Abstract:
A device is provided for displacing gas turbines, especially during maintenance thereof. The device comprises several transporter platforms which are arranged behind each other. At least one gas turbine can be positioned on each of the transporter platforms. The or each gas turbine can be displaced by displacing the transporter platforms.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a device for displacing gas turbines, i.e., aircraft engines or stationary gas turbines, or modules of a gas turbine, in particular during maintenance of same, and the corresponding method. 
   BACKGROUND 
   The maintenance and servicing, in particular repair, of gas turbines, in particular of aircraft engines, have a decisive role in determining the direct operating costs of an airplane. Thus, approximately 30% of the direct operating costs of an airplane is attributable to the aircraft engines, approximately one-third of the operating costs relating to the engines being due to the maintenance of the aircraft engines. The maintenance costs of aircraft engines are therefore responsible for approximately 10% of the total direct operating costs of an airplane. The direct consequence of this is that efficient and cost-effective maintenance and servicing/repair of aircraft engines is of decisive importance for airlines. Similar reasoning also applies to stationary gas turbines. 
   To date, maintenance and servicing of gas turbines, in particular of aircraft engines, have been performed according to the workshop principle. According to the workshop principle, at least portions of the gas turbine or aircraft engine remain in one position, i.e., in one location. Necessary work materials, tools, and personnel are brought to the gas turbine in a timely manner, so that disturbances are kept to a minimum, and a promised maintenance time is able to be observed. 
   However, the maintenance or servicing of gas turbines, in particular of aircraft engines, according to the workshop principle has the disadvantage that maintenance does not follow a defined process structure. Instead, work on gas turbines, i.e., on the aircraft engine, is performed in almost any desired sequence, which results in disturbances and delays during servicing, in particular when a plurality of gas turbines is serviced simultaneously. Therefore, maintenance of gas turbines according to the workshop principle has the disadvantage that not only is there no clear process structure, but also long times are needed for servicing and maintenance. This has a negative effect on maintenance efficiency. 
   Efficient displacement is also desirable in the manufacture of new gas turbines. 
   SUMMARY OF THE INVENTION 
   On this basis, an object of the present invention is to provide a novel device and a novel method for displacing gas turbines, in particular aircraft engines. 
   The present invention provides a device for displacing gas turbines, in particular during maintenance thereof. The device according to the present invention has a plurality of consecutive conveying platforms, at least one gas turbine being positionable on each conveying platform, and the or each gas turbine being displaceable by displacing the conveying platforms. 
   The device according to the present invention for displacing gas turbines, in particular during maintenance thereof, allows maintenance or servicing of gas turbines to be performed according to an assembly line principle. It is a basic finding of the present invention that the assembly line principle is also suitable for maintenance work or servicing work on gas turbines. The device according to the present invention makes high efficiency and short maintenance times possible when servicing gas turbines. The device according to the present invention may also be used in the manufacture of new aircraft engines. 
   According to an advantageous refinement of the present invention, the device according to the present invention has a first drive device to move the conveying platforms preferably together with the gas turbines positioned on the conveying platforms, and a second drive device to move the conveying platforms in a direction opposite to a main conveying direction of the gas turbines. This design of the device according to the present invention is particularly simple and permits reliable conveyance of the aircraft engines. 
   The device according to the present invention is preferably embedded into a floor of a workshop in such a way that the plane in which the conveying platforms lie in a resting condition lies in the plane of the floor so that the conveying platforms are accessible without impediment. This is particularly advantageous from a safety standpoint. 
   According to an advantageous embodiment of the present invention, each conveying platform has a mounting area for an adapter, the adapter being mountable in the mounting area and being adaptable to different types of gas turbines. This ensures that different types of gas turbines are movable through the consecutive work stations. 
