Abstract:
A mobile cleaning plant for cleaning shopping trolleys and similar transport systems includes a container configured to receive the shopping trolleys in hoxizontally stacked rows. The shopping trolleys are fed into an inlet on the container via a device, automatically pushed through the container on a conveyor system, and exit the container through an outlet positioned near the inlet. The conveyor system includes two tracks which run along the longitudinal axis of the container and are connected to each other via a third track which runs perpendicular to the longitudinal axis of the container. As the inlet and outlet are positioned in proximity to one another, or are the same orifice, the mobile cleaning plant does not require decoupling from a hauling device, such as a truck, prior to operation.

Description:
BACKGROUND AND FIELD OF THE INVENTION 
   The present invention relates in general to the field of the process technology of cleaning plants, and in particular to mobile cleaning systems for shopping trolleys consisting of a plurality of cleaning stations, a new circulatory type of arrangement of the individual stations being used in order to obtain processing advantages and therefore increased economic efficiency of the entire cleaning system. 
   The term “shopping trolleys” as used below refers to transport containers which today are principally used in large shops, grocery stores and supermarkets in order to facilitate for customers the transportation of goods selected in the store to the cash till and optionally the transportation of the goods purchased at the till to a transport vehicle parked in front of the store. Because of their frequent use and as a result of residues of products left behind as refuse in the trolleys, said trolleys become soiled within a short time so that it is necessary for hygienic and health reasons to subject used shopping trolleys to thorough cleaning at regular intervals in order to meet food hygiene regulations. 
   The invention relates equally to the cleaning of comparable transport devices such as boxes, crates and other containers. 
   Whereas earlier shopping trolleys had to be scrubbed and washed manually using chemical cleaning agents, fully automatic cleaning plants, which carry out the cleaning process considerably more efficiently and therefore represent a major facilitation, are increasingly used today. In addition, when using fully automatic cleaning plants, a large proportion of the cleaning personnel employed at the store can be saved. 
   Because the shopping trolleys of different stores which are to be cleaned are located at different sites and must be cleaned on site, it is necessary that the automatic cleaning plant can be transported to the place of use. 
   Conventional mobile cleaning and washing plants for shopping trolleys of all kinds generally comprise at least one cleaning station, a water treatment plant having pumps, valves, filters, pipework, containers and/or measuring instruments, a control unit, a housing in which the components listed are installed and a transport device on which the housing is mounted. 
   According to the prior art, various solutions to the problem of the automatic cleaning of trolleys are available, each of these solutions being optimised for a particular application. Certain limitations are therefore associated with each of these solutions. To explain in general terms some of the most important of these solutions, it is necessary to refer briefly to their most important aspects. 
   The invention proposed in German Patent DE 198 57 915 A1 relates to a mobile cleaning and washing plant for shopping trolleys of all kinds in which a washing box together with a cleaning fluid or water treatment plant and connecting pipes is mounted on a base frame which in turn is attached to a transport device. To clean the shopping trolleys, the mobile cleaning and washing plant, when at the desired place of use, is either placed on the supports of the base frame in front of the transport device, or remains on the transport device during the cleaning operation. 
   In the German Utility Model Application DE 298 12 683 U1, a mobile washing container is disclosed which can be used in particular for cleaning shopping trolleys, mesh boxes and merchandise baskets. This mobile washing container is a standard Eurocontainer. After the residual waste has been conveyed into a collecting tray by means of a suction fan, the transport containers to be cleaned are moved through a washing installation which includes high-pressure jets, movable and adjustable washing brushes, disinfectant jets, a drying-air duct and an oil spray device for spraying the wheels and wheel pivots of the transport containers to be cleaned. Spraying of the transport containers to be cleaned with a disinfectant by means of disinfectant jets specially provided for this purpose ensures additional hygiene. A recirculated water cleaning arrangement which carries out a water treatment process is also integrated in the mobile washing container. Because it has an independent power supply, this washing container can be used everywhere without being dependent on external power supply arrangements. 
   German Utility Model Application DE 299 01 282 U1 relates to a washing system for shopping trolleys which is equipped with its own power supply unit. This can be preferably a diesel unit which generates electric current in order to operate the electrical, pneumatic and hydraulic components contained in the washing system disclosed. The washing system also includes a purification component which purifies the used cleaning fluid so that said fluid needs to be changed less frequently. In addition, a blast air drying system is integrated to dry the shopping trolleys after washing. The washing system also includes components which lubricate the wheels and wheel axles. 
