Manually operated pump

Abstract

A manually operated pump (1) comprising a housing (2) within which a piston (3) slides in a sealed manner, associated with a hollow rod (4) enabling its movement, in opposition to a spring (20), within the housing (2), the pump having a base (5) which closes the housing (2) and is provided with an opening (11) for the rod (4), at least a portion of the housing (2) and 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 in the rod (4); the spring (20) is made of PEI. Figure for the abbreviation: Fig: 1

Description

Title of the invention: Manually operated pump FIELD OF 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. PRIORITY OF THE TECHNOLOGY

[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 manually operated pumps is the spring, which is made of metal.

[0005] Attempts have been made to produce springs from plastic materials in recent times. However, none of those known offer performance comparable to metal springs and are stable over time. Summary of the invention

[0006] The present invention aims to provide a manually operated pump that is improved compared to the prior art.

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

[0008] The present invention also has the further objective of providing a pump that is more environmentally friendly and / or recyclable than those that are known.

[0009] This object and other objects are reached 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 in 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 the casing, the pump providing a base which closes the body forming the casing and is provided with an opening for the rod, at least a part of the body forming the casing and of the piston defining a compression chamber associated with at least one element forming an inlet valve and an 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 one piece of polyetherimide, a section of the coil of the spring being dimensioned so that a circle with a diameter between 0.5 mm and 1.5 mm, preferably 0.8 mm, is inscribed inside it.

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

[0012] 3. Pump according to 1, wherein 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 outer diameter slightly smaller than an inner diameter of said spring, so as to serve as a guide for the deformation of said spring.

[0015] 6. Pump according to 1, in which the base meets said piston when it is in a higher bottom-out position, the base extending inside the body forming the casing to a calibrated height, so as to define a volume of said compression chamber, the stiffness of the spring being correlated to said height.

[0016] 7. Pump according to 1, in which said rod has a limit switch configured for meet said base before said spring is completely compressed.

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

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

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

[0020] 11. Pump according to 1, wherein the pump comprises a ring, a pusher distributor, a sealing gasket, a float tube and a cap which can be removably attached 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 features and advantages of the invention will become more apparent upon 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 accompanying drawings, in which:

[0022] [Fig.1] is a cross-sectional view, with certain parts represented schematically in dotted lines, of a manually operated pump according to the invention, in a top bottom-stroke position;

[0023] [Fig.2] represents the same section as [Fig.1], but simplified, while the pump is in a lower bottom-stroke position;

[0024] [Fig. 3] is a detail view of part of the pump of [Fig. 1]; and

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

[0026] With reference to the aforementioned figures, a manually operated pump is shown, designated globally by the reference number 1.

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

[0028] Advantageously, the body forming the housing 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 body forming the housing 2 and is provided with an opening 11 for the rod 4.

[0030] At least a part of the body forming the housing 2 and the piston 3 define a compression chamber 6 associated with at least one intake valve element 8 and a 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 in one piece of polyetherimide (PEI).

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

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

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

[0038] In addition, the body forming the housing can define a skirt 2A for limiting the lateral displacement of the spring.

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

[0040] The spring-base system, with the base protruding inside the housing body to a calibrated height, determines the volume distributed 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 way to receive it.

[0043] If it is desired 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 a higher height Hl to have a lower volume and a lower height Hl to have a higher volume).

[0044] The spring 20, and in particular its stiffness, can be precisely calibrated according to the pump's distribution volume. Consequently, the spring stiffness can be correlated to the height Hl, on which the pump's distribution volume 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 distributes a determined volume, a spring with unsuitable rigidity.

[0046] The rod 4 may have a limit switch configured to meet said base 5 before said spring 20 is fully compressed.

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

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

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

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

[0051] Advantageously, this sealing gasket 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 distribution pusher 22; the distribution pusher 22 preferably has a cantilevered structure 22A inserted in a sealed manner in an enlarged cavity 4D of said rod 4. Alternatively, the pusher 22 can of course be threaded onto the outside of the rod, also 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 part 4E coupled to each other by snap-fitting, advantageously both in PP.

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

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

[0056] In this way, once assembled, the motor can be handled as an autonomous and ready-to-use unit, i.e. 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 threaded onto the rod 4 and can define, in cooperation with said rod, said element forming discharge valve 9.

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

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

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

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

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

[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 be 19 mm.

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

[0066] This maximum thickness B depends of course on the shape of the cross-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 bottom of the stroke, 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, in fact, is dimensioned to allow the inscription (in this section) of a circle C of radius between 0.5 mm and 1.5 mm, preferably of radius of 0.8 mm.

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

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

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

[0073] As can be 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 (whose edges are connected), rhomboidal (still with connected edges) 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 will be 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, which is therefore equipped with a float (not shown) and a cap (or closing plug, also not shown) which can be attached removably 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 of an associated PP container.

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

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

Claims

Demands

1. A manually operated pump (1) comprising a housing (2) within which a piston (3) slides in a sealed manner, associated with a hollow rod (4) enabling its movement, in opposition to a spring (20), within the housing (2), the pump having a base (5) which closes the housing (2) and is provided with an opening (11) for the rod (4), at least a portion of the housing (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 in the rod (4), characterized in that the spring (20) is made in one piece of polyetherimide, a section of the spring coil 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 in which the spring (20) is made is between 1.2 gram / cm3 and 1.35 gram / cm3, and is preferably 1.27 gram / cm3.

3. Pump (1) according to claim 1, wherein the tensile modulus of the polyetherimide in 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 a part of its length, an outside diameter (Dl) slightly smaller than an inside diameter (D2) of said spring (20), so as to serve as a deformation guide for 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 position, the base extending inside the housing body to a calibrated height (Hl), so as to define a volume of said compression chamber (6), the stiffness of the spring being correlated to said height (Hl).

7. Pump (1) according to claim 1, wherein said rod (4) has a limit switch (23) configured to meet said base (5) before said spring (20) is fully compressed.

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

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, wherein 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 than 2.

045.

11. Pump according to claim 1, wherein the pump (1) comprises a ring (21), a distributor pusher (22), a sealing gasket (G), a float tube and a cap which can be removably attached 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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