The invention relates to a dispensing unit, particularly suitable for a liquid container, comprising an air pump with an air cylinder and an air piston, wherein an air chamber is defined between the air cylinder and the air piston, a liquid pump with a liquid cylinder and a liquid piston, wherein a liquid chamber is defined between the liquid cylinder and the liquid piston, an axially displaceable activating element for activating the pumps, supply-closing means for closing air supply to the air pump, and discharge-closing means for closing air discharge from the air pump.
Such a dispensing unit is for instance known from WO 2004/069418. The dispensing unit shown herein is fastened onto a liquid container by means of a threaded ring in order to obtain a foam pump. The activating element is connected to a cover with spout for dispensing foam. The activating element is movable relative to the liquid container. With the foam pump in the hand product can be dispensed by pressing the cover.
The present invention has for its object to provide a foam pump for use on a surface, for instance a draining board of a kitchen, wherein dispensing takes place with the palm of the hand. For this purpose the movable cover must take a larger form. In addition, the spout must be embodied with a length such that the other hand can receive the dispensed product. Due to the use of the long spout an outer cover, and thereby protection during transport, is not possible. A per se known locking system must be arranged in order to prevent product or foam being dispensed during transport. Locking is released by rotating the spout. In existing pumps the locking mechanism is arranged between the threaded ring and the cover by means of a rib on the cover which drops into a recess of the threaded ring. This has the result that liquid (water or foam) can run into the pump. The consequence hereof can be that this liquid is drawn in, whereby the pump can become blocked or germ formation can result in the pump because liquid becomes lodged in “dead” corners. In order to be able to realize an improved locking system wherein the above stated drawbacks are obviated, the valve system of the above mentioned, known dispensing unit must be revised.
The object of the present invention is to provide an improved dispensing unit.
For this purpose the dispensing unit is characterized according to the invention in that the air piston and the liquid piston are movable in axial direction relative to the activating element in order to form the supply and discharge-closing means for air.
In contrast to the existing dispensing unit, the closing means for air are actively switched. Actively is understood to mean mechanically. The supply-closing means are closed and the discharge-closing means are opened by moving the activating element.
In a preferred embodiment the activating element and the axially movable air piston together form the supply-closing means for air, while the activating element and the axially movable liquid piston together form the discharge-closing means for air. No additional closing means are necessary. Use is advantageously made of the components of the dispensing unit already present to form the desired seal. An exceptionally simple dispensing unit is hereby obtained at favourable cost.
The activating element is further arranged in at least axial direction between the air piston and liquid piston, so that the supply-closing means are closed and the discharge-closing means are opened by one and the same movement of the activating element. Dispensing of the product can be started with a small stroke.
In addition, the activating element preferably co-acts with the air piston for compressing the air in the air chamber. In a first part of the forward stroke the air supply to the air pump will be closed, whereafter the air is compressed in the pump in the second part.
In one embodiment an insert is fixedly connected to the activating element. The activating element preferably co-acts with the liquid piston via the insert in order to make the liquid chamber smaller. Together with the liquid piston, the insert forms a mixing chamber for mixing air from the air pump and liquid from the liquid pump.
The dispensing unit is preferably further provided with a base part which is fixedly or integrally connected to the air cylinder and/or the liquid cylinder, wherein spring means are arranged between the base part and the air piston. The spring means serve for resetting of the air piston in the return stroke.
The same spring means which co-act with axial ribs with a first length on the periphery of the activating element are utilized for the purpose of resetting the activating element in the return stroke. The activating element preferably comprises on its periphery axial ribs of a second length which co-act with the air piston. In the forward stroke it is in fact the seal between the upper edge of the air piston and the activating element (supply-closing means) which defines the stopping point. These ribs of a second length are arranged on the activating element in order to prevent damage to the relatively thin upper edge of the air piston. The first length is preferably greater than the second length. The distance between the short and long ribs on the periphery of the activating element determines the stroke the air piston can make relative to the activating element for switching the supply-closing means. The full stroke is achieved when the ribs of short length engage on protrusions on the inner side of the air piston. These protrusions are advantageously also used for engaging the spring.
The dispensing unit is preferably further provided with a locking mechanism for locking the activating element in axial direction.
In an advantageous embodiment the locking mechanism is arranged between the activating element and the base part. The locking mechanism is situated in the interior of the pump, thereby avoiding entry of water or foam into the pump as described above with reference to the prior art.
