Abstract:
A control device ( 10 ) for electro-hydraulic support frames with a casing ( 11 ) accommodating a circuit, several plug-in connectors ( 20 ) accessible from outside the casing ( 11 ) for the connection of control leads, and with actuating control elements ( 13 ) connected to the circuit. The control elements ( 14, 15, 16, 17, 18 ) are grouped together in several exchangeable modules ( 27 ), accommodated in the casing ( 11 ), which are connected to the circuit and to each other by plug-in connecting elements ( 30 ) when installed in the casing ( 11 ). The modules ( 27 ) are exchangeable independently of each other. The operating keys of a keyboard ( 16 ) and/or an indicator unit ( 18 ) can be combined in one operating module ( 28 ), which can be removed from the casing ( 11 ). The actual control of the control device in the casing ( 11 ) and operation of the support frame is permitted to continue during the exchange of the operating module ( 28 ).

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a control device for electro-hydraulic support control, with a casing accommodating the electrical and/or electronic circuit of the control device, several plug connectors accessible from the outside of the casing for the connection of control leads for the components of the support to be controlled, and with actuating control elements connected to the circuit. 
     Control devices of this construction for electro-hydraulic face support control gear are assigned to individual support frames of an underground face operation. Connecting leads for a power supply, for data transmission to the control devices of neighbouring support frames and/or to a central computer, for the feeding in of electrical signals from sensors, and for the actuation of circuits for eletromagnetic valves are connected onto the plug connectors from the individual controllers. 
     A control device of this construction is known from DE-A-197 51 007, in which a sensitive circuit is configured in the form of a circuit board which carries the plug connectors, and which is accommodated in a receiving compartment formed within the casing and sealed off from the actuating control elements, and encapsulated on all sides by a cast block, so that dirt and moisture present underground cannot penetrate to the sensitive circuit, and also the plug connectors are integrated firmly against dirt and moisture in the cast block. 
     The protection of the circuit and the plug connectors in this previously proposed control device has proved itself very effective, so that the lifetime of the circuit can be substantially increased as against older constructions (DE-A-37 08 902, DE-A-35 33 659). This has, however the consequence that if other parts of the control device, namely the actuating control elements, cease to function reliably or at all, because of their frequent, often rough actuation and frictional wear or damage, whilst the most important and also the most expensive part of the control device, namely the electrical or electronic circuit still functions perfectly, it is necessary to completely replace the control device. The replacement of the complete control device is not only expensive, but the expenditure of time in disassembly and re-assembly is comparatively large and the support frame involved cannot operate during the assembly work, so that often the entire face has to be brought to a standstill for the exchange of a single control device. 
     SUMMARY OF THE INVENTION 
     It is an aim of the present invention to address one or more of these disadvantages, and to produce a control device of the construction described at the beginning of the specification, which renders unnecessary the complete replacement in the event of the failure or wear of only one of its essential components. 
     Accordingly, the present invention is directed to a control device as described in the opening paragraph of the present specification in which the activating control elements and/or the circuit of the control device are grouped together and accommodated in the casing in several exchangeable modules, which when assembled in the casing are connected together by means of plug-in connecting elements and which are exchangeable within the casing independently of each other. 
     In accordance with the invention the control device has a modular construction, in which several different, optimally functioning actuating control elements are contained in separate exchangeable modules, whereby the circuit can also be formed as an exchangeable module, and each exchangeable module can be removed from the casing and exchanged for a new module, without the other modules having to be removed with it or replaced, so that the operation of the support frame or the face equipment need not be interrupted. 
     In a preferred embodiment a first exchangeable module is configured as an operating module having an operating keyboard, and a second exchangeable module is configured as an emergency cut-out module. 
     Advantageously the first exchangeable module, in addition to the operating keyboard, has an indicator unit. This allows the various operating conditions of the support frame to be controlled to be displayed. In this configuration, the frequently actuated operating keys are thus collected together into a module in the form of an operating keyboard, whilst an emergency cut-out switch is provided for the individual support frame in a separate module. This configuration makes it possible to remove the operating keyboard, and possibly the unit including the indicator unit, in the form of the operating module, from the control device and to exchange it for a new operating module with a new keyboard and indicator, whilst the emergency control formed by the emergency cut-out switch remains connected to the circuit, so that during this exchange the support frame controlled by the control device can continue to operate, so that during the exchange of the keyboard it is not necessary to shut down completely, only that no new manually inserted control commands can be received. 
     Preferably the exchangeable modules are arranged in separate module housings. Advantageously the exchangeable modules are accommodated sealed in their module housings. The exchangeable modules are thus also reliably protected from dirt and moisture when they are removed from the casing of the control device or before they are installed in it. Advantageously, the plug-in connecting elements are encapsulated in their module housings. 
