EP3864290A1 - Clamping device for a device for conveying fluid, and device for conveying fluid - Google Patents

Abstract

The invention relates to a clamping device for pre-tensioning a fastening element, wherein: the fastening element is suitable, in a device for conveying fluid, for fastening a diaphragm pump head part to a drive for impressing motion onto a diaphragm of the diaphragm pump head part; the clamping device has a support with a support surface for supporting a support face of the fastening element, the support having a threaded bore, which is penetrated by a screw element, and the screw element having a contact face at its front end; and the contact face of the screw element and the support surface of the support point in opposing directions and the distance between the contact face of the screw element and the support surface of the support can be changed by screwing the screw element in or out.

Description

 "Spannvorrichtunq for a device for conveying fluid and device for

 Promotion of fluid "

The invention relates to a tensioning device for applying a pretension to a fastening element, the fastening element being suitable for a

Device for conveying fluid to attach a pump head part with a drive for an impression of movement to movable elements of the pump head part, in particular to attach a diaphragm pump head part with a drive for an impression of movement to a membrane of the diaphragm pump head part. The invention further relates to a device for conveying fluid with a pump head part and a drive for impressing movement on moving elements of the pump head part, in particular with a diaphragm pump head part and a drive for impressing movement on a membrane of the diaphragm pump head part and a bolt connected to a housing of the drive, of a through hole through a housing of the

Pump head part, especially the diaphragm pump head part. The invention also relates to a method for generating a preload on the bolt of such a device. A diaphragm pump having a diaphragm pump head part is used in particular in

Areas used in chemistry, pharmacy and biotechnology, in which the media to be pumped are sometimes very expensive, so that sterile working conditions are often considered necessary, which means that contamination of the media to be pumped should be prevented. Diaphragm pumps are known which have a pump head which is fixedly connected to the drive, in particular the drive housing and the drive elements. Since the pump head is firmly connected to the other elements of the diaphragm pump, the pump head must be cleaned completely after each passage of a medium to be pumped or pumped. This means that the pump head must be completely emptied and made sterile before a new or different medium is pumped. This is time consuming.

From DE 20 2017 004 425 U1, an exchangeable pump head for a diaphragm pump is known, in which the pump head is designed and exchangeable separately from a drive and forms a hermetically sealed unit. The pump head is detachably fastened to the drive by means of a plurality of retaining clips or tensioning lugs, preferably two retaining clips. This quick-release mechanism offers a time-saving assembly of the replaceable pump head on the other pump elements, in particular the drive. A functionally reliable assembly of the pump heads is possible by means of the interchangeable pump head known from DE 20 2017 004 425 U1.

DE 20 2006 020 237 U1 discloses a diaphragm pump which consists of a pump head connected to a drive and having a plurality of pumping chambers, each of which is sealed off from a drive chamber by means of a pump membrane. The pump head is divided into an exchangeable diaphragm head part and a drive head part that is firmly connected to the drive. Due to the subdivision into the interchangeable diaphragm head part and the drive head part, the diaphragm head part that comes into contact with the media to be pumped can be easily detached from the diaphragm pump and, for example, cleaned and sterilized with connecting lines before use. The membrane head part or its membrane housing part and the drive head part or the drive chamber part are usually screwed together by means of screws in order to ensure the corresponding seal. This usually requires the use of a tool that engages the screws. In addition, it must be ensured that a certain torque of the screws is neither exceeded nor undershot.

The object of the invention is to provide a simple construction of the fastening, in which the partially inherent inadequacies and / or difficulties are reduced.

This object is achieved by the subject matter of the independent claims. Advantageous embodiments are given in the subclaims and the description below. The invention is based on the basic idea of providing a tensioning device for applying a pretension to a fastening element, the fastening element being suitable, in particular for fastening a pump head part with a drive for impressing movement on moving elements of the pump head part in a device for conveying fluid to fasten a diaphragm pump head part to a drive for imparting motion to a diaphragm of the diaphragm pump head part, the fastening element having a support surface. Fastening elements of this type are usually bolts with an undercut on which the support surface is implemented or with a projecting head on which the support surface is implemented. According to the basic idea of the invention, the clamping device provided for a device equipped in this way provides a support surface for supporting the support surface of the fastening element and a contact surface, the contact surface and the support surface pointing in opposite directions and the distance between the contact surface and the support surface being able to be changed. If the distance is increased and the contact surface lies, for example, on the pump head, in particular preferably on the diaphragm pump head or on an element which rests on the pump head, in particular on the diaphragm pump head, for example on an intermediate pressure plate, the increase in the distance leads to the generation of a Force that pushes the support surface of the fastening element away from the element against which the contact surface rests. As a result, the fastener is biased.

