Abstract:
A drift conveyor ( 1 ) has rollers ( 14 ) introduced into bearings ( 13 ) of a frame ( 12 ). An axle ( 143 ) of the roller ( 14 ) is received in a receptacle ( 1310 ) of the bearing ( 13 ), and a roller plate ( 15 ) presses the bearing ( 13 ) so that a first sealing region ( 1308 ) of the bearing ( 13 ) contacts a sealing region ( 152 ) of the roller plate ( 15 ). A rotary fastening region of the bearing ( 13 ) contacts a fastening region ( 153   a ) of the roller plate ( 15 ) and a second sealing region of the bearing ( 13 ) contacts the frame sealing region. One side of the bearing ( 13 ) has the receptacle ( 1310 ), the first sealing region ( 1308 ) and a rotary fastening region that prevents rotation of the bearing ( 13 ) with respect to the roller plate ( 15 ). An opposite side of the bearing ( 13 ) has a second region for sealing between the bearing ( 13 ) and the frame ( 12 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a bearing element for insertion into a bearing frame having a sealing function for holding a roller axle which is to be supported, to a roller plate for end-side coverage of a transport roller, to such a transport roller and to a drift conveyor which has, inter alia, a bearing frame, such a transport roller and such a bearing element. 
     2. Description of the Related Art 
     Drift conveyors which have a profile frame which is inserted into the conveyor rollers can already be found in the prior art. These conveyor rollers have axle bolts and are mounted so as to be rotatable about the axle bolts. The axle bolts are inserted into corresponding holes which are provided in the profile frame. In this context, the holes in profile frames and the diameter of the axle bolts are dimensioned with play, and the conveyor rollers can therefore be mounted in an unconstrained way. 
     Profile frames are partially manufactured from closed profiles and from profiles with covers, and the control electronics for drives and sensors can therefore be accommodated in the cavity in the profile. 
     Depending on which goods are to be transported by means of the conveyor systems, the conveyor systems must be partially cleaned. In this context efforts are made to ensure that during the cleaning process no moisture enters the interior of the profile which can damage the electronics there. To a certain extent, this is achieved by virtue of the fact that holes are not bored in the profile but instead axle mounts are attached to the closed profile from the outside. Said axle mounts are to a certain extent welded on or screwed on. This ensures that no moisture can penetrate the profile. However, the manufacture of such profiles with axle mounts which are attached to the outside is costly and expensive. Furthermore, in the known designs of conveyor systems, vibrations and disruptive noises occur in some cases during operation, with the result that the known conveyor systems can be operated only at low conveyor speeds. 
     The object of the invention is to make available means which permit advantageous manufacture of a drift conveyor which can be operated at high conveying speeds and is reliable during operation and easy to clean. 
     SUMMARY OF THE INVENTION 
     One aspect of the invention relates to a bearing element having a sealing function, for holding a roller axle which is to be supported and for insertion into a bearing frame which has an axle receptacle, a first sealing region and a rotation locking region on a first side, which is configured in such a way that rotation of the bearing element with respect to a component which adjoins on the first side, in particular with respect to a roller plate which is likewise a subject of this application, can be prevented, and which has, on a second side, lying essentially opposite the first side of the bearing element, a second sealing region for providing a seal between the bearing element and the bearing frame. In this context, the rotation locking region can preferably be embodied as a positive locking engagement region or as a frictional locking region, as is described in more detail below. Such a bearing element has the advantage that a seal is effected both between the bearing element and the bearing frame as well as between the bearing element and the roller plate, and dust and fluid therefore cannot pass through the recess in the bearing frame and into the interior of the bearing frame. The rotational locking between the bearing element and roller plate ensures that the two components cannot rotation relative to one another, and moisture, which could be transported into the interior past the seal when there is a relative rotation of the sealing faces, is prevented from entering the interior of the profile. In addition, a transport roller with a plate which is secured against rotation has a longer service life. Furthermore, the bearing element serves to protect the surface of the bearing element, and the surface quality of the bearing element therefore cannot be so easily damaged during assembly. The terms “first side” and “second side” which are used are to be understood in a functional way. The intention is to provide two sealing faces on two sides of the bearing element. In this context, the terms can be understood as two sides in the axial direction or two sides in the radial direction. If the sealing faces are provided on two sides lying axially opposite one another, this has the advantage that a seal can be generated by means of a force in the axial direction, while positively locking engagement takes place by means of a configuration on the circumferential face, that is to say in the circumferential direction. This has the advantage that the functional faces can be provided without double fitting. However, it is also conceivable to provide both functional faces on the circumference of the bearing element. The bearing element is preferably manufactured in one piece. The bearing element is preferably an injection molded component, that is to say is manufactured using an injection molding method. 
