Patent Publication Number: US-10781971-B2

Title: Autofill shutoff valve

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 62/151,593 filed Apr. 23, 2015, and entitled “CENTER FILL OF RESERVOIR FOR PUMP”; to U.S. Provisional Application No. 62/154,222 filed Apr. 29, 2015, and entitled “AUTO FILL SHUTOFF WITH LOW LEVEL”; to U.S. Provisional Application No. 62/302,395 filed Mar. 2, 2016, and entitled “RESERVOIR OVER FILL PROTECTION”; and to U.S. Provisional Application No. 62/302,417 filed Mar. 2, 2016, and entitled “AUTO FILL SHUT OFF BALL CHECK AIR VENT VALVE” the disclosures of which are hereby incorporated in their entirety. 
    
    
     BACKGROUND 
     The present disclosure relates generally to lubrication systems. More particularly, the disclosure relates to a fill system for a lubricant reservoir. 
     Machinery often requires lubrication to function. Seals, pistons, bearings, and other parts require lubrication with small, measured amounts of grease or oil over short, frequent time intervals to prevent wear, corrosion, over-lubrication, or under-lubrication. Lubricant fluid is injected at specific locations that require lubrication by lubricant metering devices. A local lubricant reservoir stores the lubricant until the lubricant is to be applied. The lubricant reservoir holds a limited volume of lubricant and must be refilled from a larger lubricant source when the lubricant reservoir is low. Lubricant fluid is drawn from the lubricant reservoir and pumped to the lubricant metering devices via a lubrication line. The lubricant metering devices are configured to inject a set, small amount of lubricant fluid to the specific location within the machinery once the pressure within the lubrication line reaches a predetermined level. After the lubricant metering devices have dispensed the lubricant, the pressure within the lubrication line is relieved, thereby resetting the lubricant system for another lubrication cycle. 
     SUMMARY 
     According to one embodiment, a lubricant reservoir includes a housing, a reservoir inlet, an actuator, and an autofill shutoff valve. The housing defines a reservoir. The reservoir inlet extends through a top of the housing. The actuator is disposed in the housing and divides the housing into an upper portion and a lower portion, and the actuator is configured to shift upwards in response to a rising lubricant level within the lower portion. The autofill shutoff valve is disposed on the housing and includes a valve body, a lubricant flowpath extending through the valve body, a lubricant inlet extending into the valve body and connected to the lubricant flowpath, a first lubricant outlet extending into the valve body and connected to the lubricant flowpath and disposed adjacent the housing and configured to provide lubricant directly to the housing, and a valve stem extending through the lubricant flowpath between the lubricant inlet and the lubricant outlet. The valve stem is movable between a first position, corresponding to a refill state, and a second position, corresponding to a filled state. The valve stem also allows lubricant to flow from the lubricant inlet to the first lubricant outlet when the valve stem is in the first position and the valve stem blocks the flow of lubricant between the lubricant inlet and the first lubricant outlet when the valve stem is in the second position. 
     According to another embodiment, an autofill shutoff valve includes a valve body, a lubricant flowpath extending through the valve body, a lubricant inlet extending into the valve body and connected to the lubricant flowpath, a first lubricant outlet extending into the valve body and connected to the lubricant flowpath, and a valve stem extending through the lubricant flowpath between the lubricant inlet and the lubricant outlet. The first lubricant outlet is disposed adjacent the lubricant reservoir and is configured to provide lubricant directly to the lubricant reservoir. The valve stem is movable between a first position, corresponding to an refill reservoir state, and a second position, corresponding to a filled reservoir state. The valve stem allows lubricant to flow from the lubricant inlet to the first lubricant outlet when the valve stem is in the first position and the valve stem seals the lubricant flowpath between the lubricant inlet and the first lubricant outlet when the valve stem is in the second position. 
