Abstract:
A method and apparatus for efficient dispensing of desiccant canisters into containers is disclosed. The apparatus includes a microprocessor that monitors a plurality of sensors, and applies control signals to a servomotor that controls a rotary disc that transports desiccant canisters from a drop chute to containers. The containers pass through the apparatus via a conveyor system. Control signals determine the position and presence of desiccant canisters and containers to ensure proper operation. Error detection and recovery features are provided to handle the case of a missing desiccant canister, and halt the apparatus upon detection of an unrecoverable error.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates packaging equipment systems. More specifically the present invention relates to a method and apparatus for automating the delivery of desiccant canisters into a container.  
       BACKGROUND  
       [0002]     Desiccants are often included in a packaged product to reduce moisture within the packaging. In particular, for pharmaceutical, food, chemical, and personal healthcare products, there is often a need for a desiccant to be placed in the container along with the product. To facilitate mass production, it is desirable to provide an efficient means for dispensing desiccant canisters into the product containers.  
       SUMMARY OF THE INVENTION  
       [0003]     The present invention provides an improved method and apparatus for automating the delivery of desiccant canisters into a container. The apparatus of the present invention has a microprocessor that receives input signals from various sensors that provide information about the presence and position of desiccant canisters and containers. The microprocessor utilizes the information provided by these sensors to determine the appropriate control parameters for the motor and air flow that serve to move the desiccant through a predetermined path to the container.  
         [0004]     It is an aspect of the present invention to provide a desiccant dispensing apparatus that can accommodate various different sized containers at a reduced cost. The apparatus of the present invention accomplishes this by eliminating the star-wheel commonly found on desiccant dispensing machines. Typically a separate star-wheel and corresponding dispenser disc would be required for each configuration. By eliminating the star-wheel, the cost for accommodating multiple configurations is dramatically reduced.  
         [0005]     It is another aspect of the present invention to provide a desiccant dispensing apparatus with reduced changeover time. The present invention utilizes a dispenser disc that accommodates all container sizes. There is no star-wheel to change out, hence changeover time is reduced.  
         [0006]     It is another aspect of the present invention to provide a desiccant dispensing apparatus that provides a more precise placement of desiccant within the container. This is accomplished in the present invention by bring the dispensing disc to a complete stop before dispensing the desiccant canister. Other dispensing apparatuses dispense desiccant while the dispensing disc is rotating. This causes the desiccant to be dispensed with an angular motion due to momentum and centrifugal force. With the apparatus of the present invention, the desiccant is dispensed into the container in vertical attitude.  
         [0007]     It is another aspect of the present invention to provide increased throughput. The apparatus of the present invention includes a microprocessor based control system that allows desiccant to be dispensed at a higher rate than continuously rotating dispensing devices, which operate in the general range of 1 to 50 rpm typically. The dispensing apparatus of the present invention has an operating range of approximately 2000 rpm, which is considerably faster.  
         [0008]     The desiccant dispensing apparatus of the present invention will be referred to as a Canister Desiccant Feeder Rotary (CDFR) for the purposes of this disclosure.  
         [0009]     The aforementioned aspects, and other advantages of the CDFR will be explained in detail in the following sections. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a side view of a rotary desiccant feeder method and apparatus of the present invention.  
         [0011]      FIG. 2  is a transverse sectional view showing internal parts for the rotary desiccant feeder.  
         [0012]      FIG. 3  is a front view of the rotary desiccant feeder.  
         [0013]      FIG. 4  is a perspective view of the rotary desiccant feeder.  
         [0014]      FIG. 5  is a top plan view of the rotary desiccant feeder.  
         [0015]      FIG. 6  is an exploded perspective view of the rotary desiccant feeder.  
         [0016]      FIG. 7  is a side view of the desiccant dispensing apparatus and system showing containers passing through the desiccant loading station.  
         [0017]      FIG. 8  is a transverse sectional view showing desiccant discharging into containers.  
         [0018]      FIG. 9  is an end view showing containers aligned with the desiccant discharge station.  
         [0019]      FIG. 10  is a top plan view showing empty containers before the discharge station and filled containers downstream of the desiccant feeder apparatus and system.  
         [0020]      FIG. 11  is a transverse sectional view showing various stations including a transfer station (St), the desiccant sensing station (Ss), the discharge station (Sd) and the empty discharge station (Se).  
