Patent Publication Number: US-9850039-B2

Title: Cap for automatic test tube recapper

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to the field of medical and forensic science testing equipment. More particularly, a cap for a test tube recapper for recapping test tubes after the contents of the test tubes has been used is presented. 
     In the medical and forensic science fields test tubes are normally used to contain blood, saliva, swab and other specimens taken from the human body. These test tubes are generally cylindrical in shape with an open top. Test tubes usually have several standard diameters, namely approximately 13 mm or 16 mm. They can also come in standard heights, namely approximately 75 mm or 100 mm. The test tube is usually capped with an original rubber or plastic stopper at the top to prevent contamination of the specimen and to protect the sample and keep it inside the test tube. 
     Test tubes are used in large quantities, particularly in the medical and pharmaceutical industries and in forensic laboratories. Larger labs or hospitals may test as many as 10,000 specimens per day, using 10,000 test tubes and caps. Once the tests have been accomplished, it is necessary to recap the specimen test tubes for proper storage. It is an object of this invention to provide a unique and specialized cap for a machine that automatically recaps test tubes once the tests have been done. 
     Since test tubes come in different diameters, it would be useful and economical to have a single cap capable of capping several different diameter tubes. It is another object of this invention to provide a single test tube cap that is able to receive several standard size diameter test tubes. 
     Since standard test tubes used in the laboratory come in different heights, it would be convenient and economical to provide a machine that is capable of recapping different height test tubes. It is a still further object of this invention to provide a cap for an automatic test tube recapper that is capable of recapping test tubes of different heights and diameters. 
     Other and further objects of this invention will become obvious upon reading the below described specification. 
     BRIEF DESCRIPTION OF THE INVENTION 
     A fully automatic test tube recapper capable of recapping thousands of test tubes per day of various sized test tubes has an upper hopper with a triangular cross-section for receiving specially designed test tubes caps. The caps are poured into the hopper and are contained within the hopper in random orientations. A pair of spaced apart silicon transport belts is separated by the diameter of the caps. These continuous belts transport the caps upwards towards a slide. Properly aligned caps are then transferred to the slide. The slide slopes downwardly toward a capping station. Misaligned caps are ejected from the transport belt before they reach the slide and are fed back into the hopper. 
     Caps are lined up and stopped at the bottom of the slide by a cap incrementing disc that allows one cap per cycle to drop onto a cap catch station. Directly above the cap catch station is a hammer drive. Directly below the cap catch station is the uncapped test tube. 
     As the hammer cycle begins, the hammer shaft is driven downwardly into the top of the cap. The cap then releases from its cap catch and is inserted into the top of the test tube. The hammer drive is located on a movable, spring-loaded base that has a movement sensor. When the cap is firmly inserted into the test tube, the hammer base rises. The reversed direction of the hammer base signals the device to withdraw the hammer shaft from the cap. As the hammer shaft rises, the incrementing disc releases another single cap into the cap catch as the conveyor for the test tube rack moves the test tube rack and a new uncapped test tube under the cap catch station. The cycle then repeats itself. 
     The caps are adapted to receive different diameter tubes. Since the hammer shaft stops and reverses only once the caps have been firmly inserted into the test tubes, the device is capable of recapping different height test tubes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         FIG. 1  is a perspective view of the device showing the major components. 
         FIG. 2  is a side view of the test tube cap. 
         FIG. 2A  is a top view of the cap. 
         FIG. 2B  is a perspective view of the top of the cap showing the notch in the nipple. 
         FIG. 3A  is a partial top view of the hopper. 
         FIG. 3B  is a side cutaway view of the lower part of the cap transport mechanism. 
         FIG. 4  is a partial perspective view of the hopper, transport and hammer assemblies. 
         FIG. 5  is a partial perspective view at the upper transport pulley area. 
         FIG. 6  is an end view of the upper transport assembly at the upper pulley. 
         FIG. 7A  is partial perspective view of the cap reject module. 
         FIG. 7B  is a top view of the cap reject module. 
