Centrifuge having a magnetic actuator for loading and unloading buckets and a method of loading/unloading the buckets on the centrifuge
For automated centrifugation of samples contained in test tubes, a centrifuge (c) has a rotating head ( 11 ) with swing-out buckets ( 30 ) for housing the test tubes. Apparatus is provided for automatically positioning each bucket in the centrifugation chamber under a safety lid and to lift each bucket out of the centrifugation chamber. Magnetic devices are provided to retain a cover on its bucket and a magnetic system is provided for removing the cover of each bucket in order to expose the test cubes to a robotic arm or similar device.
1. A centrifuge for buckets comprising a rotating head ( 11 ) rotatable around a rotation axis (b) in a centrifugation chamber ( 10 ) of the centrifuge, head trunnions integral with the rotating head and defining swing axes (a) for the buckets, a safety cover ( 19 ), an actuator for loading the buckets on the respective trunnions of the rotating head and unloading the buckets therefrom,
characterised in that said actuator ( 15 ) has magnetic bucket engaging means ( 17 ) for retaining a bucket ( 30 ) thereon.
2. A centrifuge as said in claim 1 , further comprising bucket handling means ( 27 , 28 ) for handling a bucket outside the centrifugation chamber, characterised in that said bucket handling means comprise magnetic means for engaging a bucket cover ( 32 ) provided with cooperating magnetic means ( 36 ) for cooperating with magnetic means of the handling means.
3. A centrifuge as said in claim 2 , wherein said bucket handling means comprise a rotating column ( 27 ) coaxial with the rotation axis of the rotating head and a bucket handling arm ( 28 ) provided with said magnetic means.
4. A centrifuge as said in claim 2 , for use with buckets provided with a bucket cover retained on a bucket base by magnetic means, characterised in that the magnetic means of the bucket handling means operate with a force that is stronger that the magnetic force retaining a bucket cover ( 32 ) on the bucket base ( 31 ).
5. A bucket for receiving sample test tubes for centrifuging in a centrifuge, said bucket comprising a base ( 31 ) and a removable cover ( 32 ), and having lugs ( 33 ) extending laterally outwardly from said base for swing mounting on trunnions of a centrifuge rotating head, characterised in that it further comprises magnetic means ( 35 , 35 ′) on said base and said cover for securing mutual engagement thereof, said magnetic means ( 35 , 35 ′) being of sufficient strength to retain said cover on said base during the rotation thereof in a centrifuge.
6. A bucket as said in claim 5 further comprising magnetic retaining means ( 34 ) in the base undersurface and/or magnetic retaining means ( 36 ) in the upper surface of the cover for cooperating with adjacent portions of a centrifuge when the bucket is disposed therein.
7. A bucket loading/unloading apparatus for a centrifuge for centrifuging buckets swingably applied on a centrifuge rotating head, characterised in that it comprises a vertical actuator ( 15 ) provided with a bucket-engaging plate ( 16 ) having magnetic means, said actuator being movable between a retracted position, wherein it is at a distance below a bucket supported on a centrifuge rotating head, and an extended position, wherein it presents a bucket to handling means outside of the centrifugation chamber.
8. A method for loading/unloading buckets on a rotating head ( 10 ) of a centrifuge, said buckets comprising a base ( 31 ) and a cover ( 32 ) having mutually engaging magnetic means and further magnetic means ( 34 , 36 ) in the base undersurface and on the cover, said method comprising the following steps
a. applying a bucket on a loading/unloading actuator ( 15 ) of the centrifuge
b. retaining the bucket thereon by means of magnetic force
c. retracting the actuator and leaving the bucket applied onto the rotating head ( 10 ).
9. A method for loading/unloading buckets on a rotating head ( 10 ) of a centrifuge, said buckets comprising a base ( 31 ) and a cover ( 32 ) having mutually engaging magnetic means and further magnetic means ( 34 , 36 ) in the base undersurface and on the cover, said method comprising the following steps
engaging a centrifuged bucket with loading/unloading actuator ( 15 )
moving the actuator with the bucket thereon to an extended condition, wherein the bucket ( 30 ) is outside of the centrifugation chamber of the centrifuge
magnetically engaging the bucket cover ( 32 ) with a movement arm ( 28 ) and applying thereto a magnetic force stronger than the magnetic force retaining the bucket cover on the bucket base,
removing the bucket cover from the bucket base and transferring same to a parking area.
10. A method according to claim 9 wherein said transfer is a rectilineal movement.
11. A method according to claim 9 wherein said transfer is a rotational movement.
12. A method according to claim 9 characterized in that after applying a magnetic force to the cover, the actuator is retracted with the base over it, in order to leave free the movement of the arm 28 with the cover.