Pinch valve for flowable media

Abstract

A pinch valve for flowable media, comprising a valve housing (2) in which extends a tubular valve member (4) having a flexible peripheral wall (8) and a valve channel (5) extending in its longitudinal direction, a plurality of pinch elements (23, 24) being arranged around the radial outer circumference (22) of said valve member, said pinch elements being movable toward and away from one another while executing linear working movements (28) in a working plane (25) perpendicular to the longitudinal axis (9) of the valve member (4) in order to squeeze the valve member (4) together to a greater or lesser extent, and comprising a drive device (36) for inducing the working movements (28) of the pinch elements (23, 24), said drive device comprising a drive shaft (42) which is rotatably mounted about a rotational axis (43) extending in the longitudinal direction of the drive shaft and which has an actuating section (48),into which a drive torque causing a rotary drive movement (55) of the drive shaft (42) can be introduced, wherein the drive device (36) further comprises a conversion mechanism (37) having a toothed gear (38) which converts the rotary drive movement (55) of the drive shaft (42) into the linear working movements (28) of the squeezing elements (23, 24), wherein the pinch valve (1) is designed to be manually actuated, wherein a handle (56) accessible outside the valve housing (2) is arranged on the actuating section (48) of the drive shaft (42) which is rotatably mounted on the valve housing (2), characterized in that the toothed gear (38) has an input toothing (67) which is connected in a rotationally fixed manner to the drive shaft (42) and participates in its rotary drive movement (55), as well as an input toothing (67) which is in toothed engagement with the input toothing (67) and which is connected to the squeezing elements (23,24) has a movement-coupled output toothing (68) for causing the working movements (28).

Description

[0001] The invention relates to a pinch valve for flowable media, comprising a valve housing in which a tubular valve member extends, which has a flexible peripheral wall and is penetrated in its longitudinal direction by a valve channel, around the radial outer circumference of which a plurality of pinch elements are arranged and can be moved towards and away from one another while carrying out linear working movements in a working plane perpendicular to the longitudinal axis of the valve member in order to squeeze the valve member together to a greater or lesser extent, and comprising a drive device for causing the working movement of the pinch elements.

[0002] A pinch valve of this type, known from EP 1 912 001 B1, has two stamp-like pinch elements arranged within a valve housing in radial guide slots for linear displacement. They rest against diametrically opposed areas on the outer circumference of a tubular valve member. The pinch elements can be driven by a drive device to perform working movements in the working plane, so that they squeeze the valve member to a greater or lesser extent in order to influence the flow cross-section of a valve channel passing through the valve member. The drive device has a sleeve-shaped deflection element enclosing the valve member and the pinch elements. The sleeve-shaped deflection element has a conical link structure on its inner circumference, with which it slides against the pinch elements.By means of a fluid-loaded drive piston, which is also part of the drive device, the deflection element can be moved back and forth against the force of a spring device to adjust the desired working position of the squeezing elements. Other drive mechanisms are also conceivable for the drive device, for example, electromagnetic and / or lever-type.

[0003] A pinch valve known from EP 2 663 794 B1 has a tubular valve member flanked by two pinch elements enclosed by a sleeve-shaped actuating member having on its inner side several grooves designed like a multi-start thread into which the pinch elements engage. When the actuating member is rotated, a screwing process takes place in which the multi-start thread moves over the pinch elements. Since the grooves of the multi-start thread have a varying depth, the screwing process causes a radial displacement of the pinch elements with respect to the valve member, whereby the valve member is squeezed together to a greater or lesser extent.

[0004] DE 10 2013 012 158 A1 discloses a pinch valve with two rod-shaped pinch elements arranged on diametrically opposite sides of a tubular valve member and extending through a sleeve-shaped actuating member coaxial with the valve member, which, during a linear movement, acts on the pinch elements via slotted guides in order to move them transversely to the valve member. The pinch elements also extend through a sleeve-shaped valve housing of the pinch valve, with end sections of the pinch elements protruding from the valve housing being held in place by a securing body and secured against falling out. A drive device is provided to drive the actuating member, which can be designed for electrical or manual actuation. A lever mechanism can be provided as a transmission mechanism.

[0005] US 2014 / 0 077 107 A1 discloses a pinch valve comprising a tubular valve element, an actuating element arranged on the outer circumference of the valve element, and at least one radially movable plunger arranged between the actuating element and the valve element. On the inside of the actuating element, there is at least one actuating surface extending circumferentially and axially, which bears against a plunger. Guide means ensure that upon rotation of the actuating element, the actuating surface slides on the at least one plunger and presses it radially inward, since the distance of the actuating surface from the valve element varies across its longitudinal profile.

[0006] DE 10 2018 009 537 A1 discloses a device for flushing a body cavity with a fluid, wherein the fluid is pumped out of the body cavity via two lines. The respective pumping power is regulated via controllable pinch valves, with the two pinch valves being coupled in antiparallel.

[0007] DE 10 2018 204 554 B3 discloses a pinch valve having a pinch element rotatably arranged in a valve housing, which is penetrated by a pinch element channel through which a flexible hose extends. The pinch element channel has two outer channel openings, each enclosed by an outer opening edge and opposite which is an inner opening edge of a housing channel extending through the valve housing. By rotating the pinch element, the hose is reversibly squeezed between the outer opening edges and the inner opening edges. The outer opening edges on the pinch element each have at least one local indentation, the opening of which is oriented in the direction of rotation of the pinch element required to squeeze the hose, and through which the pinched hose can extend.

[0008] US 2005 / 0 205 822 A1 discloses a pinch valve for automotive applications, the pinch valve comprising a flexible hose, an extension seat surrounding the flexible hose, a pinch extension aligned with the extension seat on the outside of the flexible hose, and a valve actuator operatively connected to the pinch extension. The valve actuator may be arranged to position the pinch extension in response to predetermined factors or in response to a control system, such as a vehicle computer.

[0009] DE 84 25 038 U1 discloses a pinch valve with a housing which contains two bores in a T-shaped arrangement, of which the first bore forming the crosspiece of the T passes through the housing and opens onto opposite sides of the housing and contains an elastically compressible hose, and with a pressure slide which is mounted in the second bore opening into the first bore and which can be displaced in the axial direction between two end positions in order to squeeze the hose, the hose being uncrushed in the first end position and completely crushed in the second end position.

[0010] The invention is based on the object of creating a pinch valve which can be easily and precisely actuated with a simple and compact design.

