Patent Publication Number: US-2021170876-A1

Title: Device for Fastening a Sliding Element to a Current Collector

Description:
The invention relates to a device for fastening a sliding element to a current collector in order to draw electrical energy from an overhead contact line to an electrically driven vehicle, and also to a current collector and an electrically driven vehicle. 
     Sliding elements of the generic type are known. They are integral parts of a current collector which is connected to an electrically driven vehicle. The sliding element is in contact with a stationary overhead contact line and serves to draw electrical energy from the overhead contact line to the electrically driven vehicle. 
     The sliding elements comprise a carrier and at least one carbon contact piece arranged on the carrier. The carrier and the at least one carbon contact piece are connected in the known way by bonding. Here, an electrically conductive adhesive is deployed. The aim is to achieve as low as possible a transition resistance between the carbon contact pieces and the carrier. The connection can also be effected by other suitable measures, for example clamping, riveting, screwing, soldering or the like. 
     The carrier can also have an air duct which is connected to a compressed air connection. Said compressed air duct extends substantially over the entire length of the carrier. Said compressed air duct serves to recognise damage or wear to the carbon contact pieces. If the damage or wear is too severe, the duct pressurized by compressed air is exposed so that a drop in pressure takes place, which is detected by a corresponding control unit. The current collector is then lowered, i.e. separated from the overhead contact line. 
     Known sliding elements are fixed by means of screw connections to the upper end of the current collector or to a rocker mounted there. Further connections such as, for example, for compressed air or electrical contactings are mounted separately. 
     When changing the sliding elements, multiple screw connections for the mechanical retention, further screw connections for the electrical connection and, if applicable, multiple pneumatic connections for the compressed air transfer must, as a general rule, be released and, after the sliding element has been changed, these have to be refixed to the replacement element. As a result, this process is very time-consuming. In addition, the fact that the sliding elements are usually changed on the roof of the vehicle leads to more difficult conditions. This results in an increased risk of incorrect installations. All in all, the process of changing sliding elements with the known fastening system in the form of screw connections can be extremely costly, due to the time-consuming nature and susceptibility to errors thereof 
     It is therefore an object of the invention to propose a system for fastening carbon contact strips to a current collector or to a rocker mounted there of an electrically operated vehicle, with which the maintenance process can be simplified, accelerated and performed more cheaply. 
     According to the invention, this object is achieved by a device having the features indicated in claim  1 . Advantageous configurations and further developments are described in the dependent claims. 
     In the case of a device according to the invention for fastening a sliding element to a current collector or to a rocker mounted there, in order to draw electrical energy from an overhead contact line to an electrically driven vehicle, the overhead contact line is arranged in a stationary manner and the current collector is connected to the vehicle. It is always assumed below that the sliding element is fastened to a current collector or to a rocker mounted there, even if only the current collector is indicated. The sliding element comprises a carrier and at least one carbon contact piece arranged on the carrier. At least one fastening point for fastening the sliding element to the current collector is formed between the sliding element and the current collector. Thanks to the formation of at least two fastening points preferably between the sliding element and the current collector, a secure fastening of the sliding element to the current collector and also, simultaneously, the secure location or respectively alignment of the sliding element with respect to the current collector is guaranteed. 
     At each fastening point between the sliding element and the current collector, at least one detent means is arranged on the side of the sliding element and, for each of the detent means, a receptacle for said detent means which is associated therewith is arranged on the side of the current collector. Each detent means and the receptacle associated therewith in each case are releasably brought into engagement with each other by inserting and locking the detent means in the receptacle associated therewith. In other words, a number of detent means are formed on the sliding element at each fastening point, and a corresponding number of receptacles associated with the detent means are formed on the current collector, which are arranged in terms of location so that the detent means for fastening the sliding element are introduced into the receptacles on the current collector, where they lock in the receptacle. The device can therefore also be referred to as a “click system”, in which the detent means are “clicked into” the respective receptacle. 
     In a first embodiment, the carrier of the sliding element can have a compressed air duct for monitoring the compressed air or respectively a damage or wear indication of the at least one carbon contact piece. The compressed air duct is supplied with compressed air and the latter is detected by a control unit. If the at least one carbon contact piece is damaged or worn too much, a drop in pressure occurs, which is detected by the control unit. The current collector is subsequently lowered and thus separated from the overhead contact line. 
     In a fastening system according to the invention, both the detent means and the receptacle associated therewith can each have corresponding through holes which form a continuous through hole for a compressed air transfer from the current collector into the compressed air duct in the carrier, if the detent means and the receptacle associated therewith are releasably brought into engagement with each other. The respective through holes in the detent means and the associated receptacle form a portion of a compressed air through hole from the current collector to the compressed air duct in the carrier of the sliding element. If the detent means and receptacle are brought into engagement, the through hole of the detent means forms the continuation of the through hole of the receptacle right into the compressed air duct of the carrier. As a result of the engaging in one another of the respective through holes in the detent means and the associated receptacle during inserting and locking of the detent means in the associated receptacle, the pneumatic connection for the compressed air transfer is consequently created, which then no longer has to be connected separately. Changing a sliding element is thus considerably accelerated and simplified. The electrical connection of the sliding elements is not affected by this. This is preferably effected with at least one screw connection. 
