Abstract:
A sliding closure for a vessel containing molten metal, having a slider unit guided in a slider housing, the slider unit having a push rod that can be connected to a drive rod of a linear drive via a coupling, wherein a mounting element for the linear drive is provided on the slider housing and receives the push rod and the drive rod on a coupling side. The mounting element is equipped with an automatically operating locking device for the linear drive. The slide closure operates reliably, both during the casting process and during transport thereof between the various stations of the plant.

Description:
FIELD OF THE INVENTION 
     The invention relates to a sliding closure for a vessel containing molten metal, having a slider unit guided in a slider housing, said slider unit having a push rod that can be connected to the drive rod of a linear drive via a coupling, wherein a mounting element for the linear drive is provided on the slider housing, said element receiving the push rod and the drive rod on the coupling side. 
     BACKGROUND OF THE INVENTION 
     Slide closures of this type are used, for example, for the continuous casting of steel in order during the casting process to steer the molten flow flowing out of the vessel and, if necessary, to interrupt it. Here it is known that the vessel must periodically be moved to and fro between the casting platform and the plant supplying the molten mass. In order to accelerate the operational procedures linear drives are provided in both stations. Here the latter are respectively pushed into the mounting element of the sliding closure where their drive rod is then coupled to the push rod of the slider unit. In European patent specification EP 0 875 320 a coupling provided for this purpose is described which facilitates the fitting and removal of the linear drive and simplifies the coupling processes. 
     However, with the known sliding closures of this type there is a risk that during operation, due to the rough method of operation or incorrect handling, the linear drive comes away from its mounting element and so causes severe disruption to the casting operation. 
     A similar thing can occur with the periodic transport of the vessel between the different stations of the plant. That is to say, there is then a risk that the sliding closure opens unintentionally if it is handled incorrectly during transport. In both cases the consequences are serious, both from a commercial point of view and with regard to the safety of the people employed here. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     The object which forms the basis of the invention is to avoid these disadvantages and to provide a sliding closure of the type specified at the start which guarantees a high degree of operational reliability even with the rough operation which is normal at casting plants. 
     This object is achieved according to the invention in that the mounting element is equipped with a locking device for the linear drive and/or a locking device for the push rod of the slider unit. 
     In this way, on the one hand it is ensured that the linear drive is held correctly in the mounting element after said linear drive has been drawn into the latter until the sliding closure leaves the one station in order to change over to the other station. On the other hand, it is also ensured that the sliding closure does not open unintentionally during transport from one station to the other. 
     Furthermore, the invention makes provision such that the locking device for the linear drive has a locking rod attached to it parallel to the axis on the drive rod and which cooperates with a spring-loaded locking catch attached to the mounting element. In the fitted state the latter encompasses the locking rod sliding therein over the whole stroke length of the drive and so causes the latter to sit securely in the mounting element for as long as it is fitted in the latter. 
     It is advantageous within the context of a simple design for the locking rod to be attached to a flange of the drive rod in the region of its coupling part. 
     According to the invention the locking rod has on the coupling side a recess which when the drive rod is drawn in can engage with the locking catch and afterwards can be released again from the locking catch. The locking and unlocking of the linear drive takes place automatically when the latter is drawn in and out with the drive rod drawn in. 
     Advantageously the locking rod has on its end facing away from the coupling a further recess which can be released from the locking catch when the drive rod is drawn out. Here the unlocking of the linear drive also takes place automatically when the latter is drawn out with the drive rod drawn out. 
     The invention also makes provision such that the locking catch is mounted laterally to the locking rod in a bolt guided within the mounting element, it advantageously being able to be spread open by turning or moving the bolt. Therefore, by operating the bolt the locking of the linear drive can be released at any time as required. 
     Furthermore, according to the invention provision is made such that the locking device has for the push rod of the slider unit a spring-loaded lever pivotably mounted in the mounting element which is provided with a detent disposed close to the pivot axis and a blocking pin disposed on the lever end facing away from the pivot axis, the detent and the blocking pin projecting into the mounting element and cooperating here with the coupling part of the drive rod or with a stop surface of the push rod. When the linear drive is drawn out of the mounting element the detent, and so the blocking pin, are automatically pivoted inwards by means of which the push rod is locked with the blocking pin. In this way one prevents the sliding closure from opening unintentionally during subsequent transport within the plant. 
