Abstract:
A venting system of a manually operated trigger sprayer vents the interior of a liquid container connected to the trigger sprayer. The trigger sprayer is provided with a vent chamber that surrounds the pump chamber, and a vent piston that surrounds the pump piston. The vent piston is received in the vent chamber for reciprocating movements with the pump piston in the pump chamber. The reciprocating movement of the vent piston alternatively opens the vent chamber to the exterior environment of the trigger sprayer and thereby vents the interior of the liquid container connected to the trigger sprayer, and closes the vent chamber thereby sealing the interior of the liquid container from the exterior environment.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     (1) Field of the Invention  
         [0002]     The present invention pertains to a venting system for a manually operated, liquid dispensing trigger sprayer. More specifically, the present invention pertains to improvements to a venting system of a manually operated trigger sprayer that vents the interior of a liquid container connected to the trigger sprayer. For the most part, the construction of the trigger sprayer is typical and includes a sprayer housing having a pump chamber, a pump piston mounted in the pump chamber for reciprocating movement, and a trigger mounted on the sprayer housing for manual manipulation of the trigger which reciprocates the pump piston in the pump chamber. The improvement comprises a vent chamber that surrounds the pump chamber and a vent piston that surrounds the pump piston. The vent piston is received in the vent chamber for reciprocating movements with the pump piston in the pump chamber. The reciprocating movement of the vent piston alternatively opens the vent chamber to the exterior environment of the trigger sprayer and thereby vents the interior of the liquid container connected to the trigger sprayer, and closes the vent chamber thereby sealing the interior of the liquid container from the exterior environment.  
         [0003]     (2) Description of the Related Art  
         [0004]     A typical manually operated liquid dispensing trigger sprayer comprises a sprayer housing that has a nozzle for dispensing liquid, a trigger mounted on the sprayer housing for movement of the trigger relevant to the housing, a pump chamber on the housing, and a pump piston operatively connected to the trigger and received in the pump chamber for reciprocating movement of the piston in the pump chamber in response to manual movement of the trigger, and a connector attaching the trigger sprayer to a liquid container. The reciprocating movement of the pump piston in the pump chamber alternately draws liquid from the liquid container into the pump chamber, and then pumps the liquid out of the pump chamber and dispenses the liquid through the nozzle of the sprayer housing as a spray or stream.  
         [0005]     Trigger sprayers of this type are often provided with some system of venting the interior of the liquid container connected to the trigger sprayer. This allows air to enter the container interior and occupy that portion of the internal volume of the container that is vacated by the liquid dispensed from the container by the trigger sprayer.  
         [0006]     Many different types of trigger sprayer venting systems have been developed in the prior art. One type of venting system employs a resilient diaphragm valve that is positioned in the interior of the sprayer housing covering over a vent hole in the sprayer housing. The vent hole communicates the interior of the sprayer housing and the interior of the connected liquid container with the exterior environment of the sprayer. A plunger is provided on the trigger member of the trigger sprayer and is positioned just outside of the vent hole. On manual manipulation of the trigger, the plunger is inserted through the vent hole and engages the diaphragm valve, displacing the diaphragm valve from its position over the vent hole. This vents the interior of the liquid container. On the return movement of the trigger the plunger is retracted out of the vent hole and the resilience of the diaphragm valve allows it to resume its position over the vent hole.  
         [0007]     However, these prior art venting systems have been found to be disadvantaged in that repeated use of the trigger sprayer causes repeated displacement of the diaphragm valve from the sprayer vent hole. The resiliency of the diaphragm valve is effected by these repeated displacements and the valve is no longer able to immediately reposition itself over the vent hole once the plunger is retracted from the vent hole. This can result in liquid leaking from the container through the vent hole should the container and trigger sprayer be knocked over on one side before the diaphragm valve repositions itself over the vent hole.  
         [0008]     Another type of venting system employs a vent cylinder on the sprayer housing and a vent piston operatively connected to the trigger of the trigger sprayer. The vent hole is positioned in the side of the cylinder and one or more small ribs are formed on the interior surface of the cylinder in the area of the vent hole. The vent piston engages in a sliding, sealing engagement with the interior surface of the vent cylinder. As the trigger is manipulated, the vent piston is pushed through the vent cylinder toward the vent hole and the ribs. The ribs engage with the periphery of the vent piston and displace the periphery from the interior surface of the vent cylinder, thereby communicating the exterior environment of the trigger sprayer around the piston and through the vent cylinder and the vent hole to the interior of the liquid container.  
