Patent Publication Number: US-11661698-B2

Title: Pressing membrane and a device having such a pressing membrane for dewatering laundry

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority on and the benefit of German Patent Application No. 20 2020 000 223.2 having a filing date of 21 Jan. 2020. 
     BACKGROUND OF THE INVENTION 
     Technical Field 
     The invention relates to a pressing membrane for a device for dewatering laundry, having a membrane base and a membrane collar which is molded on the latter and has an encircling upper periphery and a peripheral region which for releasably fastening the membrane collar by means of a fastening ring below a ram plate of a press ram emanates from said upper periphery, said ram plate being able to be moved up and down, as well as to a device for dewatering laundry having a pressing membrane that is releasably fastenable below a ram plate by way of a fastening ring, and a press ram being able to be moved up and down, and the pressing membrane having a membrane base and a membrane collar which is molded on the latter and has an encircling upper periphery. 
     Prior Art 
     Devices provided with pressing membranes for dewatering laundry, so-called dewatering presses, are used in commercial laundries for dewatering laundry of all types. To this end, liquids are largely squeezed out of washed laundry by the device having the pressing membrane. The device can optionally also serve for rinsing washed laundry. 
     A device of the type discussed here having a pressing membrane is known from EP 0 310 842 B1. This device possesses a press ram which is able to be moved up and down by a hydraulic cylinder. The press ram possesses a ram plate below which the pressing membrane is releasably fastened. The washed laundry is dewatered in a pressing basket of the device that is disposed below the press ram. When the press ram moves down in the manner performed by the hydraulic cylinder, the pressing membrane fastened therebelow compresses the laundry in the pressing basket, wherein the pressing membrane that is formed from an elastically deformable material adapts flexibly to the laundry in the pressing basket. 
     The fastening of the pressing membrane below the ram plate of the press ram is disadvantageous in the known device. This fastening takes place by way of a fastening ring which is also referred to as an “assembly ring” and by way of which the pressing membrane is tightly screw-fitted below the ram plate. To this end, the fastening ring has in particular to be precisely positioned by technicians and held below the raised ram plate so that the fastening ring can be preassembled with screws below said ram plate. As a consequence of the large diameters of pressing membranes being approximately one meter and optionally even more, the fastening rings are very heavy and therefore difficult to handle by the technicians. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention is based on the object of achieving a device for dewatering laundry and a pressing membrane provided therefor, wherein the pressing membrane by way of a fastening ring can be easily fastened below the ram plate of the device without any large effort in terms of force by the technicians. 
     A pressing membrane for achieving this object is a pressing membrane for a device for dewatering laundry, having a membrane base and a membrane collar which is molded on the latter and has an encircling upper periphery and a peripheral region which for releasably fastening the membrane collar by means of a fastening ring below a ram plate of a press ram emanates from said upper periphery, said ram plate being able to be moved up and down, wherein the membrane collar on the internal side thereof has at least one protrusion for forming an at least temporary bearing for the fastening ring until connecting the pressing membrane to the ram plate. This pressing membrane which has a lower membrane base and a membrane collar molded on said pressing membrane above the membrane base is provided with at least one protrusion that projects in relation to the internal wall of the membrane collar. The at least one protrusion is situated below an upper free periphery of the membrane collar that surrounds an upper opening across the full area of the pressing membrane. On account thereof, the fastening ring is able to be introduced and/or inserted into the membrane collar from above and is thereafter at least temporarily supported on the at least one protrusion. It suffices for the fastening ring to be supported on the at least one protrusion only until the fastening ring, preferably with screws, is connected to the lower side of the press ram, in particular the ram plate thereof, because the presence of any support of the fastening ring on the at least one protrusion of the membrane collar is required only until the fastening ring is initially connected to the ram plate. 
     As a consequence of the at least one protrusion in the interior of the membrane collar, the fastening ring does no longer have to be held after being inserted into the membrane collar. The at least one protrusion then holds the fastening ring in the region of the upper periphery of the membrane collar of the pressing membrane. The ram plate of the press cylinder can then be moved down onto the upper periphery of the pressing membrane and the fastening ring inserted in the latter until the connection between the fastening ring and the ram plate can be established, in particular with screws. The connection of the pressing membrane to the fastening ring below the ram plate can be performed without the fastening ring and/or the pressing membrane to this end having to be held below the ram plate by technicians, and without any permanent connection between the fastening ring and the pressing membrane which would necessitate that the fastening ring is also replaced when a pressing membrane is replaced. 