     In a next embodiment, the detent means can have outwardly directed projections which, on insertion of the detent means into the receptacle associated therewith, lock behind corresponding projections in the receptacle and/or in corresponding cavities in the receptacle. Accordingly, projections are formed in the interior of the receptacle, into which the detent means is inserted, which projections project into the region in which the detent means is inserted. Alternatively or simultaneously, cavities can be formed in the interior of the receptacle, which correspond to the projections on the detent means. If the detent means are now inserted into the receptacle with a corresponding application of force, the projections of the detent means are pushed behind the projections in the interior of the receptacle and/or are brought into the region of the cavities in the interior of the receptacle so that the projections of the detent means are fixed and the detent means are locked in said position. The person skilled in the art will easily recognise that the formation of projections and cavities can also be effected in the reverse manner so that the projections can be formed in the interior of the receptacle and the corresponding projections and/or cavities can be formed on the detent means. 
     Sealing elements which prevent a leakage of the compressed air can preferably be associated with the detent means and/or the receptacle. 
     The outwardly directed projections of the detent means and the corresponding projections and/or cavities of the receptacle can be formed along the entire circumference of the detent means and/or the interior of the receptacle or can be interrupted in sections. Interruptions can be provided, for example, in order to reduce the material and/or manufacturing outlay in order to form the projections and/or cavities, but also in order to simplify the penetration of the detent means in, and releasing of the detent means from, the receptacle. If, for example, projections of the detent means and projections of the receptacle are only formed in sections, the detent means and the receptacle can be rotated relative to one another for releasing, so that the respective projections are arranged offset with respect to one another in such a manner that the detent means can be released from the receptacle without exerting a great deal of force. 
     In a further embodiment, the projections of the detent means can be formed as movably supported elements and can be connected to a biasing mechanism so that, on insertion of the detent means into the associated receptacle, the movably supported elements are pressed into the interior of the detent means and, after passing through the projections and/or on reaching the cavities, are pressed out of the interior of the detent means by the biasing mechanism. Thanks to the movable formation of the projections and the resetting in the initial position by the biasing mechanism, the process of inserting the detent means into the associated receptacle and releasing the detent means from the receptacle is facilitated. It can be recognized by the person skilled in the art that even during releasing of the detent means, the movably supported elements are pressed into the interior of the detent means and are pressed out again by the biasing mechanism after passing through the projections in the interior of the receptacle. Similarly, it is obvious for the person skilled in the art that, with the same mode of operation, movably supported elements can alternatively be arranged in the interior of the receptacle, while corresponding projections and/or cavities can be provided on the detent means. 
     Furthermore, the biasing mechanism can have an operating element for manual actuation in order to move the movably supported elements into the interior of the detent means. Said operating element should be arranged such that it can be conveniently reached and operated by an engineer when changing the sliding element. In this way, the detent means can be released from the receptacle quickly and without applying a great deal of force, for example by pulling and simultaneously actuating the operating element. 
     The detent means can be released from the receptacle associated therewith by pulling with a minimum force, pulling with a simultaneous rotational movement and/or by pulling with a simultaneous actuation of the operating element. The pulling with a minimum force is, first and foremost, a possibility with the rigid formation of the projections and/or cavities on detent means and the associated receptacle, but can also be applied with all the other embodiments. The minimum force is the amount of force which is necessary to pull the detent means with its projections past the corresponding projections of the receptacle and/or to pull it out of the corresponding cavities and is dependent on the form and the material of the formed projections of the detent means or respectively of the receptacle. The pulling together with the simultaneous rotational movement is particularly advantageous if the projections of the detent means and/or the projections of the receptacle are interrupted in sections. An additional securing element can preferably also be provided, which excludes the permissible occurrence of the minimum force being exceeded, the twisting or the actuation of the operating element. 
     In yet another embodiment, the current collector can have an apparatus for receiving and aligning the carrier, in which a recess is formed at each fastening point between the current collector and the sliding element, through which recess the detent means can be inserted through the apparatus into the receptacle associated therewith. In this embodiment, an apparatus such as, for example, a trough-shaped carrier structure is arranged on the current collector, which wholly or partially receives the carrier of the sliding element and, simultaneously, the carrier and, thus, aligns the entire sliding element in its position relative to the current collector. Recesses are provided in the apparatus for receiving and aligning the carrier in the region of the fastening points, so that the detent means can be introduced through said recesses into the respective receptacles. Thanks to the apparatus for receiving and aligning the carrier, the exact installation of the sliding element is simplified and accelerated since, thanks to the apparatus for receiving and aligning the carrier, the position of the sliding element is precisely predefined. The apparatus for receiving and aligning the carrier can be formed in one piece over the entire length of the carrier or can be formed in multiple parts. 
     In the device according to the invention, the carrier can be connected in an electrically conducting manner, in particular bonded, to the at least one carbon contact piece. 
     The object is further achieved by a current collector which comprises a device according to the invention for fastening a sliding element to a current collector. 
     A further aspect of the invention is an electrically driven vehicle, in particular an electrically driven rail vehicle, which comprises the current collector according to the invention having the device according to the invention for fastening a sliding element to a current collector. 
    