     According to yet another embodiment, a method of automatically stopping the flow of lubricant to a lubricant reservoir when the lubricant reservoir is full includes flowing lubricant through an autofill shutoff valve and to internal plumbing disposed within the lubricant reservoir through a lubricant outlet of the autofill shutoff valve, shifting an actuator upward in response to a rising level of lubricant in the lubricant reservoir, and actuating a valve stem from a first position to a second position with the actuation plate, wherein the valve stem blocks the flow of lubricant through the autofill shutoff valve when in the second position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a lubricant pump and lubricant reservoir. 
         FIG. 2  is a partially exploded view of a portion of a lubricant reservoir. 
         FIG. 3A  is a cross-sectional view of a fill mechanism of a lubricant reservoir in a refill state. 
         FIG. 3B  is a cross-sectional view of a fill mechanism of a lubricant reservoir in a filled state. 
         FIG. 3C  is a cross-sectional view of a fill mechanism of a lubricant reservoir in an overfill state. 
         FIG. 4A  is a cross-sectional view of an actuator and vent valve for a lubricant reservoir in a venting state. 
         FIG. 4B  is a cross-sectional view of an actuator and vent valve for a lubricant reservoir in a sealing state. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a cross-sectional view of lubricant system  10 . Lubricant system  10  includes lubricant pump  12  and lubricant reservoir  14 . Lubricant pump  12  include wet section  16 , dry section  18 , motor  20 , outlet  22 , drive shaft  24 , locating pin  26 , reed switch  28 , and ricer plate  30 . Lubricant reservoir  14  includes base  32 , housing  34 , autofill shutoff valve  36 , actuator  38 , centerfill tube  40 , stirring assembly  42 , alignment plate  44 , connecting bolt  46 , and flag  50 . Housing  34  includes side wall  52 , top surface  54 , upper portion  56 , and lower portion  58 . Side wall  52  includes weep hole  60 . Autofill shutoff valve  36  includes valve body  62 , valve stem  64 , and lubricant flow path  66 . Actuator  38  includes top surface  68 , bottom surface  70 , vent valve  72 , seal  74 , valve protection chamber  76 , and protection mechanism  78 . Protection mechanism  78  includes valve actuation plate  80  and elastic member  82 . Centerfill tube  40  includes first end  84 , second end  86 , and shoulder  88 . Second end  86  of centerfill tube  40  includes load ports  90 . 
     Wet section  16  and dry section  18  of lubricant pump  12  are separated to prevent lubricant from traveling from wet section  16  to dry section  18 . Pump outlet  22  extends into wet section  16  and is configured to receive a lubricant supply tube to provide lubricant downstream from lubricant system  10 . Motor  20  is disposed within dry section  18 . Drive shaft  24  extends from motor  20 , through wet section  16 , and into lubricant reservoir  14 . Lubricant reservoir  14  is mounted to lubricant pump  12 , and lubricant reservoir  14  is configured to provide lubricant to wet section  16 . Base  32  is attached to wet section  16  of lubricant pump  12 . Ricer plate  30  is disposed at the connection of base  32  and lubricant pump  12 , such that lubricant flows through ricer plate  30  when entering wet section  16  from lubricant reservoir  14 . Reed switch  28  extends within wet section  16  through ricer plate  30  such that reed switch  28  is positioned flush with ricer plate  30 . Locating pin  26  is disposed on and above drive shaft  24  and engages second end  86  of centerfill tube  40 . Stirring assembly  42  is connected to drive shaft  24  and is rotatably disposed within lubricant reservoir  14 . 