     Such a bearing element is preferably configured in such a way that the first sealing region and the first rotation locking region at least partially coincide, and a first surface region of the first rotation locking region is therefore likewise configured as a first sealing face of the first sealing region. Advantages of this embodiment are in particular the fact that the function faces which ensure sealing also serve at the same time to prevent a relative movement between the adjoining components. This can ensure a very small overall size. 
     In such a bearing element, the first surface region is preferably configured in such a way that in a developed view of a sectional plane which coincides essentially with a cylinder face about a reference axis of the roller axle to be held and which runs through the first surface region, a curve runs along the surface profile, essentially along a zigzag-shaped or corrugated curve, in particular a sinusoidal curve, and the first rotation locking region is therefore embodied as a first positively locking engagement region. This reliably prevents rotation of the components. A smaller value can therefore be selected for the contact pressure between the adjoining parts than in the case of frictional locking during which the contact force has to be dimensioned as a function of the values of the coefficient friction of the adjoining components in such a way that a sufficient frictional force results. This configuration also ensures that two congruent faces are made available on the adjoining components and when the components are installed a seal-forming engagement of the functional faces is ensured even if the components are only installed rotated with respect to one another by a few degrees. During installation, it is therefore not necessary to pay attention to the precise orientation of the components with respect to one another. 
     The first surface region of the bearing element is preferably configured in such a way that the locus curves of at least some of the points on the zigzag-shaped or corrugated curve run outward in an essentially radial direction along the surface profile from the reference axis. This configuration has the advantage that the shapes for manufacture of the corresponding components can easily be manufactured. 
     According to one advantageous embodiment, such a bearing element has a surface configuration which surrounds the sealing region and which is embodied as a first part of a labyrinth seal. A further labyrinth seal has the advantage that dirt or liquid can only penetrate with great difficulty as far as the first sealing region. 
     Such a bearing element advantageously has a mushroom-like shape with a cap element and a stem element, wherein the first sealing region is arranged on the side of the cap element facing away from the stem element. The mushroom-like shape has the advantage of a flat construction, wherein different sealing faces can be provided on the cap-like element. 
     It is furthermore advantageous if the bearing element has a mushroom-like shape with a cap element and a stem element, wherein the second sealing region is arranged on the side of the cap element facing the stem element. The provision of the second sealing region on the bearing frame side has the advantage that the stem element can be provided as a positive locking engagement region which corresponds to, for example, a polygonal recess in the bearing frame which as such would be difficult to seal, while the area surrounding the bearing frame is level and smooth and can serve satisfactorily as a sealing face. 
     According to a further advantageous embodiment of the bearing element, the second sealing region is formed from a preferably resilient sealing lip in the edge region of the cap element and/or from a preferably less resilient central sealing region of the cap element which is arranged essentially adjacent to the stem element, wherein, in the state in which it is not inserted into the bearing frame, the resilient sealing lip preferably protrudes beyond the central sealing region in the direction of the bearing frame side. This has the advantage that the sealing lip can easily adapt to the surface of the bearing frame, even if the latter has an uneven surface or is bent, and that the sealing lip deforms elastically when it is inserted into the bearing frame, and ensures a seal, even without corresponding contact pressure via an adjacent component. 
