Abstract:
A pump engine assembly includes an output cylinder that may be customized to include a stop portion limiting the stroke of a piston to produce a particular output such that customized pump systems may be produced from similar parts with the exchange of only a single part—the output cylinder.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Field of the Invention 
         [0002]    Embodiments of the invention relate to pumps systems and engines used to assemble such pump systems, including pump engines having adjustable outputs and interchangeable parts for creating different outputs. 
         [0003]    State of the Art 
         [0004]    Pumps and pump systems are frequently used to dispense flowable products, including personal and beauty care products. For example, makeup, lotions, creams, and other beauty care products are frequently packaged with a pump to facilitate the dispensing of the product, to control the dose of the product, or both. In addition, some brands will offer a complete line of products to be used together. Often times, the brand-owner desires to maintain a common brand image across the branded product offerings, requiring similar looking pumps and pump systems having different outputs. While pumps and pump systems having the same aesthetics but different dosing capabilities may be made, such pump systems often require completely different parts or pump engines associated with the aesthetics to produce different dosage capabilities. Thus, to have a family of similar looking pump systems with different dosage capabilities, it is often necessary to manufacture several different pump systems or pump engines, each of which have multiple parts. In order to make all of the parts, multiple tools are required to produce the parts for each size—or dosage—of pump system. The increased capital for such duplicative parts can be costly. 
         [0005]    To reduce costs, some manufactures may provide a standard closure and pump head and then attach different pump engines thereto, wherein each of the pump engines provides a different output. In this manner, a common aesthetic look may be provided while offering different outputs for the various branded products. Typically, each of the pump engines may include an accumulator, a spring, and a piston system consisting of a piston stem and a piston seal. For different engines, each of the parts is a different size. Thus, for a first output, the accumulator, piston stem, and piston seal will have a first size and for a second output they will have a second, different size. Tools or molds for each size of component are used to manufacture the components and often times different assembly lines are required for the different engine sizes. The requirement for multiple tools and separate assembly lines increases the costs associated with making each pump. 
         [0006]    Furthermore, in many cases brand owners are looking for smaller runs of a pump system for their niche products or for products that do not have the market share of some of their larger products. When multiple sizes are required with smaller runs for products having smaller market share, the relative costs to produce the smaller runs increases due to labor costs, changeovers in manufacturing, and other factors. 
         [0007]    As a result of the costs associated with offering pump systems with variable output options, it may be difficult and prohibitively expensive to manufacture pump systems that may be tailored for differing outputs. Thus, a more cost-effective solution to providing pump systems and pump engines with different outputs is desirable. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    Pump systems according to some embodiments of the invention include pump engines having a single part that may be customized for a desired output such that the same tools, assembly lines, and other manufacturing processes may be used to manufacture pump systems having different outputs. For example, a pump system may include a closure attached to a container, a pump head moveable relative to the closure for pumping a pump engine and delivering a product, and a pump engine attached to the closure and in fluid communication with the pump head. The pump engine may include an accumulator, a valve for controlling flow of a product into an interior of the accumulator, a piston stem, a piston seal seated on an interior portion of the accumulator and attached to the piston stem, an output cylinder attached to the accumulator and within which a portion of the piston stem extends, and a spring acting on both the piston stem and the output cylinder. In various embodiments of the invention, the output cylinder may include one or more output stops configured to stop movement of the piston stem during the stroke of the pump system. An output cylinder may be customized with a output stop at a desired location to provide a desired dose from the pump engine. More particularly, if a first dosage is required, an output cylinder having an output stop at a first location may be assembled as part of the pump engine; if a second dose is required, an output cylinder having an output stop at a second location may be assembled as part of the pump engine. Thus, pump engines and pump systems having different dosages may be made utilizing all of the same parts except for the output cylinder which may be customized for a particular dose. 
