Abstract:
A click pen applicator device that provides predetermined dosing of the formulation for precise application, and rapidly primes the formulation using the dosing click mechanism to prepare the applicator for use.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is based upon and claims the benefit of priority from the prior U.S. Provisional Application Ser. No. 61/415,522, filed on Nov. 19, 2010, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a click pen applicator device, and a method of using the click pen applicator device. 
     BACKGROUND 
     Existing pen applicators generally utilize a twist function for dispensing a formulation from the pen applicator. These twist pen applicators generally include a rotating portion that is twisted or rotated relative to the remaining portion of the applicator, thereby advancing a formulation contained within the twist pen applicator. However, such twist pen applicators do not provide a predetermined dose of the formulation since the rotating portion is generally freely rotatable. Accordingly, a user is required to make a determination as to the appropriate amount of the formulation to dispense for a particular application. In addition, twist pen applicators may suffer from sealing problems. Further, such twist pen applicators generally require a substantial number of rotations of the rotating portion before the twist pen applicator is primed and ready to dispense the formulation. 
     Click pen applicators generally include an actuating portion that is pressed, or clicked, relative to the remaining portion of the applicator, thereby advancing a formulation contained within the click pen applicator. Further, such click pen applicators are conventionally known to have sealing problems that may render them less desirable than twist pen applicators, especially for formulations that may require better sealing, such as those that may tend to evaporate or experience weight loss over time. Further, click pen applicators also generally require a substantial number of clicks of the actuating portion before the click pen applicator is primed and ready to dispense the formulation. A prior art click pen  170  is illustrated in  FIGS. 17 and 18 . 
     Thus, existing pen applicators share the common problems of inadequate sealing, uncontrolled delivery of the formulation, and excessive number of actuations before the applicator is primed and ready for use. For example, inadequate sealing may result in the formulation&#39;s evaporating while the applicator is merely in storage between uses. In addition, uncontrolled delivery may result in a user&#39;s applying too much or too little of the formulation for the particular application, potentially having harmful or ineffective results. Further, excessive number of actuations for priming may lead to a user&#39;s believing that the applicator is broken, non-functional, empty, dried up, or otherwise unusable, when the applicator is in fact functional but not yet fully primed for use. 
     SUMMARY 
     Accordingly, there is a need for an applicator that improves sealing of the formulation to reduce evaporation and/or weight loss, provides predetermined dosing of the formulation for precise application, and rapidly primes the formulation to prepare the applicator for immediate use. 
     In a non-limiting embodiment of the present invention, a device for dispensing a formulation comprises a centerband having a proximal end and a distal end and defining a storage section having the formulation disposed within; an applicator section situated at the distal end of the centerband; and a multistage actuator section situated at the proximal end of the centerband for rapid priming with a click dispensing mechanism with a piston seat having two sets of external threads on a shaft with an unthreaded length therebetween. 
     In an alternative non-limiting embodiment of the invention, the multistage actuator section comprises a spiral having internal threads configured to engage with the external threads of the piston seat; and a priming spring operatively engaged between the piston seat and the spiral. 
     In an alternative non-limiting embodiment of the invention, the two sets of external threads of the piston seat have a same pitch. 
     In an alternative non-limiting embodiment of the invention, a first set of the two sets of external threads includes a length shorter than that of a second set of the two sets of external threads. 
     In an alternative non-limiting embodiment of the invention, a pitch of a second set of the two sets of external threads is configured to dispense a discrete dose with each dispensing actuation. 
     In an alternative non-limiting embodiment of the invention, the priming spring is configured to expand over the unthreaded length of the piston seat when the internal threads of the spiral do not engage the external threads of the piston seat. 
     In an alternative non-limiting embodiment of the invention, the multistage actuator section further comprises a cup attached to a distal end of the piston seat; a seal between the cup and the proximal end of the centerband; a gear operatively engaged with the shaft of the piston seat; a click spring operatively disposed between the gear and the spiral; and a spiral sleeve and a push button operatively engaged with the gear, the push button having a locking element. 
     In an alternative non-limiting embodiment of the invention, the applicator section comprises a passing seat attached to the distal end of the centerband; a seal between the passing seat and the distal end of the centerband; an orifice reducer situated inside the passing seat; a nose attached to a distal end of the passing seat; and a cap attached to the distal end of the centerband. 
     In an alternative non-limiting embodiment of the invention, the cap includes a pintel configured to seal at least one of the nose and the passing seat of the applicator section. 
     In an alternative non-limiting embodiment of the invention, the seal between the cup and the proximal end of the centerband is an o-ring, and the seal between the passing seat and the distal end of the centerband is an o-ring. 
     In an alternative non-limiting embodiment of the invention, the formulation comprises salicylic acid. 
     In yet another non-limiting embodiment of the present invention, a method of priming and dosing a formulation using a click pen dispensing device comprises priming the formulation at a priming rate using a click actuator with a piston seat having two sets of external threads on a shaft with an unthreaded length therebetween; and dosing the formulation at a dosing rate different from the priming rate using the click actuator. 
     In an alternative non-limiting embodiment of the present invention, the click actuator is actuated using one hand. 
     In an alternative non-limiting embodiment of the invention, the click actuator includes a locking element for preventing the priming and the dosing. 
     In an alternative non-limiting embodiment of the invention, the formulation comprises salicylic acid. 
     In an alternative non-limiting embodiment of the invention, the priming step includes at least one fine priming rate and a gross priming rate. 
     In an alternative non-limiting embodiment of the invention, the dosing step dispenses a predetermined dose of the formulation, and the priming step dispenses a predetermined priming dose of the formulation. 
     In yet another non-limiting embodiment of the present invention, a method of dispensing a formulation, using a device comprising a centerband having a proximal end and a distal end and defining a storage section having a distal end and a proximal end and having the formulation disposed within, an applicator section situated at the distal end of the centerband, and a multistage actuator section situated at the proximal end of the centerband, comprises priming the device by priming actuations of the multistage actuator section with a piston seat having two sets of external threads on a shaft with an unthreaded length therebetween, the priming step comprising a gross priming actuation displacing a volume greater than that of a predetermined dose; dispensing the predetermined dose of the formulation, via the applicator section, by subsequent dispensing actuations of the multistage actuator section; and applying the predetermined dose via the applicator section. 
     In an alternative non-limiting embodiment of the invention, the priming step comprises at least one fine priming actuation displacing a volume less than that of the gross priming actuation. 
     In an alternative non-limiting embodiment of the invention, the priming step comprises at least one fine priming actuation displacing a volume equal to that of the predetermined dose. 
     Other features and aspects of the present invention will become more fully apparent from the following brief description of the drawings, the detailed description of the non-limiting embodiments, the appended claims and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates a schematic perspective view of an exemplary embodiment of an assembled click pen applicator device according to the present invention. 
         FIG. 1B  illustrates a schematic side view of the exemplary embodiment of  FIG. 1A . 
         FIG. 1C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 1B  of the exemplary embodiment of  FIG. 1A . 
         FIG. 1D  illustrates a schematic top view of the exemplary embodiment of  FIG. 1A . 
         FIG. 1E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 1A . 
         FIG. 1F  illustrates a schematic perspective view of another exemplary embodiment of an assembled click pen applicator device according to the present invention. 
         FIG. 1G  illustrates a schematic side view of the exemplary embodiment of  FIG. 1F . 