     Such a bearing element advantageously has a second positively locking engagement region on the second side, preferably in the region of the stem element, wherein the second positive locking engagement region is configured in such a way that rotation of the bearing element with respect to a second component which adjoins on the second side, in particular the bearing frame, is prevented. This also prevents, in the second sealing region, that dirt or moisture is transported into the interior of the bearing frame by means of a relative rotation between the bearing element and the bearing frame. 
     In such a bearing element, the second positively locking engagement region is preferably formed at least partially from a polygonal cross-sectional region, preferably from a hexagonal cross-sectional region, of the stem element. Such a hexagonal cross-sectional region is easy to manufacture both with respect to the bearing element and with respect to the corresponding recess in the bearing frame. 
     According to a further advantageous embodiment, in such a bearing element at least one holding element is provided which is configured in such a way that, in the state in which it is inserted into the bearing frame, it engages behind a corresponding holding region of the bearing frame in such a way that the bearing element is secured against dropping or sliding out of the bearing frame, wherein the distance between the central sealing region of the bearing element and the holding element of the bearing element is essentially equal to or somewhat smaller than the distance between the holding region of the bearing element and a bearing frame sealing region which coincides with the central sealing region. This has the advantage that when the bearing element is inserted into the bearing frame tension is formed in the bearing element which causes the second sealing region to be pulled to the corresponding bearing frame sealing region. 
     In such a bearing element, the axle receptacle is embodied as a blind hole. This has the advantage that such a bearing element already has a seal-forming function even before a roller axle has been inserted into the axle receptacle and an adjacent component has been provided with a sealing face which corresponds to the first sealing face. 
     In such a bearing element, the axle receptacle is particularly advantageously embodied as a through hole. This variant is easy and cheaper to manufacture than a blind hole. Furthermore, a sprung roller axle can be pressed into the interior of the roller through the through hole, and a transport roller can therefore be easily disinstalled. 
     It is also advantageous if, in the case of such a bearing element, the axle receptacle is dimensioned, with respect to a roller axle which is to be accommodated, in such a way that a fit is provided between the roller axle and the axle receptacle, where the fit impedes or prevents rotation between the roller axle and the bearing element. Particularly in the case of non-driven rollers, such a (press) fit is sufficient to transmit torques which occur, and such a fit can more conveniently be manufactured than an additional positively locking engagement region. Furthermore, such a fit has an additional sealing function. 
     In such a bearing element, the axle receptacle preferably has a third positively locking engagement region which coincides with an axle region of the roller axle and is configured in such a way that rotation between the roller axle and the bearing element is impeded or prevented. This configuration has the advantage that even relatively large torques can be transmitted without the roller axle also rotating. 
     It is also preferred if such a bearing element is manufactured from a material which has vibration-damping and/or noise-damping and/or electrically conductive properties, and is preferably composed of polypropylene or polyamide. A polyamide with electrically conductive properties is particularly preferred as material. Such a bearing element allows the transport roller to be insulated from the bearing frame with respect to vibration and enables shocks and vibrations to be damped. Noises are reduced and the drift conveyor can be operated at higher speeds. The electrostatic charging of the transport roller can be derived via the bearing frame by means of the preferred conductive property. 
     A further aspect of the invention relates to a roller plate for end-side coverage of a transport roller of a drift conveyor, which roller plate has an axle hole for receiving a roller axle, a plate sealing region and a plate rotation locking region which is configured in such a way that rotation of the roller plate with respect to an adjoining component, in particular with respect to a bearing element as described above, can be prevented. 
     In such a roller plate the plate sealing region and the plate rotation locking region advantageously at least partially coincide, and a plate surface region of the first plate rotation locking region is therefore embodied, to the same degree, as a plate sealing face of the first plate sealing region. The advantages of such a configuration correspond to those which have been described with respect to the bearing element. 
     Likewise preferred is such a roller plate wherein the plate surface region is configured in such a way that in a developed view of a sectional plane, which corresponds essentially to a cylindrical face about a reference axis of the roller axle which is to be accommodated and which runs through the plate surface region, a curve runs along the plate surface profile, essentially along a zigzag-shaped or corrugated, in particular a sinusoidal curve. The advantages of such a configuration correspond to those which have been described with respect to the bearing element. 
