Abstract:
A laboratory automation system is described, comprising pairs of conveyor belts accommodating devices for conveying biological samples and actuated by a motorized traction device. Said motorized traction device includes a first and a second motor, each adapted to actuate both said pairs of belts a central control unit being adapted to control the simultaneous or alternating actuation of said motors.

Description:
The present invention relates to a laboratory automation system with double motor traction device for conveyor belts. 
     BACKGROUND OF THE INVENTION 
     In the field of conveying biological material specimens in a test laboratory it is known to use appropriate automation systems adapted for the purpose which allow the specimens, appropriately contained in test tubes, to interface with the pre- and post-testing modules and with the proper testing modules adjacent to the automation system itself. 
     In particular, the test tubes, each of which is inserted into a conveying device, travel along motorized conveyor belts which substantially form specimen dispatching lanes along the automation system, as described by the Applicant in patent EP-2225567. 
     Due to the size of a test laboratory and thus to the corresponding automated specimen conveying system, the above-described conveyor belts may naturally reach even considerable lengths, up to several tens of meters. 
     As mentioned, said belts are motorized, and at each rectilinear portion of the automation system there are two motors, at the opposite ends, each of which manages the actuation of one of the two pairs of belts (outbound lanes and return lanes). 
     The drivers of the belts, during their normal operation, are certainly subject to considerable stress; since test laboratories typically work non-stop all day, seven days a week, the motors which actuate the conveyor belts are always operating and this increases the risk of their deterioration and even failure. In particular, this concerns ratio motors which deteriorate due to the presence of pulsing loads which act on the gears of the ratio motors themselves, thus leading to their failure on the long run. 
     So, it would be necessary to manually act in order to replace the deteriorated or failed motor, and this would naturally imply the need to interrupt the operation of the automation system or at least of the concerned portion (i.e. that with the belts operated by the motor to be replaced) during such a maintenance operation, with obvious consequences in the form of delays in the specimen treatment procedures. 
     DE-19508492 describes a conveyor controlled either simultaneously or alternatively by a pair of motors. 
     BRIEF SUMMARY OF THE INVENTION 
     It is the object of the present invention to provide a laboratory automation system in which operation continuity is ensured, even in the unfortunate case of problems or failures of the motorized traction system of one of the two pairs of conveyor belts. 
     This and other objects are achieved by a laboratory automation system as described in claim  1 . 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       These and other features of the present invention will become further apparent from the following detailed description of an embodiment thereof, shown by way of non-limiting example in the accompanying drawings, in which: 
         FIG. 1  shows a perspective view of a portion of the laboratory automation system; 
         FIG. 2  shows a perspective view of a sliding profile of a pair of conveyor belts of the automation system; 
         FIG. 3  shows a perspective view of an end of the portion of the automation system; 
         FIG. 4  shows a perspective view of the motorized traction device; 
         FIG. 5  shows an exploded view of the motorized traction device shown in  FIG. 4 , comprising a section view perpendicular to the rotation axis of a free wheel mechanism used therein; 
         FIGS. 6 and 7  show the motorized traction device again, in a bottom and a side view, respectively. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A laboratory automation system comprises main lanes  2  and secondary lanes  3  parallel to one another ( FIGS. 1, 2 ) which accommodate parallel, motorized conveyor belts  4  made of polyurethane, having the function of conveying test tube conveying devices  5 . 
     The conveying devices  5  are usually diverted onto the secondary lane  3  to allow them to reach or pass pretesting, testing or post-testing modules or stations. 
     The system consists of modules  1  ( FIG. 1 ) assembled together in a variable number and according to different configurations to respond to the various test laboratory needs. 
     One pair of belts  4 , sliding in one direction, and one pair of belts  4 , sliding in the opposite direction, are present for each rectilinear stretch of the system (angular and T-shaped connections are also provided, if needed; in this regard see patent EP-2225567 by the Applicant). 
     Each pair of lanes  2 ,  3  is obtained from a sliding profile  6  of belt  4 , appropriately shaped and advantageously made of aluminum ( FIG. 2 ). 
     Each belt  4  is made of cross-linking polyurethane coated with impregnated fabric which ensures a low friction coefficient with the resting surface of the conveying device  5  during the movement. 
     At each end of the automation system, in order to allow the conveying device  5  to invert the movement direction, there is a motion inversion device  11  ( FIGS. 3, 6, 7 ), comprising a thin plastic disc  110 , having the function of transferring each conveying device  5  transiting from the pair of belts  4  sliding in one direction to the pair of belts  4  sliding in the opposite direction. 