[0011] To achieve the object, a pinch valve in conjunction with the features mentioned at the outset is provided with the drive device having a drive shaft which is rotatably mounted on the valve housing about a rotational axis extending in the longitudinal direction of the drive shaft and which has an actuating section into which a drive torque causing a rotary drive movement of the drive shaft can be introduced, wherein the drive device further has a conversion mechanism having a toothed gear which converts the rotary drive movement of the drive shaft into the linear working movements of the pinch elements, wherein the pinch valve is designed to be manually actuated, wherein a handle accessible outside the valve housing is arranged on the actuating section of the drive shaft which is rotatably mounted on the valve housing,wherein the gearing has an input toothing connected to the drive shaft in a rotationally fixed manner and participating in its rotary drive movement, as well as an output toothing in tooth engagement with the input toothing and coupled in motion to the squeezing elements to produce the working movements.

[0012] The pinch valve according to the invention allows the control of the flow of any flowable media, such as liquids, gases, or powdered substances. By means of the drive device, the pinch elements can be driven to perform working movements transverse to the longitudinal axis of the valve member in order to squeeze the valve member, which has a flexible peripheral wall, to a greater or lesser extent. In this way, the working positions of the pinch elements can be adjusted, either allowing media to pass through the valve channel or closing the valve channel to prevent media from passing through. In other words, the pinch elements can be used to change and / or adjust the flow cross-section provided by the valve channel.The drive force required to adjust and position the pinch elements is easily transmitted as torque to a drive shaft rotatably mounted on the valve housing, which has an actuating section designed for torque transmission. Smooth yet precise actuation of the pinch elements is ensured by a conversion mechanism equipped with a gear drive that converts the rotary drive movement of the drive shaft into the linear working movements of the pinch elements. The gear drive can be easily implemented with the desired gear ratio and yet accommodated in a small space, allowing for compact dimensions for the pinch valve overall. The low wear of the gear drive enables a long service life and thus corresponding customer benefits.The actuator can be configured either for digital "open / close" actuation or for continuously adjusting the flow cross-section provided by the valve channel between fully closed and fully open. This allows for continuous flow regulation. The valve housing, in particular, can be made of plastic at low cost or, for demanding applications, of stainless steel.

[0013] Advantageous further developments of the invention emerge from the subclaims.

[0014] According to the invention, the pinch valve is realized in a manually operated design. It can then be conveniently operated manually in an energy-autonomous manner. The manually operated pinch valve has a handle arranged on the actuating section of the drive shaft, which lies outside the valve housing and is easily grasped in order to initiate a drive torque that causes the rotational adjustment of the drive shaft. A handle implemented as a hand lever with at least one, and preferably with exactly one, manually graspable lever arm is considered particularly expedient. This enables actuation with particularly little effort and, based on the current pivot position, also allows conclusions to be drawn about the currently set operating state of the pinch valve. Instead of a hand lever, a compact toggle or a handwheel could also be provided.A manually operated pinch valve can be manufactured and operated at extremely low cost.

[0015] Nevertheless, it is readily possible to provide the pinch valve in a motor-operated design. In particular, a drive motor is considered as the drive source. The drive motor is preferably an electric motor, although a fluid motor, such as a fluid-operated rotary actuator, could also be considered. An electrically operated drive motor is particularly implemented as a stepper motor or servo motor, which facilitates extremely precise rotary positioning of the drive shaft for setting a desired flow cross-section of the valve channel.

[0016] The drive motor is conveniently mounted on the valve housing with a stator and has a rotatably driven output shaft that is connected to the actuating section of the drive shaft in a torque-transmitting manner. In a particularly cost-effective design, the actuating section is formed directly by the output shaft of the drive motor, thus eliminating the need for a shaft coupling.

[0017] In principle, the pinch valve can be implemented with any number of pinch elements, although it is considered particularly expedient if the pinch valve is equipped with just two pinch elements, which are assigned to diametrically opposed circumferential regions of the outer circumference of the valve member. These two pinch elements are movable in order to carry out their respective working movements in the axial direction of a common imaginary working axis that is perpendicular to the longitudinal axis of the valve member and lies in the working plane. This working axis, which extends centrally through the two pinch elements, is expediently spaced from the axis of rotation of the drive shaft in the longitudinal direction of the valve member and at the same time runs orthogonally to this axis of rotation when viewed in the longitudinal direction of the valve member.

[0018] An off-center arrangement of the drive shaft relative to the valve member is recommended, so that its axis of rotation is spaced from the longitudinal axis of the valve member. In particular, the drive shaft is positioned in the longitudinal area of ​​the valve housing. The axis of rotation of the drive shaft preferably coincides with the longitudinal axis of the drive shaft.

[0019] According to the invention, the gearing of the conversion mechanism has an input gearing which is connected in a rotationally fixed manner to the drive shaft and thus participates in its rotary drive movement, and furthermore an output gearing which is constantly in gear engagement with the input gearing and which is motionally coupled to the squeezing elements in order to cause their working movements.

[0020] A pinch valve design is possible in which the output teeth of the gear mechanism are formed directly on the pinch elements. In this case, each pinch element has a section of output teeth. However, a preferred embodiment of the pinch valve is one in which the output teeth are not formed directly on the pinch elements, but rather on at least one other component of the conversion mechanism located between the drive shaft and the pinch elements. This enables particularly cost-effective production of the pinch elements.

[0021] The conversion mechanism preferably includes a deflection member arranged in the valve housing between the squeezing elements and the drive shaft. The deflection member is displaceable relative to the valve housing and also relative to the valve member by the drive movement of the drive shaft, performing a linear movement referred to as a linear deflection movement in the longitudinal direction of the valve member. It has a link structure against which the squeezing elements slide, so that they slide along the link structure during the linear deflection movement of the deflection member. Thus, during the linear deflection movement of the deflection member, the squeezing elements are driven to perform their working movements at right angles to the longitudinal axis of the valve member.

[0022] It is particularly advantageous if the output gearing is arranged on the deflection element. The deflection element is preferably a one-piece body into which the output gearing is directly integrated. Such a deflection element can be manufactured cost-effectively from a plastic, for example, by injection molding.

[0023] Preferably, the deflection member is sleeve-shaped and arranged in the valve housing such that it coaxially encloses the valve member. The gate structure is expediently formed on the inner circumference of the deflection member.

[0024] During the deflection movement, the deflection element can be conveniently moved between two opposing axial end positions. One of these two axial end positions represents a shut-off position, which causes the valve channel to close and thus prevents media flow through the valve channel, while the other end position represents a release position, which is responsible for opening a maximum flow cross-section of the valve channel.

[0025] Preferably, the deflection element can be positioned continuously between these two axial end positions in order to set a free flow cross-section of the valve channel which lies between the maximum open position and the closed position.

[0026] A spring device is advantageously arranged in the valve housing, which constantly preloads the deflection element into one of its two axial end positions. The preload is advantageously applied to the shut-off position, so that the pinch valve forms a "normally closed" type. Alternatively, the spring device can also be arranged so that the deflection element is constantly preloaded into the release position. The spring device is, in particular, a mechanical spring device, although it could alternatively be designed as an air spring.