     Likewise preferred is such a roller plate in which the plate surface region is configured in such a way that the locus curves of at least some points on the zigzag-shaped or corrugated curve run outward in an essentially radial direction along the plate surface profile from the reference axis. The advantages of such a configuration correspond to those which have been described with respect to the bearing element. 
     It is advantageous in such a roller plate if it has a surface configuration which surrounds the plate sealing region and is embodied as a second part of a labyrinth seal. The advantages of such a configuration correspond to those which have been described with respect to the bearing element. 
     It is additionally advantageous if, in such a roller plate, the axle hole has at least one roller axle bearing face which is configured in such a way that the roller plate forms, with the external diameter of a corresponding roller axle, a fit which permits it to mount the roller plate on the roller axle in such a way that it can be displaced in the axial direction without significant play. As a result, the roller plate can be pressed onto the bearing element in order to produce the sealing function. 
     Likewise advantageous is such a roller plate in which the axle hole has at least one force accumulator stop which is configured in such a way that a force accumulator can act on the force accumulator stop in order to displace the roller plate in an axial direction on a roller axle wherein the force accumulator stop is preferably embodied as first or second roller axle bearing face. This ensures that the roller plate is continuously pressed onto the bearing element so that the sealing function is continuously ensured. In addition, axial play between the transport roller and the bearing frame can be compensated and a lack of parallelism between the profiles can be compensated. 
     In one preferred embodiment, in such a roller plate the axle hole extends through an axle hole continuation of the roller plate, wherein the axle hole continuation has, on the outside, a roller-bearing bearing face which is configured in such a way that the roller plate forms, with the internal diameter of a corresponding roller bearing, a fit which permits it to mount the roller plate in the roller bearing in such a way that it can be displaced in the axial direction without significant play. In this context it is advantageous that the width of the bearing face of the roller bearing prevents the roller plate from tilting, while the displaceability of the roller plate is maintained. 
     It is also preferred if, in such a roller plate, the axle hole has a fourth positively locking engagement region which corresponds to an axle region of the roller axle and is configured in such a way that rotation between the roller axle and the bearing element is prevented, wherein displacement of the roller axle with respect to the roller plate remains possible in the axial direction. 
     A further aspect of the invention concerns a transport roller which has at least one roller outer tube, at least one roller plate as described above, at least one roller bearing, which preferably has a rolling bearing, at least one roller axle and at least a first force accumulator which preferably has a first helical spring, wherein the force accumulator is configured and arranged in such a way that it subjects the roller plate to a force which is suitable for displacing the roller plate on the roller axle relative to the roller outer tube. 
     In such a transport roller, at least one roller axle is preferably arranged so as to be displaceable relative to the roller outer tube, and is subjected, by means of a second force accumulator, which preferably comprises a second helical spring, to a force which is suitable for pressing the roller axle outward relative to the roller outer tube. 
     It is advantageous if such a transport roller has two roller plates and two roller axles, of which only one of the roller plates and one of the roller axles is respectively displaceable and subjected to force. This embodiment is less expensive to manufacture than if two roller plates and two roller axles were to be spring mounted. Nevertheless a positively locking engagement region and seal are ensured between roller plates and bearing elements on both sides of the transport roller. 
     A further aspect of the invention concerns a drift conveyor, which has at least one bearing frame, at least one transport roller as described and at least one bearing element, wherein the bearing element is inserted into a corresponding recess in the bearing frame, the roller axle of the transport roller is held in the axle receptacle of the bearing element, and the roller plate is pressed onto the bearing element via the force accumulator in such a way that the first sealing region of the bearing element is in contact with the plate sealing region of the roller plate, the first positively locking engagement region of the bearing element is in contact with the plate rotation locking region of the roller plate, and the second sealing region of the bearing element is in contact with the bearing frame sealing region. 