         [0021]      FIG. 12  is a perspective cutaway view showing various stations including a transfer station (St), the desiccant sensing station (Ss), and the discharge station (Sd).  
         [0022]      FIG. 13  is a system block diagram of the dispensing apparatus of the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0023]     Referring to  FIG. 13 , microprocessor  105  is configured to receive input from a plurality of sensors  110  provide information about the presence and position of desiccant canisters and containers. The sensors include a container present sensor  125 , desiccant present sensor  130 , desiccant drop sensor  5 , and a dispenser disc home sensor  15 . Microprocessor  105  is also in communication with a servomotor  4 . The servomotor  4  includes an integrated servomotor controller  4   a , which controls the servomotor that moves the transport mechanism that moves the desiccant canisters. Microprocessor  105  is also connected to a user interface  120  that allows the user to configure the apparatus for a particular job, and provides feedback, such as operating parameters and statistics, to the user.  
         [0024]     The reader should now refer to  FIGS. 1 through 12  for the following description. Canister desiccants are fed to the CDFR from a bowl sorting device that arranges the desiccant into a single column of desiccant canisters in a base up and base down attitude. The desiccant canisters are transferred to the CDFR via drop chute  18 . Drop chute  18  is connected to CDFR dispenser housing  1  via chute adapter flange  16 . A rotary disc  12  in the CDFR has a plurality of vacant areas with rotary disc  12 , referred to as pocket holes, generally referenced as  12   a . These pocket holes  12   a  are used to transport desiccant canisters from the chute adapter flange  16 , to a container  30 . As the rotary disc  12  rotates, pocket holes  12   a  are passed through three key positions (See  FIG. 11 ): Transfer station (St) is the position where the desiccant canister is transferred from the drop chute  18  to the rotary disc  12 . Sensing station (Ss) is where the presence of a desiccant canister is verified. Discharge station (Sd) is where the desiccant canister is released into a waiting container  30  (See  FIG. 9 ). While the embodiment shown uses a separate transfer station (St) and sensing station (Ss), it is possible to combine the transfer station (St) and sensing station (Ss) into a single position. The flow of the desiccant canister through these key positions will now be described.  
         [0025]     The desiccant canister  29 , upon traveling through drop chute  18 , lands at transfer station (St) in a pocket hole of rotary disc  12  (see  FIG. 11 ). The CDFR has an integrated servomotor  4  and servomotor controller  4   a . For the purposes of this disclosure, the integrated servomotor and servomotor controller will be referred to simply as “servomotor”. Servomotor  4  is attached to CDFR dispenser housing  1  and rotates the disc mounting hub  10  via planetary gearbox  3  to provide the rotary motion to the CDFR dispenser disc  12  (See  FIG. 6 ). A CDFR dispenser housing nose  9  is removable to provide access to the CDFR for maintenance and servicing. Power and input/output (IO) lines are connected to servomotor  4  via a plurality of cables, indicated as items  24  and  25  in  FIG. 6 . The  10  signals are connected to microprocessor  105  via a wiring harness (not shown) to allow microprocessor  105  to monitor input from the sensors, and issue the appropriate commands to servomotor  4 .  
         [0026]     Servomotor  4  indexes rotary disc  12  to sensing station (Ss). At sensing station.(Ss), desiccant present sensor  130  receives input from diffuse fiber optic cable  13  to verify the presence of a desiccant canister  29  in pocket hole  12   a  of rotary disc  12 . A container present sensor  125 , comprised of laser beam receiver  7  and laser beam emitter  8  (See  FIG. 9 ) detect the presence of a container underneath discharge station (Sd). If a container is detected at discharge station (Sd), then rotary disc rotates to transport the desiccant canister  29  from sensing station (Ss) to discharge station (Sd) whereby the desiccant canister  29  drops by gravity into the container  30  at the discharge station (Sd). A desiccant drop sensor  5 , preferably an optical sensor, verifies that the desiccant canister  29  successfully dispensed into container  30 . The pocket hole  12   a  is now empty, and is able to receive another desiccant canister to be dispensed.  
         [0027]     Typical configurations of rotary disc  12  would provide a pocket hole  12   a  arrangement conducive to the desiccant size in grams, based on the height and diameter of desiccant canister  29 , and the maximum number of desiccant canisters to be dispensed into the container  30 .  
