Hand-operated pump

Abstract

Manually operated pump (1) comprising a housing body (2) inside which a piston (3) slides in a sealed manner, associated with a hollow rod (4), allowing its movement, in opposition to a spring (20), in the housing body (2), the pump providing a base (5) which closes the housing body (2) and is provided with an opening (11) for the rod (4), at least a part of the housing body (2) and of the piston (3) defining a compression chamber (6) associated with at least one inlet valve element (8) and one discharge valve element (9), the discharge valve element (9) being in communication with a cavity of the rod (4); the spring (20) is made of PEI. Figure for abstract: Fig: 1

Description

Title of the invention: Manually operated pump FIELD OF THE INVENTION

[0001] The present invention relates to a manually operated pump.

[0002] It relates in particular to a manually operated pump for cosmetic or medical products, such as creams, sprays, perfumes, etc. STATE OF THE ART

[0003] Known hand-operated pumps are made up of a large number of parts assembled together. Most of these parts are made of plastic.

[0004] A fundamental part of hand-operated pumps is the spring, which is made of metal.

[0005] Attempts have been made nowadays to produce plastic springs. However, none of those known offer performances comparable to metal springs and are stable over time. Summary of the invention

[0006] The object of the present invention is to provide a manually operated pump which is improved over the prior art.

[0007] Another object of the invention is to provide a pump which is entirely formed of plastic parts and therefore devoid of metal parts.

[0008] Another object of the present invention is to provide a pump which is more ecological and / or recyclable than those which are known.

[0009] This object and other objects are achieved by a manually operated pump made in accordance with the following technical teachings:

[0010] 1. Manually operated pump, comprising a body forming a housing inside of which a piston slides in a sealed manner, associated with a hollow rod allowing its movement, in opposition to a spring, in the body forming a housing, the pump providing a base which closes the body forming a housing and is provided with an opening for the rod, at least a part of the body forming a housing and of the piston defining a compression chamber associated with at least one element forming an inlet valve and one element forming a discharge valve, the element forming a discharge valve being in communication with a cavity of the rod, characterized in that the spring is made in a single piece of polyetherimide, a section of the coil of the spring being dimensioned so that a circle with a diameter of between 0.5 mm and 1.5 mm, preferably 0.8 mm, is inscribed inside it.

[0011] 2. Pump according to 1, in which the density of the polyetherimide in which is made the spring is between 1.2 grams / cm3 and 1.35 grams / cm3, and is preferably 1.27 grams / cm3.

[0012] 3. Pump according to 1, in which the tensile modulus of the polyetherimide in which is made the spring is between 3000 and 3500 MPa, preferably is 3200 MPa and / or in which the flexural modulus is between 3000 and 3500 MPa, preferably is 3300 MPa.

[0013] 4. Pump according to 1, in which the base is made in one piece with the spring.

[0014] 5. Pump according to 1, in which said rod has, at least on a part of its length, an outside diameter slightly smaller than an inside diameter of said spring, so as to serve as a guide for deformation of said spring.

[0015] 6. Pump according to 1, in which the base meets said piston when it is in an upper stroke bottom position, the base extending inside the housing body by a calibrated height, so as to define a volume of said compression chamber, the rigidity of the spring being correlated to said height.

[0016] 7. Pump according to 1, in which said rod has an end of travel configured for meet said base before said spring is fully compressed.

[0017] 8. Pump according to 1, in which the rod is made from a first and a second part coupled to each other by snap-fastening.

[0018] 9. Pump according to 1, in which the piston is slidably threaded onto the stem and defines, in cooperation with said stem, said discharge valve element.

[0019] 10. Pump according to 1, in which a ratio between the pitch of the spring and the thickness maximum coil diameter is between 1.8 and 2.5, preferably greater than 2, and better still 2.045.