         [0009]    According to some embodiments of the invention, an output cylinder may include venting features providing a vent path for an assembled pump system utilizing the output cylinder. Such pump systems may be used as atmospheric pumps. In other embodiments, vent features may not be included in the pump engine such that the pump engine may be used in a pump system intended to pump product from an airless system. 
         [0010]    According to still other embodiments of the invention, an output cylinder may be color coordinated with respect to the output capability provided by the output stop in the output cylinder. Color coordination may also be used to designate whether or not the output cylinder is a venting version or non-venting version. For example, a first output with a venting feature may be colored red, a second output with a venting feature may be colored blue and a second output without a venting feature may be colored green. The color coordination allows an operator on the manufacturing floor to quickly identify the necessary output cylinder to be used for assembly processes. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    While the specification concludes with claims particularly pointing out and distinctly claiming particular embodiments of the present invention, various embodiments of the invention can be more readily understood and appreciated by one of ordinary skill in the art from the following descriptions of various embodiments of the invention when read in conjunction with the accompanying drawings in which: 
           [0012]      FIG. 1  illustrates a cross-sectional view of an assembled and blown-apart pump system according to various embodiments of the invention; 
           [0013]      FIG. 2  illustrates a blown-apart, cross-sectional view of a pump engine assembly according to various embodiments of the invention; 
           [0014]      FIG. 3  illustrates an accumulator according to various embodiments of the invention; 
           [0015]      FIG. 4  illustrates a cross-sectional view of an accumulator according to various embodiments of the invention; 
           [0016]      FIG. 5  illustrates a piston seal according to various embodiments of the invention; 
           [0017]      FIG. 6  illustrates a cross-sectional view of a piston seal according to various embodiments of the invention; 
           [0018]      FIG. 7  illustrates a piston stem according to various embodiments of the invention; 
           [0019]      FIG. 8  illustrates a cross-sectional view of a piston stem according to various embodiments of the invention; 
           [0020]      FIG. 9  illustrates an output cylinder according to various embodiments of the invention; 
           [0021]      FIG. 10  illustrates a cross-sectional view of an output cylinder according to various embodiments of the invention; 
           [0022]      FIG. 11  illustrates a cross-sectional view of a pump system in operation according to various embodiments of the invention; 
           [0023]      FIG. 12  illustrates a cross-sectional view of a pump system in operation according to various embodiments of the invention; 
           [0024]      FIG. 13  illustrates a cross-sectional view of a pump system in operation according to various embodiments of the invention; 
           [0025]      FIG. 14  illustrates a closure according to various embodiments of the invention; 
           [0026]      FIG. 15  illustrates a cross-sectional view of a closure according to various embodiments of the invention; 
           [0027]      FIG. 16  illustrates a cross-sectional view of a pump engine according to various embodiments of the invention at rest; and 
           [0028]      FIG. 17  illustrates a cross-sectional view of an actuated pump engine according to various embodiments of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    A pump system  100  according to various embodiments of the invention is illustrated in  FIG. 1 . As illustrated, a pump system  100  may include an pump engine  200 —or engine assembly—attached to a closure  110  and mounted on a bottle or container  900 . A head  140  may be moveably fitted to the closure  110 . A gasket  190  may be positioned between the pump engine  200  or closure  110  and the container  900 . In some embodiments, a tube  180  may also be fitted to the pump engine  200 . 
         [0030]    A pump engine  200  that may be used with a pump system  100  according to various embodiments of the invention may include an accumulator  210 , a valve  220 , a piston  230 , an output cylinder  240 , a spring  290  and a piston stem  260  as illustrated in  FIG. 2 . In some embodiments of the invention, the accumulator  210 , valve  220 , piston seal  230 , spring  290 , and piston stem  260  may be conventional components. 
