An expansible auxiliary wheel comprising:
- a semicircular plate (1) and one semicircular arm (5) connected for pivoting motion in one of their ends, through a coupling bolt (18), which determine a resting state in which the semicircular arm (5) is in a retracted position over the body of the semicircular plate (1), and a working state where the semicircular arm (5) is in an expanded position and forms, together with the semicircular plate (1) a full rim;
- the curved perimeter of both the semicircular plate and the semicircular arm is covered by a metallic hoop (9) to produce a higher load resistance, and a rubber belt (2) is attached over the outer part of said metallic hoop, which creates traction and absorb vibrations while at work;
- the semicircular plate (1) has a hole placed in the center of the rim formed by the semicircular plate (1) and the semicircular arm (5), which has a female grooved hub (7) adapted for the installation of the semicircular plate (1);
- over said female grooved hub (7) a cam hub (3) with a predefined form is placed as the base of a cam (4);
- said cam hub (3) is connected to the semicircular plate (1) through a fastening hoop (27) which allows the cam hub (3) to turn unrestricted, and also allows the cam to rest in a horizontal position in said resting state, between the inner periphery of the semicircular arm (5) and a stop (25) placed over the body of the semicircular plate (1), placed next to the ends connected by the coupling bolt (18), taking as a reference a vertical axis that goes through the hub of the semicircular plate (1);
- located on the opposite site of the stop (25) there is a first fastening method (19) to which one end of a contraction spring (6) is affixed;
- the other end of said contraction spring (6) is affixed to a second fastening method (26) located on the free end of the semicircular arm (5), to keep said semicircular arm (5) in a horizontal position, when the wheel is at rest;
- taking as a reference the vertical axis that goes through the hub of the semicircular plate (1), and located in the opposite side of the coupling bolt (18), over the body of the semicircular plate (1) there is a bolt (10) that functions as a slot (22) guide;
- said slot is placed vertically in the free end of the semicircular arm (5), underneath the second fastening method (26), and the function of which is to guide and limit the movement of the semicircular arm (5), for the transition of the auxiliary wheel from the resting to the working state. When the cam hub (3) is turned counter-clockwise, the cam (4) pushes the semicircular arm (5) outwards, going from the resting to the working state;
- said semicircular plate (1) and semicircular arm (5) form a complete rim;
- in the distal end of the cam (4) there is a cam lock (17) that prevents said cam (4) from moving, and is characterized by a female grooved hub (7) of narrower diameter that for fixation thereof is coupled to a male grooved hub that has an inner concentric thread (11) placed in the car's wheel and is affixed with a central hexagonal screw (15) with the help of a tightening handle (16), where the metallic hoop (9) and the rubber belt (2) are fastened to each other through anchor-shaped screws (29) and nuts (30).