Device for tyre disassembling machines designed to simplify tyre assembling without excessive stretching

1. Improved device for tire disassembling machines ( 1 ) designed to simplify tire assembling without excessive stretching, which comprises: a base ( 2 ), a self-centering unit ( 4 ) rotatably mounted on the base ( 2 ) around a rotation axis ( 14 ), to stop and drive into rotation, a wheel (R) comprising a tire (P) mounted on a corresponding rim (C), an articulated arm ( 12 ) composed of a first section ( 12 a ) articulated according to a first vertical axis ( 11 ) and a support side ( 10 ) with adjustable height with respect to the base ( 2 ) of the tire disassembling machine ( 1 ), and a second section ( 12 b ) with a sliding heel-pressing tool (A) articulated with the first section ( 12 a ) by means of a joint (S) with a second vertical axis ( 13 ) placed at a distance from the said first vertical axis ( 11 ) equal to the distance between the said first vertical axis ( 11 ) and the rotation axis ( 14 ) of a self-centering unit ( 4 ), wherein said second section ( 12 ) of the arm rotates around said second vertical axis ( 13 ) so that the heel-pressing tool (A) rotates together with the tire (P), further having cam and valve train means (M) designed to determine the gradual automatic lifting of the said heel-pressing tool (A) in a predefined point of its rotation together with the tire (P), during the assembling operation of the tire on the corresponding rim (C).

2. Device of claim 1 characterized by the fact that the said means (M) are positioned in the joint (S).

3. Device of claim 1 characterized by the fact that the said means (M) comprise a brush ( 17 ) fixed to the first section ( 12 a ) of the articulated arm ( 12 ) and a pin ( 18 ) fixed to the second section ( 12 b ) of the articulated arm ( 12 ), with the pin ( 18 ) being provided with an annular groove ( 19 ), and the bush ( 17 ) being provided with a radial hole ( 20 ) in which a bolt ( 21 ) is inserted and exactly housed, ending with a point ( 21 a ) designed to be prismatically coupled with the annular groove ( 19 ) of the pivoting pin ( 18 ).

4. Device of claim 3 characterized by the fact that the groove ( 19 ) is developed for an angle in the centre of approximately 360°.

5. Device of claim 3 characterized by the fact that the said groove ( 19 ) has a first section ( 19 a ) with horizontal direction connected to a second inclined section ( 19 b ) with ascending direction.

6. Device of claim 5 characterized by the fact that the first section ( 19 a ) of the groove ( 19 ) develops for approximately a half circle arch.

7. Device as claimed in claim 1 , characterized by the fact that the heel-pressing tool (A) consists in a roll ( 15 ) supported by a cursor ( 16 ) that slides along the second section ( 12 b ), in which the said cursor ( 16 ) is provided with a peg ( 16 a ) that can be securely placed in a back position, thus allowing the free rotation of the roll ( 15 ) around the support shaft, and in a front position, thus temporarily blocking the said roll ( 15 ).