     The at least one protrusion is preferably configured such that said protrusion protrudes into an interior space of the membrane collar that is surrounded by the latter, in particular in the direction of a vertical longitudinal central axis of the membrane collar projects radially in relation to the inner wall of the membrane collar. On account thereof, the interior space of the membrane collar is constricted below the upper periphery of the latter and/or at least one step is formed here in the pressing membrane by the at least one protrusion, the fastening ring being able to be supported on said step at least until being initially connected to the lower side of the ram plate of the press ram. 
     The at least one protrusion preferably protrudes into an interior space of the pressing membrane that is surrounded by the membrane collar. The at least one protrusion in the direction of a vertical longitudinal central axis of the membrane collar and/or of the pressing membrane herein protrudes in particular radially into the interior space. The fastening ring is able to be supported on at least one such protrusion until being connected to the ram plate without slipping completely into the pressing membrane. 
     In one advantageous design embodiment of the pressing membrane the at least one protrusion forms an upper bearing face of the single protrusion or of the respective protrusion in the interior of the membrane collar. This bearing face of the single protrusion or the bearing face of all protrusions preferably lies/lie in a plane which orthogonally intersects the longitudinal central axis of the pressing membrane and/or of the membrane collar thereof. On account thereof, the fastening ring that is supported on the at least one bearing face is held in the plane of the upper periphery of the membrane collar or so as to be just below the latter, wherein this plane runs so as to be parallel to the plane of the ram plate, on account of which the fastening ring in the upper end region of the membrane collar for easy connecting to the ram plate is held in an exact alignment at least until the connection of the fastening ring below the ram plate has been established. 
     According to one advantageous potential design embodiment of the pressing membrane, the at least one protrusion is disposed so far below the upper periphery of the membrane collar that the bearing face of the protrusion or the bearing faces of a plurality of protrusions is/are situated at a spacing below the upper periphery of the membrane collar, wherein this spacing preferably corresponds to at least the height of the fastening ring. On account thereof, the fastening ring is offered up in the upper end region of the pressing membrane or of the membrane collar of the latter, respectively, such that the ram plate can be lowered tightly onto the fastening ring or down to the fastening ring so as to subsequently be able to establish the connection, in particular the screw connection, between the ram plate and the fastening ring. 
     It can be provided that the at least one protrusion of the membrane collar is disposed on the lower end of an upper peripheral portion of the membrane collar and/or the at least one protrusion delimits a lower end of the peripheral portion of the membrane collar. On account thereof, the insertion depth of the fastening ring into the pressing membrane, in particular the membrane collar of the latter, is established by the at least one protrusion. This penetration depth is preferably chosen such that the upper ring face of the fastening ring coincides with the plane of the upper periphery of the membrane collar or lies slightly below the latter. On account thereof, the fastening ring is exactly aligned and held in position by the pressing membrane for connecting the fastening ring to the ram plate. 
     It is preferably provided that a single encircling protrusion is provided in the membrane collar so as to be below the plane of the periphery of the latter. This protrusion thus represents an encircling constriction in the membrane collar of the pressing membrane and thus forms an annular encircling bearing face for the lower side of the fastening ring that is to be inserted from above into the pressing membrane. Alternatively however, a plurality of separate protrusions can also be provided within the pressing membrane so as to be spaced apart from the upper periphery of the membrane collar. Each of these protrusions has a bearing face for the lower side of the fastening ring. The bearing faces of all of the protrusions herein lie in one common plane which orthogonally intersects the longitudinal central axis of the membrane collar and/or of the pressing membrane. As is likewise the case with one encircling protrusion, this plane in the case of a plurality of protrusions runs so as to be parallel to the plane of the lower side of the ram plate such that the fastening ring on account of the protrusions is aligned so as to be parallel to the ram plate, and that a connection between the fastening ring and the ram plate which can in particular be established with screws is able to be established in a simple manner without any kind of additional alignment measures on account thereof. 
     In one advantageous potential design embodiment of the pressing membrane it is provided that the membrane collar thereof tapers toward the periphery. Alternatively or additionally, it can be provided that an external side of the membrane collar at least in the upper peripheral region tapers toward the upper free periphery. On account thereof, an elastic preload of the upper peripheral region of the membrane collar between a correspondingly annular outer collar below the ram plate can be obtained when tightening the screws of the fastening ring below the ram plate. An at least clamping connection between the pressing membrane and the ram plate takes place on account thereof. 