         [0031]    An accumulator  210  according to various embodiments of the invention may include a first opening  211  at one end thereof and a second opening  212  at an opposite end thereof. A valve seat  213  may be positioned between the first opening  211  and second opening  212 . The valve seat  213  may include a plurality of fingers  219  as illustrated in  FIG. 4  which fingers  219  may retain a ball  222  as part of the valve  220 . In other embodiments, a valve seat  213  may include a seat for a moveable plug valve, flap valve, or other type of valve. Walls of the accumulator  210  may define a product chamber  214  between the valve seat  213  and the second opening  212 . The product chamber  214  may include a cylindrical shape capable of receiving a piston seal  230 . 
         [0032]    According to some embodiments of the invention, the accumulator  210  may include a retaining ring  215  portion about a circumference of the second opening  212 . For instance, in some embodiments, a retaining ring  215  may include a lip projecting outwardly from the walls of the accumulator  210  at or near the second opening  212  as illustrated in  FIGS. 3 and 4 . In some embodiments, the retaining ring  215  may be integrally formed with—or molded as a part of—the accumulator  210 . The retaining ring  215  may snap-fit or otherwise connect with an output cylinder  240  of a pump engine  200 . 
         [0033]    In other embodiments of the invention, an accumulator  210  may include other connection features about the second opening  212  thereof. For instance, snap beads or other formations extending off of the rim of the second opening  212  may be configured to mate with another part of a pump engine  200  and to retain the accumulator  210  therewith. In other embodiments, the accumulator  210  may include a receiving channel or indentation about the rim of the second opening  212  to accept a snap-bead or other connection feature associated with another component of a pump engine  200 . In still other embodiments, an accumulator  210  may include threads allowing the accumulator  210  to be screwed onto another part of a pump engine  200 . 
         [0034]    According to some embodiments of the invention a valve  220  may include a ball valve having a ball  222  retained within the accumulator  210  adjacent a valve seat  213  as illustrated in  FIGS. 1 and 2 . The ball  222  may be made of glass, plastic, metal, or some other material or composite. Other valves  220  and valve systems may be used with various embodiments of the invention as desired. For example, a valve  220  may include a flap valve, an umbrella valve, a duck-bill valve, or other moveable plug-type valve that can perform valving functions for a pump system  100 . 
         [0035]    A piston seal  230  according to various embodiments of the invention may include a conventional piston seal  230  used with pump systems and configured to fit within and seal against the accumulator  210 . In some other embodiments of the invention, a piston seal  230  may include a body having a top flange  231  and a bottom flange  232  extending outwardly from a central portion of the body as illustrated in  FIGS. 5 and 6 . The central portion  233  of the body may include a piston seal opening  234  configured to accept a portion of the piston stem  260 . An inner flange  236  may extend upward and inward from the central portion  233  of the body and may be configured to seal against a portion of a piston stem  260 . 
         [0036]    A piston stem  260  according to various embodiments of the invention may include a conventional piston stem  260  capable of mating with a piston seal  230  to form a piston of the pump engine  200 . In some embodiments, a piston stem  260  may include a fluid lock  262  at one end of the piston stem  260  and an output opening  264  at an opposite end of the piston stem  260  as illustrated in  FIGS. 7 and 8 . The output opening  264  is connected to a piston fluid flow path  266  through an interior of the piston stem  260 . One or more input openings  268  adjacent the fluid lock  262  provide openings through a wall of the piston stem  260  to the piston fluid flow path  266 . In use, fluid may flow past the fluid lock  262 , through the one or more input openings  268  into the piston fluid flow path  266 , and out the output opening  264 . 
         [0037]    A piston stem  260  may also include one or more piston stem flanges  269  as illustrated in  FIGS. 7 and 8 . A piston stem flange  269  may extend outwardly off of an outer surface of a piston stem  260  wall. As illustrated, a piston stem flange  269  may include a circular ring extending outwardly from the main body or wall of the piston stem  260 . In some embodiments, the piston stem flange  269  may be perpendicular to the wall of the piston stem  260 . A piston stem flange  269  may be configured to mate with or secure a portion of a spring  290  there against. A piston stem flange  269  may also be configured to fit within an output cylinder  240  of a pump engine  200 . 