         FIG. 1H  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 1G  of the exemplary embodiment of  FIG. 1F . 
         FIG. 1I  illustrates a schematic top view of the exemplary embodiment of  FIG. 1F . 
         FIG. 1J  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 1F . 
         FIG. 2A  illustrates a schematic perspective view of an exemplary embodiment of a centerband according to the present invention. 
         FIG. 2B  illustrates a schematic side view of the exemplary embodiment of  FIG. 2A . 
         FIG. 2C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 2B  of the exemplary embodiment of  FIG. 2A . 
         FIG. 2D  illustrates a schematic top view of the exemplary embodiment of  FIG. 2A . 
         FIG. 2E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 2A . 
         FIG. 2F  illustrates a schematic perspective view of another exemplary embodiment of a centerband according to the present invention. 
         FIG. 2G  illustrates a schematic side view of the exemplary embodiment of  FIG. 2F . 
         FIG. 2H  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 2G  of the exemplary embodiment of  FIG. 2F . 
         FIG. 2I  illustrates a schematic top view of the exemplary embodiment of  FIG. 2F . 
         FIG. 2J  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 2F . 
         FIG. 3A  illustrates a schematic perspective view of an exemplary embodiment of a passing seat according to the present invention. 
         FIG. 3B  illustrates a schematic side view of the exemplary embodiment of  FIG. 3A . 
         FIG. 3C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 3B  of the exemplary embodiment of  FIG. 3B . 
         FIG. 3D  illustrates a schematic top view of the exemplary embodiment of  FIG. 3A . 
         FIG. 3E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 3A . 
         FIG. 3F  illustrates a schematic perspective view of another exemplary embodiment of a passing seat according to the present invention. 
         FIG. 3G  illustrates a schematic side view of the exemplary embodiment of  FIG. 3F . 
         FIG. 3H  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 3G  of the exemplary embodiment of  FIG. 3G . 
         FIG. 3I  illustrates a schematic top view of the exemplary embodiment of  FIG. 3F . 
         FIG. 3J  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 3F . 
         FIG. 3K  illustrates a schematic side view of yet another exemplary embodiment of a passing seat according to the present invention. 
         FIG. 4A  illustrates a schematic perspective view of an exemplary embodiment of a sealing element according to the present invention. 
         FIG. 4B  illustrates a schematic top view of the exemplary embodiment of  FIG. 4A . 
         FIG. 4C  illustrates a schematic side view of the exemplary embodiment of  FIG. 4A . 
         FIG. 5A  illustrates a schematic perspective view of an exemplary embodiment of an orifice reducer according to the present invention. 
         FIG. 5B  illustrates a schematic side view of the exemplary embodiment of  FIG. 5A . 
         FIG. 5C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 5B  of the exemplary embodiment of  FIG. 5B . 
         FIG. 5D  illustrates a schematic top view of the exemplary embodiment of  FIG. 5A . 
         FIG. 5E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 5A . 
         FIG. 5F  illustrates a schematic perspective view of another exemplary embodiment of an orifice reducer according to the present invention. 
         FIG. 5G  illustrates a schematic side view of the exemplary embodiment of  FIG. 5F . 
         FIG. 5H  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 5G  of the exemplary embodiment of  FIG. 5G . 
         FIG. 5I  illustrates a schematic top view of the exemplary embodiment of  FIG. 5F . 
         FIG. 5J  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 5F . 
         FIG. 6A  illustrates a schematic perspective view of an exemplary embodiment of a nose according to the present invention. 
         FIG. 6B  illustrates a schematic side view of the exemplary embodiment of  FIG. 6A . 
         FIG. 6C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 6B  of the exemplary embodiment of  FIG. 6B . 
         FIG. 6D  illustrates a schematic top view of the exemplary embodiment of  FIG. 6A . 
         FIG. 6E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 6A . 
         FIG. 6F  illustrates a schematic perspective view of another exemplary embodiment of a nose according to the present invention. 
         FIG. 6G  illustrates a schematic side view of the exemplary embodiment of  FIG. 6F . 
         FIG. 6H  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 6G  of the exemplary embodiment of  FIG. 6G . 
         FIG. 6I  illustrates a schematic top view of the exemplary embodiment of  FIG. 6F . 
         FIG. 6J  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 6F . 
         FIG. 6K  illustrates a schematic perspective view of yet another exemplary embodiment of a nose according to the present invention. 
         FIG. 6L  illustrates a schematic side view of the exemplary embodiment of  FIG. 6K . 
         FIG. 6M  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 6L  of the exemplary embodiment of  FIG. 6L . 
         FIG. 6N  illustrates a schematic top view of the exemplary embodiment of  FIG. 6K . 
         FIG. 6O  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 6K . 
         FIG. 6P  illustrates a schematic perspective view of yet another exemplary embodiment of a nose according to the present invention. 
         FIG. 6Q  illustrates a schematic side view of the exemplary embodiment of  FIG. 6P . 
         FIG. 6R  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 6Q  of the exemplary embodiment of  FIG. 6Q . 
         FIG. 6S  illustrates a schematic top view of the exemplary embodiment of  FIG. 6P . 
         FIG. 6T  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 6P . 
         FIG. 6U  illustrates a schematic perspective view of yet another exemplary embodiment of a nose according to the present invention. 
         FIG. 6V  illustrates a schematic side view of the exemplary embodiment of  FIG. 6U . 
         FIG. 6W  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 6V  of the exemplary embodiment of  FIG. 6V . 
         FIG. 6X  illustrates a schematic top view of the exemplary embodiment of  FIG. 6U . 
         FIG. 6Y  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 6U . 
         FIG. 7A  illustrates a schematic perspective view of an exemplary embodiment of a cap according to the present invention. 
         FIG. 7B  illustrates a schematic side view of the exemplary embodiment of  FIG. 7A . 
         FIG. 7C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 7B  of the exemplary embodiment of  FIG. 7B . 
         FIG. 7D  illustrates a schematic top view of the exemplary embodiment of  FIG. 7A . 
         FIG. 7E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 7A . 
         FIG. 7F  illustrates a schematic perspective view of another exemplary embodiment of a cap according to the present invention. 
         FIG. 7G  illustrates a schematic side view of the exemplary embodiment of  FIG. 7F . 
         FIG. 7H  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 7G  of the exemplary embodiment of  FIG. 7G . 
         FIG. 7I  illustrates a schematic top view of the exemplary embodiment of  FIG. 7F . 
         FIG. 7J  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 7F . 
         FIG. 8A  illustrates a schematic perspective view of an exemplary embodiment of a piston seat according to the present invention. 
         FIG. 8B  illustrates a schematic side view of the exemplary embodiment of  FIG. 8A . 
         FIG. 8C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 8B  of the exemplary embodiment of  FIG. 8B . 
         FIG. 8D  illustrates a schematic top view of the exemplary embodiment of  FIG. 8A . 
         FIG. 8E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 8A . 
         FIG. 9A  illustrates a schematic perspective view of an exemplary embodiment of a cup according to the present invention. 
         FIG. 9B  illustrates a schematic side view of the exemplary embodiment of  FIG. 9A . 
         FIG. 9C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 9B  of the exemplary embodiment of  FIG. 9B . 
         FIG. 9D  illustrates a schematic top view of the exemplary embodiment of  FIG. 9A . 
         FIG. 9E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 9A . 
