FR2634826A1 - RECIPROCATING PISTON PUMP, PARTICULARLY MANUAL OPERATION - Google Patents

Abstract

The invention relates to a reciprocating piston pump, in particular with manual actuation, the piston 12 is mounted to pivot back and forth about an axis 11 outside the chamber 2 of the pump. Preferably, this chamber is in the form of a torus sector, and the sealing is ensured by a rolling membrane 10 whose edges are fixed to the walls of the chamber and whose central part 19 is fixed to the top of the piston. This gives a pump whose actuation, by means of a lever 32, is less tiring for the operator than conventional pumps.

Description

The present invention relates to a piston pump in motion

  alternative, especially operable at

the hand.

  The origin of the invention is to be found in researches for improving manual pumps for portable sprayers used in agriculture and horticulture, but the reader will understand, on reading the following, that the invention can find some

  applications in many other areas.

  The manual pumps currently used for sprayers are generally pumps of the type comprising a cylinder with circular section in which moves back and forth a piston, also circular, provided with a seal. An actuating rod, provided with a handle, is connected to the piston, and a guide part is provided on the cylinder to hold the rod coaxial with the cylinder. On the side opposite the rod, intake and exhaust passages open into the piston, they are provided with valves arranged to allow the passage of the fluid only in one direction, namely towards the cylinder for the intake valve. , and towards

  the outside of the cylinder for the exhaust valve.

  Such a device is so simple that it seems difficult to improve. However, it has the defect of forcing the operator to move the handle rectilinearly, and of the hand which actuates it. Such a movement is not natural, the human body being rather shaped to execute movements in an arc. This makes the guide part necessary, and causes fatigue.

not required by the operator.

  The inventor therefore posed the problem of improving this old type of pump, by taking advantage of the fact that it is now possible to obtain, in particular by plastic molding, complicated parts to

a very low price.

  To achieve this result, the invention provides a pump comprising a chamber in which a piston can move, sealing means provided between the walls of the chamber and the piston, an intake duct opening into the chamber and provided with '' an intake valve or valve capable of allowing a fluid to flow towards the chamber and to oppose the passage of this fluid in the opposite direction, and an exhaust duct opening into the chamber and provided with a valve or exhaust valve capable of allowing said fluid to exit the chamber and to oppose the passage of the fluid in the opposite direction, the pump further comprising means for moving the piston back and forth, which has the particularity that the piston is mounted to pivot back and forth around an axis which does not penetrate

in the bedroom.

  Preferably, if the pump is intended to be actuated manually using a lever, the piston is mounted on an arm connected to a shaft whose axis is the pivot axis of the piston, and the lever is integral of the arm or the shaft, the latter then being integral in rotation

of the arm.

  As mentioned above, a traditional pump comprises four essential elements: the cylinder with its intake and exhaust ducts, the piston, the control rod and the guide means. These elements can be reduced to three, for example by joining the guide member to the cylinder or the piston, but this is at the cost of an increase in weight or a deterioration in the results. The invention allows, at least in theory, to have only two parts, the cylinder carrying bearings on which can pivot

  the piston-arm-lever assembly, and this assembly.

  According to a particularly advantageous embodiment, the sealing means consist of a rolling membrane whose edges are fixed to the wall of the chamber and whose central part is fixed.

on the top of the piston.

  In this case, preferably, the piston has the shape of a section of torus whose axis is the pivot axis of the piston, or wears a jacket having this shape, and the chamber has a similar shape, but with a slightly larger section to allow free play of the unrolling membrane. We get the best

reduction of dead space.

  Pumps & diaphragm but piston with straight stroke are already known. To adapt them to a piston & stroke in an arc, an adaptation is necessary. Indeed, it is necessary to avoid a relative displacement of the central part of the membrane compared

  to the piston, which would be a source of friction and wear.

  It is for this reason that the membrane is fixed on the

top of the piston.

  Other embodiments are however possible, for example it can be provided that the piston has the shape of a section of torus whose axis is the pivot axis of the piston, or wears a jacket having this shape, and the means of sealing consist of a seal fixed to the wall of the chamber and in leaktight contact with the wall of the

  piston during its movement.

  Advantageously, in this case as in the previous one, the pump comprises a pump body made up of two assembled elements, a first element comprising a first part of the chamber in the form of a torus section and the intake and exhaust ducts, as well a support for the tree, and the second element comprises the rest of the chamber. The first part of the chamber and the rest of it each form a section of toroid of approximately equal angular amplitude, and the seal, or the edge of the unwinding membrane, is held by tightening

between the two elements.

  It is also possible to provide that the piston carries on its periphery a seal, and the interior wall of the chamber has the shape of a section of torus having as its axis the pivot axis of the piston, this interior wall being in contact waterproof with seal

  seal while moving the piston.

  According to an advantageous manufacturing method, at least part of the piston is in one piece with the

  arm, and obtained by plastic molding.

  The invention will now be explained in more detail using a practical example, illustrated with the drawings, in which: Figure 1 is a vertical section of a pump according to the invention, and Figure 2 is a section according to line II-II of

Figure 1.

  FIG. 1 shows a pump, intended for a spraying device, and designed to pass a liquid from an inlet conduit i to a discharge conduit 2. The pump body 3, which is a piece of complex shape , obtained by molding, includes a pumping chamber 4, in the shape of a torus sector, open downward and extending over an arc of approximately 30 ". At the upper part of the chamber 4 open the intake duct 1 and the exhaust duct 2. The intake duct 1 is provided with an intake valve 5. The exhaust duct 2 is provided with a valve

exhaust 6.

  At its lower part, the pump body carries two extensions 7, 8, which carry the bearings 9, of the shaft 11 which carries the piston 12. These parts

will be described later.

