Cable coupler for connection of armored cable having armor layer and method of holding the armor layer

A cable coupler for connection of an armored cable having an armor layer, between a support fastener and a cylindrical housing with a cap fastener, comprising:

• a sleeve having an inclined surface, an outer surface of which is brought into contact with an inner surface of the armor layer, which protrudes from the armored cable;
• and
• a fastening ring and a support ring provided separately from each other, and a gap between the inclined surface of the sleeve and each of an inclined surface of the fastening ring and an inclined surface of the support ring, each of the fastening ring and the support ring having a small width and including on an inner surface thereof the inclined surfaces, which are formed by reducing a thickness thereof from a medial portion thereof to opposite ends thereof, wherein, of the inclined surfaces of each of the fastening ring and the support ring, at least one of said inclined surfaces is parallel to the inclined surface of the sleeve, wherein:
• the inner inclined surfaces of the fastening ring and the support ring have inclination angles similar to an inclination angle of the inclined surface of the sleeve, and an inner diameter of the fastening ring is greater than an inner diameter of the support ring;
• and
• the fastening ring has a symmetrical structure based on a medial position thereof such that the inclined surfaces thereof have the same inclination angle, the support ring has a symmetrical structure based on a medial position thereof such that the inclined surfaces thereof have the same inclination angle, and an outer diameter of the fastening ring is equal to an outer diameter of the support ring.