Method and device for dismounting self-supporting tyres

1. Method for dismounting self-supporting tyres ( 1 ) from the relative rim ( 2 ), said self-supporting tyres comprising an outer cover ( 10 ) that contains a rigid auxiliary ring ( 16 ) provided with two flexible sidewalls ( 18 , 19 ), characterised in that it comprises the operating steps of:

a) lifting a first bead ( 14 ) of the outer cover ( 10 ) away from the rim ( 2 ), so as to make a first sidewall ( 18 ) of the auxiliary ring ( 16 ) accessible;

b) inserting a dismounting tool ( 5 ) between an elastic edge of said first sidewall ( 18 ) of the auxiliary ring ( 16 ) and an edge of the rim ( 2 );

c) moving said dismounting tool ( 5 ), so as to grip the elastic edge of said first sidewall ( 18 ) and to turn a part thereof away from said rim ( 2 );

d) pushing said turned part of the first sidewall ( 18 ) outwards, making it slide in contact with the dismounting tool ( 5 ), until it passes over the edge of the rim ( 2 );

e) rotating the auxiliary ring ( 16 ) about the central axis (A) of the rim ( 2 ), so that all of the elastic edge of the first sidewall ( 18 ) interacts with the dismounting tool ( 5 ), and is thus completely lifted away from the rim ( 2 );

f) lifting both the second sidewall ( 19 ) of the auxiliary ring ( 16 ) and the second bead ( 15 ) of the outer cover ( 10 ) away from the rim ( 2 ).

2. Method according to claim 1 , characterised in that said dismounting tool ( 5 ) has a hook to grip the elastic edges of the sidewall ( 18 ) of the rigid auxiliary ring ( 16 ).

3. Method according to claim 1 , wherein after inserting the dismounting tool between the elastic edge and the edge of the rim, the dismounting tool ( 5 ) is pressed on the first sidewall ( 18 ) of the auxiliary ring ( 16 ) according to a predetermined insertion direction, so as to bend said first sidewall ( 18 ) inwards and to provide a space that allows the dismounting tool ( 5 ) itself to pass.

4. Method according to claim 3 , characterised in that said insertion direction is parallel to the central axis (A) of the rim ( 2 ).

5. Method according to claim 3 , characterised in that during said step b) the dismounting tool ( 5 ) slides in contact with the edge of the rim ( 2 ).

6. Method according to claim 3 , wherein after said dismounting tool has tuned part of said first sidewall away from the rim, said dismounting tool ( 5 ) is moved in a withdrawal direction opposite to said insertion direction.

7. Method according to claim 1 , wherein after said turned part passes over the edge of the rim, a thrust on a sidewall ( 13 ) of the outer cover ( 10 ) is exerted adjacent to a second sidewall ( 19 ) of the auxiliary ring ( 16 ).

8. Method according to claim 7 , characterised in that said thrust is exerted while the auxiliary ring ( 16 ) is rotated about the central axis.

9. Method according to claim 7 , characterised in that said thrust is exerted by a thrusting element ( 61 ) that is positioned in contact with said sidewall ( 13 ) of the outer cover ( 10 ), and that is actuated by a jack ( 62 ) to move in a direction parallel to the axis (A) of the rim ( 2 ).

10. Tyre-dismounting machine for dismounting self-supporting tyres ( 1 ), said self-supporting tyres ( 1 ) comprising an outer cover ( 10 ) that contains a rigid auxiliary ring ( 16 ) engaged to two flexible sidewalls ( 17 , 18 ), the machine comprising;

a rotary support for a tyre engaged on a rim ( 2 ), having an axis (A),

an operating head ( 4 ) carrying a dismounting tool ( 5 ), provided with a hook, said tool ( 4 ) movable in a direction parallel to the central axis (A) of the rim ( 2 ), and in a direction perpendicular to the central axis;

a debeading device ( 6 ) provided with at least one debeading disc arranged in order to act on the cover ( 10 ),

said dismounting tool ( 5 ) being associated with a jack ( 45 ) to carry out an insertion stroke, during which the tool is positioned between an elastic edge of a sidewall ( 18 ) of the auxiliary ring ( 16 ) and an edge of the rim ( 2 ), and a withdrawal stroke in the opposite direction, during which the elastic edge of said sidewall ( 18 ) is engaged by the hook;

wherein at least one of said debeading discs ( 61 ) exerts a thrust on a portion of the outer cover ( 10 ) of the tyre ( 1 ) to move said outer cover ( 10 ) and said auxiliary ring ( 16 ) in a direction parallel to said axis of the rim ( 2 ) and towards the dismounting tool ( 5 ), causing a part of the sidewall ( 18 ) to slide on said tool ( 5 ).