         [0009]     This venting system has been found to be disadvantaged in that after repeated use of the trigger sprayer, the ribs in the vent cylinder have a tendency to deform the resilient material around the periphery of the vent piston. This detracts from the ability of the vent piston to seal against the interior surface of the vent cylinder, and can result in leakage of liquid from the liquid container through the vent cylinder.  
         [0010]     It has also been noted that venting systems employing venting cylinders of the type described above have been disadvantaged in that the molding of the sprayer housing must be closely monitored to ensure that no imperfections develop in the vent cylinder of the housing. Because the sprayer housing is molded with a pump cylinder and a vent cylinder in close proximity to each other, sinks can often form in the interior surfaces of the pump cylinder and vent cylinder as the molded plastic of the sprayer housing cools. When sinks form as slight indentations in the interior walls of the pump cylinder and vent cylinder they can prevent the pump piston and vent piston peripheries from engaging in a sealing engagement with the pump and vent cylinder interior surfaces. This can result in leakage of liquid from the trigger sprayer.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention overcomes disadvantages associated with prior art venting systems of trigger sprayers by providing an improved trigger sprayer venting system that vents air to the liquid container connected to the trigger sprayer early in the pump piston stroke and for an extended period of the pump piston stroke, while preventing liquid from leaking through the venting system should the trigger sprayer and liquid container be turned on one side.  
         [0012]     Much of the construction of the trigger sprayer of the invention is common to trigger sprayers. The trigger sprayer is generally constructed with a sprayer housing that is connected by a separate connector to a fluid container. The sprayer housing is formed with a liquid pump chamber that communicates with a liquid supply passage and a liquid discharge passage that both extend through the sprayer housing. A pump piston is mounted in the pump chamber for reciprocating movement. A trigger is mounted on the sprayer housing for manual manipulation. The trigger is operatively connected with the pump piston and manipulation of the trigger reciprocates the pump piston in the pump chamber. Reciprocation of the pump piston alternatively draws liquid from the liquid container through the liquid supply passage to the pump chamber, and then pumps the liquid from the pump chamber through the liquid discharge passage and dispenses the liquid from the sprayer housing as a spray or stream.  
         [0013]     The trigger sprayer of the invention differs in construction from that of prior art trigger sprayers in the venting system provided on the trigger sprayer. The venting system is basically comprised of a vent chamber and a vent piston received inside the vent chamber for reciprocating movement of the vent piston relative to the vent chamber.  
         [0014]     The vent chamber is formed on the sprayer housing around the pump chamber of the trigger sprayer. The vent chamber has a cylindrical side wall that extends around and surrounds the pump chamber. This coaxial positioning of the pump chamber and vent chamber relative to each other reduces the probability of sinks forming in the side walls of the pump chamber and vent chamber as the plastic employed in molding the trigger sprayer cools.  
         [0015]     A vent hole is provided in a back wall of the vent chamber and communicates the interior volume of the vent chamber with the interior of the liquid container connected to the trigger sprayer. By positioning the vent hole in the back wall of the vent chamber, the vent hole is spaced from the vent piston as the vent piston reciprocates in the vent chamber. This prevents the vent hole from adversely affecting the seal provided between the periphery of the vent piston and the interior of the vent chamber.  
         [0016]     The vent chamber has a cylindrical interior surface with a first interior diameter dimension adjacent the vent hole in the back wall of the vent chamber. The interior diameter dimension remains consistent for a majority of the length of the vent chamber as it extends from the back wall. As the vent chamber approaches a distal end of the vent chamber remote from the back wall, the interior diameter dimension of the vent chamber interior surface gradually decreases, forming a necked down interior surface of the vent chamber adjacent the chamber distal end.  
         [0017]     With the vent chamber being coaxial with the pump chamber, the vent piston is formed coaxially around the pump piston. The vent piston is formed of the same resilient material as the pump piston. In a first position of the vent piston relative to the vent chamber, the peripheral surface of the vent piston engages in a sealing engagement with the necked down portion of the vent chamber interior surface. This seals the interior of the vent chamber from the exterior environment of the trigger sprayer and prevents unintended liquid leakage from the liquid container through the trigger sprayer vent chamber. On actuation of the liquid pump, the vent piston moves with the pump piston. The vent piston moves away from the necked down portion of the vent chamber interior surface toward the vent hole at the back wall of the vent chamber. This movement of the vent piston causes the peripheral surface of the vent piston to disengage from the interior surface of the vent chamber, thereby establishing a venting path between the vent piston peripheral surface and the vent chamber interior surface. This allows the interior of the liquid container connected to the trigger sprayer to vent through the vent chamber to the exterior environment of the trigger sprayer.  