         FIG. 7C  is a partial perspective view of the cap reject module. 
         FIG. 8A  is a cross-sectional view of the cap transport mechanism taken along the lines  8 A of  FIG. 5  showing a correctly loaded cap. 
         FIG. 8B  is similar to  FIG. 8A  but shows an incorrectly loaded cap. 
         FIG. 8C  is similar to  FIG. 8B  but shows the incorrectly loaded cap discharging from the belts near the top edge of the upper transport pulley. 
         FIG. 9  is a perspective view showing the area of the discharge of rejected caps back into the hopper. 
         FIG. 10  is a partial perspective view of the hammer assembly. 
         FIG. 11  is a partial side view of the incremental cap mechanism. 
         FIG. 12  is a partial top view of the incremental cap mechanism. 
         FIG. 12A  is a side view of the incremental cap mechanism showing the cap tumbling towards the cap catch. 
         FIG. 13  is a partial perspective view of the lower end of the cap transport assembly and the lower end of the hammer assembly. 
         FIG. 14  is a perspective view of the cap catch mechanism. 
         FIG. 15  is a detail perspective view of the upper drive section of the hammer mechanism. 
         FIG. 16  is a perspective view of the test tube racks and test tubes. 
         FIG. 17  is a top view of the star positioning wheel. 
         FIG. 17A  is a partial perspective view of the star positioning wheel. 
         FIG. 18  is a schematic diagram showing the automatic electronic functioning of the initial set up of the device. 
         FIG. 19  is a schematic diagram showing the automatic electronic functioning of the operation of the device. 
     
    
    
     DETAILED DESCRIPTION OF THE DEVICE 
     An automatic test tube recapping system  1  for placing hopper caps  3  onto test tubes comprises a cap hopper  2 , a transport assembly, a cap slide  4 , and a hammer assembly  6 . Test tubes  8  are loaded into trays at input bay  7  and moved on a standard conveyor belt underneath the hammer assembly  6  for recapping. The random caps  3  are transported and aligned by a cap transport assembly driven by drive assembly  5 , to be described later. The caps  3  slide down cap slide  4  and are positioned between the hammer shaft  41  and test tubes  8  for recapping. The area near the positioned test tubes  8 , cap catch  33  and hammer shaft  41  is described as the cap position station  55 . The recapped test tubes  8  and rack  50 , located on lower base  10 , then travel to output bay  9  to be removed from the machine and stored. These major elements of the device are shown in  FIG. 1 .  FIG. 1  is shown as the device is commercially delivered with coverings on some components such as the transport drive assembly  5  and the hammer assembly  6 . More detailed drawings of these assemblies are shown and described later in other drawings and the Specification. 
     The caps utilized in this machine are unique and were developed for the particular purpose of this device. The unique cap is best shown in  FIGS. 2, 2A and 2B . Since most test tubes are manufactured in two diameters, either 13 or 16 mm, the cap should preferably be able to accommodate those different diameters. The standard diameters are shown by the dimension arrows on  FIG. 2 . 
     Turning to  FIG. 2A , the unique shape of the instant cap is shown. The cap  3  is hollow with a conical body and has an upper circular top  11 . Below the top  11  of the cap  3  is a second, middle section  12  of the cap. Section  12  is integrally connected to the top  11  and has a diameter of approximately 16 mm. Below the middle section  12  of the cap is a lower small tube section  13 . This lower small tube section  13  is also integrally connected to the top  11  and middle  12  of the cap and has a diameter of approximately 13 mm. The top, middle and lower sections all have flanges adapted to receive various diameter test tubes. The bottom of the cap  3  has a rounded end  14 . Most other test tube caps do not have the two distinct sections  12  and  13  or the rounded end  14 . The rounded end  14  helps to insert the cap  3  into a test tube  8  even if the central axis of the cap and test tube are slightly off center. 
