Lock ring and threaded stud

1. A connection assembly ( 1 ) comprising:

a first member and second member ( 2 , 3 );

a threaded stud ( 15 ) for connecting said first and second member ( 2 , 3 ); and

a lock ring ( 26 ) for securing said threaded stud ( 15 ) to said first member ( 2 ); said threaded stud ( 15 ) comprising:

a first thread ( 16 ) which may screw onto said first member ( 2 ) for connection;

a second thread ( 17 ) onto which a tightening member ( 25 ) may screw; and

a non-threaded portion ( 18 ) interposed between said first and second thread ( 16 , 17 ), which fits loosely through the second member ( 3 ) for connection;

said lock ring ( 26 ) comprising:

an axial upper portion ( 40 ) and an axial lower portion ( 41 );

a first surface ( 30 ) defining said lock ring ( 26 ) on a side facing a first axis (C) of symmetry of said lock ring ( 26 ); and

a second surface ( 31 ) defining said lock ring ( 26 ) on an opposite side to said first axis (c) and being tapered inwardly from said axial upper portion ( 40 ) to said axial lower portion ( 41 );

characterized in that said first surface ( 30 ) is smooth before being inserted inside said first member ( 2 ), and a toothed impression ( 27 ) is formed in said first surface ( 30 ) when said lock ring ( 26 ) is forced onto a toothed portion ( 19 ) of said threaded stud ( 15 );

said second surface ( 31 ) being conical and adapted to be forced inside said first member ( 2 ) such that only said axial upper portion ( 40 ) interferes with said first member ( 2 ); and

a third surface of said toothed portion ( 19 ) of said stud ( 15 ), radially outwards with respect to an axis (B) of said threaded stud ( 15 ), being conical and oppositely tapered from said second surface ( 31 ), and forming said toothed impression ( 27 ) on said first surface ( 30 ) of said lock ring ( 26 ) when said second surface ( 31 ), opposite said first surface ( 30 ), of said lock ring ( 26 ) is forced inside said first member ( 2 ).

2. A connection assembly as claimed in claim 1 , characterized in that said second surface ( 31 ) is symmetrical with respect to said first axis (C).

3. A connection assembly as claimed in claim 1 , characterized in that at least one of said first and second surfaces ( 30 , 31 ) comprises a gap ( 35 ) eccentric with respect to said first axis (C).

4. A connection assembly as claimed in claim 3 , characterized in that said gap ( 35 ) comprises a cut ( 35 ) through said first and second surfaces ( 30 , 31 ) and radial with respect to said first axis (C).

5. A connection assembly as claimed in claim 4 , characterized in that said cut ( 35 ) extends through said first and second surfaces ( 30 , 31 ) along the whole axial length of said ring ( 26 ).

6. A connection assembly as claimed in claim 4 , characterized in that said cut ( 35 ) extends along a second axis (D) parallel to said first axis (C).

7. A connection assembly as claimed in claim 1 , characterized by said ring ( 26 ) being made of aluminium or magnesium.

8. A connection assembly as claimed in claim 1 , characterized in that said threaded stud ( 15 ) extends along said axis (B), and in that said toothed portion ( 19 ) is symmetrical with respect to said axis (B).

9. A connection assembly as claimed in claim 1 , characterized in that said first member ( 2 ) comprises a cylindrical seat ( 10 ) symmetrical with respect to said first axis (C) and into which said second surface ( 31 ) of said ring ( 26 ) is forced;

the maximum nominal diameter of said second surface ( 31 ) being greater than the nominal diameter of said seat ( 10 ).

10. A connection assembly according to claim 1 , characterized in that said ring ( 26 ) is made by a material softer than the material of said threaded stud ( 15 ).