Patent Application
20200108397
The invention is directed to features of a tube picking mechanism that is particularly well suited for use in a robotic, ultra-low temperature sample storage and retrieval system. The invention enables sample tubes of different diameters to be conveniently stored in tube racks and robotically retrieved from the freezer.
The assignee of the present application owns U.S. Pat. No. 7,861,540 by Robert P. Cloutier et al., issuing on Jan. 4, 2011 and entitled “Automated Storage and Retrieval System for Storing Biological or Chemical Samples at Ultra-Low Temperatures”; and U.S. Pat. No. 8,176,747 by Howard et al., issuing on May 15, 2012 and entitled “Tube Picking Mechanism for an Automated, Ultra-low Temperature Storage and Retrieval System” both of which are hereby incorporated by reference. These patents describe an automated, ultra-low temperature sample storage and retrieval system having freezer racks mounted within an insulated, ultra-low temperature freezer compartment (−80° C.). The freezer racks include trays or shelves for storing sample storage containers, which are typically tube storage racks holding an array of sample tubes. A mechanical robot is provided within the ultra-low temperature storage compartment to place the tube storage racks in an appropriate tray on the freezer rack and to retrieve the tube storage racks. The tube storage racks are typically SBS footprint compatible. The system is capable of storing other types of other SBS-formatted containers, such as microtiter plates or reservoirs, but typically these systems are used to store samples in capped sample tubes held in tube storage racks. The robot communicates with an access module in order to introduce tube storage racks into the system and retrieve tube storage racks for use outside of the system. The freezer racks have a capacity of several hundred or more tube storage racks. The present invention is directed to a tube picking apparatus that is particularly well suited for use in the automated ultra-low temperature storage and retrieval system disclosed in the above incorporated patent application, but also may be useful in other systems as well.
As explained in the above incorporated patents, biological samples stored in ultra-low temperature systems are often contained in sealed plastic laboratory tubes or vials having a diameter of 8 mm or larger. Larger tubes are sometimes called vials in the art, but both are referred herein as tubes or storage tubes. In any event, the tubes or vials are typically held in tube storage racks in arrays of, for example, 96, 48 or 24 tubes. The tube racks, as mentioned, typically have SBS footprint compatible dimensions. In some cases, a two-dimensional bar code containing identifying information is adhered to the bottom of the storage tubes and is able to be read through openings in the bottom of the SBS tube storage racks. It is known to use a two-dimensional bar code reader, e.g. at the access module, to track the samples tubes as they are placed in to the system and retrieved from the system. In some cases, a one-dimensional bar code containing identifying information is placed on the sidewall of the storage tube.
As explained in the above incorporated patents, it is not normally desirable to remove an entire SBS tube storage rack from the system when only one or a few sample tubes from a given rack are desired to be retrieved. The removal procedure allows for the ingress of moisture into the ultra-low temperature storage compartment which leads to frost build up, and also renders the other samples held in the same SBS tube rack susceptible to thawing, at least partially, even if the tube rack is removed from the system temporarily.
In order to address these issues, the above incorporated patents disclose the use of a tube picking chamber adjacent the freezer compartment, preferably incorporated into the insulated freezer door. A retractable shuttle door is located between the tube picking chamber and the ultra-low temperature storage compartment. A reach arm for the robot within the ultra-low temperature freezer compartment supplies a selected SBS tube rack (i.e., a source rack) to a specific location in freezer compartment that can also be accessed by a robotic shuttle constituting part of the tube picking mechanism. Picked tubes are loaded into another tube rack (i.e., a destination rack) that is intended to exit the system. The shuttle door for the tube picking chamber normally remains closed, isolating the tube picking chamber from the ultra-low temperature freezer compartment under normal storage conditions. When use of the tube picking mechanism is requested, dry gas is introduced into the tube picking chamber with the shuttle door closed in order to reduce the relative humidity within the chamber. A relative humidity sensor is located within the tube picking chamber for this purpose. When the relative humidity has been lowered to the desirable level, for example less than 2% relative humidity, the shuttle door is opened and cold air from the ultra-low temperature freezer compartment is allowed to flow into the tube picking chamber. A temperature sensor is also located in the tube picking chamber. The shuttle door is opened and closed as necessary to maintain the temperature in the tube picking chamber at a freezing temperature that is above the ultra-low temperature (−80° C.) in the storage compartment, preferably −5° C. to −25° C., e.g. about −20° C. In this manner, the tube picking mechanism, and its mechanical and electrical components, can operate in a less harsh environment which greatly improves reliability. On the other hand, by maintaining the tube picking chamber at a subfreezing temperature, the other samples in the pertinent source racks need not exit the system in order to retrieve the desired storage tube or tubes. This not only protects the other samples from premature thaw and harm, but also reduces the risk of moisture flow into the ultra-low temperature freezer compartment. Further, because the relative humidity is maintained at a low level within the tube picking compartment, tube racks can be shuttled in and out of the tube picking compartment at a relatively fast pace compared to shuttling through the main access module. Fast pace shuttling shortens exposure time outside of the −80° environment for samples not selected for retrieval.