         [0038]    According to various embodiments of the invention, the piston stem  260  is moveably connected to the piston seal  230  as illustrated in  FIGS. 16 and 17 . The piston seal  230  may fit around the end of the piston stem  260  adjacent the fluid lock  262  such that the fluid lock  262  may rest against the a lower portion of the central portion  233  of the piston seal  230  body as illustrated in  FIG. 16 . The inner flange  236  of the piston seal  230  may rest against or seal against an outer wall of the piston stem  260  above the one or more input openings  268 . In the rest position, the one or more input openings  268  may be sealed or closed by contact with the central portion  233  of the piston seal  230  body. Upon application of a force on the piston stem  260 —such as by application of a force on the piston stem flange  269 —towards the piston seal  230 , the piston stem  260  may move relative to the piston seal  230  such that the one or more input openings  268  are opened below a lower portion of the central portion  233  of the piston seal  230  body as illustrated in  FIG. 17 . After a defined movement a portion of the piston stem  260  directly above the one or more openings  268  may engage with an upper surface of the central portion  233  of the piston seal  230 , thereby applying a force to the piston seal  230  to move the piston seal  230  within a product chamber  214  of the accumulator  210 . Upon release of the force on the piston stem  260 —or application of a force in the opposite direction such as by spring  290 —the piston stem  260  may move relative to the piston seal  230  to close or seal the one or more openings  268  against a portion of the central portion  233  of the piston seal  230 . The fluid lock  262  may then engage a lower surface of the central portion  233  of the piston seal  230 , preventing further flow of product into the one or more openings  268  and moving the piston seal  230  in an opposite direction in the product chamber  214  of the accumulator  210 . 
         [0039]    An output cylinder  240  according to certain embodiments of the invention is illustrated in  FIGS. 9 and 10 . An output cylinder  240  may include a base wall  241  having a cylinder wall  250  projecting outward therefrom. As illustrated, the cylinder wall  250  may be perpendicular to, or substantially perpendicular to, the base wall  241 . The cylinder wall  250  may be cylindrical in shape and defines a cavity  252  within the output cylinder  240 . One or more output stops  254  may also be defined in the cylinder wall  250  or positioned within the cavity  252 . As illustrated in  FIG. 10 , an output stop  254  according to some embodiments of the invention may be formed from a thicker portion of the cylinder wall  250 . In other embodiments, an output stop  254  may include a projection off of the base wall  241  adjacent an interior surface of the cylinder wall  250 . According to still other embodiments, an output stop  254  may include a projection extending off an interior portion of the cylinder wall  250  towards an interior of the cavity  252 . According to various embodiments of the invention, an output stop  254  may follow an entire circumference of the interior surface of the cylinder wall  250 . For example, in some embodiments a portion of the cylinder wall  250  adjacent the base wall  241  is thicker over a defined distance at which point a ledge is formed where the cylinder wall  250  becomes thinner as illustrated in  FIG. 10 . The difference in the thickness of the cylinder wall  250  forms a circular ledge within an interior of the cavity  252  which ledge acts as an output stop  254  according to various embodiments of the invention. In other embodiments, an output stop  254  may only be located adjacent a portion of the interior surface of the cylinder wall  250 . For instance, one or more piers or projections may be included in the cavity  252  adjacent the cylinder wall  250  such that a top surface of each pier or projection is at a height where movement of a piston stem  260  within the output cylinder  240  may be halted. 
