US20040131473A1

US20040131473A1 - Motor pump for high-pressure washers with automatically variable flow-rate and pressure

Info

Publication number: US20040131473A1
Application number: US10/336,695
Authority: US
Inventors: Giancarlo Lanfredi; Stefano Grossi
Original assignee: Lavorwash SpA
Current assignee: Lavorwash SpA
Priority date: 2003-01-03
Filing date: 2003-01-06
Publication date: 2004-07-08
Also published as: EP1435457A1

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.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a motor pump for high-pressure washers.

Currently, many commercially available motor pumps for high-pressure washers have a plate that rotates about its own axis (driven by a driving shaft connected thereto) and is inclined with respect to said axis.

At least two pistons push against the plate and are arranged parallel to the axis in radially spaced positions.

The rotation of the plate produces an axial movement of the pistons (conversion of a rotary motion into a reciprocating motion) and therefore a pumping action.

The flow-rate and pressure are invariable, and therefore if one wishes to perform adjustments it is necessary to install downstream or upstream control and actuation systems on which the operator acts manually.

This is not particularly convenient and requires the operator to have at least some specific technical knowledge of the machine.

SUMMARY OF THE INVENTION

The aim of the present invention is to provide a motor pump for high-pressure washers the structure whereof solves the drawbacks noted in commercially available motor pumps, particularly ensuring in a fully automatic manner a considerable increase in flow-rate, even during low-pressure operation, thus ensuring high-level washing capabilities even in fields which entail particularly heavy cleaning with deposits that are difficult to remove.

Within this aim, an object of the present invention is to provide a motor pump whose structure requires no manual regulation devices, except for those for directly setting the tool being used, such as for example a cleaning lance.

Another object of the present invention is to provide a motor pump whose structure is constructively simple and thus ensures constructive levels and costs that are fully competitive with those of commercially available motor pumps having a similar functionality.

Another object of the present invention is to provide a motor pump whose structure ensures high flexibility in application both in terms of flow-rate and in terms of pressure.

Another object of the present invention is to provide a motor pump whose structure can be manufactured with known technologies and equipment.