   The method according to the present invention comprises positioning a gas turbine or gas turbine module on one or more of a plurality of conveying platforms, and moving the conveying platforms in a main direction of conveyance through a plurality of consecutive work stations in such a way that each gas turbine or gas turbine module is moved by the movement of the conveying platforms. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An exemplary embodiment of the present invention is described with reference to the drawing without being restricted thereto. In the drawing, 
       FIG. 1  shows a schematic side view of a device according to the present invention for displacing aircraft engines or aircraft engine modules during maintenance thereof, having three aircraft engines positioned on the device, in a first state; 
       FIG. 2  shows the device of  FIG. 1  in a second state; 
       FIG. 3  shows the device of  FIGS. 1 ,  2  in a third state; 
       FIG. 4  shows the device of  FIGS. 1 through 3  in a fourth state; 
       FIG. 5  shows the device of  FIGS. 1 through 4  in a fifth state; 
       FIG. 6  shows a schematic side view of an enlarged detail of the device of  FIGS. 1 through 5 ; 
       FIG. 7  shows a schematic side view of another enlarged detail of the device of  FIGS. 1 through 5 ; 
       FIG. 8  shows a schematic side view of another enlarged detail of the device of  FIGS. 1 through 5 ; 
       FIG. 9  shows the detail of  FIG. 8  in a second state; 
       FIG. 10  shows a schematic side view of another detail of the device of  FIGS. 1 through 5 ; 
       FIG. 11  shows a schematic side view of another detail of the device of  FIGS. 1 through 5 ; 
       FIG. 12  shows a schematic side view of a lifting device of the device according to the present invention according to  FIGS. 1 through 5  from below; 
       FIG. 13  shows a cross section of the device according to the present invention; 
       FIG. 14  shows the detail of the cross section according to  FIG. 13 ; 
       FIG. 15  shows another detail of the cross section according to  FIG. 13 ; 
       FIG. 16  shows a highly simplified perspective view of a detail of the device according to the present invention, and 
       FIG. 17  shows different types of aircraft engines positionable on the device according to the present invention. 
   

   DETAILED DESCRIPTION 
   The device according to the present invention and the method according to the present invention for displacing gas turbines is described in greater detail below with reference to  FIGS. 1 through 17 , using the example of aircraft engines. The device of the present invention is used for conveying, i.e., transporting, aircraft engines or aircraft engine modules for their maintenance or servicing. 
   It should be pointed out again that the device and method according to the present invention may also be used in the manufacture of new gas turbines, in particular of aircraft engines. 
   Servicing or maintenance includes the disassembly of the aircraft engine into modules and/or subassemblies and/or individual parts, inspection, and, if necessary, repair of the modules and/or subassemblies and/or individual parts and subsequent assembly of an aircraft engine from inspected and/or repaired and/or new modules and/or subassemblies and/or individual parts. The device according to the present invention is particularly well suited for displacing aircraft engines during disassembly of aircraft engines into modules, as well as for assembling an aircraft engine from modules. The device according to the present invention may, however, also be used in disassembling and assembling modules or subassemblies of the aircraft engine. It is also conceivable to use such a device in the actual repair. 
   The principle of the device according to the present invention and the method according to the present invention for displacing aircraft engines during their maintenance will first be described below with reference to  FIGS. 1 through 5 . 
     FIGS. 1 through 5  show a device  20  according to the present invention which has a total of four consecutive conveying platforms  21 ,  22 ,  23 , and  24 . An arrow  25  indicates a main direction of conveyance of device  20  according to the present invention. In  FIG. 1  conveying platform  21  situated in front in the direction of conveyance is free, i.e., unoccupied. An aircraft engine  26 ,  27 , and  28  is positioned on each of conveying platforms  22 ,  23 , and  24  positioned behind conveying platform  21  situated in front. Aircraft engines  26 ,  27 , and  28  are moved with the help of device  20  according to the present invention through consecutive work stations, device  20  according to the present invention being positioned in the area of a disassembly line in the exemplary embodiment of  FIG. 1 , which results in aircraft engines  26 ,  27 , and  28  being disassembled into modules as they are moved through the consecutive work stations according to  FIG. 1 . If, as shown in  FIG. 1 , four conveying platforms  21 ,  22 ,  23 , and  24  are provided, four work stations are also available. It is obvious that the number of conveying platforms and work stations may be varied. 