The base part preferably comprises a central sleeve which is provided on the outer periphery with at least one axial rib and wherein the activating element is provided on the inner side close to its bottom end with at least one radial groove and an axial groove connecting thereto for co-action with the rib on the base part. By rotating the activating element relative to the base part the rib is brought into line with the axial groove, and the activating element can perform an up and downward stroke necessary for dispensing product. It is of course also possible to provide the rib on the base part and the grooves on the activating element.
The dispensing unit is preferably further provided with a screw element with which the assembly of activating element, liquid and air pump can be screwed onto an opening of a liquid container.
In addition, the activating element is preferably connected fixedly or integrally to a cover which is provided with a dispensing channel which is connected to the liquid and air pump. The dispensing channel is preferably situated in a spout formed in the cover.
In order to prevent water or foam from entering the dispensing unit, the screw element and the cover together form an at least splash-proof seal.
In addition, the invention relates to a dispensing assembly consisting of a liquid container and a dispensing unit as specified herein.
The invention will be further elucidated with reference to the accompanying drawings. In the drawings:
The inner casing of smaller diameter 20 forms a liquid cylinder of a liquid pump. A liquid piston 24 is arranged for axial sliding in the liquid cylinder. A liquid chamber 30 is situated between liquid piston 24 and liquid cylinder 20.
The outer casing of large diameter 21 forms the air cylinder in which an air piston 31 is received for axial sliding. An air chamber 32 is situated between air piston 31 and air cylinder 21. A spring 33 is arranged in air chamber 32 between air piston 31 and base part 3.
An activating element 36 is arranged between air piston 31 and liquid piston 24. Activating element 36 consists of a lower part with a relatively small diameter, an upper part with a relatively large diameter and an intermediate bridging part. The bridging part has an oblique wall 51 (see also
A liquid valve 39 is arranged in liquid piston 24. The weight of this liquid valve 39 normally ensures closing of liquid pump 20,24. The underpressure created in liquid chamber 30 during suctioning also ensures that liquid valve 39 is pressed into its seat. When pressure is built up in liquid chamber 30, liquid valve 39 will be opened and the liquid will be able to flow upward out of liquid chamber 30.
Located above liquid valve 39 is a mixing chamber 40 (see
It can further be seen here that operating element 1 extends downward, wherein its bottom edge lies under an opening in threaded ring 2. Between the edge of the opening in threaded ring 2 and the outer casing of operating element 1 is arranged a standing edge 48 which provides for a splash-proof connection between operating element 1 and threaded ring 2.
Threaded ring 2 is freely rotatable relative to operating element 1 and base part 3. The dispensing unit can hereby be aligned with a liquid container when it is screwed onto the container. The container is often oval-shaped and the spout of the operating element is preferably positioned on the container such that it is lies transversely of the widest walls of the container during use. Arranged under the flanged edge of the base part is a sealing ring 49 which ensures that no liquid can leak out of the container via the screw thread.
According to the invention and as can be seen in
Liquid valve 29 forms the suction valve of the liquid pump to be further described hereinbelow, while liquid valve 26 forms a liquid transport lock. During transport and in situations wherein the container is under pressure, this liquid valve 26 ensures that the liquid cannot flow out of the dispensing unit.
As stated, the air inlet valve is closed and the air outlet valve opened during an initial, short stroke from the position shown in
In the return stroke, when operating element 1 is released, spring 33 will first displace activating element 36 upward over a short distance. The inlet valve between air piston 31 and activating element 36 is hereby opened and the outlet valve between activating element 36 and liquid piston 24 is simultaneously closed. Air can hereby be drawn in via the screw thread between threaded ring 2 and the liquid container and the inlet valve in air chamber 32 of the air pump. In addition, the spring comes into contact with inner peripheral edge 34 of air piston 31. Spring 33 therefore then provides for resetting of both activating element 36 and air piston 31 to the starting position shown in
During the return stroke piston 31 in the first instance remains stationary due to friction with the wall of air cylinder 21 and, after reaching the end its short free stroke, is carried along by the spring. This is also the case in the reverse situation for liquid piston 24. In the first instance this remains in position during the downward stroke due to the resistance with the wall of liquid cylinder 20. After reaching its short stroke it is pressed downward by insert 37.
By rotating activating element 36 from the position shown in
The shown locking mechanism provides only a locking of activating element 36 in its uppermost position (see
Number | Date | Country | Kind |
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1028827 | Apr 2005 | NL | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/NL2006/000204 | 4/19/2006 | WO | 00 | 6/19/2008 |