It is known to use a cache for temporarily holding picked sample tubes as the tubes are being transferred between source racks and a destination rack. The −80° C. system described in the above incorporated patents provides such a cache in the tube picking compartment. It is important to keep the cache relatively compact in these systems because the tube picking chamber itself is small. In addition, receptacles in the cache are orientated linearly so that the receptacles in the cache can be accessed by driving the gripper along a single axis. The shuttle carrying the source or destination rack is moved perpendicularly to the linear orientation of the cache to access sample tubes locations in different rows in the tube rack. In commercial systems, the receptacles in the cache are sized to match the size of sample tubes (e.g., 8 mm diameter or 9 mm diameter) that are intended to be stored in the system. The receptacles need to be sized properly in order to hold the sample tubes vertically within the cache; otherwise the robotic tube picking mechanism cannot reliably grip and transport the sample tubes.
An object of the invention is to facilitate the robotic picking of sample tubes having different diameters, which in turn should render the storage and retrieval system more conducive to storing samples in non-uniform sample tubes or using labware from different vendors.
The invention is an improved tube picking mechanism that is capable of robotically picking sample tubes and temporarily storing the tubes in cache when transferring the sample tubes from a source rack to a destination rack, even if the samples tubes have different sizes and diameters. The tube picking mechanism is particularly well suited for use with automated storage and retrieval systems that store samples in tubes, held in SBS tube storage racks, within an ultra-low temperature freezer (−50° C. to −90° C., e.g., −80° C.). The tube picking mechanism preferably resides in a tube picking chamber that is cooled to about −20° C. for picking and transferring tubes, and is located adjacent the −80° C. freezer compartment.
The tube picking mechanism includes a picking head that is adapted to pick and place sample tubes having a variety of diameters, and a universal cache capable of temporarily storing sample tubes having a variety of diameters in a substantially vertical orientation. Consequently, the tube picking mechanism is able to reliably grip and transport sample tubes having a variety of diameters, which in turn renders the ultra-low temperature freezer system more conducive to store racks of sample tubes having different diameters. For example, in the system described in the above incorporated patents, the tube picking feature was limited to a predesignated sample tube diameter, unless the system was physically reconfigured and in that case the tube picking feature would be limited to the reconfigured diameter. With the invention, there is no need to physically reconfigure the system to accommodate sample tubes having different diameters.
In an exemplary embodiment, the picking head and cache can be configured to pick and hold sample tubes and vials having a diameter ranging, e.g. from 8 mm to 18 mm, which is sufficient to accommodate most tubes and vials commonly used to store biological samples.
