WO2015018614A1

WO2015018614A1 - Coupling device for a metering pump

Info

Publication number: WO2015018614A1
Application number: PCT/EP2014/065243
Authority: WO
Inventors: Dan Barron
Original assignee: Robert Bosch Gmbh
Priority date: 2013-08-06
Filing date: 2014-07-16
Publication date: 2015-02-12
Also published as: DE102013215449A1

Abstract

The invention relates to a coupling device for a metering pump, having a driveshaft (1) and a profiled shaft end (2). The profiled shaft end (2) is designed to be plugged to the metering pump in a rotationally fixed manner. The driveshaft (1) has a spiral-shaped outer toothing (3) which engages into an internal spiral-shaped inner toothing (6) of a first axially movable and rotatably mounted coupling part (4) with a circular cylindrical outer surface (5). The profiled shaft end (2) is connected to a second rotatably mounted coupling part (8). The first coupling part (4) can be coupled to the second coupling part (8) in a rotationally fixed manner by an axial movement. A bearing part has a bearing recess with a circular cylindrical inner surface (11) which corresponds to the circular cylindrical outer surface (5) of the first coupling part and in which the first coupling part is inserted in an axially movable and rotatable manner.

Description

Description Title Coupling device for a metering pump

The invention relates to a coupling device for a metering pump according to claim 1. The invention relates in particular to a metering pump for the

Food area or other areas where viscous and

Perishable substances must be dispensed dosed. Most of these are relatively simple rotating positive displacement pumps, which are already known in a variety of possible forms and are found on the market. Although these positive displacement pumps work very reliably per se, after a pumping process, certain quantities of the discharged substances always remain inside these metering pumps and smaller quantities also hang in the inner or outer region of the delivery opening. The latter are the problem here, because especially at longer intervals between the pumping events such stuck substance residues can spoil, for example, by microbial contamination or by connection with the oxygen of the ambient air and become unusable. It is therefore attempted to make Dosierpumpenauslässe as possible so that either no or really only very small amounts of residue stuck to the outlets.

To close the Dosierpumpenauslass as quickly as possible and as good as possible, for example, elastic outlet valves or

outlet side arranged elastic diaphragms with self-closing outlet openings made of silicone or rubber can be used. In these purely mechanical solutions, the outlet automatically closes itself again as soon as the metering pump is no longer driven. These Although devices work reliably, but can also be problematic when substances with solids levels must be dispensed dosed, because the latter could hinder a reliable re-closing.

Another measure to reduce the risks due to contamination and / or chemical changes are disposable pumps, ie metering pumps that are intended for single use and are disposed of after emptying the container. By nature, such

Disposable dosing pumps Cheap products, usually made of plastic and usually of very simple mechanical design. The pump drive itself is not part of the disposable metering pump for cost reasons, but the interface between the disposable metering pump and the pump drive in these solutions is usually designed so that a simple coupling is possible. The latter is often a simple, twist-proof plug connection between pump drive and metering pump. An example of this can be seen in EP-1'892'417.

Furthermore, it is also known to use devices in which the residual amount remaining at the pump outlet is simply sucked back into the container after the metered delivery. For common squeeze bottles, this is easy to accomplish simply by letting the bottle, which is made of an elastic material, return to its original shape. However, ambient air is always sucked back into the bottle and this, of course, again carries the risk of premature

Deteriorate in itself, which is why you usually have to put the once opened bottles cool.

Of course, using electric or electronic pump drives, it is possible to control the sucking back specifically and to a degree that only little ambient air gets into the container. But it usually means that a corresponding control device must be present, which is the Dosing or dispensing device of course more expensive. An example of a pump with which a dripping from the outlet opening of an output line can be prevented, so with a similar albeit not the same

Problem is shown in the US-5'597'719, but this is not a rotary positive displacement pump. The latter of course means that the pump drive and also the coupling between pump drive and pump are not comparable in this case.

It is the object of the present invention to provide a simple and

To provide low-cost coupling device for a metering pump, wherein the coupling device should be particularly suitable for metering pumps which are designed as disposable metering pumps and rotating positive displacement pumps. The intended single use of the metering also explains why a non-rotatable connector between the metering pump and the

Dosage pump drive should be available. In particular, should

Coupling device but the problem of reduction in the

Pump outlet opening remaining residual amount using the method of back suction with simple mechanical means solve. This object is achieved by the feature combination of claim 1.