     Preferably the plug-in connecting elements for the operating module and/or the emergency cut-out module comprise multi-pole connectors arranged on their rear side or the rear side of the module housing, which can be connected to plug-in or socket connectors provided in the casing or to the circuit. The arrangement can be made such that the multi-pole connectors mate with the plug-in connectors on insertion of the exchangeable module into the casing of the control device; it is, however, also possible to provide connecting cabling between the multi-pole connectors on the exchangeable modules and the corresponding plug-in connectors in the casing or to the circuit, which is long enough to allow the operating module or the emergency cut-out module or another exchangeable module to be fully removed from the device casing without interrupting the connection to the electrical or electronic circuit, so that within a few seconds a new operating or emergency cut-out module can be connected to the connecting cable and permit the input of control commands manually before the individual exchangeable module is again completely installed in the casing. 
     Advantageously, the exchangeable modules can be retained in the casing by means of screws. Preferably protective caps are provided for the socket connectors in the casing and on the circuit, which can be put onto the socket connectors when the exchangeable modules are removed, so that they cannot become dirty, which could, for instance, be the case if the operating module is removed but not immediately replaced by a new exchangeable module, but the control equipment is operated over a certain period without the possibility of the manual input of control commands. Advantageously, the protective caps are secured by means of a simple retaining band or similar in the casing, so that they cannot fall out and are always kept available for when a module is removed from the equipment casing. 
     In an advantageous embodiment of the invention, the casing comprises a casing frame, open at the front and rear, into which can be inserted from the rear a circuit module accommodating the circuit and having on its rear side the plug-in connectors for the control leads, and into which the operating module and/or the emergency cut-out module can be inserted from the front. In this configuration the circuit itself is also configured as an exchangeable module and can be removed from the rear of the casing independently of the operating module and/or the emergency cut-out module. 
     Preferably, abutment elements are provided in the casing or casing frame for the positioning of the exchangeable modules, in order to provide a correct seating for the various exchangeable modules. Advantageously, the abutment elements for the exchangeable modules exchangeable from the front side of the control device comprise abutment rails running between the sides of the casing, with threaded bores for the fastening screws. In order to facilitate an especially simple removal of an exchangeable module, advantageously, the exchangeable modules are provided with handles or similar, by which they can be easily grasped after loosening of the fastening screws. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Examples of control devices made in accordance with the present invention will now be described with reference to the accompanying drawings, in which: 
     FIG. 1 shows a front elevation of a control device; 
     FIG. 2 shows a schematic representation of a cross section of the control device according to FIG. 1; and 
     FIG. 3 shows a partially exploded cross-section of a second embodiment of the control device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A control device  10  for electro-hydraulic support frame control in underground mining has a casing  11  of stainless steel, which is arranged with two indicated, carriers  9  not shown in detail, for instance on the roof cap of a support frame. 
     The casing  11  comprises a closed casing frame  12 , closed above, below and on the casing side parts. The manually actuated control elements  13  of the control device  10  are accessible from the front side of the casing  11  shown in FIG. 1, being two switches  14 ,  15  for the emergency cut-out control of the support frame in the right-hand half, and in the region lying to the left of this a keyboard  16  with operating keys  17  to initiate the various functions of the support frame and an indicator unit  18 , which displays the various operating conditions of the support frame. 
     In FIGS. 1 and 2, several plug connectors  20  are provided on the rear side  19  of the casing  11 , to which control leads for the components of the support frame to be controlled can be connected. 
     As shown in FIG. 2, the various actuated control elements, that is on the one hand the switches  14  and  15  provided for the emergency cut-out circuit and on the other the keyboard  16  with the operating keys  17  and the indicator unit  18  are arranged in separate module housings  21 ,  22  and sealed therein. In a similar fashion the plug connectors  20 , together with the electronic circuit  24  for the control device  10  are accommodated in a third module housing  25  and are encapsulated therein by a cast block  26 . The three module housings  21 ,  22 ,  25  with the components of the control device  10  accommodated in them form exchangeable modules  27 , which can be removed from the casing frame  12  and exchanged for a new module, independently of each other. 
     The operating module  28  and the emergency cut-out module  29  are electrically connected via plug-in connecting elements  30  on the rear side of their housings  21 ,  22  to the circuit module  31 . In the embodiment shown in FIG. 2 the plug-in connecting elements  30  comprise multi-pole plugs  32  arranged on the rear side of the modules  28 ,  29 ,  31  which, when the modules  28 ,  29 ,  31  are assembled, are inserted into socket connectors provided on the front side  33  of the circuit module  31 . 