     The inside surface of cap  3  has an added feature unique to this invention. The inner surface has a plurality of nipples  15 , spaced apart from each other, as best shown in  FIG. 2A , for receiving and gripping the hammer shaft. At least one but preferably three equally spaced nipples  15  are shown in the drawing figure and are preferred, but a different number of nipples or spacing of the nipples is still within the spirit and disclosure of this invention. Each nipple  15  has a notch  57  removed therefrom. This notch  15  is adapted to receive a small circumferential raised ridge  57 ′ located on the very lower end of hammer shaft  41 . The nipples  15  and notch  57  allow the caps to remain on the lower end of the hammer drive shaft  41  and to be removed therefrom during operation of the invention. 
     Turning now to  FIG. 3A , the construction and configuration of the hopper  2  is shown. The hopper has an essentially square cross-section from the top and an essentially triangular cross-section from top to bottom. The inside sides  16  of the hopper  2  are essentially triangular and slant inwardly from top to bottom as shown. Running through the approximate center of the hopper at its lowest central point  17  is a transport beltway  19 . 
     The beltway is best shown on  FIGS. 3A, 3B, 4 and 6 . The beltway housing comprises identical, mirror image sides  19 ′ as best shown on  FIG. 6 . Each side  19 ′ of the beltway has an indented metal surface designed to accept a pair of left and right identical and continuous silicon transport belts  18 . The beltway runs from the lower, bottom  17  of the hopper  2 , through one side of the hopper, and upwards toward the upper cap transport drive assembly  5 . 
     At the lower end of the transport assembly are two pulleys  20  and  21 . The hopper pulleys  20  and  21  are located near the surface of hopper side  16  as shown in  FIGS. 3A and 3B . The discharge drive pulley  21  is located above the hopper  2  and near the top of the cap slide  26 . 
     Belts  18  are continuous and wrap around lower pulleys  20  and  21  and upper transport drive pulley  22 . The drive pulley  21  turns in the counterclockwise direction in  FIG. 3B , driving the belts  18  in the direction of the arrow, from left to right on the lower part of the transport mechanism and right to left on the upper part of  FIG. 3B . 
       FIG. 4  shows the position of the various assemblies in relation to each other in the device. The lower part  19 ″ of the belt way is the part that runs through the inner hopper surface. This lower beltway  19 ″ carries caps upwards to the top part of the device, near the pulley drive motor  23 . Randomly deposited hopper caps  3  fall into the beltway and onto the silicon belts  18  and are transported on the belts to the top of the device. Properly positioned caps are then reversed, as will be explained, and travel down cap slide  26  to the recapping position. 
     Turning now to  FIGS. 5 and 6 , the operation of the beltway and belts is shown. The device has a belt drive means comprising an upper drive pulley  22  connected to drive motor  23  and drive motor output shaft  23 ′ as shown and at least one lower pulley. The drive motor  23  moves the belts  18 . Belts  18  are preferably made of urethane but can be made of other materials as well. Caps drop onto the beltway in a random orientation. Many caps will fall into proper alignment. A properly aligned cap  24  is held between the pair of belts  18  by frictional forces.  FIG. 5  shows the properly aligned cap  24  as it approaches the very top of the transport assembly. 
     As the properly aligned cap  24  is positioned on the upper pulley  22 , near the upper part of the cap slide  26 , its orientation is reversed  24 ′, as best shown in  FIG. 6 . The upper drive pulley  22  has a central circumferential discharge ridge  25  located in the center of the upper drive pulley  22  as shown. This discharge ridge is important to the discharge and recycling of improperly aligned caps, as will be explained later. 
     The cap slide  26  runs above the lower part of the continuous transport beltway as shown in  FIG. 6 . At the top of the cap slide  26  is a cap slide groove  27 . The smaller, rounded end  14  of a properly aligned reversed cap  24 ′ rides in the cap slide groove  27 . The gripping top  11  of the reversed cap  24 ′ rides on a cap slide guide  28 . The properly aligned cap  24 ′ slides down cap slide  26  into the lower, loading position, as will be explained later. As can be seen from the drawing figure, the belts  18  are completely disengaged from contact with the reversed cap  24 ′ at this point. 
