Abstract:
A fluid dispenser is provided including (a) a flexible receptacle, having a closed end and an opposed open end, being movable from a collapsed condition to an elongate condition, and having an outer surface defining a helical thread, and (b) a helical spring in threaded engagement with the helical thread to axially compress the receptacle. Fluid introduced into said receptacle moves the receptacle from its collapsed condition to its elongate condition, producing tension in the spring, the tension being effective to move the receptacle from its elongate condition to its collapsed condition to force fluid from the receptacle.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to fluid dispensers. 
     In the field of fluid dispensing, particularly the dispensing of toiletries such as shaving gels, lotions, etc., much of the present-day packaging employs either pressure, provided by fluorocarbons or other propellants, or hand-operated pumps. 
     Pressurized containers often provide excellent dispensing performance. However, these containers are generally pressurized in excess of 30 psi and at times may provide a seal leak, in which instance the package becomes incapable of expelling its contents. Pressure leaks can occur in many areas, the bottom grommet and container seams being the most vulnerable. Further, the use of propellants in pressurized containers has recently led to criticism due to possible effects on the environment. 
     Pump systems generally dispense a metered amount, and, because consumers may have different requirements, difficulty arises in providing a proper metered amount that is satisfactory to all users. Thus, the consumer may need to pump the dispenser several times to dispense a desired amount of fluid, which is viewed as an inconvenience by some consumers. Additionally, pump systems may tend to jam or clog over a period of time. 
     Various other arrangements have been proposed, in which a collapsible container contains material that is forced from an expanded condition to a nonexpanded condition by a spring mechanism that pushes axially on the base of containers to collapse it towards the dispensing end of the container. 
     SUMMARY OF THE INVENTION 
     The invention provides fluid dispensers that operate without pressurization or a pump mechanism. Advantageously, the fluid dispensers are simple to manufacture, and are relatively trouble-free during use. 
     In one aspect, the invention features a fluid dispenser including (a) a flexible receptacle, having a closed end and an opposed open end, being movable from a collapsed condition to an elongate condition, and having an outer surface defining a helical thread, and (b) a helical spring in threaded engagement with the helical thread to axially compress the receptacle. Fluid introduced into the receptacle moves the receptacle from the collapsed condition to the elongate condition, producing tension in the spring, the tension being effective to move the receptacle from the elongate condition to the collapsed condition to force fluid from the receptacle. 
     Preferred embodiments may include one or more of the following features. The dispenser further includes a container having a closed end and an opposed open end, the open end of the receptacle being attached to the container adjacent the open end of the container and the receptacle being freely supported within the container. The dispenser further includes a valve constructed to prevent fluid from being forced out of the receptacle until the dispenser is actuated by a user. The receptacle includes an outwardly projecting crest portion and an inwardly projecting root portion. The helical spring is disposed on the root portion. The helical spring is encased within the root portion. The receptacle is formed of a plastic material. The helical spring is formed of a metallic material. 
     In another aspect, the invention features a fluid dispenser including (a) a first flexible receptacle having a closed end wall and an opposed open end, and an outer surface defining a helical thread that is movable from a collapsed condition to an elongate condition, (b) a second flexible receptacle, disposed within the first receptacle, having a closed end wall attached to the closed end wall of the first receptacle and an open end adjacent the open end of the first receptacle, and (c) a helical spring threadedly received on the outer surface of the first receptacle. Fluid material forced into the first receptacle is effective to move the first receptacle from a collapsed condition to an elongate condition producing tension in the spring, and the tension in the spring is effective to move the first receptacle from an elongate condition to a collapsed condition to force material from the first and second receptacles. 
     Preferred embodiments may include one or more of the following features. The dispenser further includes a valve constructed to prevent fluid from being forced out of the receptacle until the dispenser is actuated by a user. The helical thread includes an outwardly projecting crest portion and an inwardly projecting root portion. The helical spring is disposed on the root portion. The valve includes a valve assembly constructed to translate between a closed position, in which the first and second receptacles are sealed, and an open position, in which first and second components flow simultaneously from the first and second receptacles to a dispensing head. The dispensing head defines a nozzle through which the product exits the dispensing head, a first passageway between the first receptacle and the nozzle, and a second passageway between the second receptacle and the nozzle. The valve assembly includes first and second valve seats, and a valve stem including a first valve portion for sealing against the first valve seat to seal the first receptacle and a second valve portion for sealing against the second valve seat to seal the second receptacle. The valve assembly further includes a spring that biases the first and second valve portions against the respective first and second valve seats. The valve assembly further includes a valve body, and the spring, valve stem and valve seats are contained within the valve body as a modular unit. 
