A tool for preparing coaxial cables with a ringlike outer conductor, can only ensure a fast, reproducible and high quality assembly of connectors, if it meets a number of requirements:
Cutting the central conductor, the dielectric, the outer conductor and the sheath of the cable, in accordance with the requirements of the connector to be fitted thereon.
Cutting cable conductors with no burrs or filings. A thin burr, or filings, inside the outer conductor may generate intermodulations (generally known as PIM, the acronym of Passive Intermodulations).
Automatically ensuring preparation accuracy in relation to a reference (a crest or a groove of the outer conductor), regardless of the accuracy wherewith the cable is sawed.
The invention particularly pertains to a tool meeting all the aforesaid requirements. The invention also provides a method for preparing coaxial cables with a ringlike outer conductor, as well as a tool specifically designed for that purpose.
The invention thus provides a method for preparing coaxial cables which have a sheath, a ringlike outer conductor, a central conductor and a dielectric separating the outer conductor from the central conductor, by cutting the outer conductor, the dielectric and the central conductor to length, characterized in that the cable is cut perpendicularly to its axis, in a position approximately determined in relation to a groove of the outer conductor; in that, with the help of a tool with a blade, the sheath is sheared off by rotation in a helical motion, while a guide of the tool comes to rest on the central conductor and, under the action of a positioning and abutment device of the tool, one or more supplementary blades of the tool, cut the outer conductor, the dielectric and the inner conductor, the inner conductor and the dielectric on the one hand, and the outer conductor on the other hand, respectively, and possibly the outer conductor is treated by means of a flaring tool.
The invention thus also provides a tool for preparing coaxial cables which have a sheath, a ringlike outer conductor, a central conductor and a dielectric separating the outer conductor from the central conductor, characterized in that it comprises
a blade for shearing the sheath off;
a guide which may rest on the central conductor;
a positioning and abutment tool;
one or more supplementary blades of the tool, for cutting the outer conductor, the dielectric and the inner conductor, the inner conductor and the dielectric on the one hand, and the outer conductor on the other hand, respectively.
According to the invention the tool may preferably be designed to be provided with a flaring tool for treating the outer conductor.
According to further preferred features of the invention,
the tool may in particular be composed of a cable sheath peeling knife, which holds the blade fastened by a screw, said peeling knife being screwed on a guide of a blade holder and said blade holder being fastened by a screw and holding a supplementary blade and an axle about which the inner guide may rotate, secured by a screw;
the split rings may in particular be housed between two guides and may rotate freely relative to each other and to a spring and open apart while being held in a coaxial position with respect to their housing by a split zigzag or polygonal flat spring;
said that flat spring has a pentagonal shape;
blade may in particular be fastened to form an angle of about 6 degree with respect to a plane perpendicular to the axis of the tool, which allows it to move in a helical path, as the tool rotates and advances;
said blade holder may in particular comprise two blades, in order to allow the cutting of the central conductor of the cable, in a way shifted from the cutting plane of the dielectric and of the outer conductor;
a blade holder with three blades may in particular be used;
a flaring tool may in particular be used, composed of a body, an inner guide and a blade fastened by a screw in an aperture, said blade haying a dimension (v) which is greater than the greatest radius of the dielectric and smaller than the greatest inside radius of the outer conductor;
a blade may in particular be used which is made of one piece with the blade holder and in that the cutting edge of the blade is shifted through a distance (*) from the radius.
According to further preferred features of the invention,
the method may in particular involve that, with the help of a handle or of a drilling machine, secured at the end of the blade holder, the tool is turned, while it is slightly pushed towards the cable.
the method may in particular involve that, while the tool rotates, a guide a rolling movement on the inner surface of the central conductor of the cable, avoiding the formation of filings and reducing the effort to drive the tool.