         [0040]    According to various embodiments of the invention, an output stop  254  may be configured to stop movement of a piston stem  260  in a pump engine  200  configuration or in a pump system  100 . As illustrated in  FIGS. 1 and 11-13 , a spring  290  may be positioned in the cavity  252  of the output cylinder  240  and may act on one end against a portion of the output cylinder  240 , such as against a portion of the base wall  241  of the output cylinder  240  as illustrated. An opposite end of the spring  290  may act against a portion of the piston stem  260 , such as against the piston stem flange  269 . A piston stem  260  may be at least partially positioned in the cavity  252  of the output cylinder  240  such that the spring  290  is partially compressed, applying a force to the piston stem  260 . Application of a force to the piston stem  260  at the piston stem flange  269  or adjacent the output opening  264  of the piston stem  260  may move the piston stem  260  towards the base wall  241  of the output cylinder  240  until the piston stem flange  269  is stopped by an output stop  254 . Once the piston stem flange  269  engages an output stop  254 , further movement of the piston stem  260  towards the base wall  241  is stopped, ceasing movement of the piston seal  230  in the accumulator  210  and flow of a product through the piston stem  260 . Thus, the output stop  254  dictates or controls the length of the piston stroke and the amount of product that may be pumped through the pump engine  200  for any given full stroke of the piston stem  260 . 
         [0041]    According to various embodiments of the invention, the output of a pump engine  200  may be altered by changing the position of the output stop  254  within the output cylinder  240 . Thus, one part of the pump engine  200  may be changed to alter the amount of product pumped from a pump engine  200 : the output cylinder  240 . A pump engine  200  may be assembled with any one of a plurality of output cylinders  240  having different output stop  254  locations to achieve a desired output for the pump engine  200 . For example, as illustrated in  FIG. 11 , a first output cylinder  240  may include an output stop  254  at a first location to allow a total output per stroke of approximately 0.2 mL. An output cylinder  240  having an output stop  254  at a second location may only allow a total output per stroke of approximately 0.15 mL as illustrated in  FIG. 12 . An output cylinder  240  having an output stop  254  at a third location may only allow a total output per stroke of approximately 0.12 mL as illustrated in  FIG. 13 . Other configurations could also be used such that pump engines  200  having any number of outputs could be manufactured using almost all of the same components, the only difference being the selection of the output cylinder  240  with the desired output stop  254 . 
         [0042]    In some embodiments of the invention, the output cylinder  240  may be color coded to reflect the output that is achievable utilizing the output cylinder  240  in a pump engine  200  or pump system  100 . For instance, a first output may be color coded red, a second output color coded blue, and a third output color coded yellow. On the manufacturing floor or at the manufacturing location, the color coding may allow operators to more easily identify the proper output cylinder  240  to be assembled for a given run of pump engines  200  or pump systems  100 . Thus, if a pump engine  200  having a desired first output is required, an operator may load the output cylinders  240  color coded red into the assembly machine for that assembly run. Likewise, if a third output is desired for an assembly run, an operator could change the output cylinders  240  to those color coded yellow. Similarly, an operator working with the assembly of a pump system  100  with a desired first output would be able to select the appropriate pump engine  200  assemblies to use based on the color of the output cylinder  240  of the pump engine  200 . 
         [0043]    According to various embodiments of the invention, pump engines  200  having different outputs may be easily assembled from common components in the manufacturing environment. The ability to utilize the same accumulator  210 , piston seal  230 , piston stem  260 , and spring  290  along with a custom output cylinder  240  to manufacture piston engines  200  having different outputs is advantageous in part because the common components may be run at higher cavitation rates, thereby reducing the cost of those parts. Furthermore, as in the example above, the only parts that need to be changed on an assembly line to vary the output of the final pump are the output cylinders  240 . In addition, smaller runs for particular output pump systems  100  are justifiable because smaller tools capable of producing only the output cylinder  240  do not require the capital investment required for larger tooling. This flexibility also allows for different output options to be easily manufactured and assembled without the costs of capitalizing an entire line for a particular pump system  100 . 