     A traction device  100  of the pair of conveyor belts  4  is provided again at the end of the automation system ( FIGS. 3-7 ). It comprises a first motor  111   a  which rotates a first pulley  112   a  ( FIG. 4 ) on which a first belt  113  is wound, the other end of which is wound about a third pulley  112   c.    
     The rotation of such a third pulley  112   c  is transmitted to a rubber-coated roller  115  ( FIGS. 3, 6 ) which by rotating generates the movement of the pair of belts  4  which are wound about it (for conveniently viewing the rubber-coated roller  115 , the portion of belts  4  wound about the roller itself has been omitted). At the same time, the rotation of the third pulley  112   c  actuates a further thin belt  116  ( FIGS. 6, 7 ) which, by resting on some idle pulleys  117   a ,  117   b ,  117   c  ( FIG. 6 ), rotates the plastic disc  110  thus actuating the motion inversion device  11 . 
     The traction device  100  further comprises a second motor  111   b  which rotates a second pulley  112   b , on which a second belt  114  is wound, which at the other end is wound about the first pulley  112   a  again ( FIGS. 3, 4 ). 
     The first and second pulleys  112   a  and  112   b  accommodate a first and a second free wheel  111   a  and  118   b  therein, respectively ( FIG. 5 , where said free wheels  118  and  118   b  are shown in detail). 
     The traction device  100  also comprises two supports  119   b  ( FIGS. 4, 7 ) for each of the two motors  111   a ,  111   b ; each support  119   a ,  119   b  has a joint  120   a ,  120   b  which, fixed by means of screws  121  to support  119   a ,  119   b , facilitates the possible maintenance operations on the motors, as will be described in greater detail below. 
     During the normal operation of the traction device  100  of the conveyor belts  4  of a laboratory automation system, only the first motor  111   a  is working; a rotation movement is thus imposed on the corresponding shaft  122   a  which, at a region  123 , is integral with a hub  124  (see detail in  FIG. 5 ) and with a ratchet  125 . When the shaft  122   a  is actuated, ratchet  126  engages the teeth of the first free wheel  118   a , which rotates (counterclockwise in the embodiment), thus exerting a feeding effect on pulley  112   a . As a result, the first belt  113  also slides and the third pulley  112  rotates (see the arrows in  FIG. 4 ). 
     The latter rotation causes, in turn, the rotation of the rubber-coated roller  115  ( FIG. 3 ), and thus the sliding movement of the conveyor belts  4 , as mentioned only partially shown in  FIG. 3  for viewing the rubber-coated roller  115  (note the dashed line of the belts  4 ). Furthermore, the rotation of the third pulley  112   c  again causes the sliding movement of belt  116  which by winding on the idle pulley  117   c  causes the rotation thereof, thus causing in turn the plastic disc  110  to rotate ( FIGS. 6, 7 ). 
     It is thus apparent that the action of the first motor  111   a , resulting in the sliding movement of the conveyor belts  4  and in the rotation of the plastic disc  110 , allows a conveying device  5  which is reaching the end of belt  4  (i.e. the header of the module  1  of the automation system) to be routed to the conveyor belt  4  which is sliding parallel in the opposite direction, the latter being operated, in turn, by the respective pulley (not shown in  FIG. 3 ) at the other end of the module  1  of the system. Thereby, the conveying device  5  switches from the outbound lane (or pair of lanes) to the return lane(s) and vice versa at the other end. 
     Obviously, the rotation of the first pulley  112   a  also slides the second belt ( FIG. 4 ) and thus rotates the second pulley  112   b . A counterclockwise rotation is again imposed on the second free wheel  118   b  inside the second pulley  112   b . In all cases, it is apparent that only the toothed profile  126  of the second free wheel  118   b  rotates, which slides on the ratchet  125  thereof, which is stationary as hub  124  and shaft  122   b  (since the second motor  111   b  is not operating). So, in this step, only the second free wheel  118   b  is indeed “free”, i.e. does not exert any traction but only a simple bearing function inside pulley  112   b.    
     As time goes by, the first motor  111   a  may show wear, even more if considering that the motor is used in automation systems which are never stopped. 
     The second motor  111   b  is indeed delegated to take over as “spare” traction device of belts  4 , when the first motor  111   a  is about to reach the end of its life cycle. 
     The operating logic is managed by a central control unit  50  of the automation system (conveniently shown only with reference to module  1 ) capable of discriminating the occurrence of faulty operation of the first motor  111  and of automatically switching the task of feeding belts  4  to the second motor  111   b.    