   German Patent Application DE 38 28 035 C2 discloses a machine which can be placed directly on the ground for cleaning serving trolleys, aircraft catering trolleys, kitchen trolleys or suchlike transport vehicles for groceries in which the vehicles are fed to the cleaning machine manually via a ramp, then automatically opened, pre-washed and washed, rinsed, dried and removed again manually via a ramp. The cleaning machine comprises successively arranged stations for pre-washing, washing, rinsing and drying the trolleys to be cleaned. Inside the cleaning machine the trolleys are moved through the machine at least between the zones responsible for the washing and drying processes by conveyor means installed in the floor of the cleaning machine. The underlying solution of this patent application is also distinguished by the fact that one or more collecting tanks for receiving cleaning fluid via a suction nozzle and an additional pump are connected to an intermediate tank which in turn is connected via a pressure pump for feeding and/or circulating the cleaning fluid to spraying nozzles which are mounted in both the washing and the rinsing zones. 
   A mobile cleaning plant for shopping trolleys is disclosed in U.S. Pat. No. 4,807,319. In this system, the shopping trolleys are pushed into the cleaning plant on a long side of the container, transported through the washing installation inside the container by means of a conveyor belt parallel to the longitudinal axis of the container and finally are removed from the container in the cleaned state on the opposite side. 
   Known from DE 199 36 906 is a cleaning plant for “small containers” in which the objects to be cleaned are conveyed along substantially vertical paths during their passage through the washing installation. 
   OBJECT OF THE INVENTION 
   It is an object of the present invention to provide a mobile cleaning plant for transport containers, in particular for shopping trolleys, which mobile cleaning plant can be economically and easily manufactured and permits feeding of the goods to be cleaned to and/or from the installation plant in a favourable manner with regard to process technology. 
   This object is achieved by the features of the independent claims. Advantageous embodiments are defined in the dependent claims. 
   SUMMARISING DESCRIPTION OF THE INVENTION 
   The basic invention discloses a mobile cleaning and washing plant for transport containers which can be economically and easily manufactured and which achieves the object defined in the previous paragraph. 
   Using this mobile cleaning plant, in particular shopping trolleys, which are fed in horizontally stacked rows to the mobile cleaning plant and removed therefrom after cleaning, can be efficiently and quickly cleaned. It is provided that the shopping trolleys to be cleaned, which are fed to the mobile cleaning plant in horizontally stacked rows, are automatically separated, and that the cleaned shopping trolleys, which are removed from the mobile cleaning plant again in rows, can be automatically stacked. The mobile cleaning plant is therefore suited to cleaning approx. 2000 shopping trolleys per day in a completely independent operation. 
   Because the washing installation of the mobile cleaning plant according to the invention has a U-shaped configuration, the intake and outlet of the washing installation are located at the same end of the mobile cleaning plant. The resulting advantage for processing is that the cleaned shopping trolleys can be removed from the mobile cleaning plant at the same point at which the soiled trolleys are fed to the plant. The cleaned and stacked trolleys can, therefore, be collected from the same point at which the soiled trolleys were delivered in a stacked formation for cleaning, so that time-consuming manual pushing of the cleaned trolleys back to the agreed collection point is eliminated. 
   The configuration of the washing installation is not restricted to the above-mentioned U-shape. Other horizontal transport paths in the washing installation are possible. For example, the washing installation can be so arranged that a trolley can be inserted into the container at one end and conveyed in the container initially parallel to the longitudinal axis of said container; they can then follow a travel section in a direction substantially transverse to the longitudinal axis of the container and finally leave the container on the side opposite to the intake side again on a path parallel to the longitudinal axis. 
   It is also possible for a washing installation to have more than one travel section disposed transversely to the longitudinal axis of the container. This can be provided, for example, in the form of a kind of serpentine path through of the washing installation. 
   Once the mobile cleaning plant for shopping trolleys of all kinds is ready for operation, the trolleys, which have previously been automatically separated, are transported into the plant by means of a chain or belt conveyor, air-blasted according to a preset program sequence, cleaned or washed, rinsed, dried and subjected to concluding special treatments (spraying with disinfectant and/or lubricants). The cleaned trolleys are then removed from the cleaning plant by means of the chain or belt conveyor and automatically stacked one behind the other. These processes are repeated until the desired number of trolleys has been cleaned, until the mobile cleaning plant requires maintenance or until the available supply of clean water, cleaning agent, disinfectants and/or lubricants, heating oil, compressed air, etc., has been exhausted and must therefore be replenished. 
   With regard to the supply of the trolleys to the washing plant and their removal therefrom the invention—depending on the embodiment—can have the features described below. 
   To receive a row of horizontally stacked shopping trolleys, a conveyor ramp is provided. A spring-loaded stop is located on the floor of the conveyor ramp. Guidance arrangements for the row of trolleys can also the mounted on the conveyor ramp. The stacked trolleys are now pushed manually on to the conveyor ramp and up to the stop. 
