Lightweight composite propellers for outboard motor

A lightweight composite propeller for an outboard motor, the propeller comprising:

• a hub (10) having a cylindrical body and having an axial hole (12) at a center;
• blade cores (20) disposed on an outer side of the hub (10);
• a rubber bushing (30) disposed in the hole (12) of the hub (10);
• and
• a circular ring-shaped cap (40) disposed at a front end of the hub (10) to prevent the blade cores (20) from being pulled out forward from the hub (10),
• wherein the blade cores (20) are each an assembly of a blade (21) and a core (22),
• the core (22) is formed by integrally coupling in advance a portion of a body which forms the outer side of the hub (10) to a lower end of the blade (21), and has a structure for combining and separating the hub (10) and the blade core (20),
• the core (22) has fitting grooves (22a) having a U-shaped cross-section and formed axially straight and the hub (10) has fitting projections (10a) formed axially straight, having a U-shaped cross-section, and arranged with regular intervals around the outer side, so the hub (10) and the blade core (20) are combined and separated by fitting and pulling the fitting projections (10a) into and out of the fitting grooves (22a),
• a bending portion (22a-1) is formed at a first side of each of the fitting grooves (22a) by bending both ends of the core (22) toward a central axis and a fitting portion (22a-2) extending toward the central axis is formed at a second side of each of the fitting grooves (22a) to face the bending portion (22a-1) with the fitting grooves (22a) therebetween,
• the fitting projections (10a) each have flanges (10a-1) at both sides on a top and a recession (10a-2) formed between the flanges (10a-1) at both sides, and
• when the fitting groove (22a) and the fitting projection (10a) are fitted, the bending portion (22a-1) is fitted in a left or right half of the recession (10a-2) and the fitting portion (22a-2) is fitted on any one of the flanges (10a-1) to cover the flange (10a-1).