         FIG. 10A  illustrates a schematic perspective view of an exemplary embodiment of a spiral according to the present invention. 
         FIG. 10B  illustrates a schematic side view of the exemplary embodiment of  FIG. 10A . 
         FIG. 10C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 10B  of the exemplary embodiment of  FIG. 10B . 
         FIG. 10D  illustrates a schematic top view of the exemplary embodiment of  FIG. 10A . 
         FIG. 10E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 10A . 
         FIG. 11A  illustrates a schematic perspective view of an exemplary embodiment of a priming spring according to the present invention. 
         FIG. 11B  illustrates a schematic top view of the exemplary embodiment of  FIG. 11A . 
         FIG. 11C  illustrates a schematic side view of the exemplary embodiment of  FIG. 11A . 
         FIG. 12A  illustrates a schematic perspective view of an exemplary embodiment of a gear according to the present invention. 
         FIG. 12B  illustrates a schematic side view of the exemplary embodiment of  FIG. 12A . 
         FIG. 12C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 12B  of the exemplary embodiment of  FIG. 12B . 
         FIG. 12D  illustrates a schematic top view of the exemplary embodiment of  FIG. 12A . 
         FIG. 12E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 12A . 
         FIG. 13A  illustrates a schematic perspective view of an exemplary embodiment of a click spring according to the present invention. 
         FIG. 13B  illustrates a schematic top view of the exemplary embodiment of  FIG. 13A . 
         FIG. 13C  illustrates a schematic side view of the exemplary embodiment of  FIG. 13A . 
         FIG. 14A  illustrates a schematic perspective view of an exemplary embodiment of a spiral sleeve according to the present invention. 
         FIG. 14B  illustrates a schematic side view of the exemplary embodiment of  FIG. 14A . 
         FIG. 14C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 14B  of the exemplary embodiment of  FIG. 14B . 
         FIG. 14D  illustrates a schematic top view of the exemplary embodiment of  FIG. 14A . 
         FIG. 14E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 14A . 
         FIG. 15A  illustrates a schematic perspective view of an exemplary embodiment of a push button according to the present invention. 
         FIG. 15B  illustrates a schematic side view of the exemplary embodiment of  FIG. 15A . 
         FIG. 15C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 15B  of the exemplary embodiment of  FIG. 15B . 
         FIG. 15D  illustrates a schematic top view of the exemplary embodiment of  FIG. 15A . 
         FIG. 15E  illustrates a schematic bottom view of the exemplary embodiment of  FIG. 15A . 
         FIG. 16  illustrates a schematic perspective, exploded view of an exemplary embodiment of a click pen applicator device according to the present invention. 
         FIG. 17A  illustrates a schematic perspective view of a prior art click pen applicator device. 
         FIG. 17B  illustrates a schematic side view of the prior art click pen applicator device of  FIG. 17A . 
         FIG. 17C  illustrates a schematic cross-sectional view taken along line A-A shown in  FIG. 17B  of the prior art click pen applicator device of  FIG. 17A . 
         FIG. 17D  illustrates a schematic top view of the prior art click pen applicator device of  FIG. 17A . 
         FIG. 17E  illustrates a schematic bottom view of the prior art click pen applicator device of  FIG. 17A . 
         FIG. 18  illustrates a schematic perspective, exploded view of a prior art click pen applicator device. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIGS. 1A to 1E  illustrate an exemplary embodiment of an assembled click pen applicator device  10  according to the present invention.  FIGS. 1F to 1J  illustrate another exemplary embodiment of an assembled click pen applicator device  10 ′ according to the present invention. Similar features among the exemplary embodiments are illustrated with like reference numerals. 
     The device  10 ,  10 ′ may include three sections: an applicator section  11  at a distal end, a storage section  12  in a middle section, and a multistage actuator section  13  at a proximal end. The applicator section  11  may include a passing seat  30 ,  30 ′,  30 ″, a sealing element  40 , an orifice reducer  50 ,  50 ′, a nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″, and a cap  70 ,  70 ′, the applicator section  11  configured to connect to a distal end of a centerband  20 ,  20 ′. The storage section  12  may be defined by a middle section of the centerband  20 ,  20 ′. The multistage actuator section  13  may include a piston seat  80 , a cup  90 , a sealing element  40 , a spiral  100 , a priming spring  110 , a gear  120 , a click spring  130 , a spiral sleeve  140 , and a push button  150 , the multistage actuator section  13  configured to connect to a proximal end of the centerband  20 ,  20 ′. In the exemplary embodiment of  FIGS. 1A to 1E , the cap  70  may be a push-on cap, whereas in the exemplary embodiment of  FIGS. 1F to 1J , the cap  70 ′ may be a screw-on cap. Further, the distal end of centerband  20 ,  20 ′ of device  10 ,  10 ′ may increase in diameter to match the diameter of the proximal end of the cap  70 ,  70 ′. 
       FIGS. 2A to 2E  illustrate an exemplary embodiment of a centerband  20  defining a storage section  12  in the middle section of the device  10  according to the present invention.  FIGS. 2F to 2J  illustrate another exemplary embodiment of a centerband  20 ′ defining a storage section  12  in the middle section of the device  10 ′ according to the present invention. The applicator section  11  is configured to connect to a distal end  21  of a centerband  20 ,  20 ′, and the multistage actuator section  13  configured to connect to a proximal end  22  of the centerband  20 ,  20 ′. Similar features among the exemplary embodiments are illustrated with like reference numerals. 
     The centerband  20 ,  20 ′ defining the storage section  12  of the device  10 ,  10 ′ may include a distal end  21  and a proximal end  22 . The centerband  20 ,  20 ′ may be in the shape of an elongate tube, pipe, barrel, or other similar shape defining a storage chamber  26  in its middle section configured to store and dispense a formulation. The distal end  21  of the centerband  20 ,  20 ′ may include internal grooves  24  configured to interface with components of the applicator section  11 . For example, the internal grooves  24  may interface with a passing seat  30 ,  30 ′,  30 ″ of the applicator section  11 . In addition, the proximal end  22  of the centerband  20 ,  20 ′ may include internal grooves  25  configured to interface with components of the multistage actuator section  13 . For example, the internal grooves  25  may interface with a spiral sleeve  140  of the multistage actuator section  13 . Alternatively, the centerband  20 ,  20 ′ may include threads instead of external ribs  23 , internal grooves  24 , and/or internal grooves  25  for attachment to each of the applicator section  11  and the multistage actuator section  13 . 
     In the exemplary embodiment of  FIGS. 2A to 2E , the distal end  21  of the centerband  20  may include external ribs  23  configured to interface with components of the applicator section  11 . For example, the external ribs  23  may interface with a cap  70  of the applicator section  11 , the cap  70  being a push-on cap. In the exemplary embodiment of  FIGS. 2F to 2J , the distal end  21  of the centerband  20 ′ may include a flared outer surface  27  configured to abut against a proximal end of the cap  70 ,  70 ′, which cap  70 ,  70 ′ may be engaged or threaded to the passing seat  30 ,  30 ′,  30 ″. 
     The centerband  20 ,  20 ′ may be made of polypropylene, polyethylene, and other suitable materials. Preferably, the centerband  20 ,  20 ′ is made of polypropylene. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the centerband  20 ,  20 ′ may be manufactured by injection molding, or other suitable processes. Preferably, the centerband  20 ,  20 ′ is manufactured by injection molding. 