The invention is explained in more detail below with the aid of a diaphragm pump without restricting the subject matter of the invention to a diaphragm pump. The configurations according to the invention can also be applied to other pumps.

To implement this basic idea, the invention provides for the tensioning device to be provided with a support with a support surface for supporting the support surface of the fastening element, the support having a threaded bore through which a screw element passes. The screw element has a contact surface at its front end, the contact surface of the screw element and the support surface of the support pointing in opposite directions and the distance between the contact surface of the screw element and the support surface of the support can be changed by screwing in or unscrewing the screw element.

The screw element can have a threaded pin. The screw element can have a head which is present at the rear end, which lies opposite the front end with the contact surface. The head of the screw element can have a diameter that is larger than the diameter of the threaded pin. Of the Head is not necessarily round in cross section, but can also be polygonal.

The screw element has an external thread for engagement in the internal thread of the threaded bore of the support. The external thread is in particular a fine thread. As a result, the force required to turn the screw element can be reduced; In addition, a particularly good self-locking can be achieved with a fine thread.

In a preferred embodiment, the contact surface formed at the front end of the screw element is flat. In a preferred embodiment, the flat contact surface lies in a plane which is perpendicular to the longitudinal axis of the screw element. The contact surface of the screw element is part of a mechanism with which a prestress is to be generated, namely by changing the distance between the contact surface of the screw element and the support surface of the support. This means that compressive forces are introduced by the screw element into the element on which the contact surface of the screw element lies. If the contact surface is even, this can cause deformations on the

Prevent or reduce the element on which the contact surface rests, as might occur, for example, if the contact surface were the outer surface of a cone, although it is not excluded that in another embodiment of the invention the contact surface of the screw element - possibly for other reasons of motivation - is designed as the outer surface of a cone.

The contact surface of the screw element and the support surface of the support point in the opposite direction. In a preferred embodiment, the

Contact surface of the screw element just executed and the support surface of the

Support executed flat, wherein the flat contact surface of the screw element lies in a plane which is parallel to a plane in which the flat support surface of the support lies. This type of parallel alignment of the contact surface and the support surface makes it possible to generate a pretension in a predetermined direction, namely perpendicular to the planes, by changing the distance between the contact surface and the support surface. However, embodiments are also conceivable in which a flat contact surface of the screw element does not run parallel but inclined to a flat support surface of the support. It is also conceivable that the contact surface of the screw element is not flat, but the support surface of the support is flat. It is also conceivable that the contact surface of the screw element is flat, but the support surface of the support is not flat. It is also conceivable that the contact surface of the screw element is made spherical. The distance between the contact surface of the screw element and the support surface of the support can be changed by screwing in or unscrewing the screw element. In a preferred embodiment, the distance between the contact surface of the screw element and the support surface of the support is increased by screwing in the screw element and reduced by unscrewing it. Screwing in the screw element is understood in particular in the embodiments in which the screw element has a head to mean a screw movement of the screw element which brings the head closer to the threaded hole.

In a preferred embodiment, the support is designed as a plate, particularly preferably as a round disk or as a plate-shaped element. In a preferred embodiment, the threaded hole is provided in the center of the support. In a preferred embodiment, the support surface is arranged peripherally to the center of the support.

In a preferred embodiment, the support has a plurality of support surfaces, each support surface being provided for supporting a support surface of one of a plurality of fastening elements. In the case of a design with a plurality of support surfaces, it is provided according to a preferred embodiment to arrange the support surfaces at the same distance from the center point of the support. The support surfaces are particularly preferably arranged equidistant from one another on a ring around the center of the support.

The through hole in the support can in particular be arranged centrally in the support; the through hole is particularly preferably arranged parallel to the longitudinal axis of the diaphragm pump head part; the through hole particularly preferably coincides with the longitudinal axis of the diaphragm pump head part. It is not excluded that more than one through hole is provided on the support. However, preferably only one screw element is used, which cooperates with an internal thread of a through hole of the support in order to exert a force on the diaphragm pump head part in the direction of the drive. However, there may also be two or more through holes. For each of the two, three or more through holes, a screw element which interacts with an internal thread of the respective through hole and which in turn has an external thread can be provided.

