MXPA00001070A - Improvement to a pump body and method for making same - Google Patents

Abstract

The invention concerns a pump comprising in particular a substantially cylindrical single-piece body (1) provided, in its lower part, with an intake conduit (11) forthe product and a valve consisting of a cavity (10) containing an element (2) capable of moving between a down stop (12b) corresponding to the closure of said intake conduit (11) and an up stop (12a) corresponding to the opening of said conduit (11). The invention is characterised in that the up stop (12a) is formed by at least one inner discontinuous projection (120) whereof the transverse dimension (X) measured in the cavity (10) is at least equal to 20%of the greatest dimension of the mobile element (2).

Description

IMPROVING A PUMP BODY AND METHOD FOR MANUFACTURING THE PUMP DESCRIPTION OF THE INVENTION The present invention is concerned with a pump and more particularly with an improvement in the inlet valve of the pump, also as with a process for manufacturing of such bom a. The invention is concerned with pumps of the type comprising in particular a substantially cylindrical body of a piece provided in its lower part with a hole or gate for the intake of the product and with a valve. This valve is constituted in a known manner by a seat forming a cavity and containing an element capable of moving between an obstacle or upper seal corresponding to a sealing position of the intake orifice and an obstacle or upper seal corresponding to the opening of the gate and for the filling of the pump body by the product. The stroke of the mobile element that is constituted by a ball must be adjusted to obtain the regular administration by the pump of identical constant doses. Consequently, the upper and lower obstacles or detents must be positioned with precision. According to a known solution, the upper obstacle or seal is constituted by the lower coil of REF: 32702 a helical return spring housed in the pump body. However, this spring creates problems of volume and / or compatibility with the product. A variant embodiment of this obstacle or upper retainer consists in fixing an additional part in the lower part of the pump body above the movable element. However, the production of this piece and its assembly in the pump are complex and expensive operations. In addition, it is necessary to fix on the pump body specific means to fix this piece. Another solution lies in the presence of retaining protrusions molded directly into the pump body, as in US Patent No. 2,294,568. These protrusions project to the interior of the pump body and define towards the upper part, the cavity in which the movable element is housed. However, the transverse dimension of these protuberances measured from the internal wall of the body always remains small with respect to the internal diameter of the cavity in order to allow the body to be demolded and the subsequent introduction of the mobile element into the cavity. For the same reasons, the section of these retaining protuberances does not comprise any angular area or free edge in the lower section. However, in spite of this, the projecting protrusions are sometimes crushed after their expulsion from the mold, which considerably interchanges the subsequent reliability of the pump, since the movable element can escape from its cavity. In Patent Abstracts of Japan Vol. 15 No. 392 of October 4, 1991 and Japanese Patent JP-A-316, 1066, the obstacle or upper seal of the mobile element of the valve is ensured by means of discontinuous internal projections made by cutting using a tool that incorporates a blade (blade) or blade whose profile is beveled. Furthermore, the non-aggressive profile of these projections promotes the clogging of the mobile element in the upper part of the cavity, which increases the risks of malfunctioning of the pump. All these problems are even more substantial when the pump is a miniature pump, designed for example for perfume samples or distributors of small doses of drugs. It is an object of the present invention to satisfactorily solve the technical problems presented by the prior art.

This object is obtained according to the invention by means of a pump of the type comprising in particular a substantially cylindrical body in one piece, provided in its lower part with a gate or intake port of the product and with a valve constituted by a cavity containing an element capable of moving between an obstacle or corresponding lower seal with the seal of the intake hole and a corresponding upper seal with the opening of the orifice, characterized in that the upper portion is formed by 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 feature, the projection has an inner edge from which the generatrices are substantially parallel to the axis of the body. According to a preferred embodiment, the movable element is a ball and the cavity is cylindrical-cylindrical. According to yet another characteristic, the cavity has an upper hole defined laterally by the internal projection and whose diameter is included between 50% and 90% of the largest transverse dimension of the mobile element.

According to other characteristics, the upper face of the projection is wider than its lower face. Such a projection preferably presents, at the outside of the cavity, a cut at least partially cylindrical of which the generatrices are parallel to the axis of the body. According to a particular embodiment, the upper retaining element comprises four diametrically opposed projections in two. These four projections are preferably separated by free sectors capable of allowing the product to pass. According to a specific variant, the free sectors have an included angular length of between 30 ° and 80 °. Another object of the invention is a process for manufacturing a pump, characterized in that the pump body is produced, then at least one discontinuous internal projection or protrusion is formed by modeling or tilling the internal wall of the body by means of a punching die. , of which the diameter of the head is included between 110% and 140% of the largest transverse dimensions of the mobile element. The transverse dimension of the internal projection, the upper diameter of the cavity, as well as the diameter of the head of the punching die are parameters that are chosen with reference to the largest transverse dimension of the mobile element, but which also depend on penetration of the punching die in the wall of the pump body. This depth is limited by the wall thickness available in the area dimensioned for the modeling and to determine the values of the previous parameters, it was set at 25% of the wall thickness of the pump body. According to an advantageous characteristic, the body is internally shaped or shaped by the punching die which drives the material forming the wall downwards and inwards, to partially close the cavity. According to another feature, the body is styled or internally modeled with a punching die that incorporates four blades (blades) or blades diametrically opposed in two. According to still another characteristic of the process, the movable element is introduced in the lower part of the body, before the formation of the cylindrical projection. The pump of the invention thus comprises a particularly reliable and precise inlet valve. With such a valve, the risks of the moving element jamming or leaking are virtually non-existent.