This aim and these and other objects that will become better apparent hereinafter are achieved by a motor pump for high-pressure washers having a structure of the type that comprises a plate that is inclined with respect to its axis and on which at least two pistons push, said pistons being arranged parallel to the axis in radially spaced positions, characterized in that said rotating plate is rotationally rigidly associated with a motorized support, which is arranged opposite said pistons and on which said 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 said pistons, elastic means for contrasting the variations in inclination induced by said pistons being functionally interposed between said plate and said support.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become better apparent from the following detailed description of some embodiments thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein: [0013]
FIG. 1 is a partially sectional schematic orthographic projection view of a motor pump having the structure according to the invention, in a first embodiment; [0014]
FIG. 2 is a bottom view of a plate comprised among the components of the motor pump of FIG. 1; [0015]
FIGS. 3 and 4 are sectional views of a motor pump having the structure according to the invention in a second embodiment, in two different steps of operation; [0016]
FIG. 5 is a side view of the motor pump of FIGS. 3 and 4; [0017]
FIG. 6 is a perspective view of the motor pump of FIGS. 3 and 4; [0018]
FIG. 7 is a sectional view of the motor pump of FIGS. 3 and 4, taken along a plane that is perpendicular to the plane of FIGS. 3 and 4; [0019]
FIG. 8 is a side view of a third embodiment of the motor pump according to the invention; [0020]
FIGS. 9 and 10 are sectional views of the motor pump of FIG. 8, in two different steps of operation; [0021]
FIG. 11 is a perspective view of the motor pump of FIG. 8.[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a motor pump for high-pressure washers having the structure according to the invention is generally designated by the [0023] reference numeral 10 in a first embodiment.
In particular, the [0024] motor pump 10 can be applied advantageously to high-pressure washers for which considerable variations of the operating conditions are intended.
The [0025] motor pump 10 comprises, within a hermetic casing not shown, a rotating plate 11 that is associated so as to rotate jointly with a motorized support 12 (which is also plate-like), on which the plate 11 can oscillate freely in order to vary its inclination with respect to the rotation axis 13 (axis of symmetry).
Elastic means [0026] 14 for contrasting the variations in inclination induced by two pistons 15 and 16, arranged parallel to the axis 13 in radially spaced and opposite positions with respect to the support 12, are functionally interposed between the plate 11 and the support 12.
In particular, the [0027] plate 11 has a semicircular protrusion 17 that is coupled to a complementarily shaped slot 18 of an inclined resting surface 12 a of the support 12 so that rotation occurs jointly with the possibility of oscillation between values that determine the axial movement of the pistons 15 and 16.
The elastic contrast means [0028] 14 are constituted by an elastic element 19, which rests on the plate 11 on one side and is partially inserted in a seat 20 of the support 12 so as to push in contrast with the action of the pistons 15 and 16.
In this embodiment, the [0029] elastic element 19 is constituted by a helical spring 22 and is partially inserted in the seat 20 formed in the plate 11 in a radial region that substantially corresponds to the region of the pistons 15 and 16.
A threaded [0030] stroke limiting pin 24 is further inserted axially in the elastic element 19 and is in turn coupled to a corresponding threaded hole 25 formed in the plate 11.
The [0031] pin 24 passes through a corresponding through hole 26 of the support 12.
In practice, operation is as follows: the operator, by setting appropriately the preloading of the [0032] elastic element 19 by acting on the threaded pin 24, determines the contrast force of the plate 11 on the pistons 17.
In this manner, without requiring the operator to further adjust the ratio between the pressure and the delivery, the [0033] motor pump 10 ensures that when the pressure drops there is a consequent increase in flow-rate, thus maintaining washing efficiency unchanged.
During high-pressure operation, the thrust of the [0034] pistons 15 and 16 is in fact such as to compress the spring 22 and arrange the plate 11 in a position in which it has the smallest inclination and therefore provides the smallest flow-rate.
When the pressure decreases to the minimum value, the thrust of the [0035] pistons 15 and 16 is smaller than the force of the spring, and therefore the inclination of the plate 11 reaches its maximum value and so does the flow-rate.
With reference now to FIGS. [0036] 3 to 7, a motor pump for high-pressure washers having the structure according to the invention is generally designated by the reference numeral 110 in a second embodiment.
The [0037] motor pump 110 comprises, inside a hermetic casing that is not shown, a rotating plate 111 that is rigidly rotationally associated with a motorized support 112, on which the plate 111 is free to oscillate in order to vary its inclination with respect to the rotation axis 113 (axis of symmetry).
Elastic means [0038] 114 are functionally interposed between the plate 111 and the support 112 in order to contrast the variations in inclination induced by two pistons 115 and 116, which are arranged, at a center bearing 128, parallel to the axis 113 in positions that are radially spaced and opposite with respect to the support 112.
In particular, the [0039] plate 111 has a protrusion 117 (for contact with the support 112), which is perpendicular to the plane formed by the axes of the pistons 115 and 116 and lies in an axially offset position with respect to the axis 113.
The [0040] protrusion 117 rests on an inclined surface 112 a of the support 112.
The [0041] plate 111 further has, on the opposite side with respect to the axis 113, at least one triangular tab 118 with a rounded vertex, which is in contact with a slot 125 of the support 112 on which it slides.
