Variable-rigidity extrudate obtained by continuous extrusion, and method and apparatus for producing this extrusion

Claim 2

An extrusion of elastomeric material, intended in particular to constitute a weather strip (A) for sealing and guiding a vertically-movable window pane (S) for motor-vehicle windows (R), having a constant cross-section portion with longitudinally-variable rigidity (B,C,D), characterised in that it is produced in a single operation of continuous extrusion in which the said constant cross-section portion with longitudinally-variable rigidity (B,C,D) is generated by at least two continuous flows of elastomeric materials of different composition alternately used.

Claim 3

An extrusion according to Claim 1, including three successive longitudinal portions (a₁, a₂, a₃) intended to define the rearward side, the upper side and the forward side respectively of the window (R) and having a con­stant, substantially channel-shaped section with a base part (B) and side walls (C, D) bearing sealing and guiding flanges (F, H, G, K) the base part (B) and the side walls (C, D) of the first of the three portions (a₁) being more rigid than the corresponding parts of the second and third portions (a₂, a₃), characterised in that it is produced by: the provision of an extrusion head (1) having first, second and third successive extrusion dies (3, 4, 5) of which the first two have profiles corre­sponding to that of the base part (B) and the side walls (C, D) and the third has a profile corresponding to that of the finished weather strip (A); the continuous supply to these extrusion dies of respective flows of elastomeric materials, of which that directed to the first die (3) is harder than that directed to the second die (4); and the alternate enabling and prevention of passage through the first and second extrusion dies (3, 4) for predetermined time intervals depending on the length of the first, second and third portions of the weather strip (a₁, a₂, a₃); and the recycling of the flow of elastomeric material directed to the alternately inhibited extrusion die.

Claim 6

Equipment for producing, by means of continuous extrusion, a variable-rigidity extrusion of elastomeric material, particularly a weather strip (A) for sealing and guiding a vertically-movable window pane (S) for motor-vehicle windows (R), including three successive longitudinal portions (a₁, a₂, a₃) intended to define the rearward side, the upper side and the forward side respectively of the window (R) and having a substantially channel-shaped section with a base part (B) and side walls (C, D) bearing sealing and guiding flanges (F, G, H, K), the rigidity of the base part and side walls of the first of the three portions (a₁) being greater than that of the corresponding parts of the second and third portions (a₂, a₃), characterised in that it comprises an extrusion head (1), including: - first, second and third successive extrusion dies (3, 4, 5) of which the first two have profiles cor­responding to that of the base part (B) and the side walls (C, D) and the third has a profile corresponding to that of the finished weather strip (A), - means for the continuous supply to the extrusion dies (3, 4, 5) of respective flows of elastomeric materi­als, of which that directed to the first die (3) is harder that that directed to the second die (4), - means for the alternate enabling and prevention of passage through the first and second extrusion dies (3, 4) for predetermined time intervals depending on the length of the first, second and third portions of the weather strip, and - recycling means for recycling the flow of elastomeric material directed to the alternately inhibit­ed extrusion die.

Claim 7

Equipment for producing, by means of continuous extrusion, a variable-rigidity extrusion of elastomeric material, particularly a weather strip (A) for sealing and guiding a vertically-movable window pane (S) for motor-vehicle windows (R), including three successive longitudinal portions (a₁, a₂, a₃) intended to define the rearward side, the upper side and the forward side respectively of the window (R) and having a substantially channel-shaped section with a base part (B) and side walls (C, D) bearing sealing and guiding flanges (F, G, H, K), the rigidity of the base part and side walls of the first of the three portions (a₁) being greater than that of the corresponding parts of the second and third portions (a₂, a₃), characterised in that it comprises an extrusion head (1), including: - first, second and third successive extrusion dies (3, 4, 5) of which the first two have profiles cor­responding to that of the base part (B) and the side walls (C, D) and the third has a profile corresponding to that of the finished weather strip (A), - means for the continuous supply to the extrusion dies (3, 4, 5) of respective flows of elastomeric materi­als, of which that directed to the first die (3) is harder that that directed to the second die (4), - means for the alternate enabling and prevention of passage through the first and second extrusion dies (3, 4) for predetermined time intervals depending on the length of the first, second and third portions of the weather strip, and - recycling means for recycling the flow of elastomeric material directed to the alternately inhibit­ed extrusion die.

Claim 8

Equipment according to Claim 4, characterised in that the extrusion head (1) has: - a central passage (8) communicating with the first extrusion die (3) and with a recycle conduit (9) having an associated first obturator (21) movable between an open position and a closed position, - an annular passage (15) surrounding the central passage (8) and communicating with the second extrusion die (4) and with a recycle conduit (16) having an associ­ated second obturator (22), movable between an open position and a closed position, - a pair of motorised actuators (23, 24) for control­ling the first and second obturators (21, 22) and - programmable electronic means for controlling the actuators (23, 24) to achieve alternately the opening of one obturator and the closing of the other obturator and vice versa.