     Individual, particularly preferred embodiments of the invention will be described below by way of example. In this context, the individual embodiments which are described have, to a certain extent, features which are not absolutely necessary to implement the present invention but which are generally considered to be preferred. For example, embodiments which do not have all the features of the embodiments described below will be considered as having been disclosed in such a way that they are included within the teaching of the invention. It is also conceivable for features which are described with respect to different embodiments to be combined selectively with one another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1   b  and  1   c  show two cross sections through two preferred embodiments of a bearing element according to the invention—one with a continuous axle receptacle and one with a blind-hole-like axle receptacle, 
         FIGS. 1   a ,  1   d  and  1   e  show the embodiments of the bearing element illustrated in  FIGS. 1   b  and  1   c  as a plan view, side view and as an isometric view, 
         FIG. 2  shows a drift conveyor (illustrated partially in cross section) according to the invention, 
         FIGS. 3   a  to  3   c  show a transport roller according to the invention in various views, 
         FIG. 3   d  shows an enlarged detail of the roller plate which is marked with a circle in  FIG. 3   c,    
         FIG. 4  shows an embodiment of a roller plate according to the invention, 
         FIGS. 5   a  to  5   d  show a further embodiment of a bearing element in various views and sections, 
         FIGS. 6   a  to  6   d  show a further embodiment of a roller plate in various views and sections, and 
         FIGS. 7   a  to  7   d  show the bearing element shown in  FIGS. 5   a  to  d  and the roller plate shown in  FIGS. 6   a  to  6   d , in a seal-forming contact. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 2  shows a drift conveyor  1  according to the invention which is illustrated partially in cross section. The drift conveyor  1  respectively has a bearing frame  12  on the side illustrated to the left of the figure and a bearing frame  12  to the side illustrated on the right in the figure. The bearing frame  12  is illustrated as an L-shaped profile in the drawing. However, it can also be embodied as a U-shaped profile which has a cover on one side, with the result that the bearing frame has a closed profile. It is also conceivable for other profile cross sections to be used. 
     Furthermore, the drift conveyor  1  has a transport roller  14  which has a roller outer tube  141 , a roller bearing  142 , a roller axle  143 , a first force accumulator  144  and a second force accumulator (not shown). On the one hand, a plurality of transport rollers  14  which are arranged one next to the other and on which the goods to be transported directly rest can be provided in a drift conveyor  1 . It is also conceivable for a belt to be guided over the transport rollers. 
     Roller bearing  142  is embodied in the illustrated embodiment as a rolling bearing. Other bearings such as, for example, sliding bearings are also conceivable. 
     The roller axle  143  can be embodied as a single-piece roller axle which extends over the entire width of the transport roller and projects from it on both sides of the transport roller  14 . However, it is preferred if two roller axles  143  are provided. In this way, both roller axles but preferably just one roller axle  143  can be displaceably mounted, with the result that the roller axle can be pressed in the direction of the interior of the transport roller, against a second force accumulator which is preferably formed from a helical spring and is not shown in the illustrated drawing. In this design, such a transport roller  14  can easily be inserted into the bearing frame  12  and removed therefrom, since the sprung roller axle  143  only has to be pressed into the interior of the transport roller  14  and can rebound into the axle receptacle  1310  of the bearing element  13  after insertion into the drift conveyor. 
     As is apparent in  FIG. 2 , the drift conveyor  1  also has two roller plates  15  which are arranged on the left-hand and right-hand sides of the transport roller  14 . The roller plate  15  which is shown on the left-hand side is displaceably mounted on the roller axle  143  and a force is applied to it via a first force accumulator  144  which is formed by a helical spring in the embodiment shown. As a result, the roller plate  15  on the roller axle  143  is forced in the direction of the bearing element  13 , which is shown on the left-hand side in  FIG. 2 . The first force accumulator  144  can also be formed by a leaf spring, a disk spring, rubber buffer and/or any desired other force accumulator, instead of a helical spring. 
     The force which is transmitted to the roller plate  15  by the first force accumulator  144 , and by means of which the roller plate  15  is pressed to the left onto the bearing element  13  which is also illustrated in  FIG. 2  causes corresponding regions of the bearing element  13  and of the roller plate  15  to come into contact. In addition, the bearing element  13  is pressed onto the bearing frame  12 . 