[0020] 11. Pump according to 1, in which the pump comprises a ring, a pusher distributor, a seal, a float tube and a cap removably attachable to the ring, all made of polypropylene, the weight of the spring (20) being less than 3.9% of the total weight of the pump. BRIEF DESCRIPTION OF THE FIGURES

[0021] Other characteristics and advantages of the invention will appear more clearly on reading the description of a preferred, but not exclusive, embodiment of the manually operated pump illustrated, by way of example and therefore without limitation, in the appended drawings, in which:

[0022] [Fig.l] is a sectional view, with certain parts shown schematically in dotted lines, of a manually operated pump according to the invention, in an upper stroke end position;

[0023] [Fig.2] represents the same section as [Fig.l], but simplified, while the pump is in a lower stroke end position;

[0024] [Fig.3] is a detail view of a portion of the pump of [Fig.l]; and

[0025] [Fig.4] is an axial section of the part of [Fig.3]. DETAILED DESCRIPTION OF THE INVENTION

[0026] With reference to the above-mentioned figures, there is shown a manually operated pump, generally designated by the reference number 1.

[0027] The manually operated pump 1 comprises a body forming a housing 2 inside which a piston 3 slides in a sealed manner associated with a hollow rod 4 allowing its movement, in opposition to a spring 20, in the body forming a housing 2.

[0028] Advantageously, the housing body and the rod can be made of PP. The piston 3 is preferably made of PE - LDPE or PP.

[0029] The pump provides a base 5 which closes the housing body 2 and is provided with an opening 11 for the rod 4.

[0030] At least a portion of the housing body 2 and of the piston 3 define a compression chamber 6 associated with at least one intake valve element 8 and one discharge valve element 9, the discharge valve element 9 being in communication with a cavity 4A of the rod 4.

[0031] According to the invention, the spring 20 is made from a single piece of polyetherimide (PEI).

[0032] Advantageously, the density of the plastic material (PEI) from which the spring is made can be between 1.2 grams / cm3 and 1.35 grams / cm3, and it is preferably 1.27 grams / cm3.

[0033] Advantageously, the polyetherimide from which the spring 20 is made has a tensile modulus of between 3000 and 3500 MPa, preferably 3200 MPa (ISO 527 test, 1 mm / min) and / or a flexural modulus of between 3000 and 3500 MPa, preferably 3300 MPa (ISO 178 test, 2 mm / min).

[0034] Advantageously, the spring 20 and the base 5 are made in one piece from the same plastic material as that defined above, preferably injection molded.

[0035] A free end 20B of the spring can meet a flange 4C, preferably formed in one piece with the rod 4.

[0036] The spring 20 may have a free end 20B configured in the form of a flange.

[0037] The rod 4 may have, at least over part of its length, a diameter outer diameter DI only slightly less than an inner diameter D2 of said spring 20, so as to serve as a guide for deformation of said spring 20.

[0038] Furthermore, the housing-forming body may define a skirt 2A for limiting the lateral movement of the spring.

[0039] The base 5 can meet said piston 3 when it is in an upper stroke bottom position, the base extending inside the body forming a housing by a calibrated height H1, so as to define a volume of said compression chamber 6, the rigidity of the spring preferably being correlated to said height H1.

[0040] The spring-base system, with the base protruding inside the housing body by a calibrated height, determines the volume dispensed by the pump at each actuation.

[0041] It should be noted that, as mentioned above, the spring 20 and the base can be made in two separate pieces.

[0042] For this purpose, the spring 20 may provide a flange (not shown), opposite the 20B, which rests on a surface of the base 5 configured in a suitable manner to receive it there.

[0043] If one wishes to modify the distribution volume, it is sufficient to use a base 5 (or a spring / base group) of a different height Hl (in particular of a higher height Hl to have a lower volume and of a lower height Hl to have a higher volume).

[0044] The spring 20, and in particular its rigidity, can be calibrated precisely according to the distribution volume of the pump. And consequently the rigidity of the spring can be correlated to the height H1, on which the distribution volume of the pump depends.

[0045] In the case where the spring and the base are made in one piece, it is not possible to make assembly errors, for example by using, for a pump which dispenses a determined volume, a spring having an unsuitable rigidity.