     Base  32  of lubricant reservoir  14  is mounted to lubricant pump  12  and is configured to allow lubricant to pass downstream from lubricant reservoir  14  to wet section  16  through base  32 . Side wall  52  of housing  34  extends from base  32  to define lubricant reservoir  14 , and top surface  54  is attached to side wall  52  and encloses lubricant reservoir  14 . Actuator  38  is slidably disposed within housing  34  and divides housing  34  into upper portion  56  and lower portion  58 . Lower portion  58  is configured to receive and store lubricant. Upper portion  56  is disposed on an opposite side of actuator  38  from lower portion  58  and contains air. Plate spring  48  is disposed between actuator  38  and alignment plate  44 , and plate spring  48  is configured to bias actuator  38  away from alignment plate  44 . Vent valve  72  extends through actuator  38  between top surface  68  and bottom surface  70 . Vent valve  72  is configured to allow air to pass from lower portion  58  to upper portion  56  as lubricant fills or is dispensed from lower portion  58 . Valve protection chamber  76  is disposed about and extends from a central portion of actuator  38 . Protection mechanism  78  is disposed within valve protection chamber  76 . Valve actuation plate  80  and elastic member  82  are disposed within valve protection chamber  76 . Elastic member  82  is disposed below valve actuation plate  80  and biases valve actuation plate  80  towards an uppermost portion of valve protection chamber  76 . 
     Autofill shutoff valve  36  is mounted on an exterior side of top surface  54  of housing  34 . Lubricant flow path  66  extends through valve body  62  and provides lubricant downstream through connecting bolt  46  and to centerfill tube  40 . Valve stem  64  extends through valve body  62 , and extends from autofill shutoff valve  36 , through alignment plate  44 , and into upper portion  56  of housing  34 . Alignment plate  44  is disposed on an interior side of top surface  54  opposite autofill shutoff valve  36 . First end  84  of centerfill tube  40  extends through alignment plate  44  and top surface  54 . Connecting bolt extends through valve body  62  and engages first end  84  of centerfill tube  40  thereby securing autofill shutoff valve  36  housing  34 . Centerfill tube  40  extends from connecting bolt  46 ; through alignment plate  44 , protection mechanism  78 , and actuator  38 ; and into lower portion  58  of housing  34 . Locating pin  26  extends into second end  86  of centerfill tube  40  and helps maintain the position of centerfill tube  40  within lubricant reservoir  14 . Load ports  90  extends into second end  86  of centerfill tube  40  and are configured to provide lubricant to lubricant reservoir  14  from centerfill tube  40 . Flag  50  is attached to centerfill tube  40  and disposed within lower portion  58  of housing  34 . 
     Stirring assembly is attached to drive shaft  24  and is rotated by motor  20  when motor  20  is activated. Rotating stirring assembly  42  mixes the lubricant within lubricant reservoir  14 , thereby encouraging the flow of lubricant as well as preventing the formation of and eliminating any air pockets. Flag  50  extends from centerfill tube  40  and stirring assembly  42  passes by flag  50  as stirring assembly  42  rotates. Flag  50  is configured to wipe lubricant from stirring assembly  42  as stirring assembly  42  rotates within housing  34  and passes flag  50 . In addition, flag  50  encourages mixing of the lubricant. Flag  50  is stationary such that stirring assembly  42  rotating past flag  50  creates turbulence within the lubricant. Reed switch  28  is configured to sense and alert that a level of lubricant within lubricant reservoir  14  is low. A low level alarm may be triggered by reed switch  28  to either indicate to a user that lubricant reservoir  14  should be refilled or activate a supply pump to begin supplying lubricant to lubricant reservoir  14 . The low level alarm reduces the frequency that lubricant reservoir  14  is filled, which correspondingly reduces the frequency that the supply tube is attached to autofill shutoff valve  36 . Reducing the frequency that the supply tube is attached to autofill shutoff valve  36  reduces the possibility of introducing contaminants to the lubricant from repeatedly attaching and detaching the supply tube. 
     Lubricant is loaded into lower portion  58  of housing  34  and stored within lower portion  58  until the lubricant is to be applied. When lubricant reservoir  14  runs low, lubricant reservoir  14  is refilled through autofill shutoff valve  36  and centerfill tube  40 . Reed switch  28  may provide a low level indication to a user to initiate the refilling of lubricant reservoir  14 . The lubricant supply hose is connected to autofill shutoff valve  36  and lubricant is pumped to autofill shutoff valve  36  from a supply reservoir through the lubricant supply hose. The lubricant flows into autofill shutoff valve  36  and through lubricant flow path  66 . The lubricant then flows through connecting bolt  46  and enters first end  84  of centerfill tube  40 . After entering centerfill tube  40 , the lubricant flows through centerfill tube  40  and is fed into lubricant reservoir  14  through load ports  90 . 