     This occurs by appropriately controlling each of the software drivers associated with the two motors so as to stop the first motor  111   a  and start the second motor  111   b  at the same time. 
     Such a switching occurs mandatorily in the case of sudden failure of the first motor  111   a , but may also occur according to a more complex mechanism which takes into account, for example, the exceeding of given threshold values for specific parameters of the motor which are configurable so as to trigger proper warnings at the level of the central control unit  50 . 
     For example, a maximum current value through the motor may be established, which results in a maximum value of power which may be drawn by the driver of the motor itself. Alternatively, the maximum life of a motor may be considered as a key parameter. 
     In such cases, the activation of a warning may not have the immediate switching between the two motors as a consequence; indeed, a possible decision about this topic is also processed according to a predictive logic implemented in the central control unit  50  and which allows to process data and information related to the components in hand over time (and thus during the life of a given motor or more generally of an automation system), thus determining which conditions in the past most often caused a definitive failure of the motors. 
     Thus, the decision to switch from one motor to the other or not may be taken by the central control unit  50 , taking into account both the possibly exceeded thresholds (or the limit life time of a motor) and such “historical” information on the behavior of the motors. This is obviously aimed at avoiding the situation of complete failure of the operating motor, which would stop the system, and thus at preventively switching to the other motor. 
     Obviously, the central control unit  50  may also be programmed to start the switching between the two motors in all cases when a given threshold is exceeded, and thus in the presence of a warning signal, similarly to the above-described case of motor failure. 
     On the long run, the central control unit  50  can autonomously create proper “behavior rules” which allow to operate in a timely manner when any situation occurs. 
     Therefore, when the above-described situation occurs, the first motor  111   a  is stopped by the central control unit  50  which also starts the second motor  111   b  arranged in parallel thereto; the second motor  111   b  keeps the second pulley  112   b  rotating and therefore, by means of the second belt  114 , the first pulley  112   a  and again the third pulley  112   c  by means of the first belt  113 . 
     In this case, in a symmetric manner with respect to the previous situation, it is the second free wheel  118   b  which, by virtue of the rotation imposed on the shaft  122   b  of the second motor  111   b  ( FIG. 5 ) performs a feeding effect on pulley  112   b . Instead, it is the first free wheel  118   a  to be “free” and to exert the bearing action inside pulley  112   a , while there no rotation of shaft  122   a  occurs because the first motor  111   a  is stationary. Therefore, despite the interruption of the operation of the first motor  111   a , the feeding continuity of the pair of conveyor belts  4  is certainly still ensured by virtue of the fact that the second motor  111   b  has taken over from the first. 
     In the meantime, while the automation system continues to operate without problems by virtue of the second motor  111   b , the central control unit  50  outputs an appropriate notification (which may be displayed, for example, on a graphic user interface connected to the automation system) by virtue of which an operator becomes aware of the switching and can thus replace the first motor  111 , which has just stopped working, in a very practical manner; in particular, the operator may unscrew the screws  121  and thus remove the first motor  111  from the support  119   a  and replace it with a new one, and this occurs while the newly started second motor  111   b  is working normally. 
     After the replacement, the operator manually resets the notification concerning the motor to be changed on the GUI. 
     An alternative embodiment may certainly be considered, in which the two motors  111  and  111   b  work simultaneously to share the feeding effort of the belts  4 . 
     The innovative aspect of the invention referred to a traction system of a pair of motorized conveyor belts in a laboratory automation system is thus determined by arranging a second motor for traction purposes by the side and parallel to the first. 
     Such a second motor may automatically take over the first motor, when the latter fails or is expected to be about to fail, thus ensuring operating continuity of the traction system of the concerned pair of conveyor belts, and avoiding the inconvenience related to known solutions consisting in the need to shut down the whole automation system (or at least the part of the system concerned by the failure of the belt traction system) so that an operator can manually replace the single motor present. 
     Indeed, in the solution of the present patent, the operator can however replace the failed motor but only once the second motor in parallel has been started and is thus keeping the automation system working. 
     Furthermore, the switching between the two motors is not set by an operator but is controlled at software level by a central control unit, capable of automatically passing, in case of need, the burden of traction of the belts from one motor to the other by means of the smart evaluation of a series of parameters (thresholds, life times) established beforehand and by further applying predictive criteria which result from a historical analysis of the behavior of drivers of the same type in similar systems. 
     The invention thus described is susceptible to many changes and variants, all within the scope of the inventive concept. 
     In practice, the materials used as well as the shapes and dimensions may be any, according to needs.