         [0018]     With the novel construction of the venting system of the invention described above, the trigger sprayer of the invention overcomes disadvantages commonly associated with prior art trigger sprayer venting systems. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]     Further features of the present invention are set forth in the following detailed description of the preferred embodiment of the invention and in the drawing figures wherein:  
         [0020]      FIG. 1  is a side elevation view, in section, of the trigger sprayer apparatus of the invention in the first position of the vent piston relative to the vent chamber; and,  
         [0021]      FIG. 2  is a side elevation view, in section, of the trigger sprayer of  FIG. 1  with the vent piston in its second position relative to the vent chamber. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]      FIGS. 1 and 2  show side sectioned views of the trigger sprayer of the invention that includes the novel venting system of the invention. Many of the component parts and the details of construction of the trigger sprayer shown in  FIGS. 1 and 2  are common to trigger sprayers of the prior art. Therefore, these will only be described generally. The novel venting system of the invention will be described in more detail. As is typical in the construction of trigger sprayers, most of the component parts are constructed of a plastic material.  
         [0023]     The trigger sprayer comprises a sprayer housing  12  that is molded with many of the component parts of the trigger sprayer. The bottom of the sprayer housing  12  is formed with a circular disk  14  having a peripheral flange  16 . An opening passes through the disk  14  and a liquid supply passage  18  extends upwardly through the sprayer housing from the disk. A pump chamber  22  is formed on the sprayer housing  12  and communicates through a pump port  24  with the liquid supply passage  18 .  
         [0024]     The pump chamber  22  is defined by a cylindrical side wall  26  of the chamber. The chamber also has a circular end wall  28 . The pump port  24  passes through the end wall  28 . The pump chamber side wall  26  extends from the end wall  28  to a distal end  32  of the side wall. The side wall distal end  32  surrounds a circular opening into the interior of the pump chamber. The side wall  26  has a cylindrical interior surface  34  that defines a center axis  36  of the pump chamber  22 .  
         [0025]     A liquid discharge passage  42  is also formed in the sprayer housing  12 . The liquid discharge passage  42  has a length with a proximal end  44  that communicates with the liquid supply passage  18 , and an opposite distal end  46 .  
         [0026]     A check valve  52  is mounted in the liquid discharge passage  42 , as is conventional. The check valve  52  permits liquid flow from the passage proximal end  44  to the passage distal end  46 , and prevents the reverse flow. As is also conventional, a nozzle assembly  54  is mounted to the distal end  46  of the liquid discharge passage  42 . Although particular constructions of the check valve  52  and nozzle assembly  54  are shown in the drawing figures, other equivalent types of valves and nozzle assemblies may be employed with the trigger sprayer of the invention.  
         [0027]     A connector cap  62  is mounted on the circular flange  16  of the sprayer housing  12 . The cap  62  is used in removably attaching the sprayer housing  12  to a separate liquid container. The cap  62  shown has internal screw threading for attachment to the liquid container. However, other equivalent types of connectors may be employed with the trigger sprayer of the invention.  
         [0028]     A dip tube  64  extends upwardly through the cap  62  and through the opening in the bottom disk  14  of the sprayer housing  12 . The dip tube  64  forms a portion of the liquid supply passage  18  that leads to the interior of the pump chamber  22 . A valve seat assembly  66  is mounted over the upper end of the dip tube  64  as viewed in  FIGS. 1 and 2 . A ball valve  68  is positioned on the seat assembly  66 . The ball valve  68  controls the flow of liquid through the liquid supply passage  18  to the pump chamber  22 . The valve permits the flow of liquid through the supply passage  18  to the interior of the pump chamber  22 , and prevents the reverse flow of liquid.  
         [0029]     A cylindrical pump piston  72  is mounted in the interior of the pump chamber  22  for reciprocating movements in the pump chamber. The pump piston  72  is moveable in the pump chamber  22  between a first position of the piston shown in  FIG. 1 , and a second position of the piston shown in  FIG. 2 . A coil spring  74  engages between the piston  72  and the end wall  28  of the pump chamber. The spring  74  biases the pump piston  72  to its first position. The pump piston  72  is formed integrally with a piston rod  76  that extends outwardly from the pump piston and engages with a trigger  82  of the trigger sprayer.  
