Apparatus for depositing a piece of band-like elastomeric element on a forming support in a process for building a tyre for vehicle wheels

An apparatus for depositing a piece of band-like elastomeric element on a forming support in a process for building a tyre for vehicle wheels, the apparatus comprising:

• at least one feeding conveyor belt for feeding said piece of band-like elastomeric element towards said forming support along a feeding direction;
• a detection device for detecting the actual length of said piece of band-like elastomeric element along said feeding direction, the detection device comprising at least one camera and a photocell arranged in a position adjacent to the at least one camera,
• the photocell being configured to detect a first instant of passage of a head end of said piece of band-like elastomeric element:
• a deposition device for depositing said piece of band-like elastomeric element on a deposition surface defined on the forming support, said deposition device being arranged downstream of said detection device with reference to said feeding direction;
• a pressing device for pressing said piece of band-like elastomeric element on said forming support;
• and
• a control system of said pressing device, the control system being configured to:
• a) determine a second instant of passage of a tail end of said piece of band-like elastomeric element as a function of i) said first instant of passage, ii) a nominal length of said piece of band-like elastomeric element and iii) a speed of movement of said piece of band-like elastomeric element,
• b) activate said at least one camera to acquire a single image of the tail end at the second instant of passage of the tail end of said piece of band-like elastomeric element, and to calculate said actual length of said piece of band-like elastomeric element;
• and
• c) during a deposition of said piece of band-like elastomeric element commanded by said deposition device and when said actual length is lower than a circumferential length of said deposition surface, activate said pressing device in order to stretch said piece of band-like elastomeric element so that, at the end of the deposition of said piece of band-like elastomeric element, said actual length substantially coincides with said circumferential length.