       FIGS. 3A to 3E  illustrate an exemplary embodiment of a passing seat  30  in an applicator section  11  of the device  10  according to the present invention.  FIGS. 3F to 3J  illustrate another exemplary embodiment of a passing seat  30 ′ in an applicator section  11  of the device  10 ′ according to the present invention.  FIG. 3K  illustrates yet another exemplary embodiment of a passing seat  30 ″ according to the present invention. Similar features among the exemplary embodiments are illustrated with like reference numerals. 
     The passing seat  30 ,  30 ′,  30 ″ in the applicator section  11  of the device  10 ,  10 ′ may include a distal end  31  and a proximal end  32 . The passing seat  30 ,  30 ′,  30 ″ may include a central passage  33  over its entire length, which central passage  33  may be in communication with the storage chamber  26  of the centerband  20 ,  20 ′. The distal end  31  of the passing seat  30 ,  30 ′ may include an angled end face  34 . However, other end faces may also be possible, such as flat, curved, rounded, convex, concave, and others. For example,  FIG. 3K  shows a passing seat  30 ″ having a flat end face  34 . The proximal end  32  of the passing seat  30 ,  30 ′,  30 ″ may include external ribs  35  configured to interface with the distal end  21  of the centerband  20 ,  20 ′. For example, the external ribs  35  of the passing seat  30 ,  30 ′,  30 ″ may interface with the internal grooves  24  of the centerband  20 ,  20 ′. Alternatively, the passing seat  30 ,  30 ′,  30 ″ may include threads instead of external ribs  35  for attachment to the centerband  20 ,  20 ′. In addition, the proximal end  32  of the passing seat  30 ,  30 ′,  30 ″ may include an annular groove  36  configured to receive a sealing element of the applicator section  11 . For example, the annular groove  36  may receive a sealing element  40  that may seal the interface between the passing seat  30 ,  30 ′,  30 ″ of the applicator section  11  and the distal end  21  of the centerband  20 ,  20 ′. Further, the passing seat  30 ,  30 ′,  30 ″ may include an annular flange  37  configured to interface with a nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ of the applicator section  11 . Alternatively, the passing seat  30 ,  30 ′,  30 ″ may include threads instead of the annular flange  37  for attachment to the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ of the applicator section  11 . 
     In the exemplary embodiment of  FIGS. 3F to 3J , the passing seat  30 ′ may also include threads  38  between the annular groove  36  and the annular flange  37  configured to engage with a threaded cap  70 ′. 
     The passing seat  30 ,  30 ′,  30 ″ may be made of polypropylene, polyethylene, and other suitable materials. Preferably, the passing seat  30 ,  30 ′,  30 ″ is made of polypropylene. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the passing seat  30 ,  30 ′,  30 ″ may be manufactured by injection molding, or other suitable processes. Preferably, the passing seat  30 ,  30 ′,  30 ″ is manufactured by injection molding. 
       FIGS. 4A to 4C  illustrate an exemplary embodiment of a sealing element  40  in an applicator section  11  of the device  10 ,  10 ′ according to the present invention. 
     The sealing element  40  in the applicator section  11  of the device  10 ,  10 ′ may include a circular o-ring configured and sized to fit within the annular groove  36  of the passing seat  30 ,  30 ′,  30 ″. The sealing element  40  may seal the interface between the passing seat  30 ,  30 ′,  30 ″ and the centerband  20 ,  20 ′. 
     The sealing element  40  may be made of rubber, thermoplastic rubber, silicone, and other suitable materials. Preferably, the sealing element  40  is made of rubber. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the sealing element  40  may be manufactured by injection molding, compression molding, or other suitable processes. Preferably, the sealing element  40  is manufactured by compression molding. 
       FIGS. 5A to 5E  illustrate an exemplary embodiment of an orifice reducer  50  in an applicator section  11  of the device  10  according to the present invention.  FIGS. 5F to 5J  illustrate another exemplary embodiment of an orifice reducer  50 ′ in an applicator section  11  of the device  10 ′ according to the present invention. Similar features among the exemplary embodiments are illustrated with like reference numerals. 
     The orifice reducer  50 ,  50 ′ in the applicator section  11  of the device  10 ,  10 ′ may include a distal end  51  and a proximal end  52 . The orifice reducer  50 ,  50 ′ may include a central passage  53  over its entire length, which central passage  53  may be in communication with the central passage  33  of the passing seat  30 ,  30 ′,  30 ″ and also with the storage chamber  26  of the centerband  20 ,  20 ′. The external shape of the orifice reducer  50 ,  50 ′ may be configured to fit within the central passage  33  of the passing seat  30 ,  30 ′,  30 ″, thereby taking up at least part of the volume of the central passage  33  of the passing seat  30 ,  30 ′,  30 ″. In addition, the orifice reducer  50 ,  50 ′ may include external ribs  54  configured to secure the orifice reducer  50 ,  50 ′ within the central passage  33  of the passing seat  30 ,  30 ′,  30 ″. Alternatively, the orifice reducer  50 ,  50 ′ may include threads instead of external ribs  54  for attachment to the passing seat  30 ,  30 ′,  30 ″. Further, in an alternative embodiment, the orifice reducer  50 ,  50 ′ and the passing seat  30 ,  30 ′,  30 ″ may be manufactured as a single integral part, thereby potentially resulting in cost and time savings due to the elimination of both a part and an assembly step. 
     In the exemplary embodiment of  FIGS. 5F to 5J , the orifice reducer  50 ′ may be configured to fit within the central passage  33  of the passing seat  30 ′ of  FIGS. 3F to 3J , which passing seat  30 ′ is configured to receive a threaded cap  70 ′ on threads  38 . 
     The orifice reducer  50 ,  50 ′ may be made of polypropylene, polyethylene, and other suitable materials. Preferably, the orifice reducer  50 ,  50 ′ is made of polypropylene. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the orifice reducer  50 ,  50 ′ may be manufactured by injection molding, or other suitable processes. Preferably, the orifice reducer  50 ,  50 ′ is manufactured by injection molding. 
       FIGS. 6A to 6E  illustrate an exemplary embodiment of a nose  60  in an applicator section  11  of the device  10 ,  10 ′ according to the present invention.  FIGS. 6F to 6J ,  6 K to  6 O,  6 P to  6 T, and  6 U to  6 Y illustrate alternative exemplary embodiments of a nose  60 ′,  60 ″,  60 ′″,  60 ″″ in an applicator section  11  of the device  10 ,  10 ′ according to the present invention. Similar features among the exemplary embodiments are illustrated with like reference numerals. 
     The nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ in the applicator section  11  of the device  10 ,  10 ′ may include a distal end  61  and a proximal end  62 . The nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ may include a central passage  63  over its entire length. The proximal end  62  of the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ may be configured to receive the passing seat  30 ,  30 ′,  30 ″ in the central passage  63 . For example, the central passage  63  may include an annular groove  64  configured to interface with the annular flange  37  of the passing seat  30 ,  30 ′,  30 ″, thereby securing the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ to the passing seat  30 ,  30 ′,  30 ″. Alternatively, the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ may include threads instead of the annular groove  64  for attachment to the passing seat  30 ,  30 ′,  30 ″. The distal end  61  of the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ may include an orifice  65 , which orifice  65  may be in communication with the central passage  33  of the passing seat  30 ,  30 ′,  30 ″, with the central passage  53  of the orifice reducer  50 ,  50 ′, and also with the storage chamber  26  of the centerband  20 ,  20 ′. The orifice  65  may be sized to dispense a formulation for application by a user. In addition, the distal end  61  of the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ may include brushes  66  to facilitate application and/or spreading of the formulation by a user. 