     Located at the upper end of the continuous beltway near the drive motor  23  and drive pulley  22  is a cap reject module  29 , as best shown in  FIGS. 7A, 7B and 7C . (The top view of  FIG. 7B  is rotated 90 degrees clockwise from  FIG. 7C .) This cap reject module has an irregular shape, as best shown in  FIGS. 7A and 7B . The reject module has a slanted surface  30  located under the belts  18  that is slanted downwardly and away from the drive pulley  22 . This slanted surface  30  is integrally connected to a cap discharge surface  31 . The cap discharge surface  31  is slanted downwardly toward the hopper bin, as shown in  FIG. 9 . Improperly aligned caps will fall to the bottom right of  FIG. 9  and are recycled into the hopper bin  2 . The upper part of the device and hopper bin  2  are best shown in  FIG. 1 . 
     Since the hopper caps  3  fall onto the transport belts in a random fashion and orientation, some caps will not lodge between the belts with the top suspended by the belts and the bottom oriented downward as is the case of a properly aligned cap  24  shown on  FIG. 8A . An improperly suspended cap  32 , as best shown of  FIG. 8B , would lay in the general horizontal orientation or in some other oblique orientation as shown. Since the diameter of a cap gripping top  11  is shorter than the length of the cap from top to bottom, a cap that does not fall as shown in  FIG. 8A  will fall onto and ride upon the belts  18  in an improper orientation a shown in  FIG. 8B . 
     As the improperly oriented cap  32  rides upwards and reaches the area of the upper part of the cap slide  26  and upper transport pulley  22 , the improperly aligned cap  32  either falls off the transport belts  18  by the force of gravity or comes into contact with pulley discharge ridge  25  which forces the improperly orientated cap  32  off the belts  18  supporting it as shown in  FIG. 8C . Either way, the rejected improperly aligned caps  32  fall onto surface  30 . Improperly aligned caps  32  fall onto the top slanted surface  30  of the reject module  29 , and roll by gravity toward surface  31  and ultimately back into the hopper. 
     Whereas a properly aligned cap  24 , aligned as shown in  FIGS. 8A and 6 , will stay suspended by the belts  18 , an improperly aligned cap  32  will fall from the belts  18  to be recirculated into hopper  2 . 
     As best shown in  FIGS. 5 and 6 , the path of the properly aligned and reversed cap  24 ′ is shown. A cap slide  26  has a top end located on the top of said hopper and slopes downwardly towards a lower cap catch. The cap slide  26  houses the smaller part  13  of the cap and the cap top  11  slides on the cap slide guide  28 . Reversed cap  24 ′ slides down the cap slide  26  to the bottom of the slide. The cap slide slopes downwardly toward the lower cap stop station. 
     As best shown on  FIG. 10 , located at the end of the slide  26  is a cap catch  33 . Hammer shaft  41  is above the bottom of cap slide  26  and cap catch  33  as shown. Upside down but correctly loaded reversed caps  24 ′ are incrementally allowed to tumble into cap catch  33  by the mechanism best shown on  FIGS. 11 and 12 . 
     A pair of cap incremental loading arms each has a lower end  34  and an upper end  35 . The upper ends  35  of the loading arms are rotatably connected to a cap incrementing disc or wheel  36 . The upper ends  35  of the loading arms are connected in an off-center position on disc  36  as shown to create a circular motion of the disc when the arms are pushed upwards. The incrementing wheel  36  rotates about its central axis  36 ′. Disc  36  has a cap receiving cut-out  37 , shown on  FIG. 11  in phantom lines, removed from it as shown. The cut-out makes the disc resemble a PAC-man icon. This cut-out  37  is adapted to receive one cap  24 ′ for each cycle of the loading arms. 
     The lower part  34  of the loading arms is slidably connected to the hammer shaft  41  above the cap incrementing lift  38 . The incrementing lift  38  is permanently attached to the hammer shaft  41 . As the hammer shaft  41  cycles, it rises and lifts the cap incrementing lift  38 , which in turn lifts the loading arm, which rotates the cap incrementing disc  36 . The disc then cycles a new single cap  24 ′ per cycle into the cap catch  33 . 