The object of the invention is that a coupling device for a metering pump, which has a drive shaft and a profile shaft end and which is designed for a non-rotatable plug connection with a metering pump, has at least the following features:

- The drive shaft has a spiral external toothing with a

Helix angle,

- The spiral external teeth engages in a first axially displaceable and rotatably mounted coupling part with a circular cylindrical outer surface and with a spiral-shaped internal toothing, which is the spiral-shaped

External toothing corresponds,

- The profile shaft end is connected to a second rotatably mounted coupling part, wherein the second coupling part is arranged coaxially to the first coupling part and wherein the first coupling part with the second

Coupling part by axial displacement rotatably to couple or decouple,

- A storage part has a Lagerungsausnehmung with a circular cylindrical inner surface, the circular cylindrical outer surface of the first

Coupling corresponds to parts and in the first coupling part axially

slidably and rotatably inserted.

Preferably, the metering pump is as mentioned as rotating

Positive displacement pump designed and intended for single use.

Furthermore, it is assumed that the drive shaft of

Rotary coupling device can either be driven so that the metering pump pumped out the substance to be pumped either to the pump outlet or sucked back. For rotating positive displacement pumps, this only requires a reversal of the direction of rotation.

Furthermore, it is also assumed that storage and fixing parts, which ensure the mechanical cohesion and the mutual spatial orientation and fixation of said components of the coupling device, are present or integrated or molded in the storage part. It goes without saying that such parts in the application-specific design of adjacent Dosierpumpen- and / or

Gear housing parts may be dependent.

The main characteristic of the coupling device according to the invention is that when the direction of rotation of the drive shaft is reversed, that is to say when the substance to be conveyed is sucked back, the counter-rotation of the rotating positive displacement pump only has a limited short and short rotation controlled period of time (which corresponds to a defined angle of rotation of the rotors of the rotary positive displacement pump) and that the process of

Sucking back then stops automatically. Even if the drive shaft continues to be driven in the reverse direction, the rotating one remains

Positive displacement then stand because of the dissolved coupling between the first and the second coupling part. The duration of the

Direction of rotation reversal or during this time covered angle of rotation of the rotors of the rotary positive displacement pump before decoupling the drive mechanism is by a suitable choice of

Design parameters controllable. In fact, with the helix angle and with a maximum axial displacement that the first and second coupling parts allow for complete coupling or

Decoupling require a counter rotation of the metering pump is defined by a limited period of time when the metering pump of the

Drive shaft is driven counter to the conveying direction.

A great advantage of this solution is that the principle is readily applicable to purely mechanical hand-operated metering solutions, because reversible directions of rotation of the drive axle can also be produced with suitable and simple lever conversion mechanisms.

Further features and advantages of the inventive coupling device can be seen from the following detailed description. In the following an embodiment will be explained in more detail with reference to drawings. It shows

Fig. 1 is an exploded view of the main components of

Coupling device,

2 is a perspective view of the coupling device, Fig. 3 parts of the coupling device in a plan view in coupled

Condition omitting a first storage half shell, and

Fig. 4 shows the same view of the coupling device in uncoupled

Status.

Fig. 1 shows an exploded view of the main components of

Coupling device for a metering pump.

The coupling device has a drive shaft 1 and a profiled shaft end 2, wherein the profiled shaft end 2 is designed for a non-rotatable plug connection with a (not shown) metering pump. The coupling device is connected to a drive shaft end A of a (not shown)

Drive device rotatably driven and at an output end B by means of the profile shaft end 2 inserted and rotatably connected to the metering pump. In the metering pump is preferably a simple and inexpensive to produce pump, which is intended for single use, which is why an easily detachable non-rotatable connector in the shape of the profile shaft end 2 is provided. Of course, 2 differently shaped profiles are possible at the profile shaft end, which are intrinsically safe for a twisting operation. In principle, however, the coupling with the metering pump can also take place by other means, since the invention can in principle also be used with permanently installed metering pumps.

The drive shaft 1 has a rotationally fixed and integrally formed helical external toothing 3, which has a helical angle. The spiral-shaped external toothing 3 has the shape of a spiral gear or a spiral gear. The teeth are helical or wound around the axis of rotation D in the axial direction. Although a different number of teeth may be present, nevertheless, irrespective of the number of teeth, helical external teeth will always be used hereinafter spoken. The angle at which the teeth run helically around the drive shaft 1 is referred to as Helix angle in accordance with the common definitions for helical gears. The helix angle is relatively small in the present embodiment, preferably less than 45 °.