     Other features and advantages will be apparent from the following description of a presently preferred embodiment, and from the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational sectional view showing a fluid dispenser according to one embodiment of the invention; 
     FIG. 2 is an elevational view showing the receptacle of the dispenser of FIG. 1; 
     FIG. 3 is a bottom perspective view showing the spring of the dispenser of FIG. 1; 
     FIG. 4 is an elevational sectional view showing the receptacle and spring of FIGS. 2 and 3 in an assembled condition; 
     FIG. 5 is a fragmentary sectional view showing receptacle/spring assembly according to an alternate embodiment of the invention; and 
     FIG. 6 is an elevational sectional view showing a dispenser according to another alternate embodiment of the invention. 
     FIGS. 7 and 7A are partial sectional views of a portion of a receptacle for a dispenser according to an alternate embodiment of the invention, shown in a full and empty condition, respectively. 
     FIGS. 8 and 8A are partial sectional views of a portion of a receptacle for a dispenser according to another alternate embodiment of the invention, shown in a full and empty condition, respectively. FIG. 8B is a side view of the spring used in the dispenser shown in FIGS. 8 and 8A. 
     FIG. 9 is a partial sectional view of a preform for use in manufacturing the receptacle shown in FIGS. 7-7A. 
     FIG. 10 is a cross-sectional view of a valve assembly used in the fluid dispenser. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1-4, a fluid dispenser  10  includes a valve  12  that is sealingly attached to a valve cup  14 , which in turn is sealingly fixed at the open end  16  of a container  18 , the container having a closed end opposite the valve  12  to form an enclosed container. A flexible elongated receptacle  20 , typically formed of a plastic, e.g., PET or nylon, is provided within the enclosed container for holding a fluid to be dispensed. Suitable receptacles are flexible enough to be easily compressed during dispensing, yet strong enough to withstand the applied pressure. 
     Receptacle  20  has an open end  28  that is surrounded by a skirt  29  that is sealed between a lip  30  on the container  18  and flange  31  of the valve cup  14 . The receptacle  20  has an outer surface in the form of a helical thread, the helical thread having an outwardly projecting crest portion  22  and an inwardly projecting root portion  24 . A helical spring  25 , which is constructed of steel or other metallic material, is assembled onto the receptacle  20  by threading the coils of the spring  25  onto the root portion  24  of the receptacle  20 . The elongated receptacle  20  is thus compressed axially, as shown in FIG. 4, and both axially and radially retained within the coils of the spring  25 . The spring  25  has a tang  26  disposed at the lower end thereof (FIG.  1 ), which is effective to support the lower closed end  27  of the receptacle  20 . 
     The valve  12  includes a valve stem (not shown) that is movable to provide an open or closed position of the valve, an inlet  33 , and an outlet  34 . Any type of check valve that controls fluid flow between the receptacle and the atmosphere may be used. 
     To prepare the dispenser  10  for use, the receptacle  20  is installed into the container  18  in the condition shown in FIG.  4 . That is, the spring  25  is threaded onto the surface of the receptacle  20 , after which the receptacle is assembled onto the container  18  in sealing relation with the valve cup  14 , the valve  12  also being assembled onto the valve cup. The normally closed valve is then opened by a filling head (not shown) and fluid material to be dispensed is then forced under pressure, through the open valve, into the receptacle  20  which assumes the elongated state shown in FIG.  1 . When the receptacle  20  is elongated, the coils of the spring  25  are under tension. The valve  12  is then closed to maintain the pressure within the receptacle  20 . It will be noted that, with the spring  25  disposed as shown in FIG. 4, the filling of the receptacle  20  with the fluid material will cause the receptacle  20  to elongate substantially equally over its length due to the spring constant of the spring  25 . In addition, the spring  25  prevents outward bulging of the receptacle during the filling process, ensuring a linear movement of the receptacle from the position shown in FIG. 4 to that shown in FIG.  1 . 
     To dispense fluid from the dispenser  10 , the user presses an actuator (not shown), which opens valve  12 , allowing fluid to flow from the dispenser. As a result, the spring  25  moves towards its initial compressed state, forcing the fluid out of the receptacle until the user releases the actuator and the valve  12  closes. In addition to dispensing fluid, the spring  25  also maintains linear movement of the receptacle  20 , from the position shown in FIG. 1 to that of the position shown in FIG. 4, by providing substantially equal movement of the coils in the upward direction. The contact between the spring  25  and the root  24  of the helical outer surface of the receptacle  20  maintains the bellows shape of the receptacle  20  during dispensing. 
     The characteristics of the spring  25  and valve  12  will depend on the fluid to be dispensed. Viscous fluids will generally require a higher spring pressure and/or a larger valve opening than relatively low viscosity fluids. For a given viscosity fluid, the spring force required to dispense at a desired flow rate will be determined by the valve opening size (a larger valve opening will require less spring force) and the force required to compress the receptacle (the lower the compression force, the lower the required spring force). If the valve opening size and compression force are held constant, the higher the viscosity of the fluid the higher the required spring force will be. Suitable springs may be selected empirically based on these factors. 