In a preferred embodiment, a pressure plate is provided. This is suitable for coming into contact with the diaphragm pump head part. The contact surface of the screw element lies against the pressure plate. In a preferred one Embodiment, the pressure plate can be arranged between the diaphragm pump head part and the support. As a result, an element in the form of the pressure plate can be provided which can transmit a force over a large area. A distribution of the translatory force of the end of the screw element is possible over the entire surface of the pressure plate. The pressure plate preferably has an end face whose dimensions in cross section essentially correspond to the end face of the diaphragm pump head part. The force acting on the pressure element from the end of the screw element can be distributed over the entire surface of the pressure plate.

In an alternative, likewise preferred embodiment, the contact surface of the screw element can be brought directly into contact with the diaphragm pump head part without a pressure plate being interposed.

In a preferred embodiment, the support has a recess which can accommodate the pressure plate, in particular in operating situations in which the screw element is screwed out of the threaded hole, so that the distance between the contact surface and the support surface is reduced.

In a preferred embodiment, a plate-shaped handling element is provided which is connected to the screw element, wherein rotation of the handling element rotates the screw element. The screw element can be rotated together with the handling element. In this way, a simplification of the configuration can be achieved in that the screw element can be handled by means of a handling element. In particular, this makes it possible to dispense with specially designed tools that can engage in heads of fastening elements, in particular screws. A plate-shaped handling element can form a wheel which can be rotated by means of a user's hand, as a result of which a rotary movement which is converted into the linear movement of screwing in or unscrewing the screw element can be applied in a simplified manner.

The term “plate-shaped” in the sense of the description encompasses an element having a polygonal cross-section, elliptical, circular or mixed forms of the above-mentioned shapes, which in relation to the cross-section has a slight extension in depth or height, ie perpendicular to the cross-section. The term “plate-shaped” does not exclude a structuring in the edge region by means of which the handling of the handling element, in particular the turning of the same about a longitudinal axis transverse to the cross section, can be improved very particularly preferably to the central axis of the cross section. The handling element can essentially have a contour in cross section which corresponds to the contour of the diaphragm pump head part. In particular, the handling element can have an outer dimension in cross section which corresponds to the outer dimension of the diaphragm pump head part. In particular, the handling element is rotationally symmetrical with regard to its cross section, which simplifies handling. In particular, the screw element on the handling element can be rotatably mounted in the center, so that the external thread of the screw element extends in particular in a direction that is arranged parallel to the longitudinal axis of the diaphragm pump head part. The center point of the handling element is very particularly preferably arranged on the longitudinal axis of the diaphragm pump head part. A symmetrical arrangement can in particular prevent tilting and / or an inclined, that is to say essentially undesirable, power transmission.

In a preferred embodiment, the screw element and the handling element form a unit that can be handled together, which simplifies handling and / or assembly. In the sense of the description, a common, manageable unit is understood in particular to mean that the screwing element is present on the handling element in a captive manner. If the handling element is gripped, the screw element is arranged on the handling element. The screw element can be arranged in a receptacle of the handling element.

The head of the screw element can be arranged in a recess of the handling element, which can in particular be configured in the center, the screw element being secured by means of a retaining element designed as an annular element, which can rest on the circumference both on the head of the screw element and on the edge of the recess can.

In a preferred embodiment, a slip clutch is formed between the screw element and the handling element. The slip clutch can be used in particular or can have an effect when a force which is exerted on the diaphragm pump housing by the screw element is exceeded. The slip clutch provided between the screw element and the handling element can limit the torque that can be applied to the screw element. In this way, the pressure force that can be applied to the diaphragm pump housing can be determined to a certain extent in such a way that the “tactile” or “haptic” and / or “acoustic” (a “click”) feedback from the slip clutch shows the user, that on the one hand the diaphragm pump housing is attached to the drive with sufficient compressive force, but on the other hand the compressive force is not exceeded. The slip clutch is functionally equivalent to a torque limitation that acts on the screw element. The torque can correspond to a corresponding pressure force to be set, so that it can be ensured that when a predetermined torque is reached (and the slip clutch or the torque limiter is triggered) there is sufficient pressure force on the diaphragm pump head part in the direction of the drive. In particular, a slip clutch can be formed between the screw element and the handling element in only one direction. While a slip clutch is provided for the screw element or the handling element in one direction of rotation, a direct power transmission can take place in the other direction of rotation — without a slip clutch or torque limitation.