[0027] The pinch valve can also be designed entirely without a spring device, so that only externally introduced actuating forces act on the deflection element and thus on the pinch elements.

[0028] The output gearing of the gear mechanism is advantageously located on the outer circumference of the deflecting element. In principle, it can extend around the deflecting element in the circumferential direction of the valve element, but preferably occupies only a limited circumferential section of the outer circumference of the deflecting element in the circumferential direction of the valve element.

[0029] The gearing is preferably designed as a rack and pinion gear, with the input gearing being designed as an arcuately curved gear ring and the output gearing as a linearly extending rack. In this case, the output gearing has a plurality of teeth arranged axially successively in the longitudinal direction of the valve member and spaced apart by tooth gaps, in which the arcuately curved gear ring of the input gearing can roll during the rotary drive movement of the drive shaft. In conjunction with a sleeve-shaped deflection member, the rack is preferably integrated into the deflection member as a single piece by appropriately contouring the deflection member.

[0030] Alternatively, to achieve the object in a pinch valve in conjunction with the features mentioned at the outset with regard to the subject matter of the invention, it is provided that the drive device has a drive shaft which is rotatably mounted on the valve housing about a rotational axis extending in the longitudinal direction of the drive shaft and which has an actuating section into which a drive torque causing a rotary drive movement of the drive shaft can be introduced, wherein the drive device further has a conversion mechanism which converts the rotary drive movement of the drive shaft into the linear working movements of the pinch elements and which has a gearing, wherein the gearing has an input gearing which is connected in a rotationally fixed manner to the drive shaft and which participates in its rotary drive movement, as well as an input gearing which is in gear engagement with the input gearing,having output gearing coupled in motion to the squeezing elements for generating the working movements, wherein the conversion mechanism has a deflection member which is displaceable by the rotary drive movement of the drive shaft while executing a linear deflection movement in the longitudinal direction of the valve member and which has a link structure against which the squeezing elements slideably rest such that they are driven to their working movements by the link structure during the linear deflection movement of the deflection member, wherein the drive shaft is rotatably mounted on the valve housing, wherein the deflection member is arranged in the valve housing, wherein the gearing is designed as a rack and pinion gear, wherein the input gearing is designed as an arcuately curved gear ring and the output gearing is designed as a rack having a linear extension.

[0031] Preferably, the mutual engagement between the gear ring and the rack simultaneously ensures that the deflection member equipped with the rack is secured against rotation with respect to the valve housing, so that the desired toothed engagement is reliably ensured even if the rack extends in the circumferential direction of the valve member only over part of the outer circumference of the deflection member.

[0032] The arc length of the input gear ring is, in principle, arbitrary, but an arc length of less than 360 degrees is preferred. The arc length of the input gear ring is selected in such a way that the gear engagement extends over a rotation angle of the drive shaft that corresponds to the maximum stroke of the deflection element between its two axial end positions.

[0033] It is advantageous if the pinch valve has a stop device that mechanically predetermines two opposing end positions of the rotary drive movement of the drive shaft. These two rotational end positions correspond, in particular, to two axial end positions of the deflection element, in which the pinch elements assume either a closed position that closes the valve channel or an open position that allows a maximum flow cross-section of the valve channel.

[0034] The stop device advantageously has two stop surfaces arranged on the drive shaft and thus participating in the rotary drive movement, and two counter-stop surfaces arranged on the valve housing in the pivoting path of the stop surfaces. The two stop surfaces are preferably formed by the tooth flanks of two teeth closing the ring gear on opposite sides. The latter has the advantage that the teeth can perform a dual function: firstly, transmitting a drive force and secondly, specifying the rotational end positions of the drive shaft.

[0035] Preferably, the drive shaft is associated with a manually operable blocking device for releasably blocking different rotational positions of the drive shaft. This provides the advantageous possibility of releasably fixing different sized released flow cross-sections of the valve channel, including a completely closed valve channel, without the need for a constant introduction of torque into the drive shaft to maintain a rotational position. In this way, in particular, intermediate positions between a closed position and an open position of the valve channel, which releases a maximum flow cross-section, can also be fixed. The blocking effect of the blocking device also makes it possible, in particular, to resist the actuating force of a spring device acting on the deflection element.

[0036] To realize an advantageous embodiment of the blocking device, the drive shaft is expediently axially movable to a limited extent relative to the valve housing, wherein it has a coaxially arranged axially oriented annular surface, which is axially opposite an annular counter-blocking surface arranged on the valve housing. Furthermore, in this case, the blocking device includes a manually operable clamping element engaging the drive shaft, the actuation of which can cause an axial adjustment of the drive shaft together with the blocking surface in order to position the blocking surface either in a non-rotatably clamped position with the counter-blocking surface and thus non-rotatably blocking the drive shaft, or in a release position allowing rotation of the drive shaft.

[0037] The clamping element is designed in particular as a clamping nut screwed onto the drive shaft, which can be supported on an outer surface of the valve housing when rotated relative to the drive shaft in order to exert an axial tensile force on the drive shaft, by means of which the blocking surface is clamped to the counter-blocking surface.

[0038] The blocking surface and the counter-blocking surface can be designed for frictional engagement, which facilitates continuous locking of the drive shaft in different rotational positions. In another, particularly advantageous embodiment, the blocking surface and the counter-blocking surface are structured like a toothing, so that they engage with each other in a positive-locking manner when the blocking surface is in the locked position. This type of locking provides particularly effective protection against accidental release, even in cases where the pinch valve is exposed to vibrations during use.

[0039] The invention is explained in more detail below with reference to the accompanying drawings, which show: Fig. 1 is an isometric view of a preferred embodiment of the pinch valve according to the invention in the operating state of an open position for maximum flow through the valve member, Fig. 2 the pinch valve Fig. 1 in the operating state of a closed position for interrupted flow with the valve element shut off, Fig. 3 a cross-section of the open position according to Fig. 1 engaging pinch valve according to section line III-III from Fig. 4, where the dash-dotted section of the drive shaft is also illustrated separately again uncut, Fig. 4 a longitudinal section along section line IV-IV Fig. 3, Fig. 5 a cross-section of the pinch valve in the closed position according to section line VV Fig. 6, Fig. 6 a longitudinal section of the pinch valve according to section line VI-VI Fig. 5, Fig. 7 a side view of the pinch valve with view direction according to arrow VII-VII from Fig. 3 without representation of the valve housing, and Fig. 8 the arrangement Fig. 7 in an isometric view.

[0040] The pinch valve, designated overall by reference numeral 1, has a valve housing 2 and extends along an imaginary longitudinal axis 3. The axial direction of the longitudinal axis 3 is also referred to below as the longitudinal direction 3 of the pinch valve 1 using the same reference numeral.