The contact points formed by the [0042] protrusion 117 and the tab 118 are sized so as to keep unchanged, during movements, the intersection 126 between the axis 127 of the center bearing 128 of the plate 111 and the axis 113.
The elastic contrast means [0043] 114 are constituted by a leaf spring 119 or a Belleville washer spring or a half-leaf spring, which is arranged between the support 112 and the plate 111, is fixed at one end in a seat 129 of the support 112 by means of a screw 130, and pushes so as to contrast the action of the pistons 15 and 16.
In this embodiment, the [0044] spring 119 is kept in the preloaded position by a damping element 131, which is inserted in a seat 132 formed in the support 112 in a radial region that substantially corresponds to the region of the pistons 115 and 116 and is pivoted, by means of its stem, between two tabs 118.
The [0045] damping element 131, which is fixed to the support 112 by means of its body in a manner that is not visible in the figures and acts in a per se known manner by transferring fluid between the two chambers into which its interior is divided by a piston 133, is designed to limit the vibrations of the plate 111 and to preserve the spring 119 against early breakage.
With particular reference to FIGS. [0046] 8 to 11, a motor pump for high-pressure washers having the structure according to the invention is generally designated by the reference numeral 210 in a third embodiment.
In particular, the [0047] motor pump 210 can be applied advantageously to high-pressure washers for which considerable variations in the operating conditions are intended.
The [0048] motor pump 210 comprises, within a hermetic casing that is not shown, a rotating plate 211 that is rotationally rigidly associated with a motorized support 212, on which the plate 211 is free to oscillate in order to vary its inclination with respect to the rotation axis 213 (axis of symmetry).
Elastic means [0049] 214 for contrasting the changes in inclination induced by two pistons 215 and 216, arranged parallel to the axis 213 in radially spaced and opposite positions with respect to the support 212, are functionally interposed between the plate 211 and the support 212.
In particular, the [0050] plate 211 has a diametrical lower slot 217, which has a rectangular cross-section and in which a corresponding upper portion 212 a of the support 212 is arranged.
Contact occurs between a [0051] surface 217 a of the slot 217 and an inclined resting surface 212 b of the support 212.
The [0052] plate 211 can move freely with respect to the support 212 within the limits allowed by two pins, designated by the reference numerals 227 and 228 respectively, which are inserted in the part 212 a of the support 212 and pass transversely through the plate 211 at suitable slotted holes 229 and 230, so as to produce joint rotation with the possibility of oscillations between values that determine the axial movement of the pistons 215 and 216 so as to keep unchanged the point 231 of intersection between the axis 213 and the axis 232 of a center bearing 233 arranged between the plate 211 and the pistons 215 and 216.
The elastic contrast means [0053] 214 are constituted by a tubular elastic element 219, made in this case of polyurethane, which is compressed between two mushroom- shaped elements 234 and 235, which have hemispherical heads and stems that are inserted at its ends; said tubular element rests at one end against a complementarily shaped hemispherical seat 211 a of the plate 211 and is inserted in a seat 220 of the support 212 so as to push in contrast with the action of the pistons 215 and 216.
In this embodiment, the [0054] elastic element 219 is inserted in the seat 220 formed in the support 212 in a radial region that substantially corresponds to the region of the pistons 215 and 216.
In practice, the operation of the motor pump is as follows: the operator, by appropriately setting the preloading of the [0055] elastic element 19 or 119, or by choosing the material of the spring 219, determines the contrast force of the plate 11, 111 or 211 on the pistons 15 and 16, 115 and 116, or 215 and 216.
In this manner, without requiring the operator to further adjust the ratio between the pressure and the delivery, the [0056] motor pump 10, 110 or 210 ensures, when the pressure drops, a consequent increase in flow-rate, keeping the effectiveness of the washing action unchanged.
During high-pressure operation, the thrust of the [0057] pistons 15 and 16, 115 and 116, 215 and 216 is in fact such as to compress the spring 19, 119, 219 and arrange the plate 11, 111, 211 in the position of minimum inclination and therefore minimum flow-rate.
When the pressure decreases to the minimum value, the thrust of the pistons is smaller than the force of the spring, and therefore the inclination of the [0058] plate 11, 111, 211 assumes its maximum value and so does the flow-rate.
In practice it has been found that the present invention has achieved the intended aim and objects. [0059]
In particular, attention is called to the absolutely automatic nature of the process for mutually adjusting flow-rate and pressure. [0060]
In particular, it is noted that by increasing automatically the flow-rate as the pressure decreases, the operator is ensured, without being however further involved in adjustment, an optimum level of washability even on surfaces bearing deposits that are difficult to remove. [0061]
Moreover, it is noted that all this has been achieved with an extreme constructive simplicity, which allows to produce the motor pump having the structure according to the invention at costs that are fully competitive with respect to motor pumps having a similar functionality. [0062]
It is also noted that the constructive simplicity never detracts from the overall robustness of the motor pump having the structure according to the invention, which also is highly flexible in terms of flow-rates and pressures available in various applications. [0063]
The present invention is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. [0064]
The technical details may be replaced with other technically equivalent elements. [0065]
The materials and the dimensions may be any according to requirements. [0066]

Claims

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.