     As each single cap  24 ′ is allowed to slide down the cap slide  26  past the incrementing disc  36  to the very bottom  39  of the cap slide, cap  24 ′ tumbles into cap catch. The force of gravity and the orientation of the slide causes the cap  24 ′ to flip over 135 degrees such that the top  11  of the cap is now orientated towards the top of the device and the bottom  14  of the cap is orientated downward. 
     The cap catch  33  may be funnel-shaped or square shaped but has three flat edges, parallel edges  33 ′ and third edge  33 ″. The three flat edges of the cap catch are connected by cap catch spring  40 . The cap top  11  has a flange as shown in  FIG. 2A . The top flange is slightly smaller than the length between parallel edges  31 ′ of the cap catch such that the cap  24  tumbles into the cap catch  33  as shown in  FIG. 14 . The spring  40  retains the cap  24 ′ in the cap catch  33  until the hammer shaft  41  drives the cap  24 ′ downwards. 
     Located above cap catch  33  is a hammer shaft  41 . Hammer shaft  41  is located directly above cap catch  33  as shown in  FIG. 13 . Hammer shaft  41  is a long cylindrical shaft with teeth  42  located on the shaft. Shaft  41  also has incrementing lift  38  attached to it near the bottom of the shaft. The loading arms are slidably connected on each side of the hammer shaft. The lower end  34  of left and right loading arms are positioned on each side of the shaft and above the lift  38 . Each time the hammer shaft  41  is raised, it pushes the ends  34  of the loading arms, which rotates the incrementing disc  36  such that another single cap  24  is ready to slide down the cap slide  26  and tumble into the now empty cap catch  33 . 
     Turning now to  FIGS. 10, 14 and 15 , the hammer plunger assembly is described. Above cap catch  33  and bottom of cap slide  39  are two platforms. Hammer assembly upper plate  43  is located above hammer assembly lower plate  44  ( FIG. 10 ). Lower plate  44  is supported by lower plate leg supports  47  legs and connected to the base  10  of the device as shown on  FIG. 1 . The upper plate  43  is movably connected to lower plate  44  by lower springs  46 . Rods  46 ′ connect the plates  43  and  44  as shown. Positioned around the upper part of connecting rods  46 ′ are upper springs  45 . Upper plate  43  is virtually suspended by springs  46  but the upward movement of upper plate  43  is limited by upper springs  45 . 
     A reversible drive motor  48  is fixedly attached to the top of plate  43  as shown. This drive motor has a drive gear  49  that mates with the teeth  42  on hammer shaft  41 . As the drive motor turns counterclockwise as shown in  FIG. 15 , the hammer shaft  41  moves on its downward stroke. When the lower end  56  ( FIG. 10 ) of hammer shaft  41  contacts the properly positioned cap  24 ′ positioned in cap catch  33 , the end of the hammer shaft moves into the inside of the cap and pushes on cap nipples  15 . As the hammer moves further downwardly, the spring  40  of cap catch  33  is forced outwardly, the edges  33 ′ of cap catch  33  expand and the cap  24 ′ is pushed out of the cap catch. This action is shown best on  FIG. 13 . Due to the frictional pressure between the lower end of the hammer shaft  41  and the nipples  15 , the cap  24  remains stuck to the end of shaft  41  as best shown in  FIG. 13 . 
     Cap  24 ′ is now frictionally loaded onto the end of hammer shaft  41 . One of the sections,  12  or  13 , of the cap is then firmly driven into the top of test tube  8 . If the test tube has a 13 mm diameter, the flange of section  13  seals the test tube; if the test tube has a 16 mm diameter, the flange of section  12  seals the test tube. 
