Device for the automatic demounting of a tire from a rim and machine equipped with such device
A device for automatic demounting of a tire from a rim having: a support arm ( 4 ); a demounting tool ( 10 ) articulated to the support arm ( 4 ); an attachment member ( 12 ) having one end articulated to the demounting tool ( 10 ) by a first articulation pin ( 13 ) and the other end thereof pivoted to the support arm ( 4 ) around a second articulation pin ( 14 ) extending substantially parallel to the first articulation pin ( 13 ); at least one extension appendage of the support arm ( 4 ) or a section ( 17 ) of the support arm ( 4 ), which extends beyond the second articulation pin ( 14 ); and at least one tie rod member ( 18 ) that is articulated on one side to the tool, and on the other side to the extension appendage or section ( 17 ) of the support arm ( 4 ).
1. A device for the automatic demounting of a tire from a rim having:
a support arm designed to be mounted on a tire mounting-demounting machine equipped with rotatable rim-carrier means for engaging a rim or a tired wheel and driving it in controlled rotation around a rotation axis, said support arm being liftable and lowerable in a direction substantially parallel to said rotation axis,
a demounting tool articulated to the support arm and designed to be positioned, in use, on top of or in front of said rotatable rim-carrier means,
an attachment member for the demounting tool, which has one end thereof articulated to the demounting tool by means of a first articulation pin and the other end thereof pivoted to the support arm around a second articulation pin extending substantially parallel to said first articulation pin,
comprising
at least one extension appendage of said support arm or a section of said support arm, which extends beyond said second articulation pin, and
at least one tie rod member that is articulated on one side to said tool, and on the other side to said extension appendage or section of said support arm.
2. A device according to claim 1 , comprising means for controlling the articulation between said demounting tool and said attachment member including an articulation lever system between said tool and said tie rod member.
3. A device according to claim 2 , wherein said lever system comprises one elbow-shaped lever or a pair of elbow-shaped levers pivoted on said first articulation pin and having one end articulated to said demounting tool and the other end articulated to said at least one tie rod member.
4. A device according to claim 1 , wherein said at least one extension section or appendage projectingly extends starting from said second articulation pin.
5. A device according to claim 1 , wherein said at least one extension section or appendage extends at an angle with respect to said support arm.
6. A device according to claim 1 , wherein said at least one extension section or appendage is anchored to said second pin or anchored directly to the support arm.
7. A device according to claim 1 , comprising a tappet element loaded with an elastic means for thrusting said attachment member.
8. A device according to claim 1 , wherein said support arm comprises an extendable-shortenable arm.
9. A device according to claim 1 , wherein said attachment member comprises a rectilinear metal tubular section.
10. A device according to claim 1 , wherein said tie rod member is elastically yieldable in a longitudinal direction.
11. A device according to claim 1 , comprising an upright, starting from which said support arm extends.
12. A device according to claim 1 , wherein said tie rod member is articulated to said tool around a first articulation axis which is spaced from said first articulation pin, such that a quadrilateral is delimited between said first articulation pin, said second articulation pin, and the articulation axes of said tie rod member.
13. A tire mounting-demounting machine, comprising a device according to claim 1 .