In a preferred embodiment, the screw element is supported on a peripheral surface of the handling element. This is particularly preferably an inwardly facing peripheral surface of a protruding, circumferential edge of the handling element. In this way, a particularly simple slip clutch can be created. In particular, the screw element can be supported with its head circumferentially on an annular element, preferably the holding element, with which the screw element is secured to the handling element. It can be provided, for example, that the support is released when the torque is reached or the slip clutch responds. In this respect, the power transmission between the handling element and the screw element can be released by eliminating the support. If the ring-shaped element is designed as a holding element, several functions can be achieved by means of one element.

In a preferred embodiment, at least one pressure element is provided between the screw element and the handling element, which cooperates with a profile of the handling element or annular element, in particular the holding element. Depending on the design of the profile, a power transmission can be set and / or the torque can be limited. Different types of profiles, in particular for the movement to apply a compressive force to the diaphragm pump head part or to reduce the force exerted on the diaphragm pump head part, in particular for releasing the diaphragm pump head part from the drive, can be selected.

In a preferred embodiment, several pressure elements are provided. The pressure elements can serve to support the screw element on the handling element. A symmetrical arrangement of the pressure elements around the screw element, in particular around the head of the screw element, can be advantageous. In particular, more than one pressure element can be turned around the head of the screw element be arranged at equidistant angles. In a preferred embodiment, all pressure elements are configured identically or identically, so that the same pressure is transmitted between the head of the screw element and the profile by means of the pressure elements. Embodiments are also conceivable in which the pressure elements do not run in the circumferential direction of the head of the screw element, but instead point in the axial direction. Such pressure elements can interact with a profile which is embodied on the surface of a plate, for example an annular sawtooth profile on the surface of a plate.

The profile can in particular be designed as an inner contour in the holding element. The profile can be selected and / or replaced depending on the pressure force on the diaphragm pump head part. In particular, the profile can be screwed detachably to the handling element. It can also be additionally or alternatively provided to replace the pressure element (s) in order, for example, to adjust the spring force with which the screw element is supported on the circumference.

The pressure element (s) can comprise a sleeve, a spring and an engagement piece, which can preferably be of pin-shaped or spherical shape and / or rounded at the end for engagement with the profile. The pressure element can be arranged in a recess in the head of the screw element, in particular for simple configuration. The recess preferably extends transversely to the axis of rotation of the handling element, very particularly preferably perpendicular to the axis of rotation of the handling element. Preferably two, three, four, five, six or more similar pressure elements are provided at equidistant angles around the circumference of the head of the screw element.

In a preferred embodiment, the profile has at least one asymmetrically designed recess for the pressure element, as a result of which two different types of force transmission can be set for the transmission of the force in the direction of the diaphragm pump head part (for fastening) and in the direction away from the diaphragm pump head part (for loosening). In particular, several, preferably identical or similar, recesses can be provided in the profile, wherein an equal or fewer number of pressure elements can be provided between the head of the screw element and the profile.

In a preferred embodiment, the profile in the direction of rotation for displacing the diaphragm pump head part on the drive has a driving surface inclined to a radial of the handling element, as a result of which a torque limitation or the formation of a slip clutch is made possible. A torque limitation or torque limitation can be selected, in particular, via the formation of the inclination. The inclination of the driver surface is, in particular, such that the driver surface rests closer to the engagement piece in the end region or head region of the engagement piece than at a distance from the end region or head region of the engagement piece.

In the sense of the description, the term “radial” encompasses an axis that extends radially from the center of the handling element or the axis of rotation of the handling element or of the screwing element and that is present transversely to the longitudinal axis of the diaphragm pump head part.

In a preferred embodiment, the profile in the direction of rotation for moving the screw element away from the diaphragm pump head part has a driving surface which is essentially parallel to a radial of the handling element. This can ensure that a force for loosening the fastening of the diaphragm pump head part on the drive is possible directly or with the highest possible force transmission. Functionally equivalent to a driving surface parallel to the radial, a driving surface can be formed in such a way that the engagement piece contacts the driving surface in such a way that the head region or end region of the engagement piece is spaced further from the driving surface than a region of the engagement piece that is spaced apart from the head region or end region is.

