Motor pump for high-pressure washers with automatically variable flow-rate and pressure

Abstract

A motor pump for high-pressure washers having a structure of the type that comprises a rotating plate that is inclined with respect to its axis and on which at least two pistons push, the pistons being arranged parallel to the axis in radially spaced positions. The rotating plate is associated for joint rotation with a motorized support, which is arranged opposite the pistons and on which the plate can oscillate freely in order to vary its inclination, with respect to the rotation axis, between preset values that determine the axial movement of the pistons, elastic elements for contrasting the variations in inclination induced by the pistons being functionally interposed between the plate and the support.

What is claimed is:  
     
         1 . A motor pump for high-pressure washers comprising a rotating plate that has an axis which is inclined with respect to a rotation axis thereof; at least two pistons arranged with axes thereof parallel to said rotation axis in radially spaced positions so as to push on said plate; a motorized support, arranged opposite said pistons with respect to said plate and on which said plate freely oscillates so as to vary inclination of its axis, with respect to the rotation axis, between preset inclination values that set axial movement extent of said pistons, said plate being further associated with said support for joint rotation with respect to said rotation axis; and elastic means for contrasting inclination variations induced by said pistons which are functionally interposed between said plate and said support.  
     
     
         2 . The motor pump of  claim 1 , wherein said plate has a semicircular protrusion and said support has an inclined surface with a slot that is shaped complementarily to said protrusion and in which the protrusion is coupled so that said support and said plate perform said joint rotation and said oscillations, respectively, between inclination values that set the axial movement of said pistons.  
     
     
         3 . The motor pump of  claim 1 , wherein said elastic contrast means are constituted by an elastic element that rests between said plate and said support in a radial region thereof that corresponds to a region where said pistons push on said plate.  
     
     
         4 . The motor pump of  claim 3 , wherein said elastic element is constituted by a helical spring.  
     
     
         5 . The motor pump of  claim 3 , further comprising a through hole provided in said support, a threaded pin inserted axially in said elastic element, and a corresponding threaded hole formed in said plate, said pin passing through said through hole in said support and being connected to said threaded hole in said plate.  
     
     
         6 . The motor pump of  claim 1 , wherein said plate has a protrusion which contacts said support, said protrusion being perpendicular to a plane passing through the axes of said pistons and lying in an axially offset position with respect to said rotation axis, said support having a slot, and an inclined surface on which said protrusion rests, said plate further having, on an opposite side thereof with respect to said rotation axis, at least one triangular tab with a rounded vertex in contact with said slot of said support on which it slides, with contact points of said protrusion and said at least one tab support and slot being arranged so as to keep unchanged, during movement, intersection between the axis of the plate on which said pistons push and the rotation axis.  
     
     
         7 . The motor pump of  claim 1 , wherein said elastic contrast means are constituted by a leaf spring that is arranged between said support and said plate.  
     
     
         8 . The motor pump of  claim 7 , further comprising a screw, said support having a seat, and said leaf spring being fixed at one end thereof in said seat of said support by way of said screw.  
     
     
         9 . The motor pump of  claim 1 , further comprising two tabs provided at said plate; a seat formed in said support in a radial region that substantially corresponds to a region in which said pistons push on said plate; a damping element for keeping in preloaded position said elastic means, which is inserted in said seat, said damping element being further pivoted between said two tabs of said plate.  
     
     
         10 . The motor pump of  claim 1 , further comprising two pins, which are driven into said support and pass transversely through said plate; said plate having suitable slotted holes and a diametrical lower slot that has a rectangular cross-section and in which a corresponding upper portion of the support is arranged, contact occurring between a surface of the slot and an inclined resting surface of the support, said plate being free to move with respect to said support within the limits allowed by said two pins passing through said slotted holes so as to achieve said joint rotation and oscillating movements, respectively, between said preset inclination values that set the axial movement extents of said pistons while keeping unchanged an intersection point between the rotation axis and the axis of the plate on which said pistons push.  
     
     
         11 . The motor pump of  claim 1 , wherein said support has a seat, said elastic contrast means being constituted by a tubular elastic element that rests at one end thereof against a complementarily shaped seat of said plate, inserted in the seat of the support, so as to act in contrast with a pushing of the pistons.  
     
     
         12 . The motor pump of  claim 11 , wherein said tubular elastic element is inserted in a seat of the support and further comprises two mushroom-like elements with hemispherical heads and stems inserted at ends thereof, and rests at one end with the respective mushroom-like element against a complementarily shaped hemispherical seat of said plate.  
     
     
         13 . The motor pump of  claim 12 , wherein said elastic element is made of an elastomer selected from a group comprising polyurethane and other polymeric materials with elastic features.  
     
     
         14 . The motor pump of  claim 1 , wherein said elastic means are constituted by any of a Belleville washer spring or a half leaf spring.