     When the lubricant exits centerfill tube  40  through load ports  90 , the lubricant is being loaded into lower portion  58  adjacent to the connection between lubricant reservoir  14  and lubricant pump  12 . Centerfill tube  40  thus provides lubricant proximate ricer plate  30  and stirring assembly  42 . Providing the lubricant to lubricant reservoir  14  proximate ricer plate  30  and wet section  16  fills lubricant reservoir  14  near where the pumps are loaded thereby preventing air pockets from forming within the lubricant. Furthermore, providing the lubricant to lubricant reservoir  14  proximate stirring assembly  42  encourages mixing of the newly provided lubricant, further discouraging the formation of air pockets. 
     Actuator  38  is disposed near top surface  54  of housing  34  and is configured to slide upward in response to a rising level of lubricant. Actuator  38  is configured to move in response to changes in the lubricant level as the lubricant level rises and falls within lubricant reservoir  14 . As such, it is understood that actuator  38  may be any suitable mechanism for shifting upward with the rising lubricant level, such as a follower or diaphragm. Actuator  38  may be prevented from downward travel by a restraining mechanism, such as a ring extending from centerfill tube  40  or a shelf extending into lubricant reservoir  14  from sidewall  92 . 
     As lubricant reservoir  14  is filled, the lubricant level in lower portion  58  begins to rise, and the lubricant displaces any air that was disposed within lower portion  58 . The air is vented out of lower portion  58  and to upper portion  56  through vent valve  72  in actuator  38 . The air then exits housing  34  from upper portion  56  through weep hole  60  in side wall  52 . The lubricant level continues to rise until the lubricant encounters actuator  38 . The lubricant causes vent valve  72  to shift to a closed position, wherein vent valve  72  leaktight seal with actuator  38 . With vent valve  72  in the closed position, the rising lubricant causes actuator  38  to shift upward. 
     Actuator  38  shifting upward within housing  34  causes valve actuation plate  80  to engage valve stem  64  and shift valve stem  64  from an open position, wherein the lubricant can flow through autofill shutoff valve  36 , to a closed position, wherein the flow of lubricant through autofill shutoff valve  36  is stopped. With the flow of lubricant through autofill shutoff valve  36  is cut off, the pressure within supply line builds. As such, lubricant system  10  may include a pressure switch to automatically shut off the supply pump when lubricant reservoir  14  is full. In this way, autofill shutoff valve  36  and the low level alarm triggered by reed switch  28  ensure that lubricant reservoir  14  is refilled when empty. Limiting refills to when lubricant reservoir  14  is empty limits the number of refills and decreases contaminants within the lubricant supply. In addition, autofill shutoff valve  36  ceases the flow of lubricant to housing  34  when lubricant reservoir  14  is full preventing lubricant reservoir  14  from being overfilled, thereby preventing lubricant reservoir  14  from experiencing damage due to overfilling. 
     Loading lubricant reservoir  14  through autofill shutoff valve  36  and centerfill tube  40  eliminates the need for additional external plumbing. Centerfill tube  40  loads the lubricant into lower portion  58  of lubricant reservoir  14  proximate stirring assembly  42  and ricer plate  30 . Loading the lubricant near stirring assembly  42  encourages mixing of the lubricant which helps eliminate air pockets. In addition, loading lubricant reservoir  14  near ricer plate  30 , which is disposed at the boundary of lower portion  58  and wet section  16 , allows the lubricant to be loaded directly to wet section  16 , without requiring the weight of the lubricant to force the lubricant to the pump, which also eliminates air pockets and other undesirable features from forming in the lubricant. 