     As the flange of the cap contacts the top rim of test tube  8 , the cap is in place and firmly secured. The hammer  41  now bottoms out. However, because plate  43  is spring loaded, top plate  43  along with the hammer motor  48  rise upwardly. The upward motion of the top plate  43  is detected electronically and causes the motor to reverse direction, withdrawing the hammer shaft  41  from the cap  24 ′. The stationary, spring loaded lower plate  44  absorbs the top plate falling down as shaft  41  releases the force lifting the top plate when it reversed its motion. 
     The binding force between the cap fully inserted into the test tube and firmly seated is greater than the snap force between the nipples  15  and the bottom of the hammer shaft. Therefore, when the hammer shaft moves upwards, the hammer shaft is released from the seated cap. 
     The upward motion of the shaft  41  creates contact between the upper part of lift  38  and the lower ends  34  of loading arms, which recycles the loading arms and allows a single new cap  24 ′ to be loaded into cap catch  33 . 
     One cap per cycle is loaded into the cap stop station. As the test tube is recapped, the hammer shaft withdraws upwardly, moving the loading arms and allowing another single cap to tumble onto the cap catch. The conveyor then automatically moves the test tube rack one test tube and positions another uncapped test tube under the cap and hammer shaft per cycle. 
     Test tubes  8  are loaded onto test tube racks  50  in a single line as shown in  FIGS. 16 and 17 . The test tubes  8  may be of varying diameters due to the unique sections  12  and  13  of the caps  3 . Further, because the hammer shaft may travel various distances before capping a test tube and bottoming out, the test tubes may also be of varying heights. 
     A positioning star  52  rotates around a hub  51  to incrementally detect the next test tubes as the assembly line proceeds. The next test tube is automatically advanced by the electronics. Horizontal positioning star  52  is located above the rack top  53  and between test tubes  8  and allows only one uncapped test tube at a time to be positioned at the cap catch station  55  located under the hammer shaft  41  and cap catch  33 . As a test tube is capped, the rack conveyor pushes the racks toward the outlet bay. Tine  54  is pushed from left to right in  FIG. 17 , releasing test tube  8 , now capped in its rack, to move towards the outlet bay. The next test tube in line,  8 ′ is then moved left to right and positioned at the cap stop station, under the cap catch  33  and hammer shaft  41  for the next capping cycle. 
     The device has many safety features and alarms so that automatic operation is accomplished. The electronic operation of the device, including the function of the sensors and meters, is best shown diagrammatically in  FIGS. 18 and 19 . 
     As shown in Diagram  18 , the device has sensors to detect whether or not the recapping cycle may begin. The first action is to move the hammer shaft  41  up a few steps. The reversible motor  48  then reverses and moves the hammer shaft downwards to a “Home” position, ready to recap the test tube provided a cap is in the cap catch. If the hammer does not reach the “Home” position, Alarm  1  is activated signaling a “Mechanical Error.” If the hammer is correctly positioned in the “Home” position, the device electronically checks to determine if a cap  3  is in the cap catch  33 . If the hammer shaft  41  is in the “Home” position and a cap is in the cap catch, the device is programmed to stop and await the “Start” command. 
     If a cap  3  is not in the cap catch  33 , the device cycles the hammer up and down again, which will cycle the loading arms  34 - 35  which should allow another cap to load into the cap catch. The device again checks for the presence of a cap in the cap catch. If a cap is now loaded into the cap catch, the device will stop and wait for the “Start” command. 
     If a cap is not now loaded in the cap catch, the device will then electronically check the cap slide  26  (referred to as “hopper slide” in  FIG. 18 ) and hopper  2 . First, sensors detect if the cap slide  26  is full. If it is, the device cycles the hammer shaft up and down through one or more cycles (‘N’) to again cycle the loading arms to advance the incremental disc  36 . If a cap is now in the cap catch, the device will stop and wait for the “Start” command. If not, the device signals another “Mechanical Error” in the cap advance system and Alarm  2  will be activated. 