[0041] In a housing interior 10 enclosed by the valve housing 2, a tubular element functioning as a valve member 4 extends between two media connections 6, 7 formed on the valve housing 2, which is longitudinally penetrated by a tubular channel, designated as valve channel 5, which communicates with the two media connections 6, 7. If the valve channel 5 has a free flow cross-section, as shown in Fig. 3 and Fig. 4, a flowable medium fed into one media connection 6 or 7 can flow through the valve channel 5 and exit the pinch valve 1 again at the opposite connection 7 or 6.

[0042] The valve member 4 has a longitudinal axis 9 that coincides with the axial direction of the longitudinal axis 3 of the pinch valve 1. The two media connections 6, 7 are expediently formed in two end walls 14a, 14b of the valve housing 2 that are opposite one another in the longitudinal direction 3.

[0043] The flowable medium whose flow through the pinch valve 1 can be controlled is, in particular, a liquid or a gas. The liquid can be, for example, water or a process fluid, and the gas can be, for example, compressed air. However, the pinch valve is also suitable for controlling, for example, powdery, granular, or pasty media, provided they have flowable properties.

[0044] The tubular valve member 4 is elastically deformable at least in the radial direction. It has a flexible peripheral wall 8 peripherally surrounding the valve channel 5, which is deformable, in particular in a rubber-elastically manner, at least transversely and in particular perpendicularly to the longitudinal axis 9. The valve member 4 is preferably made of an elastomer material. To increase the compressive strength, a reinforcing structure can be embedded in the peripheral wall 8.

[0045] A tubular wall section 14c of the valve housing 2 extends between the two end walls 14a, 14b, radially enclosing the housing interior 10 on the outside. It is connected, for example, in one piece with one of the end walls 14b, so that these two components 14b, 14c form, in particular, a cup-shaped housing section of the valve housing 2. The other end wall 14a is attached to the open end of the tubular wall section 14c, for example, by an ultrasonic weld. Overall, the valve housing 2 is preferably made of a plastic material, but it can also be made of metal, for example.

[0046] The valve member 4 has, for example, a flange section 4a, 4b on each of its axial end faces, which is pressed axially from the inside onto the adjacent end wall 14a, 14b in the transition area to one of the two media connections 6, 7, thereby sealing it.

[0047] Preferably, the valve member 4 is surrounded in the region of its radial outer circumference 22 by a support structure 15 which is separate from the valve housing 2 and is arranged in the housing interior 10. In a maximally radially expanded state of the valve channel 5, in which the largest possible free flow cross-section is provided to the medium flowing through, the flexible peripheral wall 8 of the valve member 4 can be supported on a support surface 16 of the support structure 15 extending all around the valve member 4, thus preventing it from overstretching.

[0048] For example, the support structure 15 has two half-shell-like support elements 17a, 17b, each with a circular arc-shaped cross-section, which are attached radially from opposite sides to the outer peripheral surface of the flexible peripheral wall 8, forming a sleeve-shaped structure. Each support element 17a, 17b has a surface portion of the support surface 16. In order for the two support elements 17a, 17b to hold together, they are inserted together with the valve member 4 enclosed by them into a support tube 18, which extends in the housing interior 10 between the two end walls 14a, 14b, to which it is fixed with one of its two axial end portions 18a, 18b.

[0049] Preferably, the support structure 5 is inserted into the housing interior 10 in the manner of a cartridge.

[0050] Arranged around the radial outer circumference 22 of the valve member 4 are a plurality of elements, referred to as squeezing elements 23, 24 and preferably designed in the manner of a stamp, which can be moved linearly back and forth in a working plane 25 perpendicular to the longitudinal axis 9 of the valve member 4. There are preferably exactly two such squeezing elements 23, 24, as is the case in the exemplary embodiment. These two squeezing elements 23, 24 are positioned in diametrically opposed circumferential regions of the radial outer circumference 22 of the valve member 4 and lie on a common imaginary axis 26 coinciding with the working plane 25, which is referred to as the working axis 26. The working axis 26 extends perpendicular to the longitudinal axis 9 of the valve member 4 and intersects this longitudinal axis 9.

[0051] Each squeezing element 23, 24 has a squeezing surface 27 on a front end side facing the flexible peripheral wall 8, wherein the squeezing surfaces 27 of the two squeezing elements 23, 24 face each other in the axial direction of the working axis 26.

[0052] Each squeezing element 23, 24 can execute a linear working movement 28 oriented in the axial direction of the working axis 26 and indicated by a double arrow. The working movement 28 can be directed both inwardly, i.e., toward the flexible peripheral wall 8, and in the opposite direction outwardly, i.e., away from the longitudinal axis 9 of the valve member 4.

[0053] Preferably, each pinch element 23, 24 has a plate-shaped basic shape with a main extension plane perpendicular to the longitudinal axis 3 of the pinch valve 1.

[0054] Within the scope of their linear working movements 28, the squeezing elements 23, 24 can be moved toward and away from each other in order to squeeze the valve member 4 more or less tightly in order to change the flow cross-section currently provided by the valve channel 5. The squeezing force is exerted by the squeezing surfaces 27 on circumferential wall sections 8a, 8b of the flexible circumferential wall 8 that are opposite one another in the axial direction of the working axis 26.

[0055] By means of the working movement 28, the squeezing elements 23, 24 can be moved in a Fig. 3 and Fig. 4, in which their mutual distance is at a maximum and in which the flexible peripheral wall 8 is not or only slightly squeezed together, so that the valve channel 5 has a maximum flow cross-section which allows a maximum flow for the medium to be controlled.

[0056] The squeezing elements 23, 24 can also be arranged in a Fig. 5 and Fig. 6, in which they are brought so close to one another by squeezing the flexible peripheral wall 8 together that opposite peripheral wall sections 8a, 8b of the flexible peripheral wall 8 in the axial direction of the working axis 26 are pressed against one another with a sealing effect, whereby the valve channel 5 is closed and no free flow cross-section is available for the medium to be controlled to pass through the valve member 4. In the axial direction of a transverse axis 32, which runs at right angles to both the longitudinal axis 9 of the valve member 4 and the working axis 26, the squeezing elements 23, 24 have a sufficiently long length in the region of their squeezing surface 27 to squeeze the flexible peripheral wall 28 together over its entire diameter.

[0057] Preferably, the squeezing elements 23, 24 can also be positioned in any intermediate positions between the open position and the closed position in order to release a flow cross-section of the valve channel 5 which lies between zero and the maximum flow cross-section released in the open position.

[0058] It can be seen that by selecting the positioning of the pinch elements 23, 24, a media flow rate for the flowing medium required for the current application of the pinch valve 1 can be set.

[0059] The support structure 15 has, in the area of ​​each of the two squeezing elements 23, 24, a preferably slot-shaped wall opening 33 through which the respective associated squeezing element 23, 24 slides to enable the working movement 28. Preferably, the boundary surface of each wall opening 33 forms a guide surface for linearly guiding the associated squeezing element 23, 24 during its working movement 28.