     A device for achieving the object mentioned at the outset is a device for dewatering laundry, having a press ram which has a ram plate and a flexible pressing membrane that is releasably fastenable below said ram plate by way of a fastening ring, said press ram being able to be moved up and down, and the pressing membrane having a membrane base and a membrane collar which is molded on the latter and has an encircling upper periphery, wherein the membrane collar on the internal side thereof has at least one protrusion which is configured as a bearing for the fastening ring at least until connecting said fastening ring to the ram plate. Accordingly, the membrane collar on the internal side thereof possesses at least one protrusion. The at least one protrusion serves as a temporary bearing for the fastening ring. 
     The bearing is maintained at least until the connection between the fastening ring and the ram plate has been established. On account thereof, the fastening ring is insertable from above into the pressing membrane, specifically only so far until said fastening ring is stopped by the at least one bearing of the membrane collar. The fastening ring is preferably thus held in the upper end region or peripheral region, respectively, of the membrane collar. After the fastening ring has been inserted into the upper end region of the membrane collar, the ram plate of the device can then be lowered completely onto the upper side of the fastening ring, or to just short of the latter, so that an at least initial and/or partial connection between the fastening ring and the ram plate can be established. Therefore, there is no longer any need for the fastening ring to be separately handled after having been inserted into the upper end region or peripheral region, respectively, of the membrane collar of the pressing membrane. Rather, said fastening ring conjointly with the pressing membrane rests on a support pad of the device such that only the ram plate has to be moved down in order for the fastening ring, and conjointly therewith, the pressing membrane to be able to be connected to the ram plate. 
     The at least one protrusion preferably forms a bearing for the fastening ring at least for initially connecting the fastening ring to a lower side of the ram plate. The lower side of the fastening ring in the upper end region of the membrane collar is then supported on this at least one bearing until said fastening ring is connected to the ram plate but not yet finally fastened therebelow. 
     According to one preferred design embodiment of the device it is provided that the fastening ring on the external wall thereof has a profiled structure, in particular an encircling protrusion in the lower end region and/or an encircling constriction preferably above the protrusion. Alternatively or additionally, it can be provided that the upper peripheral region of the membrane collar, between the upper periphery thereof and the bearing face of the at least one protrusion in the membrane collar, is provided with an internal-side profiled structure. When the fastening ring also has an external profiled structure these two profiled structures are configured such that the latter at least approximately correspond to each other. On account thereof, a form-fitting connection and/or coupling of the fastening ring to the membrane collar of the pressing membrane can be established. 
     It can furthermore be provided that a lower side of the ram plate is provided with an encircling groove which is preferably situated in the external peripheral region of the ram plate. This groove serves for receiving at least a major part of the fastening ring and of the upper peripheral portion of the membrane collar of the pressing membrane that is assigned to said fastening ring. The encircling groove is of corresponding dimensions. The groove is situated close to the external circumference of the ram plate, wherein the groove on the external side is delimited by an encircling annular collar on the lower side of the ram plate. By way of this groove, the pressing membrane at the upper peripheral region of the membrane collar thereof, conjointly with the fastening ring, can be connected in a form-fitting and/or force-fitting manner to the ram plate, specifically without it being necessary for the fastening ring to this end to be connected to the upper peripheral region of the membrane collar by adhesive bonding and/or vulcanizing. On account thereof, the fastening ring and the pressing membrane are separate parts which can be releasably connected to each other but do not have to be permanently connected to each other. 
     In the device it is preferably provided that the fastening ring is inserted from above into the pressing membrane, in particular the membrane collar of the latter, specifically so far until the fastening ring bears on the at least one protrusion, in particular the bearing face of said protrusion, and the fastening ring is held in the upper peripheral region of the membrane collar by the at least one bearing such that said fastening ring cannot slip into the pressing membrane and down onto the membrane base. 
     The pressing membrane of the device described above can advantageously be refined by individual or a plurality of the features of the pressing membrane that have been set forth at the outset. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred exemplary embodiments of the invention will be explained in more detail hereunder by means of the drawing in which: 
         FIG.  1    shows a schematic lateral view of a device for dewatering laundry; 
         FIG.  2    shows a detail II from  FIG.  1    of a pressing membrane having a fastening ring which prior to assembling on a ram plate of the device is supported in the upper peripheral region of said pressing membrane; and 
         FIG.  3    shows a detail in a manner analogous to that of  FIG.  2    with a pressing membrane which is completely fastened below the ram plate by way of the fastening ring. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The device shown in the figures is a so-called dewatering press for dewatering laundry  10  of any kind, in particular washed laundry  10 . When dewatering, the liquid still contained in the laundry  10 , in particular the so-called adsorbed liquor, is largely squeezed out of said laundry  10  by the device. The device can additionally also serve for rinsing the laundry  10  prior to the dewatering. 
