EP1000246B1 - Improvement to a pump body and method for making same - Google Patents

Abstract

A pump of the type comprising a substantially cylindrical body (1) in one piece provided, in its lower part, with a port (11) for admission of a product and with a valve constituted by a cavity (10) containing an element (2) capable of moving between a lower stop (12b) corresponding to the obturation of said admission port (11) and an upper stop (12a) corresponding to the opening of said port (11), and wherein said upper stop (12a) is formed by at least one discontinuous internal projection (12) whose transverse dimension (x) measured in the cavity (10) is at least equal to 20% of the largest transverse dimension of the mobile element (2).

Description

The present invention relates to a pump and more particularly an improvement of the intake valve of the pump as well as a method of manufacturing such a pump.

The invention relates to pumps of the type comprising in particular a substantially cylindrical body in one piece, provided, in its lower part, a product intake duct and a valve. This valve consists in known manner of a cavity forming seat and containing an element capable of moving between a lower stop corresponding to a closed position of the duct intake and a high stop corresponding to the opening of said conduit and filling the pump body with the product.

The stroke of the movable element which generally consists of a ball, must be adjusted so as to obtain regular delivery by the pump of identical and constant doses.

Therefore, the upper and lower stops must be precisely positioned.

According to a known solution, the upper stop consists of the lower coil of a helical return spring housed in the body of pump.

However, this spring creates problems of bulk and / or compatibility with the product.

An alternative embodiment of this upper stop consists in fixing an insert in the lower part of the pump body above the movable element.

However, the production of this piece and its mounting in the pump are complex and expensive operations.

In addition, it is necessary to make on the pump body specific means for fixing this part.

Another solution involves the presence of retaining bosses produced directly by molding the pump body as in the US 2,294,568.

These bosses protrude inside the pump body and demarcate upwards the cavity in which the movable element is housed.

However, the transverse dimension of these bosses measured at from the inner wall of the body, always remains weak compared to the internal diameter of the cavity to allow the mold to be removed from the mold and the subsequent introduction of the movable element into the cavity. For the same reasons, the section of these retaining bosses does not include angular area or free edge undercut. Yet despite this, sometimes when the mold is ejected, the bosses are crushed protruding, which considerably compromises the subsequent reliability of the pump insofar as the movable element can then escape from its cavity.

In Patent Abstracts of Japan Vol. 15 No. 392 of October 4, 1991 and JP-A-316 1066, the upper stop of the movable element of the valve is ensured by means of discontinuous internal projections made by cutting with a blade tool whose profile is bevelled.

However, the non-aggressive profile of these projections promotes the jamming of the movable element in the top of the cavity, which increases the risk of pump malfunction.

All these problems are even more sensitive when the pump is a miniature pump, intended, for example, for samples of perfume or dispensers for low doses of drugs.

The present invention aims to solve, so satisfactory, the technical problems posed by the prior art.

This object is achieved, in accordance with the invention, by means of a pump of the type comprising in particular a substantially cylindrical body in a single piece provided, in its lower part with a product inlet duct and a valve constituted a cavity containing an element capable of moving between a low stop corresponding to the closing of said intake duct and a high stop corresponding to the opening of said duct,
characterized in that said upper stop is formed of at least one discontinuous internal projection whose transverse dimension measured in the cavity is at least equal to 20% of the largest transverse dimension of the movable element.

According to an advantageous characteristic, said projection has a inner edge whose generatrices are substantially parallel to the axis from the body.

According to a preferred embodiment, said movable element is a ball and said cavity is cylindroconical.

According to yet another characteristic, said cavity has a upper orifice delimited laterally by the internal projection and the diameter is between 50% and 90% of the largest dimension transverse of the movable element.

According to other characteristics, the upper face of said projection is wider than its underside.

Preferably, said projection is surmounted, outside of said cavity, of an at least partially cylindrical cut whose generatrices are parallel to the axis of the body.

According to a particular embodiment, the upper stop includes four diametrically opposite projections two by two.