     The nose  60  as shown in  FIGS. 6A to 6E  includes a shape that tapers towards the distal end  61  of the nose  60 . Other shapes of the nose  60  may be possible. For example,  FIGS. 6F to 6J ,  6 K to  6 O,  6 P to  6 T, and  6 U to  6 Y illustrate alternative exemplary embodiments of a nose  60 ′,  60 ″,  60 ′″,  60 ″″ in an applicator section  11  of the device  10 ,  10 ′, in which the nose  60 ′,  60 ″,  60 ′″,  60 ″″ may include a stepped cylindrical shape, a cylindrical shape, or a tapered and stepped cylindrical shape. Additionally, other shapes may be possible. Further, alternative exemplary embodiments may include different end faces, such as angled, flat, curved, rounded, convex, concave, and others, end faces with or without brushes  66 , and/or end faces including antimicrobial additives or substances, and alternative exemplary embodiments may be configured to receive passing seats  30 ,  30 ′,  30 ″ having variously shaped end faces  34 , as described above. Moreover, in an alternative embodiment, the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ and the passing seat  30 ,  30 ′,  30 ″, and possibly the orifice reducer  50 ,  50 ′, may be manufactured as a single integral part, thereby potentially resulting in cost and time savings due to the elimination of both a part and an assembly step. 
     The nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ may be made of polyethylene, rubber, thermoplastic rubber, silicone, and other suitable materials. Preferably, the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ is made of rubber. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ may be manufactured by injection molding, compression molding, or other suitable processes. Preferably, the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ is manufactured by compression molding. 
       FIGS. 7A to 7E  illustrate an exemplary embodiment of a cap  70  in an applicator section  11  of the device  10  according to the present invention.  FIGS. 7F  to  7 J illustrate another exemplary embodiment of a cap  70 ′ in an applicator section  11  of the device  10 ′ according to the present invention. Similar features among the exemplary embodiments are illustrated with like reference numerals. 
     The cap  70 ,  70 ′ in the applicator section  11  of the device  10 ,  10 ′ may include a distal end  71  and a proximal end  72 . The cap  70 ,  70 ′ may be sized to fit over the passing seat  30 ,  30 ′,  30 ″ and nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ of the applicator section  11 . The distal end  71  of the cap  70 ,  70 ′ may include a pintel  74  configured to seal the orifice  65  of the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″. For example, the pintel  74  of the cap  70 ,  70 ′ may be sized to fit snugly within and extend for a short distance into the orifice  65  of the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″, thereby sealing the orifice  65  when the device  10 ,  10 ′ is not in use. Moreover, the cap  70 ,  70 ′ may also include a tamper-resistant feature, not shown, to indicate whether a product has been previously used. The cap  70 ,  70 ′ may also include features on its external surface to facilitate grasping, pulling, pushing, twisting, or otherwise manipulating the cap  70 ,  70 ′, such as, for example, ribs, grooves, indentations, gripping pads or surfaces, rubberized portions, and other similar features. 
     In the exemplary embodiment of  FIGS. 7A to 7E , the proximal end  72  of the cap  70  may include internal grooves  73  configured to interface with the distal end  21  of the centerband  20  of the device  10 . For example, the internal grooves  73  of the cap  70  may interface with the external ribs  23  of the centerband  20  of  FIGS. 2A to 2E , thereby protecting the applicator section  11 , in particular, the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ and brushes  66 , when not in use. In the exemplary embodiment of  FIGS. 7F to 7J , the proximal end  72  of the cap  70 ′ may include threads  75 , instead of internal grooves  73 , configured to interface with threads  38  of the passing seat  30 ′ of  FIGS. 3F to 3J , thereby protecting the applicator section  11 , in particular, the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ and brushes  66 , when not in use. 
     The cap  70 ,  70 ′ may be made of polypropylene, polyethylene, acrylonitrile butadiene styrene, styrene acrylonitrile, and other suitable materials. Preferably, the cap  70 ,  70 ′ is made of polypropylene. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the cap  70 ,  70 ′ may be manufactured by injection molding, or other suitable processes. Preferably, the cap  70 ,  70 ′ is manufactured by injection molding. 
       FIGS. 8A to 8E  illustrate an exemplary embodiment of a piston seat  80  in a multistage actuator section  13  of the device  10 ,  10 ′ according to the present invention. 
     The piston seat  80  in the multistage actuator section  13  of the device  10 ,  10 ′ may include a distal end  81  and a proximal end  82 . The piston seat  80  may include a shaft  83  having at least one thread  84 , and a support member  85  at the distal end  81  of the shaft  83 . The support member  85  at the distal end  81  may include an external rib  86  and a piston seat flange  87  configured to receive a cup that contacts the formulation to be dispensed. For example, the external rib  86  and the piston seat flange  87  may interface with a cup  90  that supports and advances the formulation. The shaft  83  may include a priming threaded portion  84   a  at the distal end  81  of the piston seat  80  adjacent to the support member  85 , an unthreaded portion  88  proximal to the priming threaded portion  84   a , and a dosing threaded portion  84   b  that extends substantially the remaining length of the shaft  83  from the unthreaded portion  88  to the proximal end  82  of the shaft  83 . The priming threaded portion  84   a  and the dosing threaded portion  84   b  may be configured to engage a spiral  100 . The priming threaded portion  84   a  and the dosing threaded portion  84   b  may have the same pitch. Alternatively, the pitch of the priming threaded portion  84   a  may be a multiple of, for example, double, the pitch of the dosing threaded portion  84   b . The priming threaded portion  84   a  may include only one turn of threads, preferably a three-quarter turn or a half turn. The axial length of the unthreaded portion  88  may be sized to displace a predetermined volume within the storage section  12 . The pitch of the dosing threaded portion  84   b  may be sized to dispense a predetermined dose, or other predetermined amount, of the formulation with each actuation of the multistage actuator section  13 . The shaft  83  may include a keyed shape configured to interface with a gear  120 . For example, the shaft  83  may include at least one flat surface  89 , and preferably two diametrically opposed flat surfaces  89 , extending the length of the shaft  83 . As a result of the keyed shape of the shaft  83 , the threads  84  of the priming threaded portion  84   a  and the dosing threaded portion  84   b  may be discontinuous around a perimeter of the shaft. That is, the at least one flat surface  89  may be substantially free of threads. 
     The piston seat  80  may be made of polyoxymethylene, and other suitable materials. Preferably, the piston seat  80  is made of polyoxymethylene. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the piston seat  80  may be manufactured by injection molding, or other suitable processes. Preferably, the piston seat  80  is manufactured by injection molding. 
       FIGS. 9A to 9E  illustrate an exemplary embodiment of a cup  90  in a multistage actuator section  13  of the device  10 ,  10 ′ according to the present invention. 