The spiral-shaped external toothing 3 engages in a first axially displaceable and rotatably mounted coupling part 4 with a circular cylindrical

Outside surface 5 and with one in a central and internal

Recess attached spiral internal teeth 6 a. The spiral-shaped internal toothing 6 corresponds to the toothing of the spiral-shaped external toothing 3, which means that the spiral-shaped external toothing can rotate in and out of the helical internal toothing 6 and thus in the helical tooth

Internal teeth 6 sliding and largely free of play is performed. The first coupling part 4 is also formed as part of a dog clutch. For this purpose, the first coupling part has axially oriented first jaws 7. The profile shaft end 2 is connected to a second rotatably mounted coupling part 8, wherein the second coupling part 8 coaxial with the first

Coupling part 4 is arranged and the first coupling part 4 with the second coupling part 8 by axial displacement rotatably to couple or decouple is able. The second coupling part 8 is also formed as part of a dog clutch and has for this purpose according to the first coupling part 4 axially oriented second jaw 9.

Both the drive shaft 1 with the attached thereon spiral

External teeth 3 as well as the profile shaft end 2 with the second

Clutch part 8 are fixedly mounted but rotatable about a rotation axis D. In the engaged state of the clutch device, the drive shaft 1 and the profile shaft end rotate synchronously. Furthermore, a storage part 10, in the present embodiment consisting of a first and a second storage half-shell 10a, 10b, with a circular cylindrical inner surface 11 is present. The circular cylindrical outer surface 5 of the first coupling part 4 corresponds to the

circular cylindrical inner surface 11 of the bearing part 10. The first

Coupling part 4 is axially displaceable and rotatably held in the bearing part 10. The first and second storage half-shell 10a, 10b are connected to each other, for example by screwing (in Fig. 2 only indicated by holes). As a result, or with other known

technical means is achieved that between the bearing part 10 and the first coupling part 4 a defined sliding friction is present or adjustable. This sliding friction is intended to both an axial and a rotational sliding of the first coupling part 4 in the intended manner

Allow storage part 10 with defined friction losses, and have a Mass that at least a portion of the introduced via the drive shaft 1 torque in a acting in the axial direction and the first

Coupling part 4 transmitted tensile or impact force can be generated. More details in the following functional description. Other obvious to those skilled solutions such as screws etc. to achieve an adjustable sliding friction are of course also possible. Thus, the bearing half shells (10a, 10b) can also be made simply from a different, softer plastic than the other parts of the coupling device.

FIG. 2 shows a three-dimensional view of the coupling device, but here in the assembled and engaged state (ie according to the situation of FIG. 3). As stated earlier, as well as in the other figures of clarity and scarcity because of all additional holding or supporting parts, which must also be present in addition to the means defined in the coupling device or like, for example, for the purpose of mechanical cohesion and mutual spatial orientation and positioning of the individual parts, omitted and not shown. It should also be noted at this point that these additional holding or supporting parts, depending on the different uses of the inventive coupling device, in various numbers and different shape may be present, so that a final enumeration would only be a hindrance and also seems immaterial.

For the function of the inventive coupling device:

FIG. 3 shows parts of the coupling device in a plan view

coupled state. To clarify the operation, the second storage half-shell 10b is omitted in this view. In the following, the coupling device is considered from the drive side S and it is further assumed that the metering pump is driven counterclockwise (counter clockwise, see arrow CCW) in this approach, and that this is also the normal conveying direction in which the metering pump delivers substance. If the second coupling part 8 were not present, the helical external toothing 3 would be unscrewed from the helical internal toothing 6 of the first coupling part 4. However, because the second coupling part 8 is rotatably and stationarily mounted as mentioned, the first

Clutch part 4 is pushed against the second coupling part 8, and because there is no alternative possibility, the first and the second coupling part 4, 8 are firmly verkuppelt and the drive shaft 1 and the profile shaft end 2 rotate synchronously.

Now, after the dosing process, the drive shaft 1 is rotated in the opposite direction (clockwise from the drive side S clockwise, see arrow CW), the helical external teeth 3 in the spiral inner teeth 6 of the first coupling part 4th

screwed. Because the drive shaft 1 with the spiral External teeth 3 but are arranged stationary and rotatable, remains as a freedom of movement for the first coupling part 4 only a co-rotation and simultaneous retraction relative to the second coupling part 8 and after a short period of time a complete uncoupling of the second coupling part 8. Of course, also here with suitable structural means be taken to ensure that this axial retraction is stopped before the spiral outer teeth 3 falls out of engagement with the spiral inner teeth 6. But this can be done with a simple stop (not shown). It makes sense to choose the positioning of the stop usually so that the coupling device works as free of play.

Fig. 4 shows parts of the coupling device in a plan view in fully uncoupled state.