     The device possesses a frame having a partially liquid-permeable base plate  11  which may optionally be assigned a reservoir for collecting the liquid squeezed out of the laundry  10 . The frame moreover possesses a press top bar  12  which is disposed at a spacing above the base plate  11 . The frame of the device furthermore possesses a plurality of, for example four, upright columns  13  which for rigidly connecting the base plate  11  in a spaced-apart manner to the press top bar  12  are provided between the base plate  11  and the press top bar  12 . 
     A hydraulic cylinder  14  (in terms of the base area) is situated in the center of the press top bar  12 . A cylinder body  15  of the hydraulic body  14  is fixedly connected to the press top bar  12  above the latter. A piston rod  16  of the hydraulic cylinder  14  that is able to retract into the cylinder body  15  and be deployed from the latter extends through the press top bar  12  and protrudes downward in relation to the latter. 
     The device furthermore possesses a press ram  17  having a ram plate  18 , and a pressing membrane  19  which is fastened therebelow and is from a flexible, in particular elastically deformable, material, preferably rubber or any other elastomer. A lower end of the piston rod  16  of the hydraulic cylinder  15  is fixedly connected to the ram plate  18  of the press ram  17 . 
       FIG.  1    shows the press ram in the raised initial position in which the piston rod  16  is moved into the cylinder body  15  of the hydraulic cylinder  14 . 
     The device furthermore possesses a pressing basket  20  which is disposed below the press ram  17 . The pressing basket  20  is completely open on the upper side and lower side thereof, and to this end is composed of an encircling basket shell  21 . In order for the laundry  10  to be loaded and dewatered, the pressing basket  20  by way of the open lower side thereof rests on the base plate  11 . The base plate  11  is configured so as to be liquid-permeable, for example by way of a pattern of through bores  22  in the base plate  11 , at least in the region of the basket shell  21  of the pressing basket  20 . 
     In the initial position of the device with a raised press ram  17  and a retracted piston rod  16  of the hydraulic cylinder  14  as shown in  FIG.  1   , an intermediate space is situated between the lower side of the pressing membrane  19  and the open upper side of the pressing basket  20 . Said intermediate space serves for loading the pressing basket  20  with laundry to be dewatered and/or to be rinsed. The loading takes place by means of a loading chute  23  which is indicatively illustrated in  FIG.  1   . 
     In the device shown, the pressing basket  20  is laterally assigned a small hydraulic cylinder  24 . A lower end of a piston rod  25  of the hydraulic cylinder  24  is connected to the pressing basket  20 . A cylinder body  26  of the small hydraulic cylinder  24  is fixedly connected to the lower side of the press top bar  12 . On account of the smaller hydraulic cylinder  24 , the pressing basket  20  can be raised after the dewatering of the laundry  10  so as to discharge from the base plate  11  a laundry block of the compressed and dewatered laundry  10 . The pressing basket  20  can optionally also be pivoted about a vertical longitudinal central axis of the smaller hydraulic cylinder  24  such that the space between the press ram  17  and the base plate  13  is vacated. 
     In the exemplary embodiment of the device illustrated in the figures, the press ram  17 , specifically the ram plate  18  as well as the pressing membrane  19  thereof, are of cylindrical configuration. Accordingly, the pressing basket  20  is also cylindrically configured specifically such that the press ram  17 , in particular the pressing membrane  19  thereof, can penetrate the pressing basket  20  through the open upper side thereof and herein compress or squeeze, respectively, and dewater and/or rinse the laundry  10 . 
     The pressing membrane  19  in the vertical cross section is configured in the manner of a hat,  FIGS.  2  and  3    showing part of said vertical cross section. To this end, the pressing membrane  19  possesses a lower circular membrane base  27  and a tubular or cylindrical, respectively, membrane collar  28  which adjoins the membrane base  27  above the latter. The lower side of the membrane collar  28  is integrally molded to the membrane base  27 , specifically such that the external side of the membrane collar  28  terminates flush with the outer periphery of the membrane base  27 . 