     The cup  90  in the multistage actuator section  13  of the device  10 ,  10 ′ may include a distal end  91  and a proximal end  92 . The distal end  91  of the cup  90  may be configured to support and advance a formulation stored in the storage chamber  26  of the centerband  20 ,  20 ′. The proximal end  92  of the cup  90  may include an internal groove  93  configured to interface with the piston seat  80 . For example, the internal groove  93  of the cup  90  may interface with the external rib  86  of the piston seat  80 , thereby securing the cup  90  to the distal end  81  of the piston seat  80 . Further, the cup  90  may include an annular groove  94  configured to receive a sealing element of the multistage actuator section  13 . For example, the annular groove  94  may receive a sealing element  40  that is configured and sized to seal the interface between the cup  90  of the multistage actuator section  13  and the proximal end  22  of the centerband  20 ,  20 ′. Further, in an alternative embodiment, the cup  90  and the piston seat  80  may be manufactured as a single integral part, thereby potentially resulting in cost and time savings due to the elimination of both a part and an assembly step. 
     The cup  90  may be made of polypropylene, polyethylene, and other suitable materials. Preferably, the cup  90  is made of polypropylene. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the cup  90  may be manufactured by injection molding, or other suitable processes. Preferably, the cup  90  is manufactured by injection molding. 
       FIGS. 10A to 10E  illustrate an exemplary embodiment of a spiral  100  in a multistage actuator section  13  of the device  10 ,  10 ′ according to the present invention. 
     The spiral  100  in the multistage actuator section  13  of the device  10 ,  10 ′ may include a distal end  101  and a proximal end  102 . The spiral  100  may include a central passage  103  over its entire length, through which the shaft  83  of the piston seat  80  may extend. A portion of the central passage  103  may also include internal threads  104  configured to engage the priming threaded portion  84   a  and the dosing threaded portion  84   b  of the shaft  83  of the piston seat  80 . The distal end  101  of the spiral  100  may include an annular channel  105  configured to receive a spring element. For example, the annular channel  105  of the spiral  100  may receive a proximal end of a priming spring  110 . Further, the proximal end  102  of the spiral  100  may include an annular channel  106  also configured to received a spring element. For example, the annular channel  106  of the spiral  100  may receive a distal end of a click spring  130 . In addition, the proximal end  102  of the spiral  100  may include at least one snap element  107 , preferably two diametrically opposed snap elements  107 , configured to engage a spiral sleeve  140 , thereby securing the spiral  100  to the spiral sleeve  140 . 
     The spiral  100  may be made of polyoxymethylene, and other suitable materials. Preferably, the spiral  100  is made of polyoxymethylene. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the spiral  100  may be manufactured by injection molding, or other suitable processes. Preferably, the spiral  100  is manufactured by injection molding. 
       FIGS. 11A to 11C  illustrate an exemplary embodiment of a priming spring  110  in a multistage actuator section  13  of the device  10 ,  10 ′ according to the present invention. 
     The priming spring  110  in the multistage actuator section  13  of the device  10 ,  10 ′ may include a distal end  111  and a proximal end  112 . The priming spring  110  may be situated over a length of the shaft  83  of the piston seat  80 . For example, the priming spring  110  may be situated substantially over the unthreaded portion  88  of the shaft  83 . The distal end  111  of the priming spring  110  may abut against a proximal surface of the piston seat flange  87  of the piston seat  80 , and the proximal end  112  of the priming spring  110  may be received in the annular channel  105  of the spiral  100 . The priming spring  110  may be configured to apply force between the piston seat  80  and the spiral  100 , such that the piston seat  80  is pushed in a distal direction and the spiral  100  is pushed in a proximal direction. The spring rate of the priming spring  110  may be configured to expand over a length of the unthreaded portion  88  of the shaft  83 , thereby displacing a predetermined volume within the storage chamber  26  of the centerband  20 ,  20 ′ when the piston seat  80  is rotated by the click mechanism such that the internal threads  104  of the spiral  100  disengage the priming threaded portion  84   a  and the priming spring  110  advances the piston seat  80  over the length of the unthreaded portion  88  of the shaft  83 . 
     The priming spring  110  may be made of steel, and other suitable materials. Preferably, the priming spring  110  is made of steel. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the priming spring  110  may be manufactured by coiling, or other suitable processes. Preferably, the priming spring  110  is manufactured by coiling. 
       FIGS. 12A to 12E  illustrate an exemplary embodiment of a gear  120  in a multistage actuator section  13  of the device  10 ,  10 ′ according to the present invention. 
     The gear  120  in the multistage actuator section  13  of the device  10 ,  10 ′ may include a distal end  121  and a proximal end  122 . The gear  120  may include a central passage  123  over its entire length, through which the shaft  83  of the piston seat  80  may at least partially extend. A portion of the central passage  123  may also include a keyed shape configured to interface with the shaft  83  of the piston seat  80 . For example, the central passage  123  of the gear  120  may include at least one flat surface  124 , preferably two diametrically opposed flat surfaces  124 , configured to engage with the shaft  83 . For example, the at least one flat surface  124  of the gear  120  may engage the at least one flat surface  89  of the shaft  83  of the piston seat  80 . In addition, the gear  120  may include a flange  125  configured to engage with a spring element. For example, the flange  125  of the gear  120  may engage a proximal end of a click spring  130 . The gear  120  may also include angled teeth  126  facing the proximal end  122  of the gear  120 , which angled teeth  126  may be configured to engage with a spiral sleeve  140  and a push button  150 . 
     The gear  120  may be made of polyoxymethylene, and other suitable materials. Preferably, the gear  120  is made of polyoxymethylene. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the gear  120  may be manufactured by injection molding, or other suitable processes. Preferably, the gear  120  is manufactured by injection molding. 
       FIGS. 13A to 13C  illustrate an exemplary embodiment of a click spring  130  in a multistage actuator section  13  of the device  10 ,  10 ′ according to the present invention. 
     The click spring  130  in the multistage actuator section  13  of the device  10 ,  10 ′ may include a distal end  131  and a proximal end  132 . The click spring  130  may be situated over a length of the shaft  83  of the piston seat  80 , and over a distal end  121  of the gear  120 . The distal end  131  of the click spring  130  may be received in the annular channel  106  of the spiral  100 , and the proximal end  132  of the click spring  130  may abut against a distal surface of the flange  125  of the gear  120 . The click spring  130  may be configured to apply force between the spiral  100  and the gear  120 , such that the spiral  100  is pushed in a distal direction and the gear  120  is pushed in a proximal direction. The spring rate of the click spring  130  may be configured to provide for positive feedback during operation of the multistage actuator section  13 . 
     The click spring  130  may be made of steel, and other suitable materials. Preferably, the click spring  130  is made of steel. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the click spring  130  may be manufactured by coiling, or other suitable processes. Preferably, the click spring  130  is manufactured by coiling. 
       FIGS. 14A to 14E  illustrate an exemplary embodiment of a spiral sleeve  140  in a multistage actuator section  13  of the device  10 ,  10 ′ according to the present invention. 
