve pin to enable the valve pin to close. While valve pins having a cylindrical or tapered front end may be satisfactory for many applications, they may have the disadvantage that backflow is very restricted between the front end of the valve pin and the surrounding gate. This arrangement may result in a build up of back pressure in the melt as the valve pin is driven forwardly. It may be very difficult to find the right timing of closing the valve pin, particularly when molding crystalline materials, which may solidify much faster than amorphous materials. If the timing (movement) is not correct, the valve pin can may act like an injector and push melt or resin material into a semi-solidified part (being molded in a mold cavity), which may result in a product (molded part) which is stressed and therefore may be unacceptable and therefore rejected, thus leading to wastage and increased costs.
By improving the melt backflow as the valve pin advances to the closed position makes the exact timing of closing less critical and somewhat overcomes this problem. Also, in some cases the build up of back pressure in the melt prevents the valve pin from advancing and becoming completely seated in the gate and thus does not provide the molded product with a cosmetically clean gate mark. While additional force may be applied to the valve pin to try to overcome the back pressure problem, this may result in increasing wear and malfunction of the actuating mechanism of the valve pin.
According to an aspect, there is provided (to resolve the problem, at least in part) a nozzle-tip apparatus (100), comprising: a nozzle-tip body (102) configured to connect with a molding-nozzle assembly (200). The nozzle-tip body (102) has a front end (104) defining an exit orifice (106). The exit orifice (106) is configured to slidably receive a valve stem (202) of the molding-nozzle assembly (200). The nozzle-tip body (102) has a pressure-relief feature (108).
Other aspects and features of the non-limiting embodiments will now become apparent to those skilled in the art upon review of the following detailed description of the non-limiting embodiments with the accompanying drawings.
The non-limiting embodiments will be more fully appreciated by reference to the following detailed description of the non-limiting embodiments when taken in conjunction with the accompanying drawings, in which:
The drawings are not necessarily to scale and may be illustrated by phantom lines, diagrammatic representations and fragmentary views. In certain instances, details not necessary for an understanding of the embodiments (and/or details that render other details difficult to perceive) may have been omitted.
Referring now to
The molding-nozzle assembly (200) may include (and is not limited to): a nozzle housing (204), and a nozzle tip insulator (206) having a tip insulator relief (208), amongst other things. The molding-nozzle assembly (200) may be configured to deliver a melt to a gate insert (300) that defines a preform dome (302), which may be part of a mold cavity. More specifically, the pressure-relief feature (108) may be configured to permit, in use, a backflow of a resin and a back pressure reduction in front of the valve stem (202).
Referring now to
Note to GREG: is there anything else you wish to state about the tolerances of the larger diameter (150) and the smaller diameter (152)?
Referring now to
Referring now to
Note to GREG: is there anything else you wish to state in this application?
It will be appreciated that the assemblies and modules described above may be connected with each other as may be required to perform desired functions and tasks that are within the scope of persons of skill in the art to make such combinations and permutations without having to describe each and every one of them in explicit terms. There is no particular assembly, components, or software code that is superior to any of the equivalents available to the art. There is no particular mode of practicing the inventions and/or examples of the invention that is superior to others, so long as the functions may be performed. It is believed that all the crucial aspects of the invention have been provided in this document.
It is understood that the scope of the present invention is limited to the scope provided by the independent claim(s), and it is also understood that the scope of the present invention is not limited to: (i) the dependent claims, (ii) the detailed description of the non-limiting embodiments, (iii) the summary, (iv) the abstract, and/or (v) description provided outside of this document (that is, outside of the instant application as filed, as prosecuted, and/or as granted). It is understood, for the purposes of this document, the phrase “includes (and is not limited to)” is equivalent to the word “comprising”. It is noted that the foregoing has outlined the non-limiting embodiments (examples). The description is made for particular non-limiting embodiments (examples). It is understood that the non-limiting embodiments are merely illustrative as examples.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CA2012/050002 | 1/5/2012 | WO | 00 | 6/18/2013 |
| Number | Date | Country | |
|---|---|---|---|
| 61434458 | Jan 2011 | US |
