Pump for supplying an application system of a liquid covering product

Abstract

A pump supplying an application system of a liquid covering product including a motor actuating at least two pistons, a drum rotated by the motor, the drum including an outer cylindrical surface having a cam profile, each piston being secured to a rod on which a roller is fastened rolling over the cam profile such that the roller connected to each piston via one of the rods is translated along the translation axis of the corresponding piston under the action of the rotation of the drum, each roller being in contact with the cam profile in an angularly offset position relative to the other rollers such that one of the pistons is moving when the other piston reaches an inversion point of its movement direction, and the pump including compensating means suitable for accelerating one of the pistons when another piston reaches an inversion point of its movement direction.

1 . A pump for supplying an application system of a liquid covering product, comprising a motor actuating at least two pistons, wherein it comprises a drum rotated by the motor, the drum comprising an outer cylindrical surface having a cam profile, wherein each of the pistons is secured to a rod on which a roller is fastened rolling over the cam profile such that the roller connected to each of the pistons via one of the rods is translated along the translation axis of the corresponding piston under the action of the rotation of the drum, and wherein each of the rollers is in contact with the cam profile in an angularly offset position relative to the position of the other rollers such that one of the pistons is moving when the other piston reaches an inversion point of the movement direction, and wherein it comprises compensating means suitable for accelerating one of the pistons when another piston reaches an inversion point of its movement direction. 
     
     
         2 . The pump according to  claim 1 , wherein the compensating means comprise means for accelerating the rotation speed of the drum during a predetermined length of time before and after the passage of one of the pistons by its inversion point. 
     
     
         3 . The pump according to  claim 2 , wherein the acceleration means comprise a control unit of the motor. 
     
     
         4 . The pump according to  claim 2 , wherein the compensating means comprise a pressure sensor placed downstream from the pistons, and the acceleration means are suitable for increasing the rotation speed of the drum as a function of a pressure value measured by the pressure sensor. 
     
     
         5 . The pump according to  claim 1 , wherein the compensating means are formed by two angular sectors of the cam profile having an incline angle, relative to a plane perpendicular to the rotation axis of the drum, larger than an incline angle of a remaining angular sector of the cam profile. 
     
     
         6 . The pump according to  claim 5 , wherein the incline angle of the angular sectors of the cam profile forming the compensating means is twice the incline angle of the remaining angular sector of the cam profile. 
     
     
         7 . The pump according to  claim 1 , wherein it comprises two pistons angularly offset by 90°. 
     
     
         8 . The pump according to  claim 1 , wherein the cam profile comprises two helical slots each extending over half the circumference of the drum, and symmetrical relative to a plane passing through the rotation axis of the drum. 
     
     
         9 . The pump according to  claim 1 , wherein the rollers are angularly offset by an angle comprised between 70° and 100°. 
     
     
         10 . The pump according to  claim 1 , wherein the offset angle of the rollers is 90°.