It should be noted that between the circular cylindrical outer surface 5 of the first coupling part 4 and the circular cylindrical inner surface 11 of

10 a certain minimum friction must be present, because at approximately frictionless storage in the bearing part 10 would otherwise turn in a subsequent re-pumping the first coupling part 4 only on the drive axle 1 and the spiral external teeth 3 and there would be no axial forces cause in that the first coupling part 4 simultaneously shifts axially in the direction of the second coupling part 8 again and engages with it again.

In the present embodiment, one can speak of a maximum axial displacement path, the first and the second coupling part 4, 8 for a complete coupling or decoupling need. Approximately it corresponds approximately to the depth of engagement or the length of the first and second jaws 7, 9 of the dog clutch. The ultimately desired short-term counter-rotation of the metering pump with a reversal of the drive direction of the drive shaft 1 can thus be determined by suitable mechanical dimensioning of the inventive coupling device. With the helix angle and with the maximum axial

Displacement path, which the first and the second coupling part for complete coupling or decoupling need, a counter-rotation of the metering pump of a limited period of time is definable when the

Metering pump is driven by the drive shaft opposite to the conveying direction.

Thus one reaches the goal, namely the reduction of at the

Pump outlet opening remaining residual amount by means of the method of back-suction with simple mechanical means. It does not need precise control of a drive motor for the generation of a

short-lasting counter-rotation. The coupling device according to the invention can be very easily connected to metering pumps which are suitable for the

Disposable are provided because the profile shaft end is designed for a non-rotatable connector with the metering pump. Overall, such a coupling device can thus be because of the simple

Insert interchangeability between the pump drive and the metering pump as an independent module and install easily in metering devices.

Since the inventive coupling device in particular for

Disposable metering pump is designed, this can preferably be made of plastic and injection molding technology.

The profile shaft end is of course adapted in the form of the rotor shaft connector of the disposable metering pump. This can, as shown in FIG. 2, be a cylindrical and one-sided flattened pin. Other forms such as toothed or square cones are just as suitable. List of reference numerals:

1 drive shaft

2 profile shaft end

3 spiral external teeth

4 first coupling part

5 circular cylindrical outer surface

6 spiral internal teeth

7 first claws

8 second coupling part

9 second claws

10 storage part

10a first storage half-shell

10b second storage half-shell

11 circular cylindrical inner surface

A drive shaft end

B output end

D rotation axis

Claims

claims:

1. coupling device for a metering pump, wherein the

Coupling device comprises a drive shaft (1) and a profiled shaft end (2), wherein the profiled shaft end (2) is designed for a rotationally fixed plug connection with the metering pump, characterized in that

- The drive shaft (1) has a helical external toothing (3) with a helical angle,

- The spiral outer toothing (3) in a first axially displaceably and rotatably mounted coupling part (4) having a circular cylindrical outer surface

(5) and with an inner spiral-shaped internal toothing (6), which corresponds to the spiral outer toothing (3) engages,

- The profile shaft end (2) with a second rotatably mounted coupling part (8) is connected, wherein the second coupling part (8) is arranged coaxially to the first coupling part (4) and the first coupling part (4) with the second coupling part (8) by axial Shift to couple or uncouple, and that

- A storage part (10) has a Lagerungsausnehmung with a

circular cylindrical inner surface (11), which corresponds to the circular cylindrical outer surface (5) of the first coupling part and in which the first coupling part is inserted axially displaceably and rotatably, is present.

2. Coupling device according to claim 1, characterized in that the helical external toothing (3) has a helix angle which is smaller than 45 °.

3. Coupling device according to claim 1 or 2, characterized

in that the helical external toothing (3) is integrally formed on the drive shaft 1.

4. Coupling device according to one of the claims 1 to 3, characterized in that the first and the second coupling part (4, 8) as

Claw coupling are formed.

5. Coupling device according to one of the claims 1 to 4, characterized in that the bearing part (10) and the first coupling part (4) are designed for the mutual exercise of a defined sliding friction.

6. Coupling device according to claim 5, characterized in that the storage part (10) has a first and a second storage half-shell

(10a, 10b).

7. Coupling device according to one of the claims 1 to 6, characterized in that with the helix angle and with a maximum axial displacement, the need the first and the second coupling part (4, 8) for a complete coupling or decoupling, a counter rotation of the metering pump is defined by a rotation angle when the metering pump is driven by the drive shaft (1) opposite to the conveying direction.

8. Coupling device according to one of the claims 1 to 7, characterized in that it is made of plastic.

9. Coupling device according to one of the claims 1 to 8, characterized in that the bearing half-shells (10a, 10b) are made of a different, softer plastic than the other parts of the

Clutch device.