   To fasten the trolleys and transport them onwards, an automatic conveyor shackle device is provided which comprises a shackle, a cable and a linear guidance unit. The conveyor shackle for fixing and transporting the trolleys is first closed. The shackle can engage, for example, directly on the last trolley of the row. The conveyor shackle is driven by means of the cable and the linear guidance unit serves to guide the movement sequence. 
   The conveyor ramp is then raised at the conveyor end—for example by means of a cable winch—to the level of the washing plant. A guidance arrangement is provided for this raising of the conveyor ramp. The ramp can preferably be provided with rollers at its opposite end to permit compensatory movement of the ramp along the ground. 
   As soon as the raised end of the conveyor ramp has reached the level of the floor of the washing plant the winch is automatically stopped by means of a limit switch. 
   The fastening of the stop is then released and by means of the above-described conveyor shackle arrangement the row of trolleys is moved forwards by one trolley—i.e. by one “stacking length”. This can also be carried out automatically. 
   Once the first trolley in the row has been moved past the stop, the stop automatically moves back upright and is again fastened. The first trolley has now been detached from the row and is pulled into the first washing station of the washing plant by means of a long-chain conveyor system. The long-chain conveyor system is, for example, guided by rails and driven by means of toothed belts. 
   On completion of the washing process, the trolley is initially located in the last washing station. From there, it is automatically moved out by means of a chain system on to the conveyor ramp which is still at the level of the floor of the washing installation. 
   By means of a second conveyor shackle arrangement which, like the first-mentioned arrangement, comprises a conveyor shackle, a cable and a linear guidance unit, the trolley is captured on the conveyor ramp. 
   As soon as the trolley is standing fully on the conveyor ramp, it is automatically moved forwards by one “stacking length” by means of the second conveyor shackle arrangement. This makes room for the following trolley which leaves the last washing station on completion of the washing process. 
   As soon as all the trolleys of the row are located on the conveyor ramp, said ramp is lowered to the ground by means of the above-described winch. A guide is provided for lowering the conveyor ramp. The part of the ramp located on the ground is moved by means of the above-described rollers. Finally, the conveyor shackle is opened and the row of trolleys is pushed manually from the conveyor ramp. 
   It should be emphasised at this point that the invention is preferably configured in such a way that the above-described sequence—unless explicitly described otherwise—takes place automatically. 
   As already mentioned, the trolleys can be transported to the mobile cleaning plant stacked one behind the other. They are then automatically separated by a device according to the invention before they are fed to the mobile cleaning plant. The trolleys are removed from said cleaning plant on the same side to which they were fed and are automatically stacked one behind the other. Decisive advantages of this system, among others, are that the mobile cleaning plant can be operated by only one person and that the plant has a far smaller space requirement in comparison to conventional cleaning plants in which shopping trolleys are guided monodirectionally through a rectilinear washing installation. The mobile cleaning plant according to the invention does not need to be uncoupled from the tractor vehicle with which the plant is transported to enable the actions comprising the cleaning process to be carried out. The uncoupling and separation of the shopping trolleys supplied to the mobile cleaning plant in stacked rows, their transportation through the plant and the bringing together of the trolleys after passing through the mobile cleaning plant can be adapted to different sizes and types of shopping trolleys. 
   Before the wet cleaning process itself, the trolleys are blasted by means of a compressed air jet as part of the dry cleaning process so that light solids can be removed and do not impede the subsequent wet cleaning. 
   To protect the mobile cleaning plant from the effects of frost, heating arrangements and an automatic temperature monitoring and control system are provided so that breakdown-free operation of the plant even at outside temperatures below freezing point is possible. 
   The mobile cleaning plant for shopping trolleys according to the invention can be composed, for example, of a total of six stations, in which the following cleaning processes take place successively for each shopping trolley fed to the plant:
         Station #1a: Blowing out of light solids and small dirt particles (suggested duration: e.g. 5 seconds per trolley);   Station #1b: Application and effect of chemical cleaning agents (suggested duration: e.g. 25 seconds per trolley);   Station #2: Washing of the trolleys with pressurised water jets from rotating high-pressure nozzles acting on the trolleys from five directions (from the front, the rear, the right, the left and above), whereby it is ensured that complete surface cleaning of the trolleys can be achieved (suggested duration: e.g. 30 seconds per trolley);   Station #3: Cleaning of the trolleys with rotary brushes, automatic watering of the brushes with used water being carried out (suggested duration: e.g. 30 seconds per trolley);   Station #4: Fine rinsing of the trolleys with clean water (suggested duration: e.g. 30 seconds per trolley);   Station #5: Drying of the trolleys by supplying hot air (suggested duration: e.g. 30 seconds per trolley);   Station #6: Final drying of the trolleys by supplying hot air (suggested duration: e.g. 30 seconds per trolley), followed by spraying with chemical disinfectants to kill morbific agents and/or application of lubricants to the wheel axles of the trolleys to reduce frictional resistance between wheels and axles (suggested duration: e.g. 30 seconds per trolley).       

