Abrading – Machine – Rotary tool
Reexamination Certificate
1997-11-04
2001-05-29
Eley, Timothy V. (Department: 3723)
Abrading
Machine
Rotary tool
C451S278000, C451S390000, C451S041000
Reexamination Certificate
active
06238278
ABSTRACT:
The invention relates to a ferrule holder for holding a ferrule in a grinding apparatus. The invention furthermore relates to a grinding and polishing apparatus for a ferrule with at least one grinding plate for grinding the surface of a ferrule, at least one ferrule holding means adapted to hold the ferrule and at least one ferrule positioning means.
Ferrules for use in fiber-optic interconnects are known, for example, from the German Patent Application DE-A-44 23 842 (Moser et al.) assigned to IMM Institut für Mikrotechnik GmbH. Such ferrules have a series of grooves into which the individual strands of the fiber-optic cables can be laid. In an interconnect for fiber-optic cables, it is crucial to ensure that the ends of the fiber-optic strands in the two halves of the interconnect are aligned. For this purpose, the ferrule disclosed in the '
842
patent application contains alignment holes into which alignment pins can be inserted.
In order to achieve optimum coupling between the two halves of the fiber-optic interconnect, it is also necessary to ensure that the matching faces of the complementary ferrules in the fiber-optic interconnect are smoothly polished and that the ends of the strands of the fiber-optic cables are planar with the surface of the ferrule. It is particularly important to ensure that when the two ferrules are connected together, the axes of the strands of the fiber optic cables in one ferrule are substantially parallel to the axes of the strands of the fiber optic cable in the other ferrule. This is difficult to achieve in conventional ferrule grinding and polishing means since it is difficult to ensure that the face of the ferrule is ground in a plane that is exactly perpendicular to the axes of the strands of the fiber-optic cable. Even slight angular deviations can lead to mismatching of the strands of the fiber-optic cable and thus to loss of signal.
The object of the invention is therefore to develop an improved holder for a ferrule which allows use in a grinding and polishing apparatus.
It is furthermore an object of the invention to produce a ferrule with a face plane substantially perpendicular to the axes of the strand of the fiber-optic cable.
It is furthermore an object of the invention to produce a ferrule holder which allows dynamic positioning of the ferrule within said grinding and polishing means.
It is furthermore an object of the invention to produce a ferrule holder which allows the use of the alignment pins within the ferrule to position the ferrule holder within the grinding and polishing apparatus.
These and other objects of the invention are solved by using a ferrule holder with a cut face and having a holder recess in said cut face adapted to-accept the ferrule and furthermore having attachment means for attaching the ferrule within said recess. Preferably the ferrule holder is substantially spherical in shape. The use of such substantially spherical ferrule holder allows dynamic adjustment of the ferrule to be carried out when the ferrule is mounted within the polishing and grinding apparatus.
Preferably the holder recess is a hole cut through said ferrule holder. This allows ease of mounting of the ferrule within the ferrule holder since it can be mounted through the side of the ferrule holder opposite from the cut face. In order to ensure that the surface of the ferrule is cut in a plane which is substantially perpendicular to that of the axes of the strands of the fiber-optic cable, the axis of the recess is substantially perpendicular to the plane of the cut face.
The ferrule can be attached within the ferrule holder by attachment means comprising a spring-loaded plate adapted to push the ferrule against one side of the recess. This spring-loaded plate is provided with a compressible surface to avoid damage to the ferrule.
In one embodiment of the invention, the spring-loaded plate is activated by a feather spring with a first end and a second end which first end is in contact with the spring-loaded plate and which second end is activated by a sledge. The sledge is mounted in a recess through the holder and is slid by means of a screw attached to one end of said sledge. The use of the sledge and screw allow very fine adjustments to be made to the pressure exerted on the ferrule and thus ensure that sufficient pressure is applied to hold the ferrule within the holder recess but not to damage the ferrule.
The objects of the invention are further solved by providing a ferrule grinding apparatus with
at least one grinding plate for grinding the surface of the ferrule, at least one ferrule holding means adapted to hold the ferrule and at least one ferrule positioning means, wherein
the said ferrule holding means and the said ferrule positioning means cooperate together to position dynamically the ferrule such that the face of the ferrule is parallel to the surface of the grinding plate.
The positioning means of the ferrule grinding apparatus preferably includes at least one guide pin which cooperates with at least one ferrule recess within said ferrule to position said ferrule. If the ferrule holder is of spherical shape, said shape of the ferrule holder allows the ferrule to be pivoted freely within the ferrule grinding apparatus. If the shape of the ferrule holder is not spherical, e.g. a cardanic mounting might be provided in order to achieve the necessary degrees of freedom with respect to pivotal movements of the ferrule holder necessary for obtaining the cooperation of the ferrule holder and said positioning means. A particularly suitable grinding apparatus has an arm with a recess in which the ferrule holder can freely rotate. In particular, as the ferrule holder is moved down onto the guide pin by the ferrule grinding apparatus, it can rotate to assume a position in which the face of the ferrule is in a plane perpendicular to the axis of the guiding pin. Since the ferrule is manufactured with the axes of the ferrule recesses—or alignment holes—substantially parallel to the axes of the strands of the fiber-optic cables, then the ferrule is positioned in an optimum polishing and grinding position.
Although the invention is described with reference to ferrules for fiber-optic cables, it should be noted that it can also find application in the grinding of ferrules for conventioal wire-cables.
REFERENCES:
patent: 4776136 (1988-10-01), Abendeschein et al.
patent: 5018316 (1991-05-01), Mulholland et al.
patent: 5140779 (1992-08-01), Grois
patent: 5201148 (1993-04-01), Rupert et al.
patent: 5216846 (1993-06-01), Takahashi
patent: 5218786 (1993-06-01), Takahashi
patent: 5351445 (1994-10-01), Takahashi
patent: 5412737 (1995-05-01), Matsuoka et al.
patent: 5640475 (1997-06-01), Takahashi et al.
patent: 2 158 750 (1985-11-01), None
patent: 88/04217 (1988-06-01), None
Eley Timothy V.
Wheatcraft Allan M.
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