Furthermore, the process of the invention makes it possible to produce projections whose transverse dimension is so large that they could not be made by molding and which, furthermore, would not allow the subsequent positioning of the movable element. The process of the invention also allows projections of various dimensions to be made in the same type of pump body, which allows mobile elements of different sizes to be used. The invention will be more easily understood on reading the following description with reference to the accompanying drawings in which: Figure 1 shows a sectional view of a pump body according to the prior art. Figures 2a and 2b show detailed views in section of an embodiment of a pump body according to the invention, respectively in the closed position of the valve and in the open position thereof. Figures 3a and 3b show partial plan views of the pump body respectively before and after styling. Figure 4a shows a profile view of a punching die used by the process of the invention.

Figure 4b shows a bottom view of the punching die of Figure 4a. Figure 5 shows a sectional view of the pump body as long as the process of the invention is carried out. The body 1 shown in Figure 1 corresponds to that of a conventional pump A used for example for spraying liquids such as perfumes. The body 1 is substantially cylindrical and is made in one piece, for example by injection molding a thermoplastic material. The body is provided in its lower part with an intake orifice 11 fed with product from a tank (not shown) and possibly extending downwards by means of a dip tube. . The intake orifice 11 opens outwardly via a hole on a valve constituted by a cavity 10 containing a moving element such as a ball 2. The ball 2 is apt to move axially between an upper retainer 12b corresponding to the sealing of the valve. orifice 11 and consequently to the closure of the valve and an upper retainer 12a corresponding to the opening of the valve and to the passage of the product towards chamber B of pump A.

The upper retainer 12b is formed by the truncated wall of the cavity 10 against which the ball 2 reaches a tight retention. The upper retainer 12a is formed in the present by means of retaining elements made directly by molding with the pump body assembly, in the upper part of the cavity 10. These retaining elements are protuberances which offer the ball 2 curvilinear contact surfaces that project slightly, that is, each protuberance has a transverse dimension of, at most 20% of the radius R of the ball 2, which is insufficient to guarantee the perfect functioning of the valve. Between these protuberances, lateral passages are arranged for the product. Figures 2a and 2b represent sectional partial 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. Here, the upper obstacle 12a is formed by at least one internal projection 120 made on the upper periphery of the cavity 10 and discontinuously, formed at least one lateral passage for the product around the ball 2.

The transverse dimension X of the projection 12a measured in the conical-cylindrical cavity 10 is at least equal to 20% of the largest transverse dimension of the mobile element and therefore of the diameter of the ball 2 or 40% of its radius R The cavity 10 is therefore defined and partially closed in its upper part by a transverse wall portion whose total length corresponds to twice the transverse dimension X, compared to at least 40% of the diameter of the ball 2 (or 80). % of the radius R) that guarantees a blocking of the ball in translation without clogging. The upper hole 10a of the cavity 10 is therefore relatively narrow and its diameter is included between 50% and 90% of the largest transverse dimension of the mobile element which corresponds to the diameter of the ball 2. The projection 120 represents an inner edge 120c of which the generatrices are substantially parallel to the axis of the body 1. The projection 120 presents to the exterior of the cavity 10 a cut-out at least partially cylindrical of which the generatrices are substantially parallel to the axis of the body 1. The face upper 120a of the projection 120 facing the cavity 10 is wider than the lower face 120b which, for reasons of simplification, is shown in the present parallel to the upper face 120a and perpendicular to the inner wall of the cavity 10 in its upper part. According to a variant mode (not shown), the lower face 10b of the projection 120 is inclined, curvilinear or constituted by a bulge but in no case has a contact zone with the ball 2 in its upper retention position for the purpose of avoiding any guide or sliding of the ball out of the cavity 10. In the valve opening position, shown in figure 2b, the ball is locked in translation by the upper retainer 12a when it is joined against the joint between the edge inner 120c and lower face 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 retention forces are directed radially with respect to the ball to prevent any binding. Figures 3a and 3b correspond to an embodiment with four projections 120, 121, 122, 123 diametrically opposed in two, on the upper periphery of the cavity 10. The ball 2 has not been shown in these figures.

The cuts 12 are interrupted at the level of the discontinuities of the projections 120, 121, 122, 123 to define free sectors 14. On the sectors 14, the profile of the internal wall of the pump body has not been modified and therefore is smooth and continuous, so as not to present any obstacle from the interior to the exterior of the cavity 10 in order to allow the free passage of the product. The projections 120, 121, 122, 123 are here centered, either on one side or the other on two perpendicular diameters. Their respective internal edges 120c, 121c, 122c, 123c have a length such that the intermediate free sectors 14 correspond to portions of alpha angles included between 30 and 80 degrees. The pump A of the invention and in particular the body 1 of the pump is produced in a conventional manner, for example by injection molding of plastics or thermoplastic material. In styling or shaping the internal wall of the body 1, at least one discontinuous internal projection 120 is made and preferably four projections separated by free sectors, when machining the internal wall of the body 1.