    
     
       The invention is explained in greater detail below with reference to drawings, wherein: 
         FIG. 1  shows a side view, a sectional view and a perspective view of a sliding element having a device according to the invention for fastening to a current collector in a first embodiment, 
         FIG. 2  shows two sectional views of the device according to the invention for fastening to a current collector in a first embodiment, 
         FIG. 3  shows a side view, a sectional view and a perspective view of a sliding element having the device according to the invention for fastening to a current collector in a second embodiment, 
         FIG. 4  shows two sectional views of the device according to the invention for fastening to a current collector in a second embodiment, 
         FIG. 5  shows sectional views of the formation of projections and cavities in the detent means and receptacle, and 
         FIG. 6  shows schematic sectional views of the arrangement of movably supported elements and of the biasing mechanism. 
     
    
    
       FIG. 1 a    shows a side view of a current collector  20  having a sliding element  10  and the device according to the invention for fastening the sliding element to an apparatus for receiving and aligning a carrier (rocker) to the current collector. The sliding element  10  has a carrier  11  and a carbon contact piece  12 , wherein the carbon contact piece is fastened with an electrically conducting adhesive to the carrier  11 . The sliding element  10  is fastened at two fastening points  30  to the current collector  20 . A compressed air feed pipe  45  is guided to the fastening points  30  via the current collector. In  FIG. 1 a   , a section A-A is identified, which is depicted in  FIG. 1 b   . A perspective view of the current collector  20  having two sliding elements  10  from  FIGS. 1 a  and 1 b    is depicted in  FIG. 1 c   . Each sliding element  10  is connected at two fastening points  30 , in each case, to the current collector  20 . 
     Electrical connections  22  for contacting the sliding element  10  are further depicted in  FIG. 1 . 
     It is assumed below that the sliding element  10  is fastened to a receptacle of the rocker, even if a fastening to the current collector is referred to. 
       FIG. 2  shows two sectional views of the device according to the invention for fastening a sliding element  10  to a current collector  20  from  FIG. 1  in the region of a fastening point  30 . In the carrier  11 , a compressed air duct  13  for compressed air monitoring or respectively compressed air detection of the carbon contact piece  12  is formed. At the fastening point  30  a detent means  31  is formed on the sliding element  10 , which detent means has a through hole for compressed air  33  in the interior. The detent means  31  is inserted and locked in a receptacle  32 . The receptacle  32  has a through hole for compressed air  34 . The fact that the detent means  31  and receptacle  32  engage in one another means that the through holes  33  and  34  form a continuous compressed air through hole through the fastening point  30 . The compressed air is guided through a compressed air feed pipe  45  into the through hole  34  of the receptacle  32 , through the through hole  34  of the receptacle  32  into the through hole  33  of the detent means  31  and from there directly into the compressed air duct  13  of the carrier  11 . Thus, no separate connection of the compressed air supply is required since the pneumatic connection is established simultaneously during the inserting and locking of the detent means  31  in the receptacle  32 . 
     In the embodiment depicted in  FIG. 2 , the receptacle  32  is fixed by means of a screw connection  71  in an adapter  70  which is, in turn, fastened by a further screw connection  72  to the current collector  20 . This allows a rapid installation and change of the device for fastening the sliding element  10  to the current collector  20 . 
       FIG. 3 a    shows a side view,  FIG. 3 b    shows a sectional view and  FIG. 3 c    shows a perspective view of a sliding element  10  having the device according to the invention for fastening to a current collector  20  in a second embodiment. As in  FIG. 1 , the sliding element  10  is formed with a carrier  11  and a carbon contact piece  12 , which is fastened with an electrically conductive adhesive to the carrier  11 . The sliding element  10  is initially introduced at two fastening points  30 , in each case, into an apparatus  40  for receiving and aligning the carrier  11  and is connected through this to the current collector  20 . The section A-A identified in  FIG. 3 a    is depicted in  FIG. 3   b.    