     The membrane base  27  in the case of the cylindrical press ram  17  shown here is provided with a circular base area. The membrane collar  28  is configured as an encircling ring or tube, respectively, having a free upper circular periphery  29 . An upper peripheral region  30  of the membrane collar  28  that extends in the direction toward the membrane base  27  emanates from the upper free periphery  29  of the membrane collar  28 . This peripheral region  30  extends across approximately 20% to 60% of the height of the pressing membrane  19 . In the case of the exemplary embodiment shown in the figure, the height of the peripheral region  30  is approximately 40% to 50% of the entire height of the pressing membrane  19 . The upper periphery  29  of the membrane collar  28  surrounds the circular upper opening  31  of the pressing membrane  19 . 
     The membrane collar  28  of the pressing membrane  19  by way of the upper peripheral region  30  is releasably connected in particular to the lower side of the dimensionally stable and/or rigid ram plate  18  of a metallic material. This connection between the press ram  17  and the ram plate  18  takes place by means of a fastening ring  32  (in industrial jargon also referred to as an “assembly ring”). The fastening ring  32 , like the ram plate, is formed from a rigid, dimensionally stable, metallic material. The fastening ring  32  is able to be released or separated, respectively, from the membrane collar  28  such that said fastening ring  32  does not also have to be replaced when replacing the pressing membrane  19 . On account thereof, the fastening ring  32  is reusable. 
     The fastening ring  32  is dimensioned such that said fastening ring  32  is able to be pushed and/or inserted by way of the upper cylindrical opening  31  of the pressing membrane  19  into the latter. According to the exemplary embodiment of  FIG.  2    it may be necessary herein for the upper periphery  29  of the membrane collar  28  to be somewhat elastically expanded. In terms of the height, the fastening ring  32  is dimensioned such that said fastening  32  is somewhat lower than the height or the length, respectively, of the peripheral region  30 . The fastening ring  32  can however also have a height which is identical to the height or the length, respectively, of the peripheral region  30 . 
     After the fastening ring  32  has been inserted into the pressing membrane  19  from above, the fastening ring  32  is surrounded by the upper peripheral region  30  of the membrane collar  28 . A longitudinal central axis of the fastening ring  32  as well as a longitudinal central axis of the pressing membrane  19  coincide herein in that said longitudinal central axes overlap. This common longitudinal central axis of the fastening ring  32  and of the pressing membrane  19  lies on a longitudinal central axis  33  of the device that runs through the hydraulic cylinder  14  and the basket shell  21  ( FIG.  1   ). 
     The fastening ring  32  is configured such that said fastening ring  32  can be releasably connected to the ram plate  18 . The fastening ring  32  is preferably screw-fitted from below to the ram plate  18  by way of a plurality of screws  34  that are distributed across the circumference of said fastening ring  32 , whereupon the latter, just like the pressing membrane  19 , is suspended below the ram plate  18 . To this end, the fastening ring  32  possesses a plurality of preferably identical thread bores  35  that are correspondingly placed. 
     A single protrusion  36  which encircles the membrane collar  28  in an annular manner is assigned to the latter at a spacing from the upper periphery  29 . The encircling protrusion  36  is preferably placed in the interior of the membrane collar  28  approximately where the peripheral region  33  of the membrane collar  28  that emanates from the upper periphery  29  terminates. Moreover, the spacing of the encircling annular protrusion  36  from the upper periphery  29  of the membrane collar  28  is chosen such that this spacing corresponds to or is somewhat larger than the height of the fastening ring  32  ( FIG.  2   ). 
     The protrusion  36  in the cross section is configured so as to be wedge-shaped in that said protrusion  36  in the direction toward the longitudinal central axis  33  tapers toward the inward end. An upper delimitation of the protrusion  36  which in the cross section is wedged-shaped herein runs horizontally, whereas a lower delimitation is directed obliquely. The horizontal delimitation of the protrusion  36  lies in a plane which is perpendicularly intersected by the longitudinal central axis  33 . The horizontal delimitation or wall, respectively, of the encircling protrusion  36  which in the cross section is wedged-shaped on account thereof forms a flat bearing face  37  on which the lower side of the fastening ring  32  rests, or is supported, respectively, at least prior to being connected to the ram plate  18 , on account thereof preventing the fastening ring  32  from dropping into the pressing membrane  19 . The encircling protrusion  36  by way of the bearing face  37  thereof moreover also delimits the insertion depth of the fastening  32  into the pressing membrane  19 . The fastening ring  32  is thus held by the encircling protrusion  36  of the pressing membrane  19 , in particular by the membrane collar  28  thereof, specifically preferably in the upper peripheral region  30  of the membrane collar  28 . The encircling protrusion  36  also serves for positioning and/or aligning the fastening ring  32  between the bearing face  37  of the encircling protrusion  36  and the upper periphery  29  of the membrane collar  28 . 