In a preferred embodiment, at least one bolt which passes through the diaphragm pump head part along the effective direction is provided and can be connected to the drive and the support. This makes it possible to use elements which are simple to manufacture and which can be constructed in a conventional manner. The diaphragm pump head part only has to have a number of through holes which corresponds to the number of bolts used. The through holes are preferably formed on the edge side around the longitudinal axis of the diaphragm pump head part and extend parallel to the longitudinal axis of the diaphragm pump head part.

In a preferred embodiment, a plurality of bolts are provided which can be releasably connected to the drive head part or the drive chamber section at the edge. In particular, more than two, very particularly preferably more than three bolts are provided, which in particular can be arranged at an angle equidistant around the drive head part or the drive chamber section in order to be able to distribute the forces occurring during the support evenly. The bolts can also pass through the pressure plate, for which purpose elongated holes are preferably provided which allow a certain tolerance in the arrangement of the pressure plate on the bolt or bolts.

In a preferred embodiment, the support has a plate-shaped component, which is also penetrated by the bolt or bolts. The support can be detachably connected to the bolt or bolts by means of a bayonet-type connection. This makes it possible to carry out a releasable, secure connection of the support to the bolt or bolts without a tool. The support can be fixed on the bolt in such a way that there is already a first compressive force on the diaphragm pump head part in the direction of the drive. A bayonet-like connection is low-maintenance and simple in design. However, a connection other than a bayonet-type connection is also possible, which securely fixes the support to the bolt or the bolt. The formation of a plate-shaped support allows good stability with a corresponding connection of the bolt or bolts. In particular, the cross section of the support can essentially correspond to the cross section of the diaphragm pump head part.

Fastening the diaphragm pump head part to the drive can be reduced to the rotation of a screw element thanks to the invention. The screw element can exert a compressive force on the diaphragm pump head part in the direction of the drive. Fastening the diaphragm pump head part to the drive can thus be reduced to consideration of the one screw element. A slight possible lengthening along the longitudinal axis through the provision of the support and the screw element is generally irrelevant for use, since even with conventional devices, access to the front was necessary in the event of a possible screw connection and there is therefore space in this direction.

The device proposed according to the invention for conveying fluid has a diaphragm pump head part and a drive for impressing movement on a diaphragm of the diaphragm pump head part and a bolt which is connected to a housing of the drive and which penetrates a through hole through a housing of the diaphragm pump head part. The device according to the invention has a tensioning device according to the invention, the bolt having a support surface which is supported by the support surface of the support of the tensioning device.

In the sense of the description, the term “diaphragm pump head part” comprises a pump head or a part or section of a pump head, which is preferably formed separately from the other elements, in particular the drive, very particularly preferably from the drive unit and the drive housing can be designed individually interchangeable. The diaphragm pump head part can in particular be handled as a unit. The diaphragm pump head part can essentially have a diaphragm housing section, a valve plate arranged between the diaphragm housing section and a diaphragm housing cover, a diaphragm plate and a swash plate. The diaphragm pump head part can have an inlet for the medium to be pumped into the pump head and an outlet from the pump head for the fluid to be pumped / pumped, the inlet and outlet preferably being provided on or in the diaphragm housing section. The membrane plate can have the pump membranes of the pump chambers. The swash plate can be connectable via a ball bearing to a pin of a drive shaft connected to the drive and tilted relative to a longitudinal axis. A drive head part connected to the drive can have the drive shaft with the ball bearing arranged on the drive pin.

The swashplate can be an interface between the two pump head parts, i.e. the diaphragm pump head part and the drive head part. The diaphragm pump head part can be pushed relatively easily with the receiving bore of the swash plate over the ball bearing fastened to the pin of the drive shaft and connected to the drive head part. The connection to the drive head part can also be carried out differently, for example non-positively or by means of bolts on the swash plate.

The drive head part can have a drive chamber part with the drive chamber to which the diaphragm pump head part can be coupled. In its drive chamber, which is open towards the drive head part, the drive chamber part can have the pin of the drive shaft with the ball bearing for receiving the swash plate.