The ball 2 is preferably inserted in the lower part of the body 1 before machining or molding, when the inner wall is still uniform. However, if the internal projection 120 is elastically deformable and / or flexible, it is then possible to proceed with the introduction of the ball after styling or shaping, by deforming the retainer on such projection. This operation of carving or stamping is effected by means of a punching punch P, such as that shown in Figures 4a and 4b. The punching die P comprises a mandrel M carrying a head T. The mandrel ensures the centering, guiding and coining of the die in the pump body during machining. The head T ensures the carving or modeling of the body by forced, axial translation of the mandrel M as shown in figure 5. For that purpose, the head T comprises at least one end, in the present case, four sheets (sheets) or blades L designed to propel the material on the wall of the body 1 above and around the ball 2, forming cuts 13 and projections 120, 121, 122, 123 as shown in figure 5. The diameter d of the head is included between 100% and 140% of the diameter of the ball by a depth of penetration of approximately 25% of the thickness of the body wall. The geometry of the sheets (sheets) L shown from below in Figure 4b determines the subsequent geometry of the cuts 13, the projections 120, 121, 122, 123 and the free sectors 14. The lower face C of the sheets L acts by its internal edge in the manner of a knife or a tooth with respect to the plastic material, causing it to run into the inside of the head. The width and length of the lower face C is previously determined as a function of the dimensions sought by the projections. The transverse dimension X of the projections to be made will depend on the volume of material driven downwards and inwards by each of the sheets L on the internal periphery of the cavity 10. Therefore this volume corresponds to the volume defined by the cuts 13. Now, this volume is in itself a function of the diameter of the head T, the width x of the lower face C and the depth of penetration, the angular length y and the height h of the leaves L. The external face 1 of the leaves L is straight and parallel to the axis of the mandrel M, while its internal face 1 'is inclined towards the mandrel M and towards the center of the head T by a beta angle close to 45 degrees in order not to to strain the ball while the head is in operation. The mandrel M comprises a face E designed to be connected against a shoulder Ib of the pump body (cf. figures 2a and 2b) in order to limit the penetration of the head T. Consequently, the position of the upper retainer 12a and consequently the The stroke of the ball 2 will be determined as a function of the height h of the leaves L with respect to the face E of the mandrel. It is noted that, in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (11)

1. CLAIMS Having described the invention as above, it is claimed as property, contained in the following claims: 1. A pump of the type comprising a substantially cylindrical body of a piece provided in its bottom with a gate or orifice for intake of the product and with a valve constituted by a cavity containing an element capable of moving between a corresponding lower retention position with the seal of the intake orifice and a higher retention position corresponding to the opening of the gate and which is defined by at least one discontinuous internal projection whose lower face partially closes the cavity and whose upper face is topped, outside of. the cavity, with a cut at least partially cylindrical whose generatrices are parallel to the axis of the body, characterized in that the projection has an internal edge from which the generatrices are substantially parallel to the axis of the body and which defines, at the junction of the underside , a line of contact with the moving element in the upper retention position, thus making it possible to avoid any jamming or sliding of the element to the outside of the cavity.
2. 2. The pump according to claim 1, characterized in that the movable element is a ball housed in a conical-cylindrical cavity which, in the upper holding position, radially splices against a circular contact line carried by the projection.
3. 3. The pump according to any of the preceding claims, characterized in that the cavity has an upper hole laterally defined by the internal projection and of which the internal diameter is included between 50% and 90% of the largest transverse dimension of the moving element .
4. The pump according to any of the preceding claims, characterized in that the surface of the upper face of the projection is wider than the surface of the lower face.
5. The pump according to any of the preceding claims, characterized in that the upper retainer comprises four diametrically opposed projections in two.
6. 6. The pump according to claim 5, characterized in that the four projections are separated, preferably by free sectors capable of allowing the product to pass.
7. 7. The pump according to claim 5, characterized in that the free sectors have an angular length included between 30 degrees and 80 degrees.
8. 8. A process for the manufacture of a pump according to any of the preceding claims, by producing the pump body with at least a discontinuous internal projection that is carved or patterned on the internal wall of the body by means of a die punching, characterized in that the projection is carved or patterned with an inner edge from which the generatrices are parallel to the body axis and which defines at the junction of the lower face a circular contact line with the moving element in the upper retention position .
9. 9. The process in accordance with the claim 8, characterized in that the body is internally adjusted by the punching die which urges the material forming the wall downwards and inwards to partially close the cavity.
10. 10. The process in accordance with the claim 8 or 9, characterized in that the body is carved or modeled internally by means of a punching die that incorporates four sheets diametrically opposed in two.
11. 11. The process according to any of claims 8 to 10, characterized in that the movable element is introduced into the lower part of the body before the formation of the internal projection.