     FIG. 1  shows the resting position of device  20  according to the present invention in which the device stands still. In this state all conveying platforms  21  through  24  lie in one plane. If aircraft engines  26 ,  27 , and  28  are to be moved in the main direction of conveyance, conveying platform  21 , situated in front in the main direction of conveyance, is cleared. This means that in the case where device  20  according to the present invention is situated in a disassembly line of the aircraft engine, the disassembly of an aircraft engine into individual modules is completed in the area of the front work station at which front conveying platform  21  is situated. After front conveying platform  21  in the direction of conveyance is cleared, it is lowered as indicated by arrow  29 . 
   Lowered conveying platform  21  is thus movable below the plane formed by conveying platforms  21 ,  22 ,  23 , and  24  in the resting state, against the main direction of conveyance as indicated by arrow  30  (see  FIG. 2 ). A front section of the front work station is cleared by lowering and moving backward conveying platform  21  originally lying in the front in the main direction of conveyance. 
   Conveying platforms  22 ,  23 , and  24 , situated behind lowered conveying platform  21 , which is moved against the main direction of conveyance, are thus movable in the main direction of conveyance. This is apparent in particular from  FIG. 3 . Thereby each conveying platform  22 ,  23 , and  24  is moved forward in the main direction of conveyance by one work station. Conveying platform  22  thus fills the section cleared by conveying platform  21  originally in the front. The work station in the rear in the main direction of conveyance is cleared as a result of each of consecutive conveying platforms  22 ,  23 , and  24  being moved forward by one work station, i.e., conveying platform  24  originally in the rear in the main direction of conveyance clears a section within a work station, also in the rear. During the movement of conveying platforms  22 ,  23 , and  24  in the main direction of conveyance, lowered conveying platform  21 , previously moved against the main direction of conveyance remains in its position. 
   By further moving lowered conveying platform  21  against the main direction of conveyance according to arrow  31  and subsequently raising it according to arrow  32 , lowered conveying platform  21 , originally in front, is movable into the section within the rear work station, cleared by conveying platform  24 , originally in the rear. This section is then occupied by platform  21 . This is apparent in particular from  FIGS. 4 and 5 . An aircraft engine is then positionable on conveying platform  21  at the work station in the rear in the main direction of conveyance. The disassembly of the aircraft engine into modules is then begun at the work station in the rear in the main direction of conveyance. 
   Aircraft engines are thus movable via the device according to the present invention through a plurality of consecutive work stations, the work stations being usable for stepwise disassembly, repair, or also assembly of the aircraft engines. Conveying device  20  makes discontinuous movement of the aircraft engines in the main direction of conveyance possible, i.e., the aircraft engines are moved at a predefined pace through the work stations. The cycle in which the aircraft engines are moved through the work stations, i.e., in which the conveying platforms are moved, is preferably sixteen hours or twelve hours. The device stands still between two cycles, i.e., remains in a resting state (see  FIG. 1 ). Work may be performed on the aircraft engines at the particular work stations within those sixteen or twelve hours. The time needed for displacing the aircraft engines, i.e., conveying platforms, is short compared to the cycle time. Thus a displacement cycle as shown in  FIGS. 1 through 5  takes approximately twenty minutes. 
   Device  20  according to the present invention is preferably embedded into a floor  33  of a workshop in such a way that the plane in which conveying platforms  21 ,  22 ,  23 , and  24  lie in a resting condition lies in the plane of floor  33 . This is apparent in particular from  FIGS. 6 ,  7 , and  13  through  15 . This ensures free access to conveying platforms  21 ,  22 ,  23 , and  24  in the resting state. Workers who must step onto conveying platforms  21  through  24  for performing disassembly, repair, or assembly work may step from floor  33  of the workshop onto conveying platforms  21  through  24  without impediment. This increases occupational safety. 