The division mentioned can provide the advantage that the swash plate is easily accessible for assembly. In the case of reusable systems, the swash plate or the pump diaphragms or the diaphragm plate, as well as other parts of the diaphragm pump head part, can be easily replaced.

The drive chamber part can be upstream of the drive housing via a chamber end part. The chamber end part can form the drive-side drive chamber wall and a bearing of the drive shaft. The drive shaft can be mounted in the chamber end part via a double ball bearing. The chamber end part can form the link to the drive housing in which the drive shaft is connected to a drive motor. The valve plate can be arranged in a shoulder of the diaphragm pump head part with lateral axial play and can be fixed in the axial direction with respect to the diaphragm housing section and the diaphragm housing cover by means of elastic sealing elements. Due to the lateral and axial play of the valve plate with simultaneous fixation in the axial direction by elastic sealing elements, a kind of floating mounting of the valve plate between the first and second housing part, in particular the membrane housing section and the membrane housing cover, is achieved. As a result, different expansion coefficients, for example during autoclaving, ie when sterilizing with superheated steam, reliably prevent tensioning of the valve plate.

The drive can have a drive chamber section with a drive chamber, which is located in front of the diaphragm housing cover. When the diaphragm pump head part is placed on the drive head part, the swash plate arranged on the diaphragm pump head part is located in the drive chamber. The swash plate is placed on a ball bearing, which is arranged on a pin of a drive shaft connected to the drive. The pin is inclined with respect to the longitudinal axis of the drive shaft in order to produce a wobbling movement of the swash plate.

The invention also provides a method for generating a preload on the bolt in a device according to the invention. In the method, the distance between the contact surface of the screw element and the support surface of the support is increased by screwing in or unscrewing the screw element in order to generate the pretension.

The invention also provides use for attaching a diaphragm pump head member to a drive for imparting motion to a diaphragm of the diaphragm pump head member using a support. The support is essentially fixed in one direction of the drive in an effective direction of the fastening. A screw element is used which passes through the support and with which the diaphragm pump head part can be moved onto the drive in the form of a linear drive.

If aspects relating to a device are described in the context of the description, these aspects also apply to the described method or the described use. A transfer of the individual versions and individual configurations mentioned for the device, the method and the use apply in an analogous or corresponding manner to the other two aspects. The invention is explained in more detail below with the aid of drawings illustrating an exemplary embodiment of the invention. In it show:

Fiq. 1 is a sectional view through a drive chamber section and a diaphragm pump head part;

Fiq. 2 shows a device for conveying fluid in an isometric view;

Fiq. 3 shows the device for conveying fluid according to FIG. 2 in a partial exploded view;

Fiq. 4 shows an exploded view of a handling element with a screw element mounted on the handling element;

Fiq. 5 shows a pressure element in a sectional illustration along its longitudinal axis; and

Fiq. 6 shows a front view of the handling element with an enlarged illustration partially broken away.

1 shows a device for conveying fluid, which is designed as a diaphragm pump 1. The diaphragm pump 1 has a drive 2, of which a drive head part configured as a drive chamber section 3 is shown in FIG. 1, and a diaphragm pump head part 4.

The diaphragm pump head part 4 essentially has a diaphragm housing part 5, a valve plate 7 arranged between the diaphragm housing part 5 and a diaphragm housing cover 6, a diaphragm plate 8 and a swash plate 9.

As can be seen, for example, from FIGS. 2 and 3, the diaphragm housing part 5 has an inlet 10. Furthermore, the membrane housing part 5 has an outlet 11.

The valve plate 7 is arranged in a shoulder 12 of the diaphragm housing part 5 between the diaphragm housing part 5 and the diaphragm housing cover 6.

The valve plate 7 has four inlet valves 13, the valve channels of which are connected on the one hand to an annular inlet chamber 14 and on the other hand to the pump chambers 15 upstream of the valve plate 7. The valve plate 7 has four exhaust valves 16, a central exhaust valve body being provided. The valve channels of the outlet valves 16 are connected on the one hand to a central outlet chamber 17 and on the other hand to the pumping chambers 15. The to the Diaphragm housing cover 6 open pump chambers 15 are each closed or limited by a pump membrane, which is designed as a section of the membrane plate 8. The pump membranes are stretched between the valve plate 7 and the diaphragm housing cover 6 and seal the respective pump chamber 15 via an annular bead which runs in a groove arranged around the pump chamber 15.