[0060] Each pinch element 23, 24 has a pressure head 34 on its rear side opposite the pinch surface 27 in the axial direction of the working axis 26. An actuating force 35 can be introduced into this actuating head 34 to move the respective pinch valve 23, 24 from the open position to the closed position. When the actuating force 35 is removed, the pinch elements 23, 24 are pushed back toward the open position by the peripheral wall 8, which expands again due to the internal pressure prevailing in the valve channel 5.

[0061] To generate the working movement 28 and in particular the actuating force 35, the pinch valve 1 is equipped with a drive device 36. This drive device 36 contains a conversion mechanism 37, which in turn has a gear transmission 38.

[0062] The drive device 36 has a drive shaft 42, which is mounted on the valve housing 2 in such a way that it is rotatable relative to the valve housing 2 about a rotational axis 43 extending in the longitudinal direction of the drive shaft 42. The drive shaft 42 has a longitudinal axis 44, with which the rotational axis 43 expediently coincides.

[0063] The drive shaft 42 expediently extends into a drive chamber 45 enclosed by the valve housing 2, which adjoins the housing interior 10 longitudinally and opens into the housing interior 10 via a window-like opening 46. To form the drive chamber 45, the housing wall of the valve housing 2 expediently has a local bulge 47.

[0064] The drive shaft 42 has a rear end section that functions as an actuating section 48, with which it protrudes from the drive chamber 45. In the region of the opening of the drive chamber 45 through which the drive shaft 42 passes, a support ring 52 is fixed in the valve housing 2, enclosing the drive shaft 42. The radial inner circumferential surface of the support ring 52 expediently forms a plain bearing surface for the rotary mounting of the drive shaft 42. A sealing ring 53 is expediently held in the longitudinal section of the drive shaft 42 that passes through the support ring 52. This sealing ring rests against the support ring 52 and seals the drive chamber 45 from the environment.

[0065] To complete the rotary bearing measures, the drive shaft 42 expediently has, at its front end section opposite the actuating section 48, a bearing socket 54a which is coaxial with the longitudinal axis 44 and which engages in a complementary wall recess 54b of the valve housing 2 and is radially supported therein in a rotatable manner.

[0066] The actuating section 48 is designed to be able to introduce a drive torque, which can cause a rotary drive movement 55 of the drive shaft 42 about the rotational axis 43, indicated by a double arrow. The drive movement 55 can be executed bidirectionally.

[0067] It is advantageous if, according to the illustrated embodiment, the pinch valve 1 is of a manually operable type. The drive torque for the drive shaft 42 can thus be conveniently introduced into the actuating section 48 by hand. For this purpose, a handle 56, accessible outside the valve housing 2, is arranged in a rotationally fixed manner on the actuating section 48. The handle 56 is, for example, a hand lever 57 with a lever arm 57a projecting radially from the rotation axis 43. The hand lever 57 is fixed in a rotationally fixed manner to or on the actuating section 48 by means of a fastening section 57b; it can, for example, be pressed or screwed on.

[0068] To cause the rotary drive movement 55, the hand lever 57 can be grasped and pivoted with one hand on the lever arm 57a.

[0069] According to another embodiment, the pinch valve 1 can also be of a motor-operated type. In this case, instead of the handle 56, a Fig. 3, a drive motor 58 is provided, indicated by a dash-dotted line, which has a stator 58a fixed to the valve housing 2 and a rotationally drivable output shaft 58b relative thereto, wherein the output shaft 58b is drivingly connected to the actuating section 48 or directly forms this actuating section 48 itself. The drive motor 58 is preferably an electric motor, which is in particular a servomotor or a stepper motor.

[0070] The conversion mechanism 37 already mentioned is designed to convert the rotary drive movement 55 of the drive shaft 42 into the linear working movements 28 of the squeezing elements 23, 24.

[0071] The conversion mechanism 37 includes the gear mechanism 38 and a deflection member 62 that cooperates directly with the squeezing elements 23, 24 to exert the actuating force 35. The deflection member 62 is sleeve-shaped and arranged in the housing interior of the valve housing 2 in a manner that coaxially encloses the valve member 4. It is preferably located there in an annular space section 63 of the housing interior 10, which is formed between the support structure 15 and the tubular wall section 14c. The deflection member 62 is linearly displaceable back and forth in the longitudinal direction 9 of the valve member 4 relative to the valve member 4 and the valve housing 2, wherein the movement that can be performed in this way is referred to as a linear deflection movement 64 for better differentiation and is illustrated in the drawing by a double arrow.

[0072] Preferably, the deflection member 62 is radially supported on the radial outer circumferential surface of the support tube 18 and / or on the radial inner circumferential surface of the tubular wall section 14c, ensuring axial displaceability, so that it experiences precise linear guidance for its deflection movement 64.

[0073] The sleeve-shaped deflecting member 62 extends radially outward beyond the application heads 34 of the squeezing elements 23, 24. Its radial inner circumferential surface is provided with a guide structure 65 that slideably engages the application heads 34 of the squeezing elements 23, 24. The guide structure 65 is configured such that the inner diameter of the sleeve-shaped deflecting member 62 gradually changes in the axial direction between a section 66a of maximum inner diameter and a section 66b of minimum inner diameter, axially spaced therefrom.

[0074] Within the scope of the linear deflection movement 64, the deflection element 62 is displaceable between two opposite axial end positions within the valve housing 2. A Fig. 3 and Fig. 4 is designated as the release position of the deflection member 62 and an opposite one, shown in Fig. 5 and Fig. 6 shows the second axial end position as the shut-off position of the deflection element 62.

[0075] In the release position of the deflection member 62, the section 66a of maximum inner diameter of the link structure 65 is at the same height as the application heads 34 of the squeezing elements 23, 24, which enables the squeezing elements 23, 24 to Fig. 3 and Fig. 4. In the shut-off position of the deflection element 62, the section 66b of minimum diameter of the gate structure 65 is at the axial height of the loading heads 34, whereby the squeezing elements 23, 24 are moved into the positions shown in the Fig. 5 and Fig. 6 visible closed position are shifted.

[0076] It can be seen that the link structure 65 exerts the actuating force 35, which serves to cause the working movement 28, on the two squeezing elements 23, 24.

[0077] Between the section 66a of maximum inner diameter and the section 66b of minimum diameter, a gradual transition expediently takes place, i.e. a gradual change in the inner diameter of the deflection member 32, so that during the deflection movement 64 a gradual, in particular smooth change in the position of the squeezing elements 23, 24 occurs.