         [0044]    An output cylinder  240  according to various embodiments of the invention may also include one or more retaining flanges  248  about an exterior portion of the cylinder wall  250  as illustrated in  FIGS. 9 and 10 . A retaining flange  248  may be configured to help retain the output cylinder  240  in an assembled state with a closure  110  of a pump system  100 . As illustrated in  FIG. 15 , a closure  110  may include a closure lip  111  projecting therefrom and configured to snap over the retaining flange  248  to retain the output cylinder  240  on the closure  110 . In this manner, a pump engine  200  may be assembled to a closure  110  as part of the final pump system  100 . A portion of the retaining flange  248  may be sloped to allow or facilitate assembly of the closure  110  to the output cylinder  240 . For example, a pump engine  200  assembly may be assembled to a closure  110  by positioning the closure lip  111  over the retaining flange  248  of the output cylinder  240 . Application of a force on the closure  110 —or on the pump engine  200 —may push the closure  110  and pump engine  200  together such that the closure lip  111  snaps over the retaining flange  248  and then retains the closure  110  and output cylinder  240  in an assembled state. 
         [0045]    An output cylinder  240  according to various embodiments of the invention may also include a plug seal wall  244  extending off of the base wall  241  in a direction opposite that of the cylinder wall  250  as illustrated in  FIG. 10 . A plug seal wall  244  may be a cylindrical shape and may have a constant thickness or a tapering thickness. The plug seal wall  244  may seat against or seal against an inner surface of an accumulator  210 . In some embodiments of the invention, the plug seal wall  244  may seal against the inner surface of the accumulator  210  such that minimal or no air or liquid may pass between the plug seal wall  244  and the accumulator  210 . In such configuration, the pump engine  200  may be used with airless pump systems that do not require any venting. In those instances where a pump engine  200  or pump system  100  is to be used as an atmospheric-type pump, sealing between the plug seal wall  244  and the accumulator  210  is not as critical because air must pass between the two components to allow air into the container  900  of the pump system  100 . 
         [0046]    According to some embodiments of the invention, an output cylinder  240  may also include a latch wall  246  extending off of the base wall  241  in the same direction as the plug seal wall  244  as illustrated in  FIGS. 9 and 10 . The latch wall  246  may be a cylindrical shape and may have a constant thickness or a tapering thickness. The latch wall  246  may also include a retention lip  247  on an interior edge of the latch wall  246 . As illustrated in  FIG. 10 , the retention lip  247  may be adjacent the end of the latch wall  246 . The latch wall  246  may also have a diameter or circumference that is greater than that of the plug seal wall  244 . In some embodiments of the invention, the latch wall  246  may be configured to accept a retaining ring  215  of an accumulator  210  in such a manner to retain the accumulator  210  and output cylinder  240  in an assembled state. For example, as part of a pump engine  200 , an accumulator  210  may be snap-fit into the output cylinder  240  such that the retaining ring  215  of the accumulator  210  snaps into the space between the latch wall  246 , bottom surface of the base wall  241 , and the plug seal wall  244 . A retention lip  247  may help to secure the retaining ring  215  and accumulator  210  to the output cylinder  240 . 
         [0047]    Some embodiments of the invention may be used with airless pump systems where no air is allowed back into a container  900  of the pump system  100 . In such instances, the attachment or seal between the accumulator  210  and output cylinder  240  is such that no air can pass through the attachment. In other instances, an atmospheric pump system may be desired. In those cases, the output cylinder  240  may include one or more air paths or vent paths on an interior surface of the latch wall  246  and through the retention lip  247  such that air may pass through an interior of the output cylinder  240 , around the accumulator  210  and output cylinder  240  connection, and into a container  900  to which a closure  110  is attached. 
         [0048]    A spring  290  according to various embodiments of the invention may include any conventional spring used with pump engines or pump systems. In addition, leaf-springs, plastic springs, and other types of springs may be incorporated with various embodiments of the invention. 
         [0049]    A head  140  according to various embodiments of the invention may include a conventional pump head  140  that may be snap-fit or otherwise connected to a closure  110  such that the head  140  is in fluid communication with the piston stem  260 . In some embodiments of the invention, a fluid flow path may be defined in the head  140  and a portion of a feature in the head  140  defining the fluid flow path may fit over an end of the piston stem  260  adjacent the second opening  212 . In some embodiments, a portion of the head  140  may rest on the piston stem flange  269  and may apply force to the piston stem  260  during actuation of the head  140  by a user. 