The drive head part has a drive chamber part 3 with a drive chamber 18 which is arranged in front of the diaphragm housing cover 6. When the diaphragm pump head part 4 is placed on the drive head part, the swash plate 9 arranged on the diaphragm pump head part 4 is located in the drive chamber 18. The swash plate 9 is placed on a ball bearing 19 which is arranged on a pin 20 of a drive shaft connected to the drive 2 . The pin 20

is inclined with respect to the longitudinal axis of the drive shaft in order to produce a wobbling movement of the swash plate 9.

Fig. 2 shows the attachment of the diaphragm pump head part 4 on the drive in an isometric view. A handling element 21 is provided for fastening, which can be rotated about the longitudinal axis L of the diaphragm pump head part 4. The handling element 21 is profiled on the circumference.

3 is an exploded view of the components provided for fastening the diaphragm pump head part 4 to the drive 2. On the circumferential side, 3 holes for bolts 22 are provided on the drive chamber section, which can be screwed to the drive chamber section 3. Four bolts 22 are provided, which are releasably connected at the edge on the edge side to the drive chamber section 3 in an equidistant manner.

The diaphragm pump head part 4 has through holes 23 which are adapted to the outer diameter of the bolts 22 and through which the bolts 22 can be guided. The diaphragm pump head part 4 can, as it were, be placed on the drive chamber section 3 in the longitudinal axis L of the diaphragm pump head part 4, the bolts 22 being guided through the corresponding through holes 23.

On the outside of the diaphragm pump head part 4, which is spaced apart from the drive 2, a pressure plate 24 is placed, which has elongated holes 25 formed on the circumference, through which the bolts 22 can be guided. The pressure plate 24 can be placed on the four bolts 22 and moved in the direction of the diaphragm pump head part 4 along the longitudinal axis L of the diaphragm pump head part 4. A support 26, which can also be referred to as a bayonet plate, is attached to the bolt 22, the position of which is fixed with respect to the longitudinal axis L of the diaphragm pump head part 4 or the direction of action of the fastening of the diaphragm pump head part 4 to the drive 2. The connection between the support 26 and the bolt 22 takes the form of a bayonet-type connection, in that the support is plugged onto the bolt 22 and rotated relative to the latter about the longitudinal axis L of the diaphragm pump head part 4. As a result, the head of the bolt 22 comes into contact with the support surface of the support 26. The support surface points away from the diaphragm pump head part 4. An undercut on the head of the bolt 22, which points in the direction of the diaphragm pump head part 4, comes into contact with this support surface. The support 26 and the pressure plate 24 are connected to one another by means of four screws 27.

The support 26 has a central through hole 28 with an internal thread. The internal thread is adapted to an external thread of a screw element 29 (FIG. 4) and the screw element 29 can extend through the through hole 28 and be rotated in the internal thread. Due to the rotation of the screw element 29 in the through hole 28, a contact surface on the front end 30 of the screw element 29 directed towards the pressure plate 24 can act on the pressure plate 24. The screw element 29 is supported on the support 26 by means of the threaded engagement and can press the pressure plate 24 and the diaphragm pump head part 4 in the direction of the drive 2.

The screw element 29 is mounted centrally in the handling element 21, which can also be referred to as a handwheel. The longitudinal axis of the screw element 29 essentially coincides with the longitudinal axis L of the diaphragm pump head part 4. The screw element 29 has a head 31 at the end opposite the end 30, which is in contact with the handling element 21. A recess 32 is formed in the handling element 21, which at least partially accommodates the head 31. On the circumferential side, recesses 33 are formed on the head 31 of the screw element 29, into which pressure elements 34 are inserted.

5, which shows a sectional illustration of the pressure elements 34, the pressure elements 34 have a sleeve 35, a spring 36 and an engagement piece 37. By means of the pressure elements 34, of which six are provided at equidistant angles around the circumference of the head 31 of the screw element 29, the screw element 29 is supported circumferentially on the handling element 21.