     The same also applies with respect to the right-hand roller plate  15  which is illustrated in  FIG. 2 . However, it will generally be sufficient if in the case of a transport roller  14  a force is applied to just one of the two roller plates because this force acts in both directions and as a result the right-hand roller plate  15  is also in contact with the right-hand bearing element  13 , and the right-hand bearing element  13  is also forced onto the right-hand bearing frame  12  by means of the right-hand roller plate  15 . 
     The type of contact between the bearing element  13  and the roller plate  15  as well as between the bearing element  13  and bearing frame  12  produces a seal between the elements. The seal comes about by virtue of the fact that, on the one hand, sealing faces which are provided are in engagement with one another, and on the other hand a relative rotation between the parts is prevented, with the result that moisture or dust cannot penetrate along the sealing faces as a result of a relative rotation. 
     The corresponding sealing regions and positively locking engagement regions of the bearing element  13  of the bearing frame  12  and of the roller plate  15  are described in more detail below. 
     The bearing element  13  is illustrated in detail in  FIGS. 1   a  to  1   e .  FIG. 1   a  shows the bearing element  13  in an isometric view. As is apparent in this figure, the bearing element  13  is preferably in the form of a mushroom with a cap element  1301  and a stem element  1304 . As is clearly apparent in  FIG. 1   a , this preferred embodiment of the bearing element  13  has a hexagonal stem element  1304 . In this preferred embodiment, the stem element  1304  therefore has a second positively locking engagement region  1312  which is formed by this hexagonal configuration of the stem element. The stem element can be inserted into a corresponding hexagonal recess in the bearing element  12 , and the bearing element  13  therefore cannot rotate in the bearing frame  12 . 
     In addition, the bearing element  13  has, on the stem element  1304 , holding elements  1305  which, when the bearing element  13  is inserted into the bearing frame  12 , can engage behind corresponding holding regions  121  of the bearing frame, with the result that the bearing element  13  is secured against dropping or slipping out of the bearing frame  12 . The holding elements  1305  also ensure that the second sealing region  1313  is also held in a seal-forming engagement with the bearing frame  12 , as is described in more detail below. 
     On the side of the cap element  1301  facing away from the stem element, a sealing region  1307   a  and a positively locking engagement region  1308  which extend in a corrugated shape are provided. In the illustrated embodiment, the first sealing region  1308  therefore advantageously coincides with the first positively locking engagement region  1307   a . The surface regions which are formed in this way correspond to a matching plate sealing region  152  and a matching plate positively locking engagement region  153   a  of the roller plate  15 , which are illustrated in  FIGS. 3   d  and  4 . 
     The corresponding regions are configured in such a way that the regions bear against one another in a planar fashion if contact comes about between the parts. By means of a corresponding contact pressure force, which is made available via the first force accumulator  144 , minimal unevenness of the surfaces which may be present are pressed smooth with the result that fluids cannot pass through the sealing faces. 
     Sealing regions and positively locking engagement regions do not need to coincide but rather cannot be of separate design. This would have the advantage that fewer precise tolerances would have to be maintained during manufacture. A sealing face could be provided in one plane, as a result of which it would be easier to manufacture than a surface with curvatures, as in the illustrated embodiment. However, the illustrated embodiment can be embodied in a space-saving fashion and does not require double fitting, as would possibly be the case with separate sealing regions and positively locking engagement regions. 
     As is illustrated in  FIG. 2 , the sealing region and positively locking engagement region are surrounded by a labyrinth seal  2 . This labyrinth seal  2  is formed from two corresponding parts of the bearing element  13  on one side and of the roller plate  15  on the other side. These two parts of the labyrinth seal  2  are denoted by the reference symbol  1309  in  FIGS. 1   b  and  1   c , and by the reference symbol  154  in  FIGS. 3   d  and  4 . This labyrinth seal prevents moisture and dust from penetrating into the sealing regions and positively locking engagement regions. 