   To reduce the consumption of clean water during rinsing of the trolleys in station #4, an atomising device which produces a mixture of air and clean water can optionally be used. Furthermore, cleaning and re-use of used water for cleaning the trolleys is provided in the solution according to the invention. For this purpose, the soiled cleaning fluid and the used water are purified in a water treatment plant by means of filters and admixture of chemical and/or biological additives and fed back into the cleaning circuit. 
   As can be readily understood by an average person skilled in the art, the basic invention is not restricted to the above-described embodiments. In addition to the features disclosed, numerous modifications and variations are possible without deviating materially from the field of. application of the present invention, as disclosed in the claims. 
   The method according to the invention can be advantageously extended, for example, to the cleaning of vehicles, storage and/or transport containers for merchandise, goods and objects of all kind such as shopping baskets, serving trolleys, beverage boxes, crates, barrels, boilers, tanks, refuse bins and/or containers of all kinds. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further advantages and utilities of the basic invention result from the subsidiary dependent claims and from the following description of a preferred embodiment of the invention which is illustrated in the following drawings, in which: 
       FIG. 1  shows a longitudinal cross-section E-F through the shopping trolley feed system  120 , the trolley removal system  122 , the container interior  402  and the mobile cleaning plant  101  located therein (view from above); 
       FIG. 2  shows a longitudinal cross-section G-H through the trolley feed system  120  and the container interior  402 , the hinged ramps  120  and  122  being in the non-raised state (side view from right); 
       FIG. 3  shows a longitudinal cross-section C-D through the trolley feed system  120 , the container interior  402  and the mobile cleaning plant  101  located therein, the hinged ramps  120  and  122  being in the raised state (side view from right), and 
       FIG. 4  shows a longitudinal cross-section A-B through the trolley removal system  122 , the container interior  402  and the mobile cleaning plant  101  located therein, the hinged ramps  120  and  122  being in the raised state (side view from right). 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The functions of the assemblies contained in a first embodiment of the present invention, as illustrated in  FIGS. 1 to 4 , are described in more detail below. 
   Cleaning Stations 
   In the individual cleaning stations  102 ,  104 ,  106 ,  108 ,  110 ,  112  and/or  114  in the preferred embodiment of the basic invention, the following cleaning processes are carried out: 
   Using an air blasting device in station  102 , solid residues, scraps of refuse and/or dirt particles are blown out. The cleaning process in stations  106  and  108  can be reinforced and accelerated by the supply of chemical cleaning agents in combination with high-pressure water and/or rotating, watered brushes. According to the preferred embodiment of the basic invention at least one rinsing process using low-pressure water is carried out in station  110  for the cleaned trolleys in order to remove residues of any chemical cleaning agents supplied. Drying processes using a hot air supply are then carried out for the cleaned trolleys in each of stations  112  and  114 , to accelerate the drying of the cleaned trolleys. On completion of the drying process, spraying of chemical disinfectants on the cleaned and dried trolleys can optionally be carried out in order to kill morbific agents. On completion of the last drying process according to the invention, an application of lubricants for the wheel axles of the trolleys can be provided to reduce the frictional resistance between the wheels and axles of the trolleys and thus to increase the service life of the wheels and axles and to keep the noise level caused by movement of the trolleys low. 
   To reliably avoid detrimental interaction between the individual cleaning, drying, disinfecting and maintenance operations carried out in the separate stations  102 ,  104 ,  106 ,  108 ,  110 ,  112  and/or  114 , and undesired mixing of used and clean water and of the chemical cleaning agents and/or disinfectants used, isolating partitions  116  can be inserted between the separate stations  102 ,  104 ,  106 ,  108 ,  110 ,  112  and/or  114  of the mobile cleaning system  101 . In this way, detrimental interaction between the cleaning, drying, disinfecting and maintenance operations carried out in the different stations, and undesired mixing of used water and clean water and of the chemical cleaning agents and/or disinfectants used can be avoided. The partitions  116  are height-adjustable and can be folded aside or rolled up. 
   The mobile cleaning plant  101  according to the invention also includes an integrated collecting trough  202  for all the stations  102 ,  104 ,  106 ,  108 ,  110 ,  112  and/or  114  in which the used water which has been diverted away is collected and directed into a used-water tank  320 . Integrated in this collecting trough  202  is a coarse sieve  118  and a monitoring unit which ensures that the air-blasted coarse dirt particles do not enter the used-water tank  320  or block the feed pipes. Arranged after said coarse sieve  118  is a filter unit with exchangeable filter elements to remove fine dirt particles from the used water before the latter reaches the used-water tank  320  to be reused for further cleaning processes. 