     The plane which orthogonally intersects the longitudinal central axis  33  in which the bearing face  37  of the encircling protrusion  36  is situated runs so as to be parallel to the encircling upper periphery  29  of the membrane collar  28  and thus also so as to be parallel to the upper opening  31  of the pressing membrane  19 . 
     The encircling protrusion  36  constricts an interior space  38  of the pressing membrane  19  that is surrounded by the membrane collar  28  to the extent that said protrusion  36  forms a sufficiently large bearing face  37  for the lower side of the fastening ring  32  that is inserted from above into the membrane collar  28 . The cross section of the encircling protrusion  38  is moreover formed such that the encircling protrusion  36  is sufficiently stable for supporting the fastening ring  32 . 
     The encircling protrusion  36  is integrally molded to the internal side of the membrane collar  28 , specifically preferably on the lower end of the upper peripheral region  30  of the membrane collar  28  are spaced apart from the periphery  29 . On account thereof, the protrusion  36  is composed of the material of the pressing membrane  19  such that the protrusion  36  is also slightly flexible but by virtue of the dimensions thereof, in particular of the cross section thereof, is sufficiently stable so as to guarantee reliable supporting of the fastening ring  32  without there being any risk of the fastening ring  32  slipping past the encircling protrusion  36  into the interior space  38  of the pressing membrane  19 . 
     An alternative exemplary embodiment of the pressing membrane  19  in which a plurality of preferably identical protrusions which are uniformly distributed on the internal circumference of the membrane collar  28  are provided instead of a single encircling protrusion  36  which protrudes into the interior space  38  of the pressing membrane  19  and/or constricts said interior space  38  is conceivable. Said plurality of protrusions can be positioned exactly like the encircling protrusion  36  and/or have an identical cross section as the encircling protrusion  36 . In order for this plurality of smaller protrusions to be able to support the weight of the fastening ring  32 , it is conceivable that these protrusions in terms of area have a larger cross section, in particular so as to be enlarged in the direction of the longitudinal central axis  33 , and/or to have a larger height. 
     The fastening ring  32  is profiled on the external circumference thereof. To this end, said fastening ring  32  possesses a lower protrusion  39  having a preferably substantially rectangular cross section, and an upper protrusion  40  which is spaced apart from said law protrusion  39  and has a preferably wedge-shaped cross section. An outer periphery of the lower encircling protrusion  39  on the external side of the fastening ring  32  in the exemplary embodiment shown possesses a somewhat larger diameter than the external circumference of the upper protrusion  40 . A lower delimitation face of the lower protrusion  39  as well as an upper delimitation face of the upper protrusion  40  run flush with the lower ring face  41 , or with the upper ring face  42 , respectively, of the fastening ring  32 . The protrusion  39  and  40  thus contribute toward the enlargement of the ring faces  41  and  42  of the fastening ring  32 . 
     An encircling groove  43  is situated between the lower protrusion  39  and the upper protrusion  40  on the external side of the fastening ring  32 , said groove  43  at the top and the bottom thus being delimited by the protrusions  39  and  40 . 
     The membrane collar  28  of the pressing membrane  19 , proceeding from the upper periphery  29 , possesses an inner encircling protrusion  44 . Said protrusion  44  for forming a bearing for the fastening ring  32  is disposed above the protrusion  36  and spaced-apart therefrom, wherein this spacing is somewhat larger than the height of the lower protrusion  39  on the external side of the fastening ring  32  ( FIG.  2   ). In terms of the cross section, the inward protrusion  44  that emanates from the upper periphery  39  of the membrane collar  28  is configured so as to correspond to the groove  43  in the external side of the fastening ring  32  wherein the cross section of the protrusion  44  on the internal side of the membrane collar  28  is preferably smaller than the groove  43  of the fastening ring  32 . On account thereof, there is play between the fastening ring  32  and the membrane collar  28  when the fastening ring  32  is inserted into the pressing membrane  19  but not yet assembled below the ram plate  18 . 
