A checking system for the contactless checking of the attitude angles of the wheels of a land vehicle (V), comprising
- at least one device for detecting the toe angle of the wheels of a vehicle (V) equipped with a pair of distance detection units (S1, S2, . . . Sn) each capable of measuring a wheel distance between a common reference plane (A-A′) parallel to a through-lane (P-P′) and a reference point on a lateral surface of a vehicle (V) including a wheel moving with respect to said at least one pair of distance detection units (S1, S2, . . . Sn), characterised in that
- the system includes a single toe angle detection device incorporated on a single vertical measuring structure (1), which is arranged on only one side of said through-lane (P-P′), on which said at least one pair of distance detection units (S1, S2, . . . Sn) is installed at a height (h) from a running plane (F) of said wheels of the land vehicle (V) and at a mutual separation (D) along a horizontal plane,
- said wheel distance being detected on a front wheel and a rear wheel of the vehicle (V) along directrix lines (L1 and L2) orthogonal to said through-lane (P-P′) and wherein
- said at least one pair of distance detection units (S1, S2, . . . Sn) is configured so as to detect said wheel distance of at least two points ((a(N−1), b(N−1), c(N−1), d(N−1), a(N), b(N), c(N), d(N)) for each of said front and rear wheels and to determine at least the following parameters:
- a first direction of advancement of the vehicle (V) on a front wheel as α=(a(N)−a(N−1))/D;
- a direction on a horizontal plane of a front wheel as β=(a(N−1)−b(N−1))/Ha;
- an apparent front wheel toe angle as β−α;
- a second direction of advancement of the vehicle (V) on a rear wheel as α1=(c(N)−c(N−1))/D;
- a direction on a horizontal plane of a rear wheel as γ=(c(N−1)−d(N−1))/Hp;
- an apparent rear wheel toe angle as γ−α1;
- where D is said mutual separation, Ha is a horizontal distance between two points (a, b) on the front wheel and Hp is a horizontal distance between two points (c, d) on the rear wheel,
- at least said parameters being combined to supply a check index.