     Alternatively, the locking device for the push rod can have two detents projecting into the mounting element and which are connected to one another by means of a connecting rod rotatably mounted in the mounting element, and which cooperate with stop surfaces of the linear drive and of the push rod which are advantageously formed by a stroke limitation bolt disposed laterally to the latter in the push rod and by a supporting plate of the linear drive that can be pushed into the mounting element. Upon drawing the linear drive into the mounting element the two detents are pivoted outwards and the push rod can move freely within the mounting element. If the linear drive is drawn out, both detents then pivot inwards again to such an extent that the push rod is locked by the detent cooperating with its stop surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the following the invention is described in greater detail by means of a number of exemplary embodiments with reference to the drawings. These show as follows: 
         FIG. 1  is a longitudinal section of a sliding closure according to the invention, 
         FIG. 2  is detail II from  FIG. 1  with a cylinder lock for the linear drive in the uncoupled state, rotated about 180° and shown in enlarged form, 
         FIG. 3  is a section along line III-III in  FIG. 2 , 
         FIG. 4  is a side view of detail II from  FIG. 1 , 
         FIG. 5  is a section along line V-V in  FIG. 2 , 
         FIG. 6  is a side view in the direction of arrow VI in  FIG. 3 , shown in perspective, 
         FIG. 7  is detail II from  FIG. 1  with a transport lock for the push rod of the slider unit, also in the uncoupled state, rotated about 180° and shown in enlarged form, 
         FIG. 8  is a top view of the detail from  FIG. 7 , 
         FIG. 9  is a section along line IX-IX in  FIG. 7 , 
         FIG. 10  is a side view of the detail from  FIG. 7 , 
         FIG. 11  is a section along line XI-XI in  FIG. 7 , 
         FIG. 12  is a side view in the direction of arrow XII in  FIG. 9 , shown in perspective, 
         FIG. 13  is a side view in the direction of arrow XIII in  FIG. 9 , also shown in perspective, 
         FIG. 14  is detail II from  FIG. 1  with a version of the transport lock, also rotated about 180° and shown in enlarged form, 
         FIG. 15  is a top view of the detail from  FIG. 14 , 
         FIG. 16  is a section along line XVI-XVI in  FIG. 14 , 
         FIG. 17  is a section along line XVII-XVII in  FIG. 14 , 
         FIG. 18  is a section along line XVIII-XVIII in  FIG. 14 , 
         FIG. 19  is a side view in the direction of arrow XIX in  FIG. 16 , shown in perspective, and 
         FIG. 20  is a side view in the direction of arrow XX in  FIG. 16 , also shown in perspective. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a sliding closure  1  on a vessel containing molten metal which is shown in the figure partially as a ladle  2 . The ladle  2  has an outer steel coating  3 , a fire-resistant lining  4  and an outlet  5  which is formed by a fire-resistant perforated brick  6  and a fire-resistant casing  7 . Disposed on the outlet  5  is the sliding closure  1  comprising a housing upper part  8  with a fire-resistant base plate  9  inserted in the latter, a housing frame  10  and a slider unit  11  braced releaseably within the latter, having a fire-resistant slider plate  12  and a discharge casing  13  adjacent to the latter. By moving the slider unit  11  and the slider plate  12  inserted within the latter longitudinally, the outlet  5  can be brought from the opening position illustrated into a restricting or closure position. 
     In order to move the slider unit  11  to and fro the latter can be connected via a push rod  14  and a coupling  15  to the drive rod  16  of a linear drive  17  in the form of a hydraulic cylinder/piston unit. The linear drive  17  is generally fitted onto the ladle  2  filled with molten metal and equipped with the closed sliding closure  1  when said ladle is brought onto the casting platform. After emptying the ladle the linear drive  17  is taken away from the ladle again. Next the ladle is transported by a crane away from the casting platform to a ladle location. Here the process described is repeated with a drive positioned at the ladle location. 
     On the slider housing  8 ,  10  a mounting element  18  receiving the push rod  14  and the drive rod  16  on the coupling side is provided for the linear drive  17 . The coupling  15  located here is in the form of a catch coupling. As can be seen from  FIG. 2  it comprises a flange-type coupling part  19  on the push rod  14  and a coupling part  20  formed by two catch elements on the drive rod  16 , in the coupled state the catch elements encompassing the coupling part  19  with a form fit. The linear drive  17  is pushed into the mounting element  18  on the side. Then the coupling is produced automatically by moving the drive rod  16  towards the slider unit  11 . Uncoupling likewise takes place automatically when one pulls the linear drive  17  out of the mounting element  18 . 
     Disposed in the mounting element  18  there is a locking device  21  for the linear drive  27  which, as can be seen from  FIGS. 2 to 6 , is composed of a locking rod  22  and a locking catch  23  cooperating with the latter. The locking rod  22  is attached to a flange  24  of the drive rod  16  in the region of its coupling part  20 . It is aligned axially parallel to the drive rod  16 . 
     The locking catch  23  is mounted laterally to the locking rod  22  in a bolt  25  which is guided within the mounting element  18 . Its two catch elements are thus held by the bolt  25 . By taking away the bolt  25 , if so required the catch elements can be released from the mounting element, by means of which the locking of the linear drive is cancelled. 
     The locking rod  22  has two recesses in the form of annular grooves  26 ,  27  which correspond to the stroke end positions of the drive rod  16 . The diameter of the annular groove  26  has dimensions such that upon inserting the linear drive  17  in the mounting element  18  with a drawn in drive rod the annular groove  26  can engage with the locking catch  23 , whereas when the linear drive  17  is drawn out it can be released from the locking catch  23 . 