A retractable shuttle door separates the tube picking chamber from the ultra-low temperature freezer compartment. A shuttle for the tube picking mechanism moves between the tube picking chamber and the freezer compartment in order to shuttle tube racks one at a time in to the tube picking chamber and vice versa. Source racks with tubes that have been selected for extraction from the system are taken to a designated location within the freezer compartment by the freezer robot. The shuttle for the tube picking mechanism receives the source rack from the robot and transports the tube rack through the shuttle doorway into the tube picking chamber, at which time the door is closed. The shuttle preferably moves horizontally along a linear y-axis. A tube picking head located within the tube picking chamber moves horizontally along a perpendicular x-axis, and also moves vertically along a z-axis. The tube picking head has a pair of gripping jaws that are able to grip and transport a single tube after it has been lifted from a receptacle in a tube rack located on the shuttle. In order to pick a selected tube from a tube rack on the shuttle, the shuttle is indexed along the y-axis and the picking head is indexed along the x-axis. The system also preferably includes a presenter push pin located beneath the shuttle tray. The presenter push pin remains aligned with the tube picking head along a vertical z-axis. The tube picking head also includes a vertical shucker rod, which engages the top (cap) of the selected sample tube. The push pin is moved upward to engage the bottom of the selected storage tube held in the tube rack, and the sample tube is lifted from the tube rack while being held by the shucker rod from above and the push pin from below in order to provide clearance above the rack and other tubes in the rack for gripping jaws. Once the sample tube is secured in the gripping jaws, the picking head can move vertically upward to lift the tube completely clear from the rack and the other tubes in the rack, and then moved along the x-axis to set the picked tube in the cache within the tube picking chamber. Once the storage tube is set in the cache, the tube picking mechanism can then be used to pick another selected tube from the same source rack if desired. All picked tubes are transferred to the cache, at least until the cache is full. Once all of the selected storage tubes have been selected from the source rack located on the shuttle within the tube picking chamber, the shuttle door is opened and the shuttle transports the tube rack back to the designated location within the freezer compartment. The shuttle then retracts and the shuttle door closes while the freezer robot returns the source rack to its original storage location. The tube picking process repeats itself as described above until all of the selected tubes have been placed in the cache, or the cache becomes full.
Once all of the selected tubes have been placed in the cache or the cache becomes full, a “destination rack”, preferably an empty tube rack, is transported to the designated location within the freezer compartment. The destination rack is intended to be filled with storage tubes for retrieval and exit from the system through the access module. The tube picking mechanism shuttles the destination rack into the tube picking chamber and loads the storage tubes from the cache into the receptacles in the rack. The tube picking mechanism then returns the destination rack to the freezer compartment. If no more storage tubes are selected for retrieval from the system, the freezer robot will pass the destination rack to the access module for extraction from the system. If additional storage tubes are selected for retrieval, the freezer robot will move the destination rack to a holding shelf within the freezer compartment. The freezer robot and the tube picking mechanism will then again coordinate to transfer selected storage tubes from tube racks in the freezer compartment into the cache in the tube picking chamber, and consequently load the tubes from the cache into the destination rack. This process is continued until all of the tubes selected for retrieval have been loaded into the destination rack or, alternatively, the destination rack becomes full, at which time the freezer robot transports the destination rack to the access module for extraction from the system.
Use of the cache within the tube picking chamber allows for relatively fast paced shuttling of the tube racks from the freezer compartment into the tube picking chamber with the same shuttling mechanism being used for both the source racks and the destination rack. Yet, exposure time outside of the −80° C. environment is kept at a minimum for samples not selected for retrieval. In addition, it allows for the tube picking chamber to be relatively compact because it does not require room to park a destination rack within the tube picking chamber.
The tube storage racks, including source racks and destination racks, must be sized to match the sizes of tubes or vials stored in and retrieved from the system. In one aspect, the invention is directed to a method of retrieving at least one sample tube having a first diameter from the system using a destination rack configured to hold sample tubes having the first diameter, and retrieving at least one sample tube having a second different diameter from the system using a different destination rack configured to hold sample tubes having the second diameter. This is accomplished in accordance with the invention using one tube picking mechanism and one cache, each configured to accommodate tubes and vials of different sizes and diameters.
The cache in the exemplary embodiment has two parallel banks of vertical cam plates and two parallel axels. The vertical cam plates in each bank are mounted on a respective axel and are able to pivot independently of the other vertical cam plates mounted on the axel. The cam plates are weighted to fall naturally to a home position, but rotate when a sample tube exerts force against an inner edge of the respective vertical cam plate. The inner edges of the vertical cam plates on one bank of the cache are separated from the inner edges of the vertical cam plates on the other bank by an elongated space. The space provides room for the sample tubes and also the presenter push pin from below.
The inner edges of the respective vertical cam plates have an arcuate cam profile that is oriented with an upper end of the edge being spaced farther away from the opposing bank than a lower end of the edge. The vertical cam plates are mounted on the respective axel so that each plate rotates inward from the home position when a sample tube is moved downward between the respective cam plate and the opposing bank of plates such that the point of contact between the inner edge and the sidewall of the sample tube is tangential. This configuration holds the sample tube vertically, and centers the sample tube along the central plane between the banks of cam plates.
