Air extractor pump for waterbeds

This application claims priority to German Patent Application No. 102007060957.6 filed on December 14, 2007 incorporated herein in its entirety.

The invention relates to an air extractor pump for waterbeds according to the preamble of patent claim 1.

An air extractor pump of this type comprises a piston constructed in a tube-shaped cylinder, said piston being able to slide longitudinally therein and carrying at the front end bottom side, a valve flap closeably covering a through-bore, while the opposite end of said piston is equipped with a discharge bore.

The piston can be manually slid longitudinally within a cylinder constructed as case open at the top, and the cylinder also has at its bottom-side end a valve flap closing a correlated through-bore, while simultaneously, at the lower end of the cylinder, a screw-on adapter is provided permitting the lower end of the cylinder housing to be screwed onto a correlated filler neck of a waterbed.

In order then to remove any air bubbles trapped in a waterbed, the method is known of lifting the filler neck of the waterbed in order to raise the same above the level of the water in the waterbed. Subsequently, the filler neck which is firmly connected to the waterbed is screwed in at the underside of the cylinder in a corresponding screwing motion and connected tightly to the cylinder.

The piston rod then is moved up and down, and the pump used generally is very simple to operate. This means that when the piston is pulled out of the cylinder housing, air is sucked out of the filler neck of the waterbed and thereby reaches the intermediate space between cylinder and underside of the piston. With the next piston stroke, now in reverse direction, the air stored in the said intermediate space is moved through the piston, because the cylinder-side valve flap is closed in this process and the piston-side valve flap is opened. Thereby, the air is displaced to the cylinder and discharged through the piston upwards and outside.

In principle, an air extractor pump of this type has proven itself; however, the manufacturing cost of a pump of this type is extraordinarily high and it does not function with sufficient operational reliability.

It has been determined that in air extractor pumps known to the art the screw-on adapter disposed at the underside of the cylinder is only glued to the case-shaped cylinder housing, which is associated with the disadvantage that during the gluing process, adhesive residue can penetrate into the interior of the cylinder, thereby impairing the stroke motion between piston and cylinder. Furthermore, adhesive residue leaked to the outside impairs the appearance and is difficult to remove from the external surface of the piston. Moreover, the adhesion is not ensured to be firm and tight all around, which is associated with the disadvantage that unwanted air can penetrate between the screw-on adapter at the underside of the cylinder and the cylinder itself during the pumping process.

Moreover, a method is known to the art whereby the valve flap—comprising an elastomeric bendable strap—is attached immediately to the cylinder-side screw-on adapter, which is associated with a high amount of labor. Valve flaps of this type are attached only with a pin inserted through a corresponding bore in the bottom of the screw-on adapter, and the pin is subsequently fused. This type of attachment does not ensure secure attachment of the valve flap, and in addition, the problem arises that during the fusing process, fusing material may penetrate through the said bore to the upper side of the valve flap, thereby preventing the same from forming a tighter closure on the bottom of the screw-on adapter.

Furthermore there again, penetrating adhesive residue possibly reaching the said sealing surface when the screw-on adapter is being glued to the cylinder housing, may lead to a malfunction of the pump.

A further disadvantage lies in the fact that the through-holes for the sealing coverage by the valve flaps are only bored, and as a rule, are also not deburred. Due to the resulting burs, a secure sealing surface in direction of the elastomeric bendable valve flap is not achieved.

A further disadvantage lies in the fact that for the piston, as well, the only method known to attach the valve flap disposed at the underside of the piston, on the inside, is through the entire length of the piston with a corresponding special tool. Consequently the disadvantage arises that a secure attachment of the valve flap in the piston cannot be ensured and that the sealing surface to be found by the valve flap at the bottom of the piston is not subjected to clean finishing work.

Therefore then, as a whole, an air extractor pump according to the prior art has the disadvantage that the parts mentioned are only glued on and that the attachment of the valve flaps is insufficient and not well sealed.

The invention thus has the object of refining an air extractor pump for waterbeds of the type mentioned above in such a way that the same will function with operational reliability, can be assembled free from adhesive, and can be manufactured at lower cost and with higher functional reliability.

In order to achieve the object of the invention, the invention is characterized by the enabling disclosure of claim 1.

An essential feature of the invention lies in the fact that the valve flaps are attached in the area of separately constructed valve cases, wherein the piston-side valve case, as well as the cylinder-side valve case each have a plug-in piece and engage with the piston as well as with the cylinder in a correlated, sealed plug-in connection.

Based on the enabling disclosure, the essential advantage arises that an adhesive-free function with absolute operational reliability of the air extractor pump is ensured by the fact that the piston-side valve case as well as the cylinder-side valve case are each equipped with an external plug-in piece to plug the same into the piston or the cylinder, respectively. Thus, instead of an assembly with adhesives, a plug-in assembly is proposed, and furthermore it is proposed that the valve flaps themselves no longer be connected immediately and firmly with surfaces connected to the cylinder and the piston, but that rather they be attached in separate parts. The said separate parts, which according to the invention are constructed as valve cases, have the advantage that they can be finished very well, since the through-hole located therein is produced free from burs, because it is produced in an injection molding procedure, and that therefore, a bore with subsequent deburring is not needed.

In the same way, therefore, the advantage arises that the respective bottom sides of the valve cases containing the through-holes are constructed absolutely evenly and cleanly and without any contamination, since these have also been produced in the said injection molding procedure and need no further finishing work.

Thanks to the plug-in assembly of the two valve cases into the cylinder or the piston, the advantage arises that there is no longer the danger that leaking adhesive residue stain the sealing surface for the valve flap in the valve case, thereby making the function of the entire air extractor pump questionable.

A further feature of the invention lies in the fact that the respective valve flap can be snapped into a correlated slit in the bottom surface of the respective valve case in the manner of a snap-in connection. Thereby, a particularly simple attachment with particular operational reliability is achieved, since the said snap-in connection absolutely prevents a later separation of the valve flap, because the snap-in connection works with operational reliability, and furthermore, the secure seating of the valve flap can be easily checked by the person assembling the air extractor pump. This was not possible with the prior art, because there, the valve flaps had to be disposed immediately in deep components of the piston and the cylinder and had to be attached with the aid of very long construction tools. This is avoided according to the invention.

Thanks to the fact that an adhesive connection is avoided overall, a preferred refinement of the invention provides that the cylinder-side valve case is held in the cylinder in a way to be prevented from twisting, in order to ensure that the pushed-on valve case is not unintentionally twisted when it is screwed onto a correlated external thread of the filler neck of a waterbed.

An antitwist protection of this type is also simply achieved by the fact that with the injection molding tool for the manufacture of the cylinder case, radially inward-pointing ridges are constructed to work in conjunction with correlated longitudinal grooves on the external circumference of the valve case, fixing the same without the possibility of twisting.

The subject of the present invention does not only derive from the subject of the individual patent claims, but also from the combination of the individual patent claims with one another.