[0046] The rod 4 may have an end of travel configured to meet said base 5 before said spring 20 is completely compressed.

[0047] The end of travel (and the corresponding diameter) is very useful, especially for keeping the spring guided during the working phases of the spring.

[0048] This is all the more true for a spring made of plastic, polyetherimide, so as not to exhaust it or harm its operation.

[0049] The pump may comprise a ring 21 for fixing said housing body 2 to a container with which said pump 1 may be associated, said ring preferably being connected in a snap-fit manner to said housing body 2.

[0050] Advantageously in the coupling with the container, which will for example provide a threaded neck, it is possible to insert a sealing gasket G, sandwiched between the body forming the housing and the container itself.

[0051] Advantageously, this sealing joint G can be made of PP, PE or LDPE, as can the float (not shown) associated with the spring.

[0052] The rod 4 can be associated in a substantially sealed manner with a dispensing pusher 22; the dispensing pusher 22 preferably has a cantilever structure 22A inserted in a sealed manner in an enlarged cavity 4D of said rod 4. As a variant, the pusher 22 can of course be threaded onto the outside of the rod, still in a sealed manner.

[0053] For efficient assembly of the pump engine, the rod 4 can be made from a first 4B and a second 4E part coupled to each other by snap-fastening, advantageously both made of PP.

[0054] The rod is therefore mounted by threading the spring group 20-base 5 onto the first part 4B of the rod and by snap-coupling this group with the second part 4E of the rod, onto which the piston 3 has previously been threaded.

[0055] The spring-base group can also furthermore be coupled by snap-fastening with the housing body 2, for example by means of an undercut 40.

[0056] In this way, once mounted, the motor can be handled as a stand-alone entity and ready for use, that is to say for subsequent coupling with the ring 21 and the pusher 22, also preferably made of polypropylene (PP).

[0057] To conclude the description, it should be specified that the piston 3 can be slidably fitted onto the rod 4 and can define, in cooperation with said rod, said discharge valve element 9.

[0058] In fact, the piston, by lifting under the effect of the pressure present in the compression chamber 6, releases a passage 30 which puts the cavity 4A of the rod into communication with the compression chamber, precisely for distribution.

[0059] With particular reference to [Fig.4], the configuration of the spring 20 will now be described in more detail.

[0060] The spring 20 can advantageously be formed of three turns, but it is possible for the number of turns to be between 2.5 and 5.

[0061] The pitch P of the spring can advantageously be between 4 mm and 8 mm, preferably 5.4 mm.

[0062] The useful height E of the spring 20, in other words that between the two flanges or between the flange and the base, can be between 13 and 25 mm, preferably 16.2 mm. The useful height is of course considerably influenced by the number of turns.

[0063] Advantageously, the ratio between the useful height E and the number of turns is between 5 and 6, and is advantageously 5.4.

[0064] The total height A of the spring 20, in other words the total height between the two flanges, excluding the base 5 - if it is integrated into the spring - can be between 15 mm and 28 mm, preferably 19 mm.

[0065] The maximum thickness B of each turn may be between 1.8 and 4 mm, preferably 2.64 mm.

[0066] This maximum thickness B of course depends on the shape of the section of the coil.

[0067] Advantageously, the maximum thickness B is correlated to the pitch of the spring P (and consequently to the useful height E) of the spring 20.

[0068] Advantageously, to prevent the coils of the spring, at the end of their travel, from being completely compressed, the ratio between the pitch P of the spring and the maximum thickness of the coil B is between 1.8 and 2.5, preferably greater than 2, even better is 2.045.

[0069] The section of the coil is, in fact, sized to allow the inclusion (in this section) of a circle C with a radius of between 0.5 mm and 1.5 mm, preferably with a radius of 0.8 mm.

[0070] The radius of the circle C can correspond to the outer connecting radius R of each turn.

[0071] The angle Q, useful for demolding the spring 20 from the mold, can be between 20° and 55°, preferably 40°.