The distance between the banks of cam plates can be selected to determine the range of diameters of tubes or vials that can be stored in the cache, e.g. 8 mm to 18 mm. It is possible to make the distance between the respective parallel axels adjustable in order to change the range of diameters of tubes or vials that can be stored in the cache.
The tube picking head in the exemplary embodiment includes an actuator, a linkage connecting the actuator to the gripping jaws and springs in the linkage connecting the respective gripping jaw to the linkage. The actuator is activated to open and close the gripping jaws and springs in the linkage enable the distance between the opposing gripping jaws when closed to adjust depending on the diameter of the sample tube being held. The combination of gripping jaws capable of holding and transporting sample tubes and vials having a range of diameters, and a cache capable of temporarily holding sample tubes and vials having a range of diameters, provides significant advantage in terms of overall system flexibility and use.
It is believed that the invention resides not only in the combination of various system components as described herein, but also in the manner in which the above described components are used in order to provide the stated objects of the invention. Also, as mentioned, the invention is particularly well suited for use with the automated, ultra-low temperature storage and retrieval system disclosed in the above incorporated co-pending patent application, but certain aspects can also be used in other applications as well such as in a main freezer compartment in a −20° C. system.
The foregoing and other aspects, objects, features and advantages of the invention will be apparent to those skilled in the art from the following drawings and description of the preferred embodiment of the invention.
The figures illustrate various aspects of an exemplary embodiment of the invention.
The system 10, which incorporates a tube picking mechanism 20 constructed in accordance with the invention, is designed to store SBS footprint compatible tube storage racks containing tubes or vials. For example, the system 10 will be used to store tube racks containing arrays of 8 mm storage tubes, or tube racks containing arrays of 16 mm vials, or a combination of racks containing these tubes and vials of this size as well as other sizes. The system 10 generally includes an insulated freezer body 12, an internal freezer rack 18 and robot mechanism 14, a custom insulated door 16. The freezer body 12 can take the form of an upright −80° C. freezer body designed for ultra-low temperature storage for pharmaceutical, biotech, and blood bank applications.
Several components are on the insulated custom door 16 in this exemplary embodiment of the invention. The door 16 includes an access module 22 in which sample storage containers, such as tube racks, are placed in order for transfer into the storage shelves on the freezer rack 18 within the freezer body 12. An electrical control and pneumatic package is also mounted to the insulated door 16 as are servomotors and magnetic couplers for driving the robot 14. Three electric motors 17 on the door 16 for driving the robot 14 within the freezer body 12 are shown in
Referring now to
The tube picking mechanism 20 also includes a tube picking head 48 and a universal cache 46. The specific components of the tube picking head 48 are described in detail with respect to
The universal cache 46 is located, in accordance with the exemplary embodiment of the invention, within the tube picking chamber 24. The purpose of the cache 46 is to temporarily store picked tubes within the tube picking chamber 24 until an appropriate time for loading the picked tubes into a destination rack for extraction from the system. The universal cache 46 is configured in the exemplary embodiment of the invention to hold tubes and vials having a variety of sizes, for example, sizes ranging from 8 mm tubes to 16 mm vials. The cache 46 is aligned linearly along the x-axis underneath the picking head 48. The x-axis underneath the picking head 48 is located at a fixed distance along the y-axis which the rack shuttle 40 moves along. Generally, to pick a tube, the shuttle 40 is indexed along the y-axis within the tube picking chamber 24 in order to align a row of tubes in the storage rack on the shuttle 40 in the appropriate y-axis position for the picking head 48. The z-axis plate 52, carriage 50 and picking head 48 are moved along the x-axis to hover over a selected storage tube in the rack on the shuttle 40. The picking head 48 then picks the selected tube from the rack on the shuttle 40. Once the selected tube is picked from the rack, the z-axis plate 52, carriage 50 and picking head 48 are moved along the x-axis to a selected position over the universal cache 46, and the picked tube is set into the cache 46.