   Device  20  according to the present invention has a first drive device for moving conveying platforms  21  through  24 , preferably together with aircraft engines  26 ,  27 , and  28  positioned on conveying platforms  21  through  24 , in the main direction of conveyance. The first drive device for moving conveying platforms  21  through  24  includes a plurality of friction wheels  34 . Such a friction wheel  34  is illustrated in  FIG. 11 . Friction wheel  34  is driven by an associated motor  35  and transmits the drive power of motor  35  to conveying platforms  21 ,  22 ,  23 , and  24 . At least one friction wheel  34  of this type is situated in the area of each work station. This ensures that, as conveying platforms  21  through  24  move in the main direction of conveyance, at least one active friction wheel  34  is available to each conveying platform  21  through  24 . Preferably at least one of the friction wheels is provided on each side of conveying platforms  21  through  24 . 
   To enable simple movement of conveying platforms  21  through  24  in the main direction of conveyance, multiple running wheels  36  are assigned to conveying platforms  21  through  24 , in particular along their longitudinal sides. These running wheels are shown, for example, in  FIGS. 6 ,  7 ;  10 ,  11 . As apparent in particular from  FIGS. 10 and 11 , running wheels  36  run on guide rails  37  or guide bars, which extend in particular on both sides of conveying platforms  21  through  24 . This enables reliable guidance of conveying platforms  21  through  24  and also allows conveying platforms  21  through  24  to move in the main direction of conveyance with low resistance. 
   To move a lowered conveying platform  21  against the main direction of conveyance, device  20  according to the present invention has a second drive device. The second drive device is designed as a chain conveyor  38 . Chain conveyor  38  is illustrated in  FIGS. 6 through 9  in particular. 
   Chain conveyor  38  extends over the entire area of the work stations situated between the work station in the front in the main direction of conveyance and the work station in the rear in the main direction of conveyance. Chain conveyor  38  extends at least in some sections in the area of the work station in the front in the main direction of conveyance and the work station in the rear in the main direction of conveyance. This is apparent in particular in  FIGS. 6 and 7 . Chain conveyor  38  includes a conveyor chain  40  rotating according to arrow  39 . Deflecting rollers  41  for conveyor chain  40  are situated in the area of the work station in the front in the main direction of conveyance and the work station in the rear in the main direction of conveyance. Therefore, a lowered conveying platform  21  is movable by chain conveyor  38  against the main direction of conveyance below other conveying platforms  22  through  24 . 
   It should be pointed out here that the first drive device for moving conveying platforms  21  through  24  in the main direction of conveyance should not exceed an speed value of approximately 2 m/min. For the second conveying device for moving lowered conveying platforms against the main direction of conveyance, speed values of up to 4 m/min are possible Therefore, the second conveying device permits faster displacement of the conveying platforms than the first conveying device. 
   As apparent from  FIGS. 8 and 9  in particular, one of friction wheels  34  is also positioned in the area of deflecting roller  41 . Thus,  FIG. 8  shows how a conveying platform  21  to be moved, located in the area of the work station in the rear in the main direction of conveyance, is just engaged by respective friction wheel  34 .  FIG. 9  shows the same system as  FIG. 8 , but with a conveying platform  21  moved against the main direction of conveyance into the work station in the rear in the main direction of conveyance. Friction wheels  34  are therefore positioned at an end in the front in the main direction of conveyance of the particular work stations; thus, conveying platforms  21  through  24  are in contact with friction wheels  34  over the entire distance to be traveled. 
   To raise or lower conveying platforms, which are to be transported against the main direction of conveyance, device  20  according to the present invention has lifting devices. A first lifting device  42  is positioned in the area of the work station in the front in the main direction of conveyance. A second lifting device  43  is positioned in the area of the work station in the rear in the main direction of conveyance. First lifting device  42  is best illustrated in  FIG. 6 . Second lifting device  43  is shown in  FIG. 7  in two different positions, namely in a first lowered position and in a second raised position. Lifting devices  42 ,  43  are lowered and raised with the aid of lift cylinders  44  associated with lifting devices  42 ,  43 . Lift cylinders  44  are preferably designed as hydraulic cylinders. 