         [0030]     The trigger  82  has a length with opposite proximal  84  and distal  86  ends. The trigger proximal end  84  mounts the trigger  82  to the sprayer housing  12  for movement of the trigger relative to the sprayer housing. Preferably, the trigger  82  pivots relative to the sprayer housing  12 . The trigger  82  operative connection to the piston rod  76  and the pump piston  72  causes the reciprocating movement of the pump piston in the pump chamber  22  in response to movements of the trigger.  
         [0031]     A shroud  92  covers over much of the exterior of the sprayer housing  12 . The shroud  92  gives an aesthetically pleasing appearance to the trigger sprayer.  
         [0032]     Much of the construction of the trigger sprayer described to this point is conventional. The novel venting system of the trigger sprayer is provided by a vent chamber  94  and a vent piston  96 .  
         [0033]     The vent chamber  92  is comprised of a cylindrical side wall  96  and a circular end wall  98  that is coplanar with and an extension of the pump chamber end wall  28 . The vent chamber side wall  96  extends around and surrounds the pump chamber  22 . A vent opening  102  passes through the end wall  98  and communicates an interior volume of the vent chamber  92  with the interior of the liquid supply passage  18 . The vent chamber side wall  96  has a cylindrical interior surface  104  that defines a center axis of the vent chamber. The vent chamber center axis is coaxial with the pump chamber center axis  36 . The vent chamber interior surface  104  has a consistent interior diameter dimension as the side wall  96  extends from the end wall  98  toward a distal end  108  of the side wall. As the vent chamber side wall  96  approaches the distal end  108 , a portion  112  of the side wall interior surface necks down to a smaller interior diameter dimension compared to that of the rest of the side wall interior surface  104 .  
         [0034]     The vent piston  94  is an integral part of the pump piston  72  and the piston rod  76 . The vent piston  94  is cylindrical and extends around and surrounds the pump piston  72 . Thus, the vent piston  94  and pump piston  72  have the same center axis. As seen in  FIGS. 1 and 2 , the pump piston  72  is entirely contained inside the vent piston  94 . The vent piston  94  extends from the piston rod  76  across the pump piston  72  to a peripheral end portion  114  of the vent piston. This peripheral end portion  114  of the vent piston engages in a sliding, sealing engagement with the interior surface  104  of the vent chamber  92 . As seen in  FIG. 1 , the vent piston end portion  114  tapers slightly radially away from the remainder of the vent piston  94  as it extends to the distal end of the vent piston. This provides for a resilient sealing engagement of the vent piston peripheral end portion  114  with the necked down portion  112  of the vent chamber interior surface  104  in the first position of the vent piston shown in  FIG. 1 . In this first position of the vent piston  94 , the sealing engagement of the vent piston peripheral surface portion  114  with the necked down portion  112  of the vent chamber seals the exterior environment of the trigger sprayer from the interior of the vent chamber  94  and the interior of the liquid container connected to the trigger sprayer.  
         [0035]     On operation of the trigger sprayer, as the trigger  82  is squeezed to the position shown in  FIG. 2 , the vent piston  94  moves to its second position relative to the vent chamber  92 . In the second position of the vent piston  94  shown in  FIG. 2 , the peripheral surface portion  114  of the vent piston becomes disengaged from the necked down portion  112  of the vent chamber side wall. This provides a flow path of venting air from the exterior environment of the trigger sprayer through the vent chamber  92  between the vent piston  94  and the vent chamber side wall  96  and through the vent chamber opening  102  to the interior of liquid container connected to the trigger sprayer. In this manner, on operation of the liquid pump of the trigger sprayer, the interior of the liquid container connected to the trigger sprayer is vented.  
         [0036]     On release of the trigger  82 , the coil spring  74  returns both the pump piston  72  and vent piston  94  to their positions shown in  FIG. 1 . In the position of the vent piston  94  shown in  FIG. 1 , the peripheral surface portion  114  of the vent piston again engages in sealing engagement with the necked down portion  112  of the vent chamber side wall  96 , thus sealing the interior of the vent chamber  94  from the exterior environment of the sprayer.  
         [0037]     With the novel construction of the venting system of the invention described above, the trigger sprayer of the invention overcomes disadvantages commonly associated with prior art trigger sprayer venting systems.  
         [0038]     Although the trigger sprayer of the invention has been described above with reference to a specific embodiment of the sprayer, it should be understood that other variations of the sprayer may be arrived at without departing from the invention&#39;s scope of protection provided by the following claims.