[0078] The gear transmission 38 has two continuously meshing gears 67, 68, one of which is arranged on the drive shaft 42 and is referred to as the input gear 67, while the other is arranged on the deflection member 62 and is referred to as the output gear 68. The input gear 67 is fixedly attached to the drive shaft 42 so that it participates in its rotary drive movement. The output gear 68 is fixedly arranged on the deflection member 62 so that it participates in its linear deflection movement 64. During the rotary drive movement 55, the meshing between the input gear 67 and the output gear 68 converts the rotary drive movement 55 into the linear deflection movement 64.At the same time, the linear deflection movement 64 of the deflection member 62 oriented in the longitudinal direction 3, 9 is converted into the working movements 28 of the squeezing elements 23, 24, which are also linear but oriented at right angles to the deflection movement 64.

[0079] In the advantageous embodiment of the gearing 38 implemented by way of example, the drive shaft 42 is aligned such that its axis of rotation 43, which coincides with the longitudinal axis 44, extends parallel to the working plane 25. The drive shaft 42 is placed off-center with respect to the valve member 4, wherein the axis of rotation 43 is spaced apart from the valve member 4 in the radial direction with respect to the longitudinal axis 9 of the valve member 4. Preferably, the axis of rotation 43 is spaced apart from the working plane 25 and accordingly also from the working axis 26 in the longitudinal direction of the valve member 4. By way of example and preferably, the drive shaft 42 is arranged such that the axis of rotation 43, when viewed in the longitudinal direction 3 according to the Fig. 3 and Fig. 5 is aligned perpendicular to the working axis 26.

[0080] In other words, the axis of rotation 43 expediently runs parallel to the transverse axis 32 of the valve member 4 explained above.

[0081] Conveniently, the gearing 38 is designed as a rack and pinion gear, which is the case in the illustrated embodiment. The input gearing 67 consists of an arcuately curved gear ring 72, whose center of curvature lies on the rotational axis 43, while the output gearing 68 is designed as a rack 73 with a rectilinear extension and a rack longitudinal axis 74 that runs parallel to the longitudinal axis 3.

[0082] The rack 73 is arranged in the region of the radial outer circumference of the deflecting member 62 and, in particular, is integrated into the deflecting member 62. The deflecting member 62 is, in particular, a one-piece body with the rack 73 directly molded into it.

[0083] The teeth 73a of the rack 73 are arranged linearly in the axial direction of the rack's longitudinal axis 74, leaving gaps between the teeth. Each of these teeth 73a has a longitudinal extension with a tooth longitudinal axis 75, wherein the tooth longitudinal axis 75 runs transversely to the rack's longitudinal axis 74 and, in the preferred embodiment, is arranged at a right angle thereto. Accordingly, the rack 73 is preferably straight-toothed.

[0084] In this case, the gear ring 72 arranged on the drive shaft 42 also has a corresponding straight toothing. Its teeth 72a are arranged successively in the circumferential direction of the longitudinal axis 44 and each have a longitudinal extension with a tooth longitudinal axis 76 which extends parallel to the axis of rotation 43.

[0085] Deviating from the illustrated embodiment, the input gearing 67 and the output gearing 68 can also be designed as helical gears. This makes it possible, among other things, to align the drive shaft 42 so that its rotational axis 43 coincides with the longitudinal axis 3 of the pinch valve 1. This enables a particularly slim design of the pinch valve 1.

[0086] Due to the meshing engagement between the input toothing 67 and the output toothing 68, the deflecting member 62 is simultaneously secured against rotation with respect to the valve housing 2. This offers the exemplary possibility of limiting the circumferential extent of the output toothing 68 around the central longitudinal axis 9 of the valve member 4. The rack 73 occupies only a partial circumference of the deflecting member 62 and is located only in an outer circumferential region of the deflecting member 62 facing the drive chamber 45.

[0087] The input toothing 67 can protrude through the window-like opening 76 into the annular space section 63 in order to engage there with the output toothing 68.

[0088] A rotation of the drive shaft 42 causes the deflection member 62 to move linearly in the valve housing 2 while performing the linear deflection movement 64, wherein the direction of movement of the deflection member 62 depends on the direction of rotation of the drive shaft 42.

[0089] In principle, the gear ring 72 could be a full ring extending all the way around the drive shaft 42. However, it is preferably designed as a partial ring whose circumferential extent with respect to the longitudinal axis 44 is less than 360 degrees, wherein the arc length between the two teeth 72a, referred to as end teeth 77, is selected application-specifically and is, for example, 90 degrees.

[0090] The design of the gear ring 72 as a partial ring enables the advantageous implementation of a stop device 78 for mechanically specifying two opposing end positions of the rotary drive movement 55 of the drive shaft 42. At one of these end positions, the deflection element 62 assumes the blocking position, and at the other, the release position. Thus, the squeezing elements 23, 24 can be positioned very precisely in the open or closed position without additional monitoring measures by simply limiting the angle of rotation of the drive shaft 42.

[0091] The stop device 78 preferably has two stop surfaces 82, which are formed by the tooth flanks of the two end teeth 77 facing away from each other in the direction of rotation of the drive shaft 42. Furthermore, the stop device 78 has two housing-fixed counter-stop surfaces 83, which are formed, for example, on one or more wall projections of the valve housing 2 and protrude into the drive chamber 45 such that a counter-stop surface 83 lies in the path of movement of one of the stop surfaces 82. Depending on the direction of rotation of the drive shaft 42, either one or the other end tooth 77 runs onto the counter-stop surface 83 lying in its path of movement to limit the angle of rotation, whereby the drive shaft 42 is positioned in terms of the angle of rotation.

[0092] The pinch valve 1 can be designed such that the deflection movement 64 of the deflection element 62 can be caused exclusively by the actuating force introduced by the gear mechanism 38. In this way, stable axial end positions of the deflection element 62 can be realized very easily.

[0093] Preferably, however, the pinch valve 1 is equipped with a spring device 84 that causes or at least supports the deflection movement 64 in one of the two possible directions of movement. The illustrated pinch valve 1 is equipped accordingly, comprising a mechanical spring device 84, by which the deflection member 62 is constantly biased into the shut-off position, which accompanies the closed position of the pinch elements 23, 24. This offers a safety aspect, since the pinch valve 3 closes automatically in the event of damage to the gear mechanism 38. Furthermore, a spring device 84 acting in the closing direction can ensure that the pinch elements 23, 24 are pressed against the valve member 4 with a predetermined squeezing force in the closed position, thus ensuring secure closure of the valve channel 5 without excessive stress on the flexible and, in particular, rubber-elastic peripheral wall 8.

[0094] In a non-illustrated embodiment, the spring device 84 is installed so that it constantly biases the deflection member 62 into the release position.

[0095] Preferably, the spring device 84 is a compression spring device. It is designed in particular as a helical spring, but could also consist of a disc spring assembly, for example.

[0096] The spring device 84 is preferably located in the housing interior 10, and in particular in the annular space section 63. For example, it is axially interposed between the deflecting member 62 and the one end wall 14a. It consists, for example, of a conical spring tapering toward the deflecting member 62.