     It may be desirable to manufacture the receptacle and the spring as a compound unit, to facilitate final assembly of the dispenser. FIG. 5 shows such an alternate embodiment of the invention, in which the root  24   a  of the helical outer surface of receptacle  20   a  has an inwardly projecting portion  36  that is formed about the spring  25 . The assembly of the spring  25  and receptacle  20   a  forms a unit that can be easily assembled into the container  18 . 
     FIG. 6 shows a dispenser  110  that is suitable for dispensing a composition that includes two components that should be stored separately. In dispenser  110 , a second receptacle  120  is disposed within receptacle  20 , so that a second component can be stored separately from the component in the receptacle  20 . The two components of the composition are either mixed while being dispensed, or dispensed to a mixing head and then dispensed from the mixing head as a mixture. The inner receptacle  120  has a closed end  127  that is attached to the closed end  27  of the receptacle  20  in sealing engagement. The upper, open end  128  of inner receptacle  120  is sealingly engaged to the lower surface of a valve  112 , the valve  112  being attached to the valve cup  14  in similar manner to that of the valve  12 , described in detail at FIGS. 1-4. The inner receptacle  120  may be manufactured of the same material as the outer receptacle  20  and may take a similar form having a helical-shaped outer surface, or have a non-helical bellows-shape. 
     Still referring to FIG. 6, the valve  112  has an outlet opening  34  to the atmosphere and an inlet opening  33  allowing fluid to flow from the inner receptacle  120  when the valve  112  is open. Additionally, an opening  133  is provided from the outer receptacle  20  into the valve  112  to allow fluid to flow from the receptacle  20  into the valve. The components may be mixed within the valve  112  in any manner well-known in the art, may flow in separate streams through the opening  34  to be mixed in the atmosphere upon release, or may be dispersed to a secondary mixer (not shown) mounted above the valve cup  14 . 
     Valves that are suitable for use in this embodiment of the invention are described, e.g., in the assignee&#39;s co-pending application U.S. Ser. No. 09/574,312, titled “Systems for Dispensing Multi-component Products”, the disclosure of which is incorporated herein by reference. A valve of this type is shown in FIG.  10  and described briefly below. 
     As shown in FIG. 10, valve subassembly  17  includes a valve body  60 , which is constructed to be mounted on valve cup  13  and crimped in place. Valve body  60  defines a central passage  62 , and a plurality of side openings  64 . Inner wall  66  of valve body  60  includes a plurality of ribs  68  and a shoulder  70 , to support a spring  72 . Valve stem  74  is mounted within a spring  72 , which biases first valve portion  76  against first valve seat  78  and second valve portion  80  against second valve seat  82 , so that both valve portions are biased towards a closed position. Preferably valve seats  78  and  82  are resilient gaskets, to provide a fluid-tight seal when the valve is in a closed position. Valve stem  74  also includes a central bore  79 , in communication with passage  56  of the dispensing head, and a plurality of openings  81  which are unavailable for fluid flow from chamber  7  when the valve is closed, but which allow the second component to flow from chamber  7  into passage  56  when the valve opens. 
     Dispensing head  50  includes an actuating stem  84 , which extends into and seats in a cup-shaped area  86  of the valve stem  74 . When actuator  52  is depressed, actuating stem  84  presses valve stem  74  down, against the biasing force of spring  72 . This movement simultaneously moves both valve portions away from the corresponding valve seats, moving the dispensing system to its open position, shown in FIG.  2 A. Importantly, the two valves are opened simultaneously, and no material is released from either chamber into the passages to the nozzle until the actuator is depressed. When the valves are opened, the first component flows from chamber  8 , through openings  64  in the valve body and past valve portion  76 , into passage  54 . Simultaneously, the second component flows from chamber  7 , through openings  81  in the valve stem and into passage  56 . 
     Other embodiments are within the claims. 
     For example, as shown in FIGS. 7-7A, receptacle  20  may include a rigid, inwardly extending base portion  51  so that, when the receptacle is emptied, and thus completely compressed (FIG.  7 A), there is less residual material left in the receptacle. (FIG. 7A shows the receptacle only, for clarity; the spring would be assembled onto the receptacle in a manner similar to that shown in FIGS. 8-8A.) The receptacle can be molded in the position shown in FIG. 7, or can be molded with the inwardly extending base portion  51  initially extending outwardly (FIG. 9) and the base portion pushed in prior to filling. 
     An alternative way of achieving the same objective (i.e., emptying the receptacle as much as possible) is shown in FIGS. 8-8A. In this embodiment, spring  25  includes an upwardly extending tang  26 , which is pressed flat when the receptacle is full, and subsequently springs up as the receptacle is emptied, to push out residual fluid after the receptacle is completely compressed. When the tang springs up, it pushes upward on the bottom portion of the receptacle which then rolls into itself, as shown in FIG.  8 A.