   Feeding, Conveying and Removing the Trolleys 
   For the ingress  402   b  and egress  402   c  of the trolleys, electrically, hydraulically and/or pneumatically driven feed and removal devices can be used, for example, hinged ramps  120  and/or  122 , lifting platforms, rising cylinders  304 , conveyor belts  204  and/or winches  302 . 
   The temporal coordination and control of the feed and removal of the trolleys and of the work sequences in the individual stations  102 ,  104 ,  106 ,  108 ,  110 ,  112  and/or  114  of the mobile cleaning system  101  are carried out according to the preferred embodiment of the basic invention by a central control system which additionally controls the marginal conditions required for cleaning the shopping trolleys. 
   These marginal conditions can be, for example, the quantity of clean water, lubricants and/or chemical cleaning agents and disinfectants supplied, the quantity of used water removed, and physical parameters such as the temperature and/or pressure of clean water, used water, lubricants and/or chemical cleaning agents and disinfectants and the timing of the supply and removal of these fluids. 
   As can be seen in particular in  FIG. 1 , it is provided according to the present invention that the intake  402   b  for admitting the shopping trolleys to be cleaned and the outlet  402   c  for the cleaned trolleys are arranged on the same side  402   a  of the container  402 . According to the present embodiment, this side is the rear end face of the container. The present invention therefore departs from the known principle of washing installations (in which ingress and egress take place at opposite ends of the washing installation) in that the intake and the outlet are arranged at the same end of the container. This has the advantage that the container  402 , in the manner of a semitrailer of a heavy goods vehicle, for example, can remain on the latter and need not be uncoupled, lowered or the like during operation. Moreover, this configuration has the advantage that the rear portion  320  of the container  402  can be used in an economic manner to house units, containers, etc. 
   As can also be seen in  FIG. 1 , it is provided according to the present embodiment that the actual “washing installation” includes at least two parallel tracks. This means that at least two stations of the “washing installation” are arranged in a laterally offset manner with respect to each other and to the longitudinal axis of the container  402 . As a result, a U-shaped arrangement of the washing installation is produced, the two legs of the “U” representing the tracks in which the washing stations are arranged, and the connecting link of the “U” corresponding to a conveyance of the trolleys or the like transversely to the longitudinal axis of the container  402 . 
   As already stated, according to the inventive mobile cleaning plant  101 , the washing installation follows a substantially U-shaped path, so that the intake  402   b  and the outlet  402   c  of the washing installation are located at the same end  402   a  of the container  402 . This results in the processing advantage that the cleaned trolleys are removed from the mobile cleaning plant at the same point at which the soiled trolleys are fed to the plant. In addition to the advantageous layout of the container  402 , this results in the further advantage that the cleaned and stacked trolleys can be collected from the same point to which the soiled (stacked) trolleys were previously delivered for cleaning. Time-consuming manual pushing of the cleaned trolleys back to a collection point is therefore eliminated. 
   The container  402  has in its interior a floor-mounted conveyor device  204  which conveys the trolleys in at least one section  102 ,  104  and/or  106 , and  110  and/or  112  substantially parallel to the longitudinal axis of the container  402 , and in at least one further section  108  and/or  110  substantially transversely to the longitudinal axis of the container  402 . The trolleys are therefore transported in three directions: first, parallel to the longitudinal axis of the container  402  into the latter (from station #1a and #1b to station #3), then transversely to the longitudinal axis of the container  402  (from station #3 to station #4) and finally parallel to the longitudinal axis of the container  402  (from station #4 to station #6) and out of the latter. 
   For automatic conveyance of the trolleys from the ramp into the washing installation, a long-chain conveyor system is provided. Here, guidance is effected by means of rails and drive by means of toothed belts. Inside the washing installation the automatic conveyance of the trolleys is effected by means of a chain drive. 
   The trolley is pushed from the second to the third washing station by pneumatic means. From the third to the fourth washing station conveyance takes place transversely to the longitudinal axis of the container, the trolley being gripped at the front by means of two pneumatic parallel grippers and pushed into the fourth washing station by means of a pneumatically driven linear unit. Conveyance from the fourth to the fifth washing station and onwards to the sixth washing station is again carried out by pneumatic means and chain conveyor. 
   To feed the shopping trolleys to be cleaned to the mobile cleaning plant  101  in the container  402 , trolleys in K stacked rows
 