[0097] The spring device 84 preferably has an annular cross-section and is preferably arranged coaxially to the longitudinal axis 3.

[0098] The gearing 38 is expediently equipped with a tooth flank play such that in the closed position of the squeezing elements 23, 24, the optionally provided spring device 84 with its spring force is responsible for generating the squeezing force acting on the valve member 4.

[0099] The pinch valve 1 is expediently equipped with a manually operable locking device 85, with which the drive shaft 42 can be releasably locked in various rotational positions relative to the valve housing 2, which are set by the rotary drive movement 55. This also allows intermediate positions of the pinch elements 23, 24 between the open position and the closed position to be fixed for any desired length of time.

[0100] According to a preferred design of the blocking device 85, which is implemented in the illustrated embodiment, the drive shaft 42 is axially movable to a limited extent relative to the valve housing 2 in the axial direction of its longitudinal axis 44. The drive shaft 42 has, inside the drive chamber 45, a radially projecting annular collar 86 which is arranged coaxially to the support ring 52 and which has an annular blocking surface 87 on its end face axially facing the support ring 52. The annular collar 86 is connected to the drive shaft 42 in a rotationally fixed manner and is formed, for example, by an annular body which is mounted on the drive shaft 42 in a rotationally fixed manner. Axially opposite the blocking surface 87 is an annular counter-blocking surface 88 which is formed on the support ring 52.

[0101] The drive shaft 42 is not only rotatable with respect to the valve housing 2, but also slightly axially displaceable, wherein the linear movement limitation is realized in one direction by the interaction between the blocking surface 87 and the counter-blocking surface 88 and in the other direction by an interaction between the bearing socket 54a and the base surface of the wall recess 54b.

[0102] A manually operable clamping element 92 of the blocking device 85 makes it possible to exert a tensile force 93 on the drive shaft 42 and thus also on the blocking surface 87 supported thereon, whereby the entire drive shaft 42, including the blocking surface 87, is axially displaced in the direction of the support ring 52 and its blocking surface 87 is pressed against the counter-blocking surface 88. By appropriately tightening the clamping element 92, the blocking surface 87 and the counter-blocking surface 88 can be clamped together so tightly that the drive shaft 42 is non-rotatably blocked with respect to the valve housing 2. The position assumed by the blocking surface 87 with respect to the valve housing 7 is referred to as the blocking position.To re-enable the rotational mobility of the drive shaft 42, the clamping element 92 can be manually released so that the blocking surface 87 can move away from the counter-blocking surface 88 to assume a release position. The drive shaft 42 can then rotate freely.

[0103] By way of example, the clamping element 92 is designed as a clamping nut 92a, which is screwed onto an external thread 94 of the end section of the drive shaft 42 protruding from the valve housing 2. By manually rotating it according to the double arrow 95, the clamping nut 92a can be screwed onto the external thread 94 in such a way that it rests on a support surface 96 of the support ring 92 facing it and thereby exerts the above-described tensile force 93 on the non-rotating drive shaft 42. This moves the blocking surface 87 into the blocking position. By rotating the clamping nut 92a in the opposite direction, the tensile force 93 can be removed, so that the blocking surface 87 can return to the release position.

[0104] Deviating from the embodiment in which the support surface 96 is realized on a separate support ring 52 inserted into the valve housing 2, the support surface 96 can also be formed directly on the valve housing 2.

[0105] Preferably, both the blocking surface 87 and the counter-blocking surface 88 are structured in a toothed manner, so that the blocking surface 87, in the blocking position, engages with the counter-blocking surface with a positive locking effect effective in the direction of rotation of the drive shaft 42. A blocking device 85 designed in this way offers a high level of security against accidental rotation of the drive shaft 42. Even if the clamping nut 92a should become slightly loose, a positive toothing engagement between the toothed blocking surface 87 and the toothed counter-blocking surface 88 is maintained and prevents rotation of the drive shaft 42. This is the case even if a spring device 84 is present, which exerts a torque on the drive shaft 42 via the toothed gear 38.

[0106] By way of example, both the blocking surface 87 and the counter-blocking surface 87 have an annular gear ring 87a, 88a coaxial with the rotational axis 43, each with alternating teeth and tooth spaces arranged one after the other. The gear rings 87a, 88a are complementary to one another. They have the same diameter and are located opposite one another with their tooth crests facing one another in the axial direction of the rotational axis 43. In the blocking position, the teeth of one gear ring 87a engage axially in the tooth spaces of the other gear ring 88a.

[0107] It is understood that there is nevertheless the alternative possibility of designing the blocking surface 87 and counter-blocking surface 88 as pure friction surfaces which, in the blocking position of the blocking surface 87, rest against one another in a purely frictional manner.

[0108] In the illustrated embodiment, the current operating state of the pinch valve 1 can be easily read based on the current pivot position of the hand lever 57. Nevertheless, there is the advantageous possibility of providing a reading scale for verifying the current operating state. This can simplify, in particular, the setting of intermediate flow positions.