         [0050]    In some embodiments of the invention, a head  140  may also include an orifice at an output end of the fluid flow path. An orifice cup, valve, seal, or other feature conventionally used with pumps and sprayers may be inserted into the orifice to control or define an output from the pump system  100 . 
         [0051]    In further embodiments of the invention, a head  140  and closure  110  may include mating features configured to provide a locking capability for a pump system  100 . For example, an interior portion of the head  140  may include ribs extending inwardly and a closure  110  may include posts upon which those ribs may rest in a locked position—preventing movement of the head  140 —and open areas in which the ribs may move during actuation without hinderance of the posts. Rotation of the head  140  may move the ribs into and out of a locked position or a position in which the ribs and posts align or do not align. 
         [0052]    Conventional gaskets  190  may be used with various embodiments of the invention. 
         [0053]    Conventional containers  900  may be used with various embodiments of the invention. In some embodiments, a container  900  may include a threaded closure system for mating with a closure  110  and in other embodiments a container  900  may include a snap-fit, bayonet, or permanent snap closure system allowing the container  900  and closure  110  to attach to each other. 
         [0054]    A pump engine  200  according to certain embodiments of the invention may be assembled prior to assembly with a pump system  100 . For example, in some embodiments of the invention, a pump engine  200  may be assembled in a first location and then shipped or transported to a second location for final assembly with at least some of the pump system  100  components. Assembly of a pump engine  200  according to certain embodiments of the invention involves the assembly of the components illustrated in  FIGS. 1 and 2 . 
         [0055]    In some embodiments of the invention, a pump engine  200  may be assembled using the following method: a spring  290  may be inserted into an interior of the output cylinder  240 ; a piston stem  260  may be inserted through the output cylinder  240  to secure the spring between the output cylinder  240  and a piston stem flange  269  such that the fluid lock  262  of the piston stem  260  extends through an opening in the output cylinder  240 ; a piston seal  230  is press fit over the fluid lock  262  to connect the piston stem  260  to the piston seal  230 ; a ball  22  is inserted into an accumulator  210 ; and the accumulator  210  is snap-fit into the output cylinder  240 . When the fluid lock  262  of the piston stem  260  is forced through the opening in the piston seal  230 , it cannot be pulled back through the piston seal  230 , thereby retaining the piston seal  230 , output cylinder  240 , spring  290 , and piston stem  260  in an assembled state such that it may be fitted to and connected with an accumulator  210  having a valve  200  assembled therewith. The final assembly results in a pump engine  200  according to various embodiments of the invention. 
         [0056]    In some embodiments of the invention, a pump system  100  may be assembled using the following method: a pump engine  200  may be snap-fit to a closure  110 ; a pump head  140  may be snap-fit onto the closure such that it is in fluid communication with the piston stem  260  of the pump engine  200 ; a dip tube  180  may be—optionally—assembled to the first opening  211  of the accumulator  210  of the pump engine  200 ; a gasket  190  may be assembled inside the closure  110 ; and the closure  110  may be attached to a container  900 . Alternatively, the closure  110 , head  140 , and dip tube  180  may be assembled with the pump engine  200  and transported or shipped to a filling location where it may be assembled to a container  900  on, or as part of, a conventional fill line or filling process. 
         [0057]    While various embodiments of the invention have been described with respect to a pump or pump dispenser, it is understood that a pump engine  200  or output cylinder  240  according to embodiments of the invention could be incorporated into a fine-mist sprayer, trigger sprayer, or other device to provide optional outputs for such devices. 
         [0058]    While various embodiments of the invention are described herein, it is understood that the particular embodiments defined by the appended claims are not to be limited by particular details set forth in the description, as many apparent variations thereof are contemplated. Rather, embodiments of the invention are limited only by the appended claims, which include within their scope all equivalent devices or methods which operate according to the principles of the embodiments of the invention described.