Jaw, wheel-holder unit and tyre changing apparatus

A wheel-holder unit for a tyre changing apparatus, the wheel-holder unit comprising a head, the head being rotatable about an axis of rotation, and a lift actuator, connected to the head to move it along a trajectory having at least a vertical component, parallel to the weight force, wherein the head includes a plurality of jaws which are angularly spaced around the axis of rotation and which are movable towards and away from each other between a position where they are distal from, and a position where they are proximal to, the axis of rotation of the head, wherein each jaw of the plurality of jaws is a jaw for clamping a wheel rim in a tyre changing apparatus provided with a wheel-holder unit having a head, the jaw comprising a body extending along a longitudinal direction parallel to a longitudinal axis between a first end and a second end, and extends along a transverse direction, perpendicular to the longitudinal direction, and extends along a clamping direction, perpendicular to the transverse direction and to the longitudinal direction, and wherein the jaw includes a top surface, a first lateral surface, a second lateral surface and a bottom surface, the body including:

• a connecting portion, located at the first end of the jaw, configured to be connected to the head of the wheel-holder unit;
• a base portion extending along the longitudinal direction and defining the bottom surface of the jaw;
• a first abutment wall, extending from the base portion along the transverse direction and along the clamping direction;
• a second abutment wall, extending from the base portion along the transverse direction and along the clamping direction away from the bottom surface of the jaw, the second abutment surface wall being longitudinally spaced from the first abutment wall by a working distance;
• an abutment surface, longitudinally interposed between the first abutment wall and the second abutment wall and connected thereto, the abutment surface defining a portion of the top surface of the jaw located between the first abutment wall and the second abutment wall,
• wherein the abutment surface comprises a first portion, connected to the first abutment wall and extending along a first plane parallel to the longitudinal direction and parallel to the transverse direction for the entirety of the first portion, and a second portion, connected to the first portion and to the second abutment wall, the second portion extending along a second plane parallel to the transverse direction and inclined with respect to the longitudinal direction so that the second portion is at an increasingly larger distance from the bottom wall, along the longitudinal direction from the first portion to the second abutment wall,
• wherein the first portion of the abutment surface has a longitudinal length greater than 30% of the working distance,
• a switch element, including an inclined wall extending from a first end to a second end and having a first portion and a second portion, located between the first end and the second end so that the first portion is connected to the first end and the second portion is connected to the second end, the switch being removably connectably to the body, so that
• in a first position, the switch element is located in a connecting zone of the body longitudinally interposed between the first abutment wall and the second abutment wall, with the first end proximal to the first abutment wall and the second end proximal to the second abutment wall, the inclined wall being configured to come into contact with the wheel rim, wherein, with the switch located in the connecting zone, the first portion and the second portion of the switch element extends along the longitudinal direction, so that a ratio between the longitudinal length of the first portion and the second portion of the switch element is different than a ratio between the longitudinal length of the first portion and the second portion of the abutment surface, and
• in at least a second position, the switch element is removed from the abutment surface of the body and it is on the outside of the connecting zone.