Claims

[1] Pinch valve for flowable media, comprising a valve housing (2) in which extends a tubular valve member (4) having a flexible peripheral wall (8) and through which a valve channel (5) extends in its longitudinal direction, around the radial outer circumference (22) of which a plurality of squeezing elements (23, 24) are arranged, which can be moved towards and away from one another while executing linear working movements (28) in a working plane (25) perpendicular to the longitudinal axis (9) of the valve member (4) in order to squeeze the valve member (4) together to a greater or lesser extent, and comprising a drive device (36) for causing the working movements (28) of the squeezing elements (23, 24), which drive device has a drive shaft (42) which is rotatably mounted about a rotational axis (43) extending in the longitudinal direction of the drive shaft and which has an actuating section (48),into which a drive torque causing a rotary drive movement (55) of the drive shaft (42) can be introduced, wherein the drive device (36) further comprises a conversion mechanism (37) having a toothed gear (38) which converts the rotary drive movement (55) of the drive shaft (42) into the linear working movements (28) of the pinch elements (23, 24), wherein the pinch valve (1) is designed to be manually actuated, wherein a handle (56) accessible outside the valve housing (2) is arranged on the actuating section (48) of the drive shaft (42) which is rotatably mounted on the valve housing (2), , characterized bythat the gearing (38) has an input toothing (67) which is connected in a rotationally fixed manner to the drive shaft (42) and which participates in the rotary drive movement (55) thereof, and an output toothing (68) which is in tooth engagement with the input toothing (67) and is movement-coupled with the squeezing elements (23, 24) for causing the working movements (28). [2] Pinch valve according to claim 1, characterized by that the handle (56) is a hand lever (57) provided with a lever arm (57a). [3] Pinch valve according to claim 1, characterized bythat the conversion mechanism (37) has a deflection member (62) arranged in the valve housing (2), which is displaceable by the rotary drive movement (55) of the drive shaft (42) while performing a linear deflection movement (64) in the longitudinal direction of the valve member (4) and which has a link structure (65) against which the squeezing elements (23, 24) bear in a sliding manner such that they are driven to their working movements (28) by the link structure (65) of the deflection member (62) during the linear deflection movement (64). [4] Pinch valve for flowable media, comprising a valve housing (2) in which extends a tubular valve member (4) having a flexible peripheral wall (8) and through which a valve channel (5) extends in its longitudinal direction, around the radial outer circumference (22) of which a plurality of squeezing elements (23, 24) are arranged, which can be moved towards and away from one another while executing linear working movements (28) in a working plane (25) perpendicular to the longitudinal axis (9) of the valve member (4) in order to squeeze the valve member (4) together to a greater or lesser extent, and comprising a drive device (36) for causing the working movements (28) of the squeezing elements (23, 24), which drive device has a drive shaft (42) which is rotatably mounted about a rotational axis (43) extending in the longitudinal direction of the drive shaft and which has an actuating section (48),into which a drive torque causing a rotary drive movement (55) of the drive shaft (42) can be introduced, wherein the drive device (36) further comprises a conversion mechanism (37) having a toothed gear (38) which converts the rotary drive movement (55) of the drive shaft (42) into the linear working movements (28) of the squeezing elements (23, 24), the toothed gear (38) comprising an input toothing (67) which is connected in a rotationally fixed manner to the drive shaft (42) and participates in its rotary drive movement (55), and an output toothing (68) which is in toothed engagement with the input toothing (67) and is motionally coupled to the squeezing elements (23, 24) to cause the working movements (28), the conversion mechanism (37) comprising a deflection member (62),which is displaceable in the longitudinal direction of the valve member (4) by the rotary drive movement (55) of the drive shaft (42) while performing a linear deflection movement (64) and which has a link structure (65) against which the squeezing elements (23, 24) are slidably mounted such that they are driven to their working movements (28) by the link structure (65) of the deflection member (62) during the linear deflection movement (64), wherein the drive shaft (42) is rotatably mounted on the valve housing (2), wherein the deflection member (62) is arranged in the valve housing (2), , characterized by that the toothed gear (38) is designed as a rack and pinion gear, wherein the input toothing (67) is designed as an arcuately curved toothed ring (72) and the output toothing is designed as a toothed rack (73) having a linear extension. [5] Pinch valve according to claim 4, characterized bythat it is designed to be actuated by a motor, wherein a drive motor (58) is attached to the valve housing (2), the output shaft (58b) of which is connected to the actuating section (48) of the drive shaft (42) in a torque-transmitting manner. [6] Pinch valve according to one of claims 3 to 5, characterized by that the output toothing (68) is arranged on the deflection member (62). [7] Pinch valve according to one of claims 3 to 6, characterized by that the deflection member (62) is sleeve-shaped and coaxially encloses the valve member (4), wherein the link structure (65) is expediently formed on the inner circumference of the deflection member (62). [8] Pinch valve according to one of claims 3 to 7, characterized bythat the deflection member (62) is displaceable between two mutually opposite axial end positions by the linear deflection movement (64), wherein one of the two axial end positions represents a shut-off position causing the valve channel (5) to close and the other of the two axial end positions represents a release position responsible for releasing a maximum flow cross-section of the valve channel (5). [9] Pinch valve according to claim 8, characterized by that a spring device (84) is arranged in the valve housing (2), by means of which the deflecting member (62) is constantly prestressed into one of its two axial end positions, expediently into the shut-off position. [10] Pinch valve according to one of claims 6 to 9, characterized bythat the output toothing (68) is formed on the radial outer circumference of the deflecting member (62), wherein it expediently extends only along a limited section of the outer circumference of the deflecting member (62) in the circumferential direction of the longitudinal axis (9) of the valve member (4). [11] Pinch valve according to claim 4, characterized by that the gear ring (72) extends over an angle of less than 360 degrees, wherein it expediently has an angle of 90 degrees. [12] Pinch valve according to one of claims 1 to 11, characterized bythat it has only two squeezing elements (23, 24) which are placed in diametrically opposite circumferential regions of the radial outer circumference (22) of the valve member (4) and which, in order to carry out their working movements (28), can be moved in the axial direction of a common working axis (26) which is perpendicular to the longitudinal axis (9) of the valve member (4) and lies in the working plane (25), which is expediently spaced in the longitudinal direction of the valve member (4) from the axis of rotation (43) of the drive shaft (42) and runs orthogonally to the axis of rotation (43) of the drive shaft (42). [13] Pinch valve according to one of claims 1 to 12, characterized by that the drive shaft (42) is arranged off-center with respect to the valve member (4), wherein its axis of rotation (43) is spaced from the longitudinal axis (9) of the valve member (4). [14] Pinch valve according to one of claims 1 to 13, characterized bythat it has a stop device (78) for specifying two mutually opposite end positions of the rotary drive movement (55) of the drive shaft (42), which has two stop surfaces (82) arranged on the drive shaft (42) and two counter-stop surfaces (83) arranged stationary with respect to the valve housing (2), wherein the two stop surfaces (82) are expediently formed by the tooth flanks of two teeth (72a, 77) closing the ring gear (72) on mutually opposite sides. [15] Pinch valve according to one of claims 1 to 14, characterized by that the drive shaft (42) is assigned a manually operable blocking device (85) for releasably blocking different rotational positions of the drive shaft (42). [16] Pinch valve according to claim 15, characterized byin that the drive shaft (42) is axially movable to a limited extent relative to the valve housing (2) and has, in a coaxial arrangement, an axially oriented annular blocking surface (87) of the blocking device (85), which is axially opposite an annular counter-blocking surface (88) of the blocking device (85) arranged stationary with respect to the valve housing (2), wherein a manually operable clamping element (92) of the blocking device (85) engages the drive shaft (42), the actuation of which causes an axial adjustment of the drive shaft (42) together with the blocking surface (87), whereby the blocking surface (87) can be positioned optionally in a blocking position which is non-rotatably clamped to the counter-blocking surface (88) and thereby non-rotatably blocks the drive shaft (42) or in a release position which enables rotation of the drive shaft (42). [17] Pinch valve according to claim 16, characterized bythat the clamping element (92) is designed as a clamping nut (92a) screwed onto an external thread (94) of the drive shaft (42), which can be supported on a support surface (96) that is stationary with respect to the valve housing (2) during a rotary actuation (95) in order to exert an axial tensile force on the drive shaft (42) that causes the blocking surface (87) to be clamped against the counter-blocking surface (88). [18] Pinch valve according to claim 16 or 17, characterized by that the blocking surface (87) and the counter-blocking surface (88) are structured in a toothed manner so that they engage with each other in a form-fitting manner when the blocking surface (87) is in the blocking position.

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