       FIG. 4  shows two sectional views of the fastening point from  FIG. 3 . The apparatus  40  for receiving and aligning the carrier  11  is formed as a trough-shaped carrier structure which corresponds to the form of the carrier  11 . The trough-shaped structure  40  is connected by means of a screw connection  73  to the current collector  20 . If the sliding element  10  having the carrier  11  is to be fastened to the current collector  20 , it is placed at both fastening points  30 , in each case, in the trough-shaped structure  40 , and in this manner simultaneously aligned. At each fastening point  30 , the detent means  31  is guided through a recess in the trough-shaped structure  40  and into the receptacle  32  where it locks. In this second embodiment as well, a compressed air feed pipe  45  is provided, which guides compressed air from the current collector  20  through the through holes  33  and  34  which are in engagement with one another into the compressed air duct  13  of the carrier  11 . 
     In  FIG. 5 , the formation of outwardly directed curved projections  35  of the detent means  31  and corresponding projections  36   a  or respectively cavities  36   b  of the receptacle  32  are depicted, by way of example, in three sectional views. 
       FIG. 5 a    shows an embodiment, in which projections  36   a  corresponding to the projections  35  of the detent means  31  are formed in the receptacle and, following the insertion of the detent means  31  into the receptacle  32 , are locked in the direction of the depicted arrow behind the projections  36   b.    FIG. 5 b    shows the situation if cavities  36   b  corresponding to the projections  35  of the detent means  31  are formed in the receptacle  32 .  FIG. 5 c    shows a combination form from  FIGS. 5 a  and 5 b   . In all of the depicted variants, the projections can be formed along the entire circumference of the detent means  31  or respectively the interior of the receptacle  32  or can be formed with interruptions. 
       FIG. 6  schematically shows the formation of a projection  35  of the detent means  31  as a movably supported element  50  which is connected to a biasing mechanism  55 . The rest position of the movably supported element  50  is depicted in  FIG. 6 a   . The movably supported element  50  is pressed outwards by the biasing mechanism  55  and at least partially arranged projecting from the detent means  31  so that it forms an outwardly curved projection  35 .  FIG. 6 b    shows the movably supported element  50  pressed by an action of force, depicted by an arrow identified with F, into the interior of the detent means. This position of the movably supported element  50  is taken up when the detent means  31  is inserted into the receptacle  32 . As soon as the movably supported element  50  is guided past a projection  36   a  of the receptacle  32  or arrives in the region of a cavity  36   b  in the receptacle  32 , the movably supported element  50  is pressed outwards again by the biasing mechanism  55  so that the movably supported element  50  locks behind the projection  36   a  or in the cavity  36   b.  In addition, the biasing mechanism  55  can have an operating element  60  (not depicted) which can be actuated by an engineer when installing or changing the sliding element, in order to move movably supported elements  50  into the interior of the detent means  31  and, in this manner, facilitate the installation and release of the sliding element  10  from the current collector  20 . 
     REFERENCE NUMERALS 
       10  Sliding element 
       11  Carrier 
       12  Carbon contact piece
 
 13  Compressed air duct
 
 20  Current collector
 
 22  Electrical connection
 
 30  Fastening point
 
 31  Detent means
 
 32  Receptacle for detent means  31 
 
 33 ,  34  Through hole for compressed air
 
 35  Projection of the detent means  31 
 
 36   a  Corresponding projection in the receptacle  32 
 
 36   b  Corresponding cavity in the receptacle  32 
 
 40  Apparatus for receiving and aligning the carrier  11 
 
 45  Compressed air feed pipe
 
 50  Movably supported element
 
 55  Biasing mechanism
 
 60  Operating element
 
 70  Adapter for fastening to the current collector  20 
 
 71 ,  72 ,  73  Screw connection