     On the second side  1311  of the bearing element  13 , a second sealing region  1313  is provided, which is formed by a sealing lip  1302  and by a central sealing region  1303  in the illustrated embodiment. The sealing lip  1302  is preferably of more resilient design than the central sealing region  1303 , with the result that the sealing lip  1303  fits snugly against corresponding sealing regions of the bearing frame  12  when the bearing element  13  is inserted into a matching recess of the bearing frame  12  and is pressed against the bearing frame  12  by means of the roller plate  15  via the force accumulator  144 . In contrast, the central sealing region can withstand a contact pressure force which results from the applied force of the force accumulator  144 , and can contribute to improved tightness by virtue of the contact pressure force. 
     By virtue of the holding elements  1305 , a corresponding sealing effect can already come about without a force being transferred to the sealing element  13  via the force accumulator  144 . It is preferred here if the stem element  1304  of the bearing element  13  has a certain degree of intrinsic elasticity, with the result that a tension is generated in the bearing element  13  by means of correspondingly selected dimensions between the holding element  1305  and the central sealing region  1303 , on the one hand, and the corresponding material thickness of the bearing frame  12 . By virtue of this tension, the sealing lip  1302  and/or the central sealing region  1303  fits snugly against the bearing frame  12 , even if the transport roller  14  is not yet inserted into the bearing frame  12 . 
     In this case, it is particularly preferred if the bearing element  13  has a blind-hole-like axle receptacle  1310  since in this case the profile, which is formed by the bearing frame  12 , is sealed even without the roller axle or transport roller  14  being inserted. 
     On the other hand, a bearing element  13  which has a continuous axle receptacle  1310  has the advantage that, when the transport roller  14  is disinstalled, for example a sprung roller axle  143  can be pressed through the bearing element  13  from behind, and can therefore be easily disinstalled. 
     A further preferred aspect of the bearing element  13  concerns a vibration-damping property of the bearing element  13 . The bearing element is preferably manufactured from polypropylene and even more preferably from polyamide. By virtue of the material properties it is possible to avoid steel-to-steel contact between the roller axle  143  and the bearing frame  12 . This configuration of the bearing element  13  allows vibrations to be damped and therefore reduces loading on the components. This leads to a longer service life of the parts. Furthermore, noise is avoided. Sensitive goods which are to be conveyed on the drift conveyor  1  can also be conveyed at higher speeds than would be the case with drift conveyors without corresponding bearing elements. 
       FIG. 4  shows a roller plate  15  in cross section. Roller axle bearing faces of the roller plate in the axle hole  151  are denoted by the reference symbol  155 . The roller plate  15  is mounted on the roller axle  143  by means of these roller axle bearing faces  155 . In this context, a corresponding fit between the roller plate  15  and the roller axle  143  preferably ensures that the roller outer tube  141  of the transport roller  14  is preferably mounted without play on the axle by means of the roller bearing  142 , and a corresponding intermediately connected component by means of the roller plate  15 . 
     The fit between the roller plate  15  and roller axle  143  is therefore preferably dimensioned in such a way that, on the one hand, play-free bearing of the transport roller  14  is ensured and, on the other hand, the roller plate  15  is displaceable on the roller axle  143  and can be displaced from the force accumulator  144  to the bearing element  13  and the bearing frame  12 . 
     The same applies to a fit between the bearing face  158  of the roller bearing and the roller bearing  142 . Play-free bearing is also preferably ensured between these two components, and displaceability between the roller bearing  142  and the roller plate  12  is also advantageous here. 
     The roller plate  15  is illustrated in  FIG. 4  by an additional force accumulator stop  156 . The force accumulator stop  156  provides, on the one hand, an engagement face for the first force accumulator  144 , by means of which engagement face the roller plate  15  can be pressed onto the bearing element  13 . On the other hand, in the illustrated embodiment the force accumulator stop  156  has a further roller axle bearing face  155 . The second roller axle bearing face  155  prevents the roller plate  15  from tilting on the roller axle  143 . Since the roller plate  15  in the illustrated embodiment has an undercut between the two roller axle bearing faces  155  on the left-hand side and on the right-hand side in the figure, such a roller plate  15  can only be manufactured with difficulty using an injection molding method. It is therefore likewise conceivable to embody such a roller plate  15  with a continuous roller axle bearing face  155 . However, it is preferred to provide just one roller axle bearing face  155  on the left-hand side. In this case, the force accumulator  144  could act on the stop face which is illustrated on the left in the figure. Tilting of the roller plate  15  on the roller axle  143  is prevented in this case by means of the fit between the roller plate  15  and the roller bearing  142 . 