These four projections are preferably separated by sectors free likely to let pass the product.

According to a specific variant, the free sectors have a angular length between 30 ° and 80 °.

Another object of the invention is a method of manufacturing a pump characterized in that the pump body is produced and then formed at least one discontinuous internal projection by shaping the internal wall of said body by means of a punch whose diameter of the head is between 110% and 140% of the largest transverse dimension of the movable element.

The transverse dimension of the internal projection, the diameter of the upper hole of the cavity as well as the diameter of the head of the punch are parameters that are chosen with reference to the largest transverse dimension of the mobile element but which also depend on the depth of penetration of the punch into the wall of the body of the pump. This depth is limited by the available wall thickness in the area intended for shaping and has been fixed, for the determination values of the above parameters, at 25% of the wall thickness of the pump body.

According to an advantageous characteristic of the process, one shapes internally said body by pushing back with the punch, the material constituting the wall downwards and inwards so as to close partially the cavity.

According to another characteristic, said interior is shaped body with a punch with four diametrically opposed blades two to of them.

According to yet another characteristic of the process, which introduces the movable element into the lower part of the body, prior to the formation of said internal projection.

The pump of the invention thus comprises an intake valve particularly reliable and precise. With such a valve, the risks of jamming or exhausting of the moving element are practically nonexistent.

In addition, the method of the invention makes it possible to produce projections whose transverse dimension is so important that they would not be achievable by molding and which, moreover, would not allow the setting in place of the movable element.

The method of the invention also makes it possible to carry out projections of various dimensions on the same type of pump body, this which allows the use of mobile elements of different sizes.

• la figure 1 représente une vue en coupe d'un corps de pompe selon l'art antérieur ;
• les figures 2a et 2b représentent des vues de détail en coupe d'un mode de réalisation d'un corps de pompe selon l'invention, respectivement en position de fermeture et en position d'ouverture du clapet ;
• les figures 3a et 3b représentent des vues partielles de dessus du corps de pompe respectivement avant et après façonnage ;
• la figure 4a représente une vue de profil d'un poinçon utilisé par le procédé de l'invention ;
• la figure 4b représente une vue de dessous du poinçon de la figure 4a ;
• la figure 5 représente une vue en coupe du corps de pompe pendant la mise en oeuvre du procédé de l'invention.

The invention will be better understood on reading the description which follows, accompanied by the drawings in which:

• Figure 1 shows a sectional view of a pump body according to the prior art;
• Figures 2a and 2b show detailed sectional views of an embodiment of a pump body according to the invention, respectively in the closed position and in the open position of the valve;
• Figures 3a and 3b show partial top views of the pump body respectively before and after shaping;
• FIG. 4a represents a profile view of a punch used by the method of the invention;
• Figure 4b shows a bottom view of the punch of Figure 4a;
• 5 shows a sectional view of the pump body during the implementation of the method of the invention.

The body 1 shown in Figure 1 corresponds to that of a traditional pump A used, for example, for sprayers liquids such as perfumes.

The body 1 is substantially cylindrical and is produced in a single piece, for example, by injection molding of a material thermoplastic.

The body 1 is provided in its lower part 1a with a conduit inlet 11 supplied with product from a tank (not shown) and possibly extended downwards by a dip tube.

The intake duct 11 opens out through an orifice 11a onto a valve consisting of a cavity 10 containing a movable element such than a ball 2.

The ball 2 is capable of moving axially between a low stop 12b corresponding to the obturation of the conduit 11 and therefore to the closing of the valve, and a high stop 12a corresponding to the opening said valve and the passage of the product towards the chamber B of the pump A.

The lower stop 12b is formed by the frustoconical wall of the cavity 10 against which the ball 2 comes into sealing contact.

The upper stop 12a is formed here of retaining elements produced directly by molding, with the entire pump body, at the upper part of the cavity 10.

These retaining elements are bosses which provide the ball 2 of the slightly projecting curvilinear contact surfaces, that is to say that each boss has a transverse dimension of at most 20% of the radius R of ball 2, which is insufficient to guarantee a perfect functioning of the valve.