R k ≡R k,1 ′:={STR k,1 , . . . , STR k,n , . . . , STR k,N } (for 1≦k≦K),
 
each row consisting of N shopping trolleys (N≈20), are pushed manually or mechanically on to a lowered hinged ramp  120  until the front trolley of the row R k,1 ′ (STR k,1 ) touches a retaining cylinder  126  at the end of the hinged ramp  120 . Next, the cable of a winch  302 , the end of which is provided with a special hook, is hooked on to the last trolley of the row R k,1 ′ (STR k,N ). Then the hinged ramp  120  is raised by means of the rising cylinder  304 . As this happens, the winch  302 , which may be arranged above or below the trolleys of the row R k,1 ′, maintains the trolleys in position. After the hinged ramp  120  has been raised, the last N−1 trolleys STR k,2  to STR k,N  of the row R k,1 ′ are conveyed by means of the winch  302  up to the retaining cylinder  126  at the end of the hinged ramp  120 , the first trolley of the row R k,1 ′ (STR k,1 ) being separated from the row R k,1 ′ by means of an automatic separating mechanism consisting of a cylinder  124  for longitudinal conveyance. of the trolleys and slave cylinders  128  mounted transversely to the longitudinal axis of cylinder  124 .
 
   After the first trolley (STR k,1 ) has been separated the remaining row will be denoted below by
 
R k,2 ′:={STR k,2 , . . . , STR k,N }⊂R k,1 ′ (for 1≦k≦K).
 
Once the trolley STR k,l  separated from the row R k,1 ′ has been transported into the mobile cleaning plant  101 , the winch  302  maintains the trolleys in position or again transports the remaining N−2 trolleys of the row R k,2 ′ (STR k,3  to STR k,N ) up to the retaining cylinder  126  at the end of the hinged ramp  120 , the first trolley of the row R k,2 ′ (STR k,2 ) at the same time being separated from the row R k,2 ′ by means of the above-mentioned automatic separation mechanism consisting of the cylinder  124  for longitudinal conveyance of the trolleys and the slave cylinders  128  mounted transversely to the longitudinal axis of the cylinder  124 .
 
   The row remaining after the separation of the nth trolley (STR k,n ) will be denoted in general below as
 
R k,n+1 ′:={STR k,n+1 , . . . , STR k,N }œR k,n ′œ . . . œR k,1 ′ (for 1≦k≦K).
 
For 1≦n≦N−2 the following steps are then carried out:
 
   Once the trolley STR k,n  separated from the row R k,n ′ has been transported into the mobile cleaning plant  101 , the winch  302  maintains the trolleys in position or again transports the remaining N−(n+1) trolleys of the row R k,n+1 ′ (STR k,n+2  to STR k,N ) up to the retaining cylinder  126  at the end of the hinged ramp  120 , the first trolley of the row R k,n+1 ′ (STR k,n+1 ) at the same time being separated from the row R k,n+1 ′ by means of the above-mentioned automatic separation mechanism consisting of the cylinder  124  for longitudinal conveyance of the trolleys and the slave cylinders  128  mounted transversely to the longitudinal axis of the cylinder  124 . 
   In the last step after the separation of the (N−1)th trolley(STR k,N−1 ), only the “row”
 
R k,N ′:={STR k,N }œR k,N−1 ′ . . . œ . . . œR k,1 ′ (for 1≦k≦K)
 
remains behind, consisting of a single trolley (STR k,N ). This last trolley (STR k,n ) is then transported by means of the winch  302  into the mobile cleaning plant  101 .
 