     The spiral sleeve  140  in the multistage actuator section  13  of the device  10 ,  10 ′ may include a distal end  141  and a proximal end  142 . The spiral sleeve  140  may include a central cavity  143  over its entire length, inside of which the shaft  83  of the piston seat  80 , the spiral  100 , the gear  120 , the click spring  130 , and a push button  150  may each be at least partially situated. The proximal end  142  of the spiral sleeve  140  may include external ribs  144  configured to engage with the centerband  20 ,  20 ′. For example, the external ribs  144  of the spiral sleeve  140  may engage the internal grooves  25  of the centerband  20 ,  20 ′. Alternatively, the spiral sleeve  140  may include threads instead of external ribs  144  for attachment to the proximal end  22  of the centerband  20 ,  20 ′. The distal end  141  of the spiral sleeve  140  may include at least one snap groove  145 , preferably two diametrically opposed snap grooves  145 , configured to receive the at least one snap element  107  of the spiral  100 , thereby securing the spiral  100  to the spiral sleeve  140 . Further, the spiral sleeve  140  may also include angled teeth  146  facing the distal end  141  of the spiral sleeve  140 , which angled teeth  146  may be configured to engage with the angled teeth  126  of the gear  120 . Moreover, the spiral sleeve  140  may also include at least one locking groove  147 , preferably two diametrically opposed locking grooves  147 , configured to receive at least one locking element of the push button  150 . 
     The spiral sleeve  140  may be made of acrylonitrile butadiene styrene, styrene acrylonitrile, polyoxymethylene, and other suitable materials. Preferably, the spiral sleeve  140  is made of acrylonitrile butadiene styrene. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the spiral sleeve  140  may be manufactured by injection molding, or other suitable processes. Preferably, the spiral sleeve  140  is manufactured by injection molding. 
       FIGS. 15A to 15E  illustrate an exemplary embodiment of a push button  150  in a multistage actuator section  13  of the device  10 ,  10 ′ according to the present invention. 
     The push button  150  in the multistage actuator section  13  of the device  10 ,  10 ′ may include a distal end  151  and a proximal end  152 . The push button  150  may include a central cavity  153 , inside of which the shaft  83  of the piston seat  80  and the gear  120  may be at least partially situated. The distal end  151  of the push button  150  may include angled teeth  154  facing the distal end  151  of the push button  150 , which angled teeth  154  may be configured to engage with the angled teeth  126  of the gear  120 . Further, the push button  150  may also include at least one locking element  155 , preferably two diametrically opposed locking elements  155 , configured to engage at least one locking groove  147  of the spiral sleeve  140 . Moreover, the proximal end  152  of the push button  150  may be configured to facilitate comfortable operation of the multistage actuator section  13  of the device  10 ,  10 ′, and may include features on its external surface to facilitate grasping, pulling, pushing, twisting, or otherwise manipulating the cap  70 ,  70 ′, such as, for example, ribs, grooves, indentations, gripping pads or surfaces, rubberized portions, and other similar features. 
     The push button  150  may be made of acrylonitrile butadiene styrene, styrene acrylonitrile, polyoxymethylene, and other suitable materials. Preferably, the push button  150  is made of acrylonitrile butadiene styrene. In addition, the materials may be chosen based on the particular application and requirements of the device  10 ,  10 ′, as well as the particular formulation that is to be dispensed. Further, the push button  150  may be manufactured by injection molding, or other suitable processes. Preferably, the push button  150  is manufactured by injection molding. 
       FIG. 16  illustrates an exploded view of an exemplary embodiment of a click pen applicator device  10 ,  10 ′ according to the present invention. 
     In the foregoing description, it is understood that the particular descriptions of grooves of one component and ribs/elements of another component may be switched, such that ribs/elements may be provided in place of grooves, and vice versa. Further, it is understood that other connection mechanisms besides ribs and grooves, snap elements and grooves, locking elements and grooves, or threads, may be used to effect the interengagement of the various components of the device  10 ,  10 ′, such as, for example, other mechanical engagement features, press-fitting, interference fitting, adhesive, and others. 
     The assembled click pen applicator device  10 ,  10 ′ may be substantially airtight to prevent evaporation and/or weight loss of the formulation stored in the storage chamber  26  of the centerband  20 ,  20 ′. In this regard, the sealing element  40  situated in the annular groove  94  of the cup  90 , the sealing element  40  situated in the annular groove  36  of the passing seat  30 ,  30 ′,  30 ″, and the pintel  74  of the cap  70 ,  70 ′ may all contribute to the airtight sealing of the formulation in the storage chamber  26 . In addition, the two sealing elements  40  may be the same or different sizes depending on the parts and interface to be sealed. Further, the device  10 ,  10 ′ may also include tape around the outside of the cap  70 ,  70 ′ to cover and/or seal the interface between the cap  70 ,  70 ′ and the centerband  20 ,  20 ′. Moreover, the formulation stored in the storage chamber  26  of the centerband  20 ,  20 ′ may also be provided in a bag, pouch, or similar container to further improve the airtight sealing of the formulation within the device  10 ,  10 ′. 
     The device  10 ,  10 ′ may be hand assembled, which assembly may be facilitated by tools, jigs, and other suitable assembly aids. Alternatively, all or portions of the device  10 ,  10 ′ may be assembled by an automated system. 
     A method of using the click pen applicator device  10 ,  10 ′ according to the present invention may include the steps of priming the formulation at a priming rate, and dosing the formulation at a dosing rate. The click pen applicator device  10 ,  10 ′ having a multistage actuator section  13  according to the present invention may allow for rapid priming using a click dosage mechanism. 
     In an initial, e.g., purchased, state of the device  10 ,  10 ′, all components of the device  10 ,  10 ′ are assembled. In the storage section  12 , the storage chamber  26  of the centerband  20 ,  20 ′ may be substantially filled with a formulation, e.g., a salicylic acid compound such as a wart remover formulation. In the applicator section  11 , some of the formulation may contact the proximal end  52  of the orifice reducer  50 ,  50 ′, and further, some of the formulation may be present within the central passage  53  of the orifice reducer  50 ,  50 ′. However, in order to prevent overflow and/or spillage during initial assembly of the device  10 ,  10 ′ having the formulation in the storage chamber  26 , an air gap may be present between the distal fill level of the formulation and the proximal end  52  of the orifice reducer  50 ,  50 ′ in the initial, purchased state. In the multistage actuator section  13 , the piston seat  80  and cup  90  may be in their most proximal position in the initial, purchased state of the device  10 ,  10 ′. That is, the priming threaded portion  84   a  may be engaged with the internal threads  104  of the spiral  100 , thereby positioning the cup  90  in its most proximal position and also compressing the priming spring  110  between the piston seat  80  and the spiral  100 . 
     Further, in the initial, purchased state of the device  10 ,  10 ′, the push button  150  may be in its locked position, in which the push button  150  is rotated about a longitudinal axis of the device  10 ,  10 ′ such that the at least one locking element  155  of the push button  150  may be received in the at least one locking groove  147  of the spiral sleeve  140 . Before using the device  10 ,  10 ′, if the push button  150  is in the locked position, the push button  150  may be rotated about the longitudinal axis of the device  10 ,  10 ′ such that the at least one locking element  155  of the push button  150  is no longer received in the at least one locking groove  147  of the spiral sleeve  140 . 
     The priming step prior to dosing of the formulation may allow the formulation to fill any air gaps and/or empty volume of the storage section  12  and/or the applicator section  11 . For example, during the priming step, the formulation may fill in any air gap between the distal fill level in the storage chamber  26  and the proximal end  52  of the orifice reducer  50 ,  50 ′. In addition, the formulation may fill the empty volumes of the central passage  53  of the orifice reducer  50 ,  50 ′ and substantially all of the central passage  33  of the passing seat  30 ,  30 ′,  30 ″. Further, the formulation may also partially fill the empty volume of the orifice  65  of the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″. Thus, the priming step allows the formulation to be primed and ready for use by a user during the dosing step. 