     When moving the drive rod  16  the locking rod  22  is also moved, the locking catch  23  encompassing the latter in the region between the annular grooves  26 ,  27  so strongly that it is then impossible to release the locking rod  22  from the locking catch  23  laterally to its longitudinal axis. Therefore, during its whole working stroke the linear drive  17  remains securely locked, and so automatically acting locking and unlocking is produced which takes place without any manual operation. 
     The diameter of the annular groove  27  has dimensions such that it can be released from the locking catch  23  when the linear drive  17  is drawn out of the mounting element  18 . It is therefore possible, if so required, to remove the linear drive, even when the drive rod  16  is drawn out. Furthermore, the locking rod  22  serves to prevent the drive rod  16  from rotating. 
     The sliding closure according to  FIGS. 7 to 13  is equipped with a locking device  28  for the push rod  14 . It comprises a lever  29  mounted pivotably in the mounting element  18  with a tappet  31  close to the pivot axis  30  and a blocking pin  32  on the lever end facing away from the pivot axis, the tappet  31  and the blocking pin  32  projecting into the mounting element  18  and cooperating here with the coupling part  20  of the drive rod  16  and with a stop surface  33  of the push rod  14 . A stroke limitation bolt  34  with a handle  35  pushed into the push rod  14  laterally to the longitudinal axis forms the stop surface  33 . 
     The pivot axis  30  of the lever  29  sits in a bearing block  36  which is attached to the mounting element  18 . The lever  29  is acted upon by a spring  37  with an adjustment screw  38  in the inwardly pivoting direction. 
       FIG. 9  shows the locking device  28  with the lever  29  pivoted in. In the position shown the drive rod  16  is drawn in, whereas the push rod  14  adopts its end position with the slider closed. In order to couple the drive rod  16  onto the push rod the former is drawn out within the mounting element  18  until the coupling is produced between the two. It thus actuates the tappet  31 , by means of which the lever  29  is pivoted out, and the latter takes the blocking pin  32  out of the trajectory of the stroke limitation bolt  34 . The push rod  14  can therefore move freely within its working stroke for as long as the drive rod  16  and the push rod  14  are coupled. 
     If, however, the coupling is released again and the drive rod  16  drawn back, the tappet  31  can then pivot back into its initial position, by means of which the spring-loaded lever  29  pivots back and the blocking pin  32  projects once again into the trajectory of the stroke limitation bolt  34 . In this way it is ensured that after the linear drive  17  has been dismantled, the sliding closure does not open unintentionally because then the push rod  14  is locked by the blocking pin  32 . With this locking device  28  automatically acting locking and unlocking has in turn been produced. 
     With the sliding closure according to  FIGS. 14 to 20  the locking device  28  for the push rod  14  has two detents  47 ,  48  projecting into the mounting element  18  which are connected to one another by a connecting rod  39  rotatably mounted in bearing blocks  43 , and cooperate with stop surfaces  41  of the push rod  14  and of the linear drive  16 . This stop surface  41  of the linear drive  17  is provided in a supporting plate  42  of the linear drive that can be pushed into the mounting element  18 , whereas the stop surface of the push rod  14  is located on an elevation of the latter. 
     The locking device  28  according to  FIGS. 14 to 20 , which also acts automatically, functions in the same way as the locking device according to  FIGS. 7 to 13 . 
     Before inserting the linear drive  17  into the mounting element  18  the detents  47 ,  48  are pivoted into this mounting element  18 . Upon drawing the linear drive into the mounting element the supporting plate  42  strikes the detent  48  with the stop surface  41  and pushes it out to such an extent that the detent  47  connected to it via the connecting rod  39  pivots out of the trajectory of the push rod  14 . Therefore, the push rod  14  can move freely for as long as the linear drive  17  is inserted in the mounting element  18 . 
     If the linear drive is drawn out of the mounting element  18 , both detents  47 ,  48  can then pivot back with the result that the detent  47  then projects into the trajectory of the stroke limitation bolt  34  again. It is thus achieved that after the linear drive has been removed, the sliding closure does not open unintentionally during transport because the push rod  14  is then locked by the detent  47  in cooperation with the stop on the push rod. 
     As can be seen from the figures, the sliding closure according to  FIGS. 2 to 6  is only equipped with one cylinder lock in the form of the locking device  21  for the linear drive  17 . With the sliding closures according to  FIGS. 7 to 17  and  14  to  20 , instead of this the cylinder lock is combined with a transport lock in the form of the locking device  28  for the push rod  14 . It is therefore possible within the framework of the invention to incorporate both locking devices individually or together into the locking closure, particularly as in the latter case their functions obviously complement one another. 
     Due to the design proposed for the latter, it is also possible, without a great deal of complexity, to incorporate the locking devices subsequently into existing sliding closures.