A sidewall 64 of the picking chamber 24 includes a one dimensional barcode reader 68, such as a DC-powered reader from Keyence. The one dimensional bar code reader 68 is mounted to the wall 64 so that its field of view extends into the tube picking chamber 24 in line with the tube picking head 48 and a mirror assembly 66. The mirror assembly 66 is provided on the carriage 50 for the picking head 48 on the side opposite the barcode code reader. As shown in
The z-axis plate 52 includes not only a vertical drive for the carriage 50 and picking head 48, but also a vertical drive for a presenter push pin assembly 70. The presenter push pin assembly 70 includes a vertical presenter push pin 72 that moves with the z-axis plate 52 such that it remains aligned along the z-axis of the picking head 48, and is configured to move up and down along the z-axis below the shuttle 40 and the universal cache 46. The presenter push pin 72 is mounted via a mounting bracket attached to the end of an L-shaped presenter arm 74. The presenter arm 74 has a vertical rail 78 that is mounted via linear bearings 76 on the z-axis plate 52. A stepper motor mounted to the z-axis plate 52 drives a pulley and belt, and the presenter arm 74 is clamped to the belt such that operation of the stepper motor causes the presenter push pin 72 to move upward or downward along the z-axis for the picking head 48. Note that the motion of the presenter arm 74 and pin 72 along the z-axis can be independent of the z-axis motion for the picking head 48.
Referring to
The tube gripping mechanism 80 has an upper plate 82 and a lower plate 84, which house the components of the spring loaded linkage mechanism. The upper plate 82 has a central opening 86, and the lower plate 84 also has a central opening 88, which is aligned with the central opening 86 on the upper plate 82 when the mechanism 80 is assembled. The plates 82, 84 include slotted openings 126A, 126B, 126C, 126D and 128A, 128B, 128C, 128D for guiding the motion of linkage rods 102, 104, 106 and 108, which in turn moves the ends of the linkage arms 94, 96, 98 and 100 to position the gripping jaws 90, 92 in response to the activation of the pneumatic actuator 116 and the shifting of the u-bracket 114. Referring to
Each side of the u-bracket 114 includes a triangular opening 130A, 130B, each having an angular cam surface 130A, 130B. When the actuator 116 is activated to extend the u-bracket 114 as shown in
The components of a universal cache 46, constructed in accordance with the exemplary embodiment of the invention, are shown unassembled in
Each vertical cam plate 138 has a center of mass offset from the respective axel 140A, 140B such that the plate rotates towards the home position unless a sample tube is placed in the cache 46 between the banks 136A, 136B. In the embodiment shown, there are three holes in each vertical cam plate 138, namely hole 152 which is used to mount the cam plate on the respective axel 140A, 140B and holes 154 which are included to lighten the respective side of the cam 138 and shift the center of mass so that it naturally rotates to the home position. The longitudinal homing plates 150A, 150B for each bank 136A, 136B stops the rotation of the respective vertical cam plates in the home position.
Referring to
It can be seen that cache 46 is capable of accepting and holding tubes and vials having a variety of diameters. For small tubes having a diameter of 8 mm it is desirable that the distance 158 between the arcuate inner edges 156 of opposing cam plates 138 be approximately 5 mm. This ensures that a sufficient number of cam plates 138 are displaced and rotate when the tubes are inserted. It is possible to adjust the distance 158 in the embodiment of the cache 46 shown in the drawings, e.g. in case the range of diameters of the tubes or vials expected to be stored in the cache 46 needs to be accommodated. The distance 158 is adjusted by changing the height of the respective homing plates 150A, 150B on the cache base 142, which in turn changes the rotational orientation of the cam plates 138 when they are in the home position, but also changes the distance 158. In practice, the adjustment can be done by providing a fixture with a calibrated rib through the slot 148 and between the inner edges 156 of the cam plates 138. Then, the height of the longitudinal homing plates 150A, 150B is set to the appropriate height to support the cam plates 138 defined by the calibrated rib.
The exemplary embodiment of the invention has been described herein with respect to use with an ultra-low temperature (−80° C.), automatic storage and retrieval system. However, many of the features described herein may be useful in storage systems that store samples at freezing temperatures above or below the ultra-low temperature range. Those skilled in the art should appreciate that these features, among others, while useful in connection with tube picking mechanisms located in a tube picking chamber adjacent an ultra-low temperature (−80° C.) freezer compartment, are also useful in other applications as well. For example, the tube picking mechanism can be used in applications outside of or not including a cold chamber.
| Number | Date | Country | |
|---|---|---|---|
| 62741053 | Oct 2018 | US |
