Patent ID: 8511518

Claim:
A volumetric doser ( 10 ) for batching liquid or pasty pharmaceutical substances, comprising: a cylinder ( 1 ); a piston ( 2 ), mobile along internal walls ( 49 ) of the cylinder ( 1 ) for displacing liquid or pasty pharmaceutical substances; a stem ( 3 ) exiting from the cylinder ( 1 ) for moving the piston ( 2 ); wherein: the volumetric doser ( 10 ) is provided with a coupling member ( 9 ) to which the stem ( 3 ) is fixable, the coupling member ( 9 ) having a substantially U-shaped form and comprising: a base ( 11 ) and two facing lateral walls ( 12 , 13 ) which originate from the base ( 11 ); and wherein the piston ( 2 ) and the coupling member ( 9 ) are reciprocally conformed such that the coupling member ( 9 ) can embrace a part ( 17 ) of the piston ( 2 ) and can perform limited oscillations with respect to the piston ( 2 ) axis; wherein the coupling member ( 9 ) comprises two sliding wings ( 14 , 15 ) which are respectively fixed to free ends of the lateral walls ( 12 , 13 ) of the coupling member ( 9 ) itself and which project such as to face the base ( 11 ) of the coupling member ( 9 ); and wherein the piston ( 2 ) comprises: a first part ( 16 ) conformed such as to enable sealed sliding of the piston ( 2 ) along the internal walls ( 49 ) of the cylinder ( 1 ), a second part ( 17 ) rigidly fixed to the first part ( 16 ) and conformed such as to be embraced by the coupling member ( 9 ), and gullies ( 18 , 180 ) interposed between the first part ( 16 ) and the second part ( 17 ) of the piston ( 2 ) such as slidingly to receive the sliding wings ( 14 , 15 ) of the coupling member ( 9 ); the coupling member ( 9 ) being able to slide along the gullies ( 18 , 180 ) of the piston ( 2 ) when it embraces the second part of the piston ( 2 ); and, further comprising at least a blocking element ( 19 , 20 ), the coupling member ( 9 ) being provided with at least a through-hole ( 21 , 22 ), the second part ( 17 ) of the piston ( 2 ) affording at least an opening ( 23 , 24 ) in a relative wall ( 25 ) facing the coupling member ( 9 ) when the coupling member ( 9 ) embraces the second part ( 17 ) of the piston ( 2 ), the through-hole ( 21 , 22 ) and the opening ( 23 , 24 ) being arranged such that when the coupling member ( 9 ) embraces the second part ( 17 ) of the piston ( 2 ) the blocking element ( 19 , 20 ) is insertable in the through-hole ( 21 , 22 ) in order at least partially to occupy the opening ( 23 , 24 ) and thus to limit the possibility that the coupling member ( 9 ) might move with respect to the piston ( 2 ) when the coupling member ( 9 ) embraces the second part ( 17 ) of the piston ( 2 ).