  The chamber 4 is extended downwards by means of an extension 13, formed of a segment of O-tube, extending over approximately 30, and which carries on one of its ends a flange 14. The lower edge of the chamber also carries a flange 15 provided externally with a thread 16. A clamp 17, internally threaded, clamps the flanges 14 and 15 against each other, by screwing onto the thread 16. A membrane 18, which s extends into the chamber 4, is clamped by its edges between the flanges 14 and 15. This membrane 18 which is an important element of the pump, is present, before assembly, in the form of a plane provided, roughly in its central part, with a thicker part 19. This thicker part carries, on one of its faces, two studs 20 and 21 provided with snap projections 22. The piston 12, in the form of a disc, has two holes intended for receive the pins 20 and 21, and thus fix the membrane on the piston for its entry ment. The piston 12 carries a jacket 23, in the shape of a torus segment, extend over envirton 45 ′, and provided with a flat upper part 24 which comes to rest on the piston, and which is also provided with holes for the nipples 20 and 21. This jacket 23, immobilized against the piston 12 by means of the pins 20, 21, with their latching projections 22, is prevented

  by them to pivot relative to the axis of the piston.

  The piston 12 is carried by a piston rod, with cross section, and in the shape of an arc of a circle. At its end opposite the piston, the rod 25 is secured to an arm 26, which is substantially perpendicular to it. The arm 26 is crossed by a square bore 27, of dimensions

  adapted to the shaft 11, which is itself of square section.

  Bearings 28 and 29 are placed between the shaft 11 and the bearings 9 and 10. These bearings have a cylindrical outer surface of revolution, adapted to that of the bearings 9 and 10, and an internal bore with square section, adapted to that of

tree 11.

  The shaft 11 can slide in the bearings 28, 29 and in the bore 27 of the arm 26. It can in particular be disassembled, for transport, pushed in to reduce the size of the assembly, or placed in another position allowing easy activation. To immobilize it, in the working position or in the storage position, the bearings 28, 29 each carry a male conical extension 20, onto which a tubular adjustment rod 31 can be screwed, the end of which is also conical. The screwing of the adjustment rod 31 serves to tighten the extensions 30 against the shaft 11, and to immobilize it in position, the bearings being themselves immobilized in axial position by the bearings 9 and 10

and arm 26.

  There is shown at 32, in Figures 1 and 2, a portion of the rod of the actuating lever which controls the shaft 11. In Figure 1, there is shown, in dashes, the position occupied by the rod of the lever when the

piston is in the down position.

  Although the example described corresponds to a preferred type of embodiment, it should be noted that other embodiments are possible. In particular, the shape of the pumping chamber 4, with its extension 13, does not necessarily have the shape of an O-ring segment. This form is only chosen to limit the importance of the dead volume. It would be the same if, instead of providing a rolling membrane, a non-deformable piston in the form of a torus segment of suitable length was used, with a fixed joint, which could, for example, be clamped between the flanges 14 and 15. On the contrary, if a piston carrying sealing means sliding on the surface of the chamber is used, this surface should necessarily have the shape of a

hollow torus segment.

Claims (8)

  1. Pump comprising a chamber (4) in which a piston (12) can move, sealing means provided between the walls of the chamber and the piston, an intake duct (1) opening into the chamber and provided an intake valve or valve (5) capable of allowing a fluid to flow towards the chamber and to oppose the passage of this fluid in the opposite direction, and an exhaust duct (2) opening into the chamber (4) and provided with an exhaust valve or valve (6) capable of allowing said fluid to exit the chamber and of opposing the passage of the fluid in the opposite direction, the pump further comprising means (27 , 25, 26) for moving the reciprocating piston, characterized in that the piston is mounted to pivot reciprocally about an axis (11) which does not penetrate into bedroom.   2. Pump according to claim 1 and designed to be actuated manually using a lever, characterized in that the piston is mounted on an arm (26) connected to a shaft (11) whose axis is l pivot axis of the piston, and the lever is integral with the arm or the shaft, the latter then being integral in rotation of the arm.   3. Pump according to claim 1 or 2, characterized in that the sealing means consist of a rolling membrane (18) whose edges are fixed to the wall of the chamber and whose part   central (19) is fixed on the top of the piston.   4. Pump according to claim 3, characterized in that the piston has the shape of a section of torus whose axis is the pivot axis of the piston, or carries a jacket (23) having this shape, and the chamber has a similar shape, but with a slightly larger section for   allow free play of the unrolling membrane.   5. Pump according to claim 1 or 2, characterized in that the piston has the shape of a section of torus whose axis is the pivot axis of the piston, or carries a jacket (23) having this shape, and the sealing means consist of a seal fixed to the wall of the chamber and in leaktight contact with the wall of the piston during the displacement of the latter.   6. Pump according to one of claims 3 to 5,   characterized in that the pump comprises a pump body made up of two assembled elements, a first element (1) comprising a first part of the chamber (4) in the form of a torus section and the intake and exhaust ducts (1 , 2), as well as a support (9, 10) for the shaft (11), and the second element (13) comprises the rest of the chamber, the first part of the chamber and the rest of the latter forming each a section of torus of approximately equal angular amplitude, and the edge of the unrolling membrane (18), or the seal, being maintained by tightening between the two elements.   7. Pump according to claim 1 or 2, characterized in that the piston carries on its periphery a seal, and the inner wall of the chamber has the shape of a torus section having as its axis the pivot axis of the piston, this inner wall being in leaktight contact with the seal while the piston is moving.   8. Pump according to one of claims 1 to 7,   characterized in that at least a part of the piston is in one piece with the arm, and obtained by molding of plastic material.