       FIG. 2  is a partially exploded view of lubricant reservoir  14 . Lubricant reservoir  14  includes housing  34 , actuator  38 , centerfill tube  40 , alignment plate  44 , connecting bolt  46 , and plate spring  48 . Actuator  38  includes top surface  68 , bottom surface  70 , vent valve  72 , seal  74 , valve protection chamber  76 , and protection mechanism  78 . Valve protection chamber  76  includes sidewall  92 , groove  94 , and retaining clip  96 . Protection mechanism  78  includes valve actuation plate  80 . Centerfill tube  40  includes first end  84  and anti-rotation surface  98 . Alignment plate  44  includes collar  100 , aperture  102 , and anti-rotation feature  104 . Connecting bolt  46  includes head  106  and shank  108 . Shank  108  includes lubricant ports  110 . 
     Actuator  38  is disposed within housing  34 . Seal  74  extends from an outer circumferential edge of actuator  38  to form a leaktight seal within housing  34 . Sidewall  92  extends from top surface  68  and defines valve protection chamber  76 . Groove  94  extends about an interior surface of sidewall  92 . Retaining clip  96  is disposed in valve protection chamber  76  within groove  94 , and is disposed near a top portion of valve protection chamber  76 . Valve actuation plate  80  is disposed within valve protection chamber  76  below retaining clip  96 , such that retaining clip  96  secures valve actuation plate  80  within valve protection chamber  76 . Vent valve  72  extends through actuator  38  and allows air to pass from below actuator  38  to above actuator  38  as well as from above actuator  38  to below actuator  38 . Vent valve  72  also creates a seal to prevent lubricant from flowing from below actuator  38  to above actuator  38 . 
     Alignment plate  44  is configured to be disposed on an interior side of top surface  54  (best seen in  FIG. 1 ) of housing  34 . Plate spring  48  is disposed between alignment plate  44  and actuator  38 , and plate spring  48  is configured to bias actuator  38  away from alignment plate  44 . Collar  100  of alignment plate  44  extends through an opening in top surface  54 . Centerfill tube  40  extends through alignment plate  44 , protection mechanism  78 , and actuator  38  as centerfill tube  40  extends through housing  34 . First end  84  of centerfill tube  40  extends through collar  100  of alignment plate  44  and is attached to shank  108  of connecting bolt  46 . Anti-rotation surface  98  is disposed on an exterior side of centerfill tube  40 . Anti-rotation surface  98  mates with anti-rotation feature  104  on alignment plate  44  such that alignment plate  44  prevents centerfill tube  40  from rotating within housing  34 . Aperture  102  extends through alignment plate  44 . Aperture  102  is configured such that valve stem  64  (shown in  FIG. 1 ) may pass through aperture  102  to engage valve actuation plate  80 . 
     Head  106  of connecting bolt  46  is attached to shank  108 . Shank  108  is attached to first end  84  of centerfill tube  40 . Shank  108  may include external threading configured to mate with internal threading within first end  84  of centerfill tube  40 . Load ports  90  extend into shank  108 . Shank  108  is preferably hollow such that lubricant is provided to centerfill tube  40  through shank  108 . The lubricant enters shank  108  from lubricant flow path  66  (shown in  FIG. 1 ) through load ports  90 . 
     Lubricant is loaded into lubricant reservoir  14  during filling, and actuator  38  is configured to move upward within housing  34  as a lubricant level within housing  34  rises. The lubricant flows through a fill valve and to connecting bolt  46 . The lubricant enters shank  108  of connecting bolt  46  through load ports  90  and flows to first end  84  of centerfill tube  40 . The lubricant then flows through centerfill tube  40  and is loaded into lubricant reservoir  14  through an end of centerfill tube  40  disposed opposite first end  84 . Connecting bolt  46  thus connects the fill valve to both lubricant reservoir  14  and to centerfill tube  40 . 