     A further embodiment of the invention is illustrated in  FIGS. 5 to 7  and described in the text which follows. 
     The embodiment is very similar to what is described above. In order to avoid unnecessary repetitions, reference is therefore made just to the features which provide new aspects compared to the embodiment already described. The reference symbols which have essentially denoted identical features are retained. 
     In this embodiment, the rotation locking region of the bearing element  13  is embodied as a friction locking region  1307   b . In this embodiment, no positive locking engagement is provided on the first side  136  of the bearing element  13 . Rotation of the bearing element with respect to the adjoining roller plate  15  is prevented by means of the contact pressure between the respective components and, if appropriate, additionally by means of an O ring  3  located between them, as is clearly apparent in  FIGS. 7   a  and  7   c . The O ring is arranged in a groove in the roller plate  15 . The rotation locking region is provided as a friction locking region  1307   b  in a preferably concave base of the groove, as can be seen. 
     The groove has, as illustrated, a cross-sectional shape which preferably corresponds essentially to a partial circle and which is somewhat larger than the cross-sectional diameter of the O ring  3 . On the side of the groove facing the roller axle, the edge of the groove projects somewhat in the direction of the O ring, and a slight undercut is therefore formed, preventing the O ring  3  from being able to slip out of the groove in the unassembled state and causing it to therefore be securely held in said groove. Alternatively, the groove can also be provided on the bearing element  13 . 
     Dependent on the torque which is to be transmitted, the contact pressure force which is transmitted via the first force accumulator  144  to the roller plate  15  is dimensioned in such a way that, with consideration of the coefficient of friction between the materials of the roller plate  15  and of the bearing element  13 , a corresponding frictional force is produced in the circumferential direction. 
     As is apparent in particular in  FIGS. 7   b  and  7   c , in this embodiment the roller plate  15  and the bearing element  13  are not in direct contact. The contact pressure force is therefore not large enough to compress the O ring, which is more elastic than the roller plate  15  and the bearing element  13  to such an extent that the roller plate  15  and the bearing element  13  come into direct contact. 
     However, it is conceivable for the dimensions of the components and the contact pressure force to be selected such that the O ring is compressed to such an extent that the roller plate and the bearing element come into contact. Such a contact face can serve as a further sealing face between the roller plate  15  and bearing element  13 . In addition, it is also conceivable for the O ring to be entirely omitted and for the friction locking region  1307   b  and plate friction locking region  153   b  to be in direct contact with one another. In addition it is conceivable for the described O ring  3  to be provided, in the embodiment first described, with a corresponding groove on one of the components in addition to the positively locking engagement region  1307   a  or the plate positively locking engagement region  153   a  described there. 
     As is shown in  FIGS. 5   a  to  5   d , the holding element  1305  is embodied in the shown embodiment in the form of an elastic clip which, when the bearing element  13  is inserted into the bearing frame  12 , can initially yield in the outward direction and subsequently spring back elastically in order to engage behind the holding region  121  of the bearing frame. Such an embodiment of the holding element  1305  can also be provided in the embodiment described first. 
     As is apparent in  FIG. 7   b , in the assembled state of the components the contact pressure force is transmitted from the roller plate  15  to the bearing element  13  via the O ring  3 . In the illustrated preferred embodiment, the O ring  3  presses onto a frictional locking region  1307   b  of the bearing element  13 , on the rear of which, directly behind this region, an annular central sealing region  1303  is formed, which annular central sealing region  1303  is spaced apart somewhat from the stem element  1305 . For this reason, the contact pressure force is satisfactorily transmitted to this central sealing region  1303 , which produces a good sealing effect.