     The three exchangeable modules  27  of the control device  10  can be retained in the casing frame  12  by means of screws  35 . The circuit module  31  is inserted from behind, that is from the rear side  19  of the casing  11 , into the casing frame  12 , until its front side  33  lies against a surrounding abutment rail  34  arranged to project inwards in the casing frame  12 . In this position the circuit module  31  can be secured by means of fastening screws  35 , which are screwed through the casing side parts  36 ,  37  into the module housing  25  of the circuit module  31 . 
     The parts of the control device which wear out more rapidly than the circuit module, as a result of inappropriate and rough handling, namely the operating module  28  and the emergency cut-out module  29 , are accessible from the front side  38  of the casing  11  and can be exchanged. They are fastened by screws  35 , which are accessible from the front, and which are inserted through front side flanges  40  on the operating module  28  and the emergency cut-out module  29  and screwed into fastening rods  41 , which are welded in between the upper and lower sides of the casing frame  12  in the casing  11  along the side parts of the casing  36 ,  37  and between the two exchangeable modules  27 . 
     The various exchangeable modules  27 , especially the operating module  28  or the emergency cut-out module  29 , can be removed with very little effort from the casing  11  of the control device  10 , without the need for a complete disassembly of the control device  10 , whereas in the previously proposed devices all the connecting leads must be first removed from the plug connectors  20  and the device removed from the support frame. In the control device  10  according to the present invention, it is necessary, for instance for the exchange of the operating module  28 , only to loosen the front fastening screws  35  and to withdraw the module  28  forwards from the casing frame  12 . In order to facilitate this, the operating module  28  has two handles  42  to the right and left alongside its keyboard  16  on its front side, by which it can easily be grasped and drawn out from the casing  11 . In this way, the multi-pole plug  32  is drawn out of the connecting socket on the circuit module  31 , which is readily possible, even when the support frame controlled by the control device  10  is not set to a standstill, but continues to be operated. Following the complete removal of the operating module  28  from the casing  11 , a new module  28  can be fitted. Since the associated support frame is not necessarily directed via the keyboard  16 , but also can often be controlled by the control device of a neighbouring support frame (neighbourhood control), it is possible also to repair the operating module  28  and to install it again later. So as, in this instance, to prevent the socket connector for the operating module on the front side  33  of the circuit module  31  becoming dirty, a protective cap  43  is positioned close to the socket connector with a retaining band  44  on the front side  33  of the circuit module  31 , which is put onto the socket connector following the disassembly of the operating module  28 , and protects it safely against moisture and dirt. 
     Similarly, the emergency cut-out module  29  can also be removed from the casing  11  from the front, after the associated fastening screws  35  have been loosened. Since the large emergency cut-out switches  14 ,  15  can be readily grasped about their periphery, additional handles can be dispensed with for the emergency cut-out module  29 . 
     FIG. 3 shows a second embodiment of the control device, in which the plug connection between the operating and emergency cut-out modules  28 ,  29  on the one hand and the circuit module  31  on the other hand is not accomplished via multi-pole plugs arranged directly on the modules  28 ,  29 ,  31 , but in which between the circuit module  31  on the one hand and the operating module  28  or the emergency cut-out module  29  on the other hand, cable connectors  45  are provided, which permit the operating module  28  and the emergency cut-out module  29  to be removed from the casing  11 , without interrupting the electrical connection to the circuit module  31 . In this embodiment full functional capability of the control device  10  thus remains, with the possibility of an input of control commands via the keyboard  16  and the actuation of the emergency cut-out switch  14 ,  15  when the modules  28 ,  29  are already removed from the casing  11 , and is only interrupted for the few seconds which are required to remove the plug connection between the cable  45  and the socket connector or the multi-pole plug  32  and to connect on a new module  28 ,  29 . This also has the advantage that the full functional capability of the new replacement module  28 ,  29  can be tested before it is inserted in the casing  11  and secured there by the fastening screws  35 . 
     The invention is not limited to the embodiments shown and described herein as many modifications are possible, which do not depart from the scope of the invention. It is thus conceivable, not to arrange the keyboard  16  and the indicating unit  18  in one operating module, but to divide them between two or more modules, if this is more practical for a particular case. Also, since the circuit module  31  is subjected to practically no wear due to operation, and therefore normally works for a long period without difficulties, it is possible in a simplified modification of the control device according to the invention to configure the circuit module  31  as non-exchangeable, and to integrate the complete circuit  24  with the plug connectors  20  fixed in the casing. The fastening of the exchangeable modules  27  in the casing  11  can, instead of with the fastening screws  35 , also be effected by suitable connector retaining elements such as, for instance plug staples or similar, when contamination of the dirt-sensitive threads of the fastening screws with coal dust or similar has to be minimised to inhibit their becoming difficult to operate.