Between these bosses are formed lateral passages for the product.

Figures 2a and 2b show partial sectional views of an embodiment of the body 1 of a pump according to the invention respectively in the closed and open position of the valve.

The upper stop 12a is here formed of at least one internal projection 120 produced on the upper periphery of the cavity 10 and so discontinuous with at least one side passage for the product around the ball 2.

The transverse dimension X of the projection 12a measured in the cylindroconical cavity 10 is at least equal to 20% of the largest transverse dimension of the movable element and therefore of the diameter of the ball 2 or at 40% of its radius R.

The cavity 10 is therefore delimited and partially closed in its upper part by a transverse wall portion whose total length corresponds to twice the transverse dimension X, i.e. at least 40% the diameter of the ball 2 (or 80% of the radius R), which guarantees a translational locking of the ball without jamming.

The upper opening 10a of the cavity 10 is therefore relatively narrow and its diameter is between 50% and 90% of the largest transverse dimension of the mobile element which here corresponds to the ball diameter 2.

The projection 120 has an inner edge 120c whose generatrices are substantially parallel to the axis of the body 1.

The projection 120 is surmounted, outside the cavity 10, by a at least partially cylindrical cutout 13 whose generatrices are substantially parallel to the axis of the body 1.

The upper face 120a of the projection 120 which is turned towards the outside of the cavity 10 is wider than the lower face 120b which is shown here for reasons of simplification, parallel to the face upper 120a and perpendicular to the internal wall of the cavity 10 in its upper part.

According to a variant, not shown, the lower face 120b of the projection 120 is inclined, curvilinear or consists of a bulge but in no case has a zone of contact with the ball 2 in position high stop to avoid any guide or sliding of the ball out of cavity 10.

In the valve open position, shown in the figure 2b, the ball is blocked in translation by the upper stop 12a coming from resting against the junction between the inner edge 120c and the face lower 120b of the projection 120.

Consequently, the contact area between the projection 120 and the ball 2 is materialized by a substantially circular line on which the support forces are directed radially with respect to the ball so as to avoid jamming.

Figures 3a and 3b correspond to an embodiment with four projections 120, 121, 122, 123 diametrically opposite two to two on the upper periphery of the cavity 10. In these figures, the ball 2 was not represented.

The cuts 13 are interrupted at the discontinuities projections 120, 121, 122, 123 to delimit free sectors 14.

On sectors 14, the profile of the internal wall of the body of pump has not been modified and is therefore smooth and continuous, so as not to present no obstacle from the inside to the outside of the cavity 10 to allow free passage of the product.

The projections 120, 121, 122, 123 are here centered, on the one hand and on the other, on two perpendicular diameters.

Their respective inner edges 120c, 121c, 122c, 123c have a length such that the free sectors 14 intermediate correspond to portions of angles α between 30 ° and 80 °.

The pump A of the invention, and in particular, the body 1 of said pump is produced in a traditional way, for example, by molding injection of plastic or thermoplastic material.

Then, by shaping the internal wall of the body 1, minus one discontinuous internal projection 120, and preferably four projections separated by free sectors, shaping the inner wall of the body 1.

Preferably, the ball 2 is introduced into the lower part 1a of the body 1 prior to shaping, when the internal wall is still uniform.

However, if the internal projection 120 is elastically deformable and / or flexible, it is then possible to introduce the ball after shaping, by deforming support on said projection.

This shaping or stamping operation is carried out by means of a punch P such as that shown in FIGS. 4a and 4b.

The punch P comprises a mandrel M carrying a head T. The mandrel M provides centering, guiding and setting of the punch in the pump body during shaping.

The head T ensures the shaping of the body by axial translation and force of the mandrel M as shown in FIG. 5.

For this purpose, the head T comprises at least one, and here four blades L intended to repel the material on the wall of the body 1 above and around the ball 2, forming the cutouts 13, and the projections 120, 121, 122, 123 as shown in FIG. 5.

