Communications: radio wave antennas – Antennas – Rod type
Reexamination Certificate
2000-09-12
2001-11-13
Le, Hoanganh (Department: 2821)
Communications: radio wave antennas
Antennas
Rod type
C343S702000, C029S600000
Reexamination Certificate
active
06317102
ABSTRACT:
The present invention relates to a method and a tool for manufacturing an antenna unit, in particular an antenna unit for mobile phones and similar. The invention also relates to an antenna unit manufactured according to this method.
Antenna units for mobile phones normally have a central, preferably resilient, metallic core, for example in the form of a wire or tubular core, usually with a circular cross-section, and a jacket enclosing the resilient core, consisting of a suitable thermoplastic material, preferably of a kind being particularly fluid, the jacket mainly serving to improve the aesthetic impression of the antenna unit. The design of the upper end of the antenna unit and its base may vary from one manufacturer to another.
Hitherto, attempts have frequently been made to centre the metallic core in the best possible way in a tubular jacket material, which either is manufactured beforehand or is being manufactured, for example by injection moulding, when the resilient core is introduced into the jacket. These operations are quite cumbersome and usually lead to considerable centering difficulties. The metallic, resilient core may therefore occupy exceedingly odd positions and bending shapes in the enclosing jacket.
The purpose of the present invention is to create a method and a tool to be used when manufacturing an antenna unit, which method may be performed easily and rapidly, and which ensures that the metallic core occupies a well defined and uniformly centered position in the manufactured antenna unit. The method concerns the manufacture of an antenna unit, including a metallic core, which is tubular or in the form of a wire and which is preferably resilient, and a jacket which encloses the core partially or fully, and which is made of an injectable material. A tool is used for injection moulding, said tool being split in a parting plane comprising the longitudinal, central axis through the core. The method is characterised essentially in that the isolating jacket is injected in at least two steps, wherein the core in a first step is provided with a first jacket portion substantially shaped like a tubular semi-cylinder while the remaining part of the core is supported in a first mould cavity portion adapted to the shape of the core, whereupon at least a part of the injection moulding tool and the core with the injected first jacket portion are displaced in relation to each other, such that the core with the injected first jacket portion is supported in a mould cavity portion shaped for this purpose. Thereafter, the still bare portion of the core, in a second step, is provided with a second jacket portion, being supplementary to the first-mentioned jacket portion and being shaped substantially like a tubular semi-cylinder.
According to the invention, it is suitable that the antenna unit, preferably through combined radial and axial injection, such that a certain rotation and turbulence occurs in the injected material, is provided with a knob, situated in a separate mould cavity around the upper end of the core and in intimate contact with at least the first injected jacket portion. It should also be possible, after minor modification of the tool, to manufacture so called dual-antenna units, i.e. antenna units containing two parallel antenna cores, situated side by side at some distance from each other in said parting plane of the tool. Preferably one is somewhat shorter than the other so as to be adapted to the prevailing frequency intervals.
It should also be possible, after corresponding modifications of the tool, to manufacture also so called telescopic aerials in a similar manner.
Further suitable features are stated in claims
2
through
17
.
REFERENCES:
patent: 4725395 (1988-02-01), Gasparaitis
patent: 5341149 (1994-08-01), Valimaa et al.
patent: 5353493 (1994-10-01), Harada et al.
patent: 5836072 (1998-11-01), Sullivan et al.
patent: 2305298A (1997-04-01), None
Patent Abstracts of Japan, abstract of JP 9-174596 A (Murata Mfg. Co. Ltd.), Jul. 8, 1997.
Jacobson & Holman PLLC
Le Hoang-anh
Munkplast International AB
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