     If the cap slide  26  is not full on initial detection, the device automatically turns on the transport drive motor  23  (referred to as “hopper motor” in Diagram  18 ) for a period of time (‘XX’). This operation should load more caps into the cap slide if caps are available. If this operation does not result in the cap slide sensor showing a full cap slide, Alarm  3  will be activated showing that the hopper  2  is empty. However, if the cap slide  26  is now full, the hammer shaft cycles, which should load a cap  3  in cap catch  33 . If the device now senses a cap in the cap catch, it will stop and wait for the “Start” command. If a cap is still not in the cap catch Alarm  2  will be activated. 
     Sensors that are capable of determining if caps or other moving pieces of the invention are located in a particular position are well known in the art. These sensors, in and of themselves, alone and apart from the other mechanism shown and described herein, are not considered to be part of the novelty of this device. 
     Once the device determines that a cap  3  is in the cap catch  33  and the hammer shaft  41  is in the “Home” position, the device is ready to start. The operation of the device from the “Start” position will now be described. 
     Turning now to  FIG. 19 , a “Start” switch starts the input bay conveyor in motion for “YY” seconds, set by the operator, once the initializing procedure ( FIG. 18 ) is set for “Start.” If a rack  50  of test tubes  8  is available, the rack  50  advances on the conveyor through the cap station  55 . A single test tube  8  passes through the positioning star  52  until an uncapped test tube  8  is positioned under the cap catch  33 . The rack conveyor then stops. The uncapped test tube  8  need not be exactly centered under the cap  24 ′ since the cap  24 ′ has a rounded lower end  14 . The rounded lower end allows the cap  24 ′ in cap catch  33  to be pushed into the uncapped test tube  8  even if it is slightly off-center. Once the test tube is positioned, the hammer shaft drives the cap into the test tube and recaps the test tube. The hammer shaft bottoms out on the top edge of the test tube and the hammer base upper plate  43  is raised. The hammer motor  48  then reverses, the cap is released from the lower end of the hammer shaft, and the hammer shaft continues upwards until it reaches its “Home” position. As this action is cycled another uncapped test tube is advanced under the cap catch. The next cycle then begins with a new cap and uncapped test tube positioned in the correct recapping position. 
     Several safety features are built into the operation system of the invention. If for some reason the hammer shaft continues to drive the cap  24 ′ downward into the test tube without raising the hammer base plate  43 , a current overflow meter on the hammer motor  48  will stop the motor movement and activate Alarm  5 . If the cap  24 ′ is not released from the bottom of the hammer shaft  41 , Alarm  4  will activate. Alarms  4  and  5  signal to the operator that a mechanical error has occurred. 
     If no uncapped test tube is detected after the conveyor continues to advance the rack, all of the test tubes from that rack are now recapped. The fully recapped test tube rack is then conveyed into the output bay and the finished rack of recapped test tubes is pushed out of the device. Once this is accomplished, the device automatically advances the next rack of uncapped test tubes from the input bay to the tube detection station under the cap catch and the cycle repeats itself for each uncapped test tube in the next rack. If the output bay is full, Alarm  5  will activate to signal to the operator that the output bay is full. The output bay must then be emptied before another rack from the input bay is conveyed to the cap catch station. 
     Sensors that are capable of determining if an uncapped test tube, a recapped rack of test tubes or other moving pieces of the invention are located in a particular position are well known in the art. The current overflow meter of the hammer motor is also well known in the art. These sensors and meters, in and of themselves, alone and apart from the other mechanism shown and described herein, are not considered to be part of the novelty of this device. 
     This device is operated by a PLC, a programmable logic circuit. The PLC is the “brain” of the device and directs the various motors, sensors and meters to perform the functions described above. The function and operation of a PLC is well known in the art. The programming of the PLC to perform the above functions is not, in and of itself, apart from the device mechanisms described, considered to be part of the novelty of this invention. A person with ordinary skill in the art can program the PLC to perform the functions described herein. 
     Obviously, it is the interaction of the various major elements of this invention that comprise the novelty of the device. Minor variations of the parts and substitution of certain of the elements with equivalent elements is within the disclosure and novelty of this device. For example, the hopper  2  could take a slightly different shape or the beltway could be placed slightly differently. However, the disclosure herein is considered to be of the preferred embodiment.