     In the exemplary embodiment shown, the encircling protrusion  44  in the upper region of the membrane collar  28  constricts the opening  31  of the latter to the extent that the encircling end of the protrusion  44  has a diameter which is somewhat smaller than the external diameter of the lower external protrusion  39  of the fastening ring  32 . In the exemplary embodiment shown, the protrusion  44  constricts the interior space  38  of the membrane collar  29  approximately as much as protrusion  36  which for forming the bearing face  37  for the fastening ring  32  not yet assembled below the ram plate  18  is situated at a spacing below said protrusion  44  ( FIG.  2   ). It is however also conceivable that the constriction of the internal diameter of the membrane collar  28  by the upper protrusion  44  is less than by the protrusion  36  for forming the bearing for the fastening ring  32 . In this instance, the fastening ring  32  is more easily insertable into the membrane collar  28  with less expansion of the upper end region of said membrane collar  28 . 
     An upper part of the external wall of the membrane collar  28  that points toward the periphery  29  tapers toward the periphery  29  at least in terms of the external diameter. This tapered part extends across at least half the height of the pressing membrane  19 . 
     The ram plate  18  is provided with an encircling groove  45  which opens toward the lower side of said ram plate  18 . This encircling groove  45  is situated in the external circumferential region of the ram plate  18  ( FIG.  3   ) such that an external ring wall  46  of the groove  45  is somewhat spaced apart from the external circumferential face  47  of the ram plate  18 . The ram plate  18  in this instance possesses an albeit only narrow ring wall for externally delimiting the groove  45 . The groove  45  is furthermore delimited by an internal ring wall  48  and a circular wall for forming a groove base  49 . The doughnut-type groove base  49  lies in a plane which is perpendicularly intersected by the longitudinal central axis  33  and runs so as to be parallel to the lower side and/or to the upper side of the ram plate  18 . The internal ring wall  48  of the groove  45  runs so as to be perpendicular to the groove base  49  and parallel to the longitudinal central axis  33 . The external ring wall  46  of the groove  45  runs so as to be slightly oblique such that said external ring wall  46  has a frustoconical shape that surrounds the longitudinal central axis  33  in concentric manner, wherein the inclination of the external ring wall  46  is directed in such a manner that the spacing of said external ring wall  46  from the cylindrical external circumferential face  47  of the ram plate  18  slightly increases toward the groove base  49  ( FIG.  3   ). 
     The encircling groove  45  which in the lower side of the ram plate  18  is open at the bottom has a depth which corresponds to the height of the fastening ring  32  or, as in the exemplary embodiment shown, is slightly less than said height and alternatively may also be somewhat larger. In terms of the width, the groove  44  is dimensioned such that, in the case of a fastening ring  32  which is completely assembled below the ram plate  18  and tightly screw-fitted below the ram plate  18  with the screws  34 , the fastening ring  32  as well as the major part of the upper peripheral region  30  of the membrane collar  28  fill the groove  44 , and at least part of the peripheral region  30  of the membrane collar  28  is held so as to be tightly pressed under preloading in the groove  44 . The inner upper protrusion  44  below the periphery  29  of the membrane collar  28  herein engages in the outer groove  43  of the fastening ring  32  and preferably completely fills the latter ( FIG.  3   ). This results in the form-fitting connection between the pressing membrane  19  and the ram plate  18  by way of the fastening ring  32 . Moreover, an additional force-fitting connection between the pressing membrane  19 , the ram plate  18 , and/or the fastening ring  32  can arise on account of at least part of the upper peripheral region  30  of the membrane collar  28  being compressed in the groove  45  ( FIG.  3   ). 
     The method for assembling the afore-described pressing membrane  19  below the ram plate  18  proceeds as follows: 
     With the pressing basket  20  pivoted away, the pressing membrane  19  is positioned below the raised ram plate  18  specifically preferably such that the longitudinal central axis of the pressing membrane  19  lies on the longitudinal central axis  33  of the device. The fastening ring  32  is subsequently inserted and/or pushed in from above into the pressing membrane  19  through the opening  31 , specifically so far that the fastening ring  32  is supported on the bearing face  37  of the protrusion  36 , preferably at the lower end of the peripheral region  30  of the membrane collar  28 . This can be performed manually or optionally with the aid of a lifting device. 