     The priming step may be performed by the multistage actuator section  13  at a priming rate. The device  10 ,  10 ′ may be primed from its initial, purchased state by pressing the push button  150  of the multistage actuator section  13 , i.e., the click pen dosage mechanism. Each press of the push button  150  may move the piston seat  80  and the cup  90  in a distal direction at the rate of a dosing click, thereby advancing the formulation and filling some of the air gaps and/or empty volume in the storage section  12  and/or the applicator section  11  by a dosing amount. After a first actuation of the push button  150 , the priming threaded portion  84   a  of the piston seat  80  may disengage from the internal threads  104  of the spiral  100 . Due to the force of the priming spring  110  pushing the piston seat  80  in a distal direction away from the spiral  100 , the piston seat  80  and the cup  90  may move in a distal direction after disengagement of the priming threaded portion  84   a  and the internal threads  104 . In addition, after such disengagement of the priming threaded portion  84   a , because the piston seat  80  includes an unthreaded portion  88  to which the internal threads  104  of the spiral  100  do not engage, the force of the priming spring  110  may advance the piston seat  80  and the cup  90  a distance substantially equivalent to the length of the unthreaded portion  88  of the piston seat  80 , thereby effecting rapid priming of the formulation using the same click pen dosing mechanism. Thus, the disengagement of the priming threaded portion  84   a  and the rapid advancement of the piston seat  80  and the cup  90  under force of the priming spring  110  over the unthreaded length  88  of the piston seat  80  facilitates rapid filling of the air gaps and/or empty volume in the storage section  12  and/or the applicator section  11 . 
     Accordingly, the priming step at the priming rate according to the present invention allows the device  10 ,  10 ′ to be primed and ready for use by a user very quickly and efficiently. The first priming actuation may take up an empty volume of the device  10 ,  10 ′ that would have normally required many, e.g., forty to seventy or more, individual actuations using a conventional actuating mechanism. However, the priming step according to the present invention is substantially transparent to the user because the user simply actuates the multistage actuating section  13  in a known manner, i.e., by pressing the push button  150 . No additional or different steps or actuations are required by the user to effect rapid priming. The rapid priming also eliminates the possibility that a user may think a dispensing device is broken, non-functional, empty, dried up, or otherwise unusable due to the high number of required priming actuations before dosing of the formulation actually begins. 
     Although the above description refers to a first actuation of the priming step that leads to disengagement of the priming threaded portion  84   a  and the internal threads  104 , the first actuation may include more than one actuation of the push button  150  before disengagement depending upon the number of threads in the priming threaded portion  84   a  and the rate of rotation of the click mechanism. Preferably, fewer than ten, and more preferably, only one or two, actuations of the push button  150  may be required to effect disengagement of the priming threaded portion  84   a  and the internal threads  104 . The number of actuations required to effect such disengagement may depend on the length of the priming threaded portion  84   a , for example, one turn of threads, preferably a three-quarter turn or a half turn. 
     Further, the priming rate may depend on the dimension of the unthreaded length  88  of the piston seat  80 , the spring rate of the priming spring  110 , the friction force of the sealing element  40 , and/or the viscosity or other characteristics of the formulation. For example, the unthreaded length  88  of the piston seat  80  may be sized such that the air gaps and/or empty volume of the storage section  12  and/or the applicator section  11  may be substantially filled when the piston seat  80  and the cup  90  advance in a distal direction over the unthreaded length  88  of the piston seat  80 . In addition, the spring rate of the priming spring  110  may be configured to provide sufficient force to advance the piston seat  80  and the cup  90 , taking into consideration the friction force of the sealing element  40  engaged between the cup  90  and the centerband  20 ,  20 ′, and the viscosity and other characteristics of the formulation. 
     After disengagement of the priming threaded portion  84   a  and the internal threads  104 , and after advancement of the piston seat  80  and the cup  90  over an unthreaded length  88  of the piston seat  80 , the dosing threaded portion  84   b  of the piston seat  80  may then engage the internal threads  104  of the spiral  100  upon further actuations of the push button  150 . In order to fully effect priming of the device  10 ,  10 ′ before the formulation is ready to be dispensed, the priming step may require one or more actuations of the push button  150  after engagement of the dosing threaded portion  84   b  with the internal threads  104 , although it may be preferable that the device  10 ,  10 ′ is ready to dispense the formulation without any such additional actuations. 
     The dosing step may be performed by the multistage actuator section  13  at a dosing rate. The formulation may be dosed with each actuation of the push button  150  after the dosing threaded portion  84   b  of the piston seat  80  has engaged the internal threads  104  of the spiral  100 . Each press of the push button  150  may move the piston seat  80  and the cup  90  in a distal direction, thereby advancing and dispensing a predetermined dose of the formulation from the storage chamber  26  of the centerband  20 ,  20 ′ through the central passage  53  of the orifice reducer  50 ,  50 ′, through the central passage  33  of the passing seat  30 ,  30 ′,  30 ″, and out of the orifice  65  of the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″. 
     The dosing rate may depend on the pitch of the dosing threaded portion  84   b  of the piston seat  80  and the corresponding pitch of the internal threads  104  of the spiral  100 . For example, the pitch of the dosing threaded portion  84   b  and the internal threads  104  may be configured such that a single actuation of the push button  150  dispenses a predetermined dose of the formulation from the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″. 
     Accordingly, the device  10 ,  10 ′ according to the present invention allows for both rapid priming of the formulation for quick and reliable use after purchase, and also predetermined dosing of the formulation thereafter, while utilizing a click dosage mechanism with a multistage actuator section  13 . Thus, the device  10 ,  10 ′ drastically improves the priming rate of the device  10 ,  10 ′ while simultaneously providing precise control of the dosing rate, but does so without complicating the steps for using the device  10 ,  10 ′. 
     When a user wishes to store the device  10 ,  10 ′ after use, the device  10 ,  10 ′ may be stored in an airtight manner to prevent evaporation and/or weight loss of the formulation, and may also be locked to prevent inadvertent or accidental dispensing of the formulation. In this regard, a cap  70 ,  70 ′ may be placed over the passing seat  30 ,  30 ′,  30 ″ and nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ and engaged with the distal end  21  of the centerband  20 ,  20 ′. For airtight storage, the cap  70 ,  70 ′ may include a pintel  74  that may be configured to fit snugly within and at least partially extend into the orifice  65  of the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″, and may at least partially extend into the central passage  33  of the passing seat  30 ,  30 ′,  30 ″. The cap  70 ,  70 ′ may also protect the nose  60 ,  60 ′,  60 ″,  60 ′″,  60 ″″ and the brushes  66  from damage. For locking of the device  10 ,  10 ′, the push button  150  may be rotated about a longitudinal axis of the device  10 ,  10 ′ such that the at least one locking element  155  of the push button  150  may be received in the at least one locking groove  147  of the spiral sleeve  140 . Accordingly, the device  10 ,  10 ′ according to the present invention may be safely and securely stored with minimal risk of evaporation, weight loss, and accidental operation. 
     The foregoing description discloses only non-limiting embodiments of the present invention. Modification of the above-disclosed exemplary click pen applicator device, and a method of using the same, which fall within the scope of the invention, will be readily apparent to those of ordinary skill in the art. 
     Accordingly, while the present invention has been disclosed in connection with the above non-limiting embodiments, it should be understood that other embodiments may fall within the spirit and scope of the invention, as defined by the following claims.