The diameter d of the head is between 110% and 140% of the bimetal diameter for a penetration depth of about 25% of the thickness of the body wall

The geometry of the blades L shown in bottom view on the Figure 4b, determines the subsequent geometry of the cutouts 13 of the projections 120, 121, 122, 123 and free sectors 14.

The lower face C of the blades L acts by its edge outside the like a knife or a tooth vis-à-vis the plastic in causing it to flow towards the inside of the head.

The width and length of the underside C is determined beforehand depending on the dimensions sought for the projections.

The transverse dimension X of the projections to be produced will depend on the volume of material pushed down and inward by each blades L on the inner periphery of the cavity 10. This volume therefore corresponds to the volume delimited by the cutouts 13. However, this volume is itself a function of the diameter of the head T, of the width x the underside C and the depth of penetration, the length angular y and the height h of the blades L.

The outer face l of the blades L is straight and parallel to the axis of the mandrel M while their internal face is inclined towards the mandrel M and towards the center of the head T with an angle β close to 45 ° so as not to use the ball when working the head.

The mandrel M has a face E intended to come into abutment against a shoulder 1b of the pump body (see Figures 2a and 2b) to limit the sinking of the T head.

Consequently, the position of the upper stop 12a, and therefore, the stroke of ball 2, will be determined according to the height h of blades L with respect to the face E of the mandrel.

Claims (11)

1. Pump of the type comprising a substantially cylindrical body (1) in one piece provided, in its lower part, with a port (11) for admission of the product and with a valve constituted by a cavity (10) containing an element (2) capable of moving between a lower stop (12b) corresponding to the obturation of said admission port (11) and an upper stop (12a) corresponding to the opening of said port (11), which is defined by at least one discontinuous internal projection (120) whose lower face (120b) partially closes said cavity and whose upper face (120a) is topped with, outside said cavity, an at least partly cylindrical cut-out (13) whose generatrices are parallel to the axis of the body (1),
   characterized in that said projection (120) presents an inner edge (120c) of which the generatrices are substantially parallel to the axis of the body (1), and which defines, upon joining the lower face (120b), a contact line with the mobile element (2) in the upper stop thus preventing said element from being stuck or sliding outside the cavity (10).
2. Pump according to Claim 1, characterized in that said mobile element is a ball housed in a conico-cylindrical cavity (10) which radially abuts in the upper stop against a circular contact line borne by said projection (120).
3. Pump according to one of the preceding Claims, characterized in that said cavity (10) presents an upper orifice (10a) laterally defined by the inner projection (12) and of which the inner diameter is included between 50% and 90% of the largest transverse dimension of the mobile element (2).
4. Pump according to one of the preceding Claims, characterized in that the upper face (120a) of said projection (120) is wider than its lower face (120b).
5. Pump according to one of the preceding Claims, characterized in that the upper stop (12a) comprises four projections (120, 121, 122, 123) diametrally opposite in two's.
6. Pump according to Claim 5, characterized in that the four projections are separated, preferably by free sectors (14) capable of allowing the product to pass.
7. Pump according to Claim 5, characterized in that the free sectors (14) present an angular length included between 30° and 80°.
8. Process for manufacturing a pump according to one of the preceding Claims, with the pump body (1) being produced with at least one discontinuous internal projection (120) which is formed by fashioning the inner wall of said body by means of a punching die (P), characterised in that said projection (120) is fashioned with an inner edge (120c) whose generatrices are parallel to the axis of said body and which defines, upon joining the lower face (120b), a circular contact line with the mobile element (2) in the upper stop.
9. Process according to Claim 8, characterized in that said body is internally fashioned by the punching die (P) pushing the material constituting the wall downwardly and inwardly so as partly to close the cavity (10).
10. Process according to Claim 8 or 9, characterized in that said body (1) is internally fashioned by a punching die (P) incorporating four blades (L) diametrally opposite in two's.
11. Process according to one of Claims 8 to 10, characterized in that the mobile element (2) is introduced in the lower part of the body (1) prior to the formation of said inner projection (120).

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