   Lifting device  42  in the front in the main direction of conveyance is shown in  FIG. 12  in a view from below. Next to floor  33  (see  FIG. 6 ), a first end  45  of lifting device  42  has pivot bearings  46 . First end  45  of lifting device  42  is pivotably attached to floor  33  via pivot bearings  46  and is pivotable about pivot bearing  46  upon operation of lift cylinder  44 . End  47 , opposite end  45  of lifting device  42 , has recesses  48 . Chain conveyor  38  extends into recesses  48 . This ensures that a lowered conveying platform  21  is immediately engaged by chain conveyor  38 . To prevent uncontrolled movement of a lowered conveying platform due to the force of gravity, a braking device  49  for a conveying platform is assigned to a mid-section of lifting device  42 . 
   It is furthermore within the scope of the present invention that gaps between conveying platforms  21 ,  22 ,  23 ,  24 , and floor  33  of the workshop are minimized. This is apparent in particular from  FIG. 15 . This ensures that, when workers step on conveying platforms  21  through  24  for performing work steps on the aircraft engines, neither tools nor disassembled parts of the aircraft engine may fall through gaps into an area below conveying platforms  21  through  24 . According to  FIG. 15 , a cover  50  situated in the plane of floor  33  or the plane of conveying platforms  21  through  24  is provided for this purpose between the actual conveying platform  21  through  24  and floor  33 . Cover  50  covers a gap  51  between work platforms  21  through  24  and floor  33 . Therefore, falling tools or parts of an aircraft engine are caught by cover  50  and are not able to drop into gap  51 . 
   According to a further aspect of the present invention, a surface of conveying platforms  21  through  24  is provided with an anti-slip coating. In disassembling or performing other work on aircraft engines, lubricants and other liquids, such as oil and kerosene, may come out of the aircraft engine. The anti-slip coating of the surface of conveying platforms  21  through  24  ensures that even if oil or kerosene comes out of the aircraft engine, workers have secure footing on the conveying platform. Conveying platforms  21  through  24  are preferably twelve meters long and four meters wide. 
     FIG. 16  shows a perspective view of a conveying platform  21  through  24  having an aircraft engine  26  through  28  positioned on the conveying platform. The aircraft engine is held on the conveying platform by an adapter  52 . Adapter  52  is mounted in a mount area  53  of the conveying platform. Adapter  52  has a total of four props  54 . Two of these props  54  are situated on either side of the aircraft engine. The position and spacing of props  54  in mount area  53  is individually adaptable to the particular type of aircraft engine. This makes it possible to mount different types of aircraft engines on conveying platforms  21  through  24 . Props  54  are assigned to a front area of the engine. A rear area of the engine is supported by two conventional props  55 . 
     FIG. 17  illustrates that different engine types may be positioned on conveying platforms  21  through  24 . Thus,  FIG. 17  shows four conveying platforms, a different aircraft engine TWK 1 , TWK 2 , TWK 3  or TWK 4  being situated on each of these conveying platforms. The aircraft engine types are standard engines and are known to those skilled in the art.  FIG. 17  shows the different dimensions of the different aircraft engine types and their different applications of force to conveying platforms  21  through  24 . Furthermore,  FIG. 17  also shows that both front props  54  and rear props  55  may be situated in different positions on conveying platforms  21  through  24 . 
   The device according to the present invention allows reliable and safe movement of aircraft engines to be serviced through consecutive work stations. The device according to the present invention renders possible servicing or maintenance of aircraft engines according to the assembly line principle. The method according to the present invention may be carried out with the aid of the device according to the present invention. The device according to the present invention has a simple design. It is implementable in a cost-effective manner.