     The ram plate  18  is subsequently moved down by the hydraulic cylinder  14 , specifically only so far that said ram plate is just shy of contacting the upper side of the fastening ring  32  but the screws  34  can already be initially screwed into the threaded bore  35  in the fastening ring  32  from the ram plate  18 . However, before the screws  34  are screwed into the threaded bores  35  of the fastening ring  32 , the fastening ring  32  and/or the pressing membrane  19  are positioned and aligned below the ram plate  18  such that the longitudinal central axes of the threaded bores  35  of the fastening ring  32  are in alignment with the longitudinal axes of the screws  34  which have been pushed through the ram plate  18 , or that the longitudinal central axes of the through bores of the ram plate  18  are in alignment with the longitudinal central axes of the threaded bores  35  when the screws have not yet been inserted, respectively. This alignment is facilitated by the play between the upper peripheral region  30  of the membrane collar  28  and the fastening ring  32 , in particular between the protrusion  39  and the groove  43 , which is still present when the pressing membrane  19  has not yet been connected to the ram plate  18 . 
     Once the screws  34  have been initially screwed into the fastening ring  32 , the ram plate  18  is further moved down by the hydraulic cylinder  14 , specifically so as to be close above the periphery  29  and/or the fastening ring  32 , or until said ram plate  18  bears on the periphery  29  and/or the fastening ring  32 . The upper periphery  29  of the membrane collar  28  then contacts the groove base  49  of the groove  45  in the lower side of the ram plate  18 . The screws  34  thereafter are tightened to the extent that also the upper side of the fastening ring  32  bears on the groove base  49  and under preloading is pressed against the groove base  49  by the screws  34 . In this tightening of the screws, at least a major part of the upper peripheral region  30  of the membrane collar  28  and/or the groove  44  of the membrane collar  28  are/is clamped between the ram plate  18 , in particular the external frustoconical ring wall  46  of the groove  45  in the ram plate  18 , and the fastening ring  32 , on account of which an at least form-fitting, preferably also force-fitting, connection between the pressing membrane  19  and the fastening ring  32 , the latter not being permanently connected to the pressing membrane  19  by adhesive bonding, vulcanizing, or in any other manner, is established. 
     After fastening the pressing membrane  19  below the ram plate  18  in the manner described above, the assembly procedure of the press ram  17  is completed. The press ram  17 , conjointly with the pressing membrane  19  which by way of the fastening ring  32  is assembled below the ram plate  18 , can now be raised by the hydraulic cylinder  14 , and pivoting of the pressing basket  20  back to the operating position thereof shown in  FIG.  1    can take place. The device, in particular the dewatering press, is then ready for operation. 
     Disassembling of a pressing membrane  19  that is worn or to be replaced, respectively, takes place in the reverse order. After disassembling the pressing membrane  19 , the fastening ring  32  is pulled upward out of the latter, wherein the fastening ring  32  until being pulled out of the pressing membrane  19  again rests on the protrusion  36  at the lower end of the peripheral region  30  of the membrane collar  28 . The fastening ring  32  originating from the pressing membrane  19  to be replaced can then be reused for a new pressing membrane  19  which is to be assembled below the ram plate  18 . 
     Alternatively to the approach described above, it is also possible for the pressing basket  20  to be left in the operating position shown  FIG.  1    in order for a pressing membrane  19  to be assembled below the ram plate  18 . In this instance, the pressing membrane  19  to be freshly assembled is positioned on the pressing basket  20  with the ram plate  18  raised. In order to prevent the pressing membrane  19  from slipping into the pressing basket  20  herein, a board and/or beams is/are first placed on or across, respectively, the pressing basket  20 , the pressing membrane  19  to be freshly assembled and, unless having occurred earlier, the fastening ring  32  being inserted from above until bearing on the protrusion  36 , being supported on said board and/or beams. 
     LIST OF REFERENCE SIGNS 
     
         
           10  Laundry 
           11  Base plate 
           12  Press top bar 
           13  Column 
           14  Hydraulic cylinder 
           15  Cylinder body 
           16  Piston rod 
           17  Press ram 
           18  Ram plate 
           19  Pressing membrane 
           20  Pressing basket 
           21  Basket shell 
           22  Through bore 
           23  Loading chute 
           24  Hydraulic cylinder 
           25  Piston rod 
           26  Cylinder body 
           27  Membrane base 
           28  Membrane collar 
           29  Periphery 
           30  Peripheral region 
           31  Opening 
           32  Fastening ring 
           33  Longitudinal central axis 
           34  Screw 
           35  Threaded bore 
           36  Protrusion 
           37  Bearing face 
           38  Interior space 
           39  Protrusion 
           40  Protrusion 
           41  Lower ring face 
           42  Upper ring face 
           43  Groove 
           44  Protrusion 
           45  Groove 
           46  External ring wall 
           47  External circumferential face 
           48  Internal ring wall 
           49  Groove base