         [0028]     The number of desiccant pockets holes  12   a  in an arrangement is divided into 360 degrees of rotary disc  12  at equal angles around the center point, i.e. Example configurations include 6 pocket holes at 60 degree increments, and 4 holes at 90 degree increments. Other configurations are possible without departing from the scope of the present invention.  
         [0029]     The pocket holes  12   a  are arranged on rotary disc  12  at predetermined radius Rh. For each pocket hole  12   a , a corresponding dowel pin  26  is pressed in to rotary disc  12  along the centerline between center of pocket hole  12   a , and center of rotary disc  12  at radius Rd (See  FIG. 12 ). Dowel pins  26  are utilized provide feedback of the pocket hole  12   a  location to the servomotor  4 .  
         [0030]     The servomotor  4 , via its integrated motor controller, provides an encoder pulse count for positioning the desiccant pocket holes  12   a  within the rotary disc  12  to align with the CDFR dispenser housing cover  2  and the discharge hole  2   a  in the CDFR dispenser housing cover  2  (See  FIG. 2 ). An incremental motion profile equal to the angle of the desiccant pocket holes  12   a  in the rotary disc  12  and the encoder pulse count ensure the motion for incremental move of the rotary disc  12  aligns to the discharge hole  2   a  in the CDFR dispenser housing cover  2 . The servomotor  4  allows for the user to contour the profile of the rotary disc  12  motion for a given desiccant size and weight, container size and output rate. Program parameters of the servomotor  4  include the acceleration, deceleration and velocity of the rotary disc  12  to achieve a given output rate.  
         [0031]     To index a pocket hole  12   a  to the next position, the servomotor  4  rotates rotary disc  12  until the next dowel pin  26  arrives at disc home sensor  15  (See  FIGS. 4 and 6 ). In a preferred embodiment, disc home sensor  15  is an inductive proximity sensor that serves as a dowel sensor. Thus, by locating the position of the dowel  26 , the corresponding pocket hole  12   a  is in a known position. Servomotor  4  rotates a predetermined number of degrees, based on the configuration of rotary disc  12 . For example, if rotary disc  12  has  6  pocket holes  12   a , then servomotor  4  will rotate 60 degrees. The fine positioning of the rotary disc will then be performed, based on feedback from disc home sensor  15 .  
         [0032]     The CDFR provides error monitoring and recovery functions during its operation. During normal operation, containers are delivered to the desiccant feeder of the present invention by conventional conveyor systems and are aligned so that the open end of the containers is properly aligned and passes under the discharge station (Sd). Specifically,  FIG. 8  shows a plurality of containers, indicated as reference  30 , on a conveyor (not shown) that are to receive a desiccant canister from the CDFR. Container  30   a  is at discharge station (Sd). Desiccant canister  29   a  is about to be dispensed into container  30   a . Containers indicated as  30   b  already have received a desiccant canister  29   b.    
         [0033]     If no desiccant canister  29  is sensed at the sensing station (Ss), an error signal E 1  is generated (See  FIG. 13 ). This signal can serve to stop or slow the conveyor. As an initial error recovery strategy, rotary disc  12  is rotated to place the next pocket hole  12   a  at the sensing station (Ss). If a desiccant canister  29  is now present, error signal E 1  is cleared, and normal operation resumes. This allows operation to continue uninterrupted, even if a desiccant canister occasionally fails to arrive at transfer station (St) during a particular cycle. After a predetermined number of attempts, the CDFR is halted, as a more serious error is likely. Similarly, at discharge station (Sd), if desiccant drop sensor  5  does not detect a desiccant canister dispensing into container  30 , error signal E 1  is generated, and the CDFR is halted.  
         [0034]     If a jam at the discharge station (Sd) prevents dispensing of desiccant canister  29 , the rotary disc  12  rotates desiccant canister  29  beyond the discharge station (Sd) to the exit station (Se), whereby the desiccant canister can then exit the CDFR.  
         [0035]     Accordingly, the reader will see that the present invention provides an efficient means for dispensing desiccant canisters into containers. Although the descriptions above contain many specific details, these should not be construed as limiting the scope of the invention, but merely as providing illustrations of some of the presently preferred embodiments of this invention. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.