   Automatic separation of the trolleys fed to the mobile cleaning plant 
   As was mentioned above, the automatic separating mechanism operates by means of pneumatically or hydraulically actuated retaining cylinders  126  and slave cylinders  128  mounted transversely to the longitudinal axis of a cylinder  124  which is used for longitudinal conveyance of the trolleys. The cylinder  124  has two associated slave cylinders  128  which in each case engage behind the four wheels of a trolley to be transported into the mobile cleaning plant  101 . Once the cylinder  124  has reached its stop position after longitudinally conveying a trolley STR i , the front wheels of the trolley STR i  concerned are located on a chain or belt conveyor  204  and are transported further thereon. During actuation of the cylinder  124 , the retaining cylinders  126  maintain the next trolley STR i+1  in its position so that its predecessor (STRI) can be fed to the mobile cleaning plant  101 . Once the trolley STR i  is in the mobile cleaning plant  101  the retaining cylinders  126  release the trolley STR i+1  so that it can be moved into the stop position by the winch  302 . The chain or belt conveyor  204  is preferably arranged in the floor of the container  402  and equipped with special catch units by means of which the trolleys are moved through the mobile cleaning plant  101 . These catch units preferably engage behind the wheels of a trolley. 
   Energy Supply of the Mobile Cleaning Plant 
   For the self-sufficient energy supply of all electrically, hydraulically and/or pneumatically driven feed, cleaning and removal devices for the trolleys at least one power generator can be used to ensure that the mobile cleaning plant  101  can be operated independently of external energy sources. 
   Further Features of Preferred Embodiments of the Solution According to the Invention 
   In the preferred embodiment of the basic invention, the unlocking of the coin-operated locks of the trolleys before feeding the trolleys into the mobile cleaning plant  101 , and the locking of the coin-operated locks of the trolleys after removal of the trolleys from the mobile cleaning plant  101  are done manually. The invention can, however, be extended in a simple manner to include an automatic unlocking and locking mechanism. 
   The solution according to the invention also provides a water treatment plant which purifies the used water produced and captured after each cleaning process by making use of chemical and/or biological additives, so that it can be reused for further cleaning processes. For this purpose, there is provided at least one collecting trough  202 , a grating, a coarse sieve  118  and/or a filter with exchangeable filter elements for collecting used water and capturing coarse and/or fine dirt particles located therein to ensure that cleaned used water can be reused to clean trolleys after being conducted back into the mobile cleaning plant  101 . 
   To protect the mobile cleaning plant  101  from the effects of frost, a heating device with temperature monitoring can additionally be provided. 
   In addition, the mobile cleaning plant  101  in the preferred embodiment of the basic invention also includes
         numerous pumps for supplying and removing clean and used water, cleaning agents, disinfectants and lubricants;   numerous valves serving to prevent backflow, as blocking devices and/or pressure-reducing devices;   filters for cleaning the soiled used water;   pipework for the supply and removal of clean and used water, cleaning agents, disinfectants and lubricants;   containers or tanks for storing fresh and used water, cleaning agents, disinfectants, lubricants and heating oil;   measuring instruments to measure liquid levels, temperature and pressure;   a device for regulating the operating temperature;   a blower device for blowing out fine dirt particles;   a blower device for supplying hot air for the drying processes, and   a water treatment plant for purification of the soiled used water,
 
which are not represented in the Figures for reasons of clarity.
       

   The meanings of the symbols in  FIGS. 1 to 4  which are provided with reference numerals can be found in the attached list of reference numerals. 
   List of Reference Numerals 
   
     
       
             
             
           
         
             
                 
             
             
               No. 
               Symbol 
             
             
                 
             
           
           
             
               100 
               Longitudinal cross-section E-F through the shopping 
             
             
                 
               trolley feed system, the trolley removal system, the 
             
             
                 
               container interior and the mobile cleaning plant 
             
             
                 
               located therein (view from above) 
             
             
               101 
               Mobile cleaning plant consisting of a total of six 
             
             
                 
               cleaning stations 
             
             
               102 
               Station #1a: blowing out of light solids and small 
             
             
                 
               dirt particles (suggested duration: e.g. 5 seconds 
             
             
                 
               per trolley) 
             
             
               104 
               Station #1b: application and effect of chemical 
             
             
                 
               cleaning agents (suggested duration: e.g. 25 seconds 
             
             
                 
               per trolley) 
             
             
               106 
               Station #2: washing of the trolleys with pressurised 
             
             
                 
               water jets from rotating high-pressure nozzles 
             
             
                 
               acting on the trolleys from five directions (from 
             
             
                 
               the front, the rear, the right, the left and above), 
             
             
                 
               whereby it is ensured that complete surface cleaning 
             
             
                 
               of the trolleys can be achieved (suggested duration: 
             
             
                 
               e.g. 30 seconds per trolley) 
             
             
               108 
               Station #3: cleaning of the trolleys with rotary 
             
             
                 
               brushes, automatic watering of the brushes with used 
             
             
                 
               water being carried out (suggested duration: e.g. 30 
             
             
                 
               seconds per trolley) 
             
             
               110 
               Station #4: fine rinsing of the trolleys with clean 
             
             
                 
               water (suggested duration: e.g. 30 seconds per 
             
             
                 
               trolley) 
             
             
               112 
               Station #5: drying of the trolleys by supplying hot 
             
             
                 
               air (suggested duration: e.g. 30 seconds per 
             
             
                 
               trolley) 
             
             
               114 
               Station #6: final drying of the trolleys by 
             
             
                 
               supplying hot air, followed by spraying with 
             
             
                 
               chemical disinfectants to kill morbific agents 
             
             
                 
               and/or application of lubricants to the wheel axles 
             
             
                 
               of the trolleys to reduce frictional resistance 
             
             
                 
               between wheels and axles (suggested duration: e.g. 
             