[0072] The dimensioning of the section of the spring 20 results from the definition of a circular section (more precisely of radius R) to which material is “added” to facilitate the step of demolding and extraction from the injection mold, so as to create the angle Q described above and to define the final shape of the section of the coil.

[0073] As seen in [Fig.4], the shape of the section of the coil is substantially trapezoidal, with a lower base curved in an arc of a circle.

[0074] Other shapes that can be used to achieve the same object are a pure trapezoidal section (with the edges connected), rhomboidal (always with the edges connected) or elliptical.

[0075] In all cases, the radius of the circle inscribed in the section of the coil will always be between 0.5 mm and 1.5 mm, preferably 0.8 mm.

[0076] The weight of the spring 20 (alone or with the base 5) is advantageously less than 3.9% of the total weight of the finished pump, therefore provided with a float (not shown) and a cap (or closing plug, also not shown) which can be removably attached to the ring 21.

[0077] Even more advantageously, the weight of the spring 20 is less than 3.5% of the total weight of the finished pump and a PP container associated therewith.

[0078] This ensures the possibility of recycling the pump of the present invention in the polypropylene (PP) recycling sector.

[0079] Various embodiments of the invention have been described, from which other modes and other embodiments based on the same inventive concept can be conceived.

Claims

Claims

1. Manually operated pump (1), comprising a housing body (2) inside which a piston (3) slides in a sealed manner, associated with a hollow rod (4) allowing its movement, in opposition to a spring (20), in the housing body (2), the pump providing a base (5) which closes the housing body (2) and is provided with an opening (11) for the rod (4), at least a part of the housing body (2) and of the piston (3) defining a compression chamber (6) associated with at least one inlet valve element (8) and one discharge valve element (9), the discharge valve element (9) being in communication with a cavity of the rod (4), characterized in that the spring (20) is made in one piece from polyetherimide, a section of the coil of the spring being dimensioned so that a circle (C) with a diameter between 0.5 mm and 1.5 mm,preferably 0.8 mm.,

2. Pump (1) according to claim 1, wherein the density of the polyetherimide from which the spring (20) is made is between 1.2 grams / cm3 and 1.35 grams / cm3, and is preferably 1.27 grams / cm3.

3. Pump (1) according to claim 1, wherein the tensile modulus of the polyetherimide from which the spring (20) is made is between 3000 and 3500 MPa, preferably is 3200 MPa and / or wherein the flexural modulus is between 3000 and 3500 MPa, preferably is 3300 MPa.

4. Pump (1) according to claim 1, wherein the base (5) is made in one piece with the spring (20).

5. Pump (1) according to claim 1, wherein said rod (4) has, at least over part of its length, an outside diameter (D1) slightly smaller than an inside diameter (D2) of said spring (20), so as to serve as a guide for deformation of said spring (20).

6. Pump (1) according to claim 1, wherein the base (5) meets said piston (3) when it is in an upper stroke bottom position, the base extending inside the housing body by a calibrated height (Hl), so as to define a volume of said compression chamber (6), the rigidity of the spring being correlated to said height (Hl).

7. Pump (1) according to claim 1, wherein said rod (4) has an end of travel (23) configured to meet said base (5) before said spring (20) is completely compressed.

8. Pump (1) according to claim 1, in which the rod is made from a first (4B) and a second part (4E) coupled to each other by snap-fastening.

9. Pump (1) according to claim 1, wherein the piston (3) is slidably threaded onto the rod (4) and defines, in cooperation with said rod, said discharge valve element (9).

10. Pump according to claim 1, in which a ratio between the pitch (P) of the spring and the maximum thickness (B) of the coil is between 1.8 and 2.5, is preferably greater than 2, and even better 2.

045.

11. A pump according to claim 1, wherein the pump (1) comprises a ring (21), a distributor pusher (22), a seal (G), a float tube and a cap removably attachable to the ring, all made of polypropylene, the weight of the spring (20) being less than 3.9% of the total weight of the pump.

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