A holding element 38 is screwed to the handling element 21 by means of screws 39. On the inner contour of the holding element 38, the engagement pieces 37 are the Pressure elements 34 engaged. An inner contour in the form of a profile is formed on the holding element 38, as can be seen in FIG. 6, which shows a front view of the handling element 21 with a partially broken away, enlarged illustration, and also again in detail Z in FIG. 4 is made clear. The profile 40 has a recess 41 for each engagement piece 37, in which the

Engagement piece 37 is engaged. For each of the pressure elements 34 shown in FIG. 4, a recess 41 is provided in the profile 40 of the holding element 38 at a corresponding point. The recesses 41 are configured identically. Fig. 6 shows a different effect when turning the

Handling element 21 due to the asymmetrically designed profile 40. With respect to the recess 41, the profile 40 is designed asymmetrically in such a way that a driving surface 42 for the clockwise rotation, as shown schematically in FIG. 6, is inclined with respect to the radial of the handling element 21 has. Due to the inclination, the profile 40 functions together with the pressure element 34 when it is turned clockwise, like a slip clutch. Above a certain torque, which acts on the screw element 29, the engagement piece 37 of the pressure element 34 disengages from the recess 41 with continued rotation. The engagement piece 37 can slip out of the recess 41, which enables the inclined driving surface 42.

In the event that the handling element 21 is rotated counterclockwise, the engagement piece 37 is in engagement with a driving surface 43 of the profile 40, which runs essentially parallel to the radial of the handling element 21. With a counterclockwise rotation of the handling element 21, it is possible - in contrast to a clockwise rotation - to ensure a constant power transmission. The engagement piece 37 cannot leave the recess 41 during a counterclockwise rotation.

Claims

Claims: 1. tensioning device for applying a prestress to a fastening element, the fastening element being suitable for fastening a diaphragm pump head part (4) to a drive (2) for imposing movement on a diaphragm of the diaphragm pump head part (4) in a device for conveying fluid, wherein the tensioning device has a support (26) with a support surface for supporting a support surface of the fastening element, the support (26) having a threaded bore through which a screw element (29) passes, and the screw element (29) at its front end ( 30) has a contact surface, the contact surface of the screw element (29) and the support surface of the support (26) pointing in the opposite direction and the distance between the contact surface of the screw element (29) and the support surface of the support (26) by screwing or unscrewing the Screw element (29) can be changed. 2. Clamping device according to claim 1, characterized by a pressure plate (24) which is suitable for coming into contact with the diaphragm pump head part (4), the contact surface of the screw element (29) abutting the pressure plate (24). 3. Clamping device according to claim 1 or 2, characterized by a plate-shaped handling element (21) which is connected to the screw element (29), and a rotation of the handling element (21) rotates the screw element (29). 4. Clamping device according to claim 3, characterized in that a slip clutch is formed between the screw element (29) and the handling element (21). 5. Clamping device according to one of claims 3 or 4, characterized in that the screw element (29) is supported on a peripheral surface of the handling element (21). 6. Clamping device according to one of claims 3 to 5, characterized in that between screw element (29) and handling element (21) at least one pressure element (34) is provided which interacts with a profile (40) of the handling element (21). 7. Clamping device according to claim 6, characterized in that the Pressure element (34) has a sleeve (35), a spring (36) and an engagement piece (37), the sleeve (35) being arranged on the screw element (29) and the engagement piece (37) engaging in the profile (40). 8. Clamping device according to claim 7, characterized in that the Pressure element (34) is arranged in a recess (33) on the head of the screw element (29). 9. Clamping device according to one of claims 6 to 8, characterized in that the profile (40) has at least one asymmetrically designed recess (33) for receiving a part of the pressure element (34). 10. Clamping device according to claim 9, characterized in that the profile (40) has a driving surface (42, 43) inclined to a radial of the handling element (21). 1 1. Clamping device according to one of claims 9 or 10, characterized in that the profile (40) one to a radial of the Handling element (21) has a substantially parallel driver surface (43). 12.Device for conveying fluid with a diaphragm pump head part (4) and a drive (2) for imparting motion to a diaphragm of the diaphragm pump head part (4) and a bolt (22) connected to a housing of the drive (2), which has a through hole ( 23) passes through a housing of the diaphragm pump head part (4), characterized by a tensioning device according to one of claims 1 to 11, wherein the bolt (22) has a support surface which is supported by the support surface of the support (26) of the tensioning device. 13. A method for generating a bias on the bolt (22) of a device according to claim 12, characterized in that for generating the bias, the distance between the contact surface of the screw element (29) and the support surface of the support (26) by screwing in or unscrewing the Screw element (29) is enlarged.