             
                 
               30 seconds per trolley for each operation) 
             
             
               116 
               Partition between the different stations 
             
             
               118 
               Coarse sieve with monitoring unit for retaining 
             
             
                 
               blown out solid dirt particles 
             
             
               120 
               Hinged ramp for feeding the trolleys into the mobile 
             
             
                 
               cleaning plant before start of cleaning 
             
             
               122 
               Hinged ramp for removing trolleys from the mobile 
             
             
                 
               cleaning plant and stacking trolleys on completion 
             
             
                 
               of cleaning 
             
             
               124 
               Cylinder for longitudinal conveyance of the trolleys 
             
             
                 
               to the chain or belt conveyor 204 
             
             
               126 
               Retaining cylinder mounted transversely to the 
             
             
                 
               longitudinal axis of cylinder 124 and serving as the 
             
             
                 
               stop point for separating the front trolley from 
             
             
                 
               trolleys fed to the mobile cleaning plant in stacked 
             
             
                 
               rows 
             
             
               128 
               Slave cylinder mounted transversely to the 
             
             
                 
               longitudinal axis of cylinder 124 which engages 
             
             
                 
               behind the front wheels of a trolley separated from 
             
             
                 
               its row and detaches the trolley from the row 
             
             
                 
               through the longitudinal motion of cylinder 124 
             
             
               200 
               Longitudinal cross-section G-H through the trolley 
             
             
                 
               feed system and the container interior, the hinged 
             
             
                 
               ramps 120 and 122 being in the non-raised state 
             
             
                 
               (side view from right) 
             
             
               202 
               Trough for collecting used water and conducting same 
             
             
                 
               to a used-water tank 
             
             
               204 
               Chain or belt conveyor in the floor of the 
             
             
                 
               container, equipped with special catch units by 
             
             
                 
               means of which the trolleys are conveyed through the 
             
             
                 
               mobile cleaning plant 
             
             
               300 
               Longitudinal cross-section C-D through the trolley 
             
             
                 
               feed system, the container interior and the mobile 
             
             
                 
               cleaning plant located therein, the hinged ramps 120 
             
             
                 
               and 122 being in the raised state (side view from 
             
             
                 
               right) 
             
             
               302 
               Winch for retaining and conveying further the 
             
             
                 
               trolleys for automatic feeding of same into the 
             
             
                 
               mobile cleaning plant 
             
             
               304 
               Rising cylinder for feeding the trolleys into the 
             
             
                 
               mobile cleaning plant 
             
             
               306 
               High-pressure pump 
             
             
               308 
               Low-pressure pump 
             
             
               310 
               Control unit for coordinating the time sequences of 
             
             
                 
               the cleaning processes and for regulating physical 
             
             
                 
               parameters (temperature, pressure) 
             
             
               312 
               Generator for autonomous power supply for all units 
             
             
                 
               used 
             
             
               314 
               Combined storage tank for clean water and used water 
             
             
               316 
               Tanks for clean and used water, cleaning agent, 
             
             
                 
               disinfectants, lubricants and heating oil 
             
             
               318 
               Filter unit with exchangeable filter elements for 
             
             
                 
               removing fine dirt particles from the used water 
             
             
               320 
               Liquid tank with separating membrane for two 
             
             
                 
               different liquid media 
             
             
               400 
               Longitudinal cross-section A-B through the trolley 
             
             
                 
               removal system, the container interior and the 
             
             
                 
               mobile cleaning plant located therein, the hinged 
             
             
                 
               ramps 120 and 122 being in the raised state (side 
             
             
                 
               view from right) 
             
             
               402 
               Semitrailer or container as housing for the mobile 
             
             
                 
               cleaning plant into which the trolleys to be cleaned 
             
             
                 
               are introduced and from which they are removed in 
             
             
                 
               the cleaned state 
             
             
                402a 
               Rear end of the semitrailer or container 402 
             
             
                402b 
               Intake for feeding the trolleys to be cleaned into 
             
             
                 
               the mobile cleaning plant 
             
             
                402c 
               Outlet for removing the cleaned trolleys from the 
             
             
                 
               mobile cleaning plant