The present invention relates to a stacker crane with an improved sliding mechanism and to a storage for storing containers of biological material test tubes provided with said stacker crane.
Stacker cranes, also more simply referred to as stackers, are now employed in the most various fields of industrial automation for the automated transport of different types of materials inside large warehouses, as well as for inserting and/or picking material from specific locations of shelves, often significantly high off the ground.
The sliding movement of the movable structure of the stacker in known solutions is promoted, in particular in movements along direction y, by the presence of wheels, which adequately accompany the movement of the movable structure along the tracks.
Problems appear with a sliding movement of this type since a lack of accuracy and/or instability can occur in certain cases. This can be due for example to the presence of frictions during the sliding movement, various imbalances caused by the progressive wearing out of the wheels over time, impurities depositing on the wheels or still again to the possibility of an unscrewing at the fastenings between the movable structure and wheels.
All malfunctions can have serious consequences such as the stacker stoppage during the sliding movement thereof or a coming out of the wheels from the tracks, promoted by the fact that there is a given clearance during the translation along the tracks. The latter drawback can naturally result in the transported material falling or even the stacker overturning.
The risks described above occur in even greater measure the higher the stacker is, or if it is designed to transport particularly heavy materials or materials sensitive to overturning.
Patent Application AT505757 A4 describes a stacker crane for loading and unloading a rack from locations of a shelf, provided with a telescopic extension. In particular, the telescopic extension comprises a first telescopic section connected to the stacker crane and a second telescopic section connected to the first telescopic section. Such a solution therefore allows the rack to move easily during the loading and unloading operations from the locations, but involves a significant mechanical stress when the load is cantilevered moved by means of the aforesaid telescopic extension. The mechanical stress is only partly reduced by means of the use of suitable support rollers, which reduce the bending moment loaded on the second portion of the telescopic extension, to the detriment of the stress on the first section of the extension.
With particular reference to the field of laboratory automation plants designed to move test tubes containing biological material samples, there is an increasingly stronger need to arrange conveniently cooled storages inside the plant. Such storages allow the biological samples analyzed to be stored for a longer or shorter time so that they are available again to the plant as needed for a repetition of the analyses by modules connected to the automation. The need for increasingly more storage space therefore requires the use of increasingly voluminous storages and the necessary application of suitable movement systems, for example of the type corresponding to the aforesaid stacker cranes, thus also adding the problems disclosed above connected with movement to the complexities of the storing systems themselves.