     As the lubricant is loaded into lubricant reservoir  14 , a stirring assembly, such as stirring assembly  42  (shown in  FIG. 1 ), rotates within the lower portion of lubricant reservoir  14 . The rotation of the stirring assembly exerts a rotational force on centerfill tube  40 . However, as centerfill tube  40  extends through alignment plate  44  anti-rotation surface  98  engages anti-rotation feature  104  to prevent centerfill tube  40  from rotating. In addition, valve stem  64  extends through aperture  102  to prevent alignment plate  44  from rotating relative to housing  34 . As such, valve stem  64  extends through aperture  102  to prevent alignment plate  44  from rotating, and anti-rotation surface  98  engages anti-rotation feature  104  to prevent centerfill tube  40  from rotating. 
     The lubricant flows into lubricant reservoir  14  and the lubricant level rises until the lubricant interfaces with bottom surface  70  of actuator  38 . When the lubricant reaches bottom surface  70 , vent valve  72  is shifted to a closed position by the lubricant thereby creating a seal through actuator  38  and preventing any lubricant from flowing from below actuator  38  to above actuator  38 . Vent valve  72  closing creates a leaktight seal and the rising level of lubricant forces actuator  38  up within lubricant reservoir  14 . Actuator  38  continues to rise until valve protection plate  80  encounters valve stem  64  and forces the valve stem from an open position to a closed position. With valve stem  64  in the closed position the flow of lubricant is blocked, thereby stopping the fill process when lubricant reservoir  14  is full. 
       FIG. 3A  is a cross-sectional view of lubricant reservoir  14  in a refill state.  FIG. 3B  is a cross-sectional view of lubricant reservoir  14  in a filled state.  FIG. 3C  is a cross-sectional view of lubricant reservoir  14  in an overfill state. Lubricant reservoir  14  includes housing  34 , autofill shutoff valve  36 , actuator  38 ′, centerfill tube  40 , alignment plate  44 , connecting bolt  46 , and plate spring  48 . Actuator  38 ′ is substantially similar to actuator  38  and similar reference numbers will be used to identify similar components. Housing  34  includes side wall  52 , top surface  54 , upper portion  56 , and lower portion  58 . Side wall  52  includes weep hole  60 . Autofill shutoff valve  36  includes valve body  62 , valve stem  64 , lubricant flow path  66 , lubricant inlet  112 , first outlet  114 , second outlet  116 , first retaining member  118 , second retaining member  120 , bias spring  122 , shoulder  124 , and bulb  126 . Valve stem  64  includes first end  128 , second end  130 , and sealing portion  132 . First retaining member  118  includes first throat seal  134 , first alignment sleeve  136 , and first retaining clip  138 . Second retaining member  120  includes second throat seal  140 , second alignment sleeve  142 , and second retaining clip  144 . Actuator  38 ′ includes top surface  68 , bottom surface  70 , vent valve  72 ′, seal  74 , valve protection chamber  76 , and protection mechanism  78 . Valve protection chamber  76  includes sidewall  92 , groove  94 , retaining clip  96 , and first annular recess  146 . Protection mechanism  78  includes valve actuation plate  80  and elastic member  82 . Valve actuation plate  80  includes top surface  148 , bottom surface  150 , plateau  152 , and second annular recess  154 . Centerfill tube  40  includes first end  84 , shoulder  88 , and plate retaining clip  156 . Alignment plate  44  includes collar  100  and aperture  102 . Connecting bolt  46  includes head  106  and shank  108 . Shank  108  includes lubricant ports  110 . 
     Actuator  38 ′ is disposed within housing  34  and divides housing  34  into upper portion  56  and lower portion  58 . Weep hole  60  extends through side wall  52  to connect lubricant reservoir  14  to the atmosphere. Seal  74  extends from an outer edge of actuator  38  and engages side wall  52 . Vent valve  72 ′ extends through actuator  38 ′ between top surface  68  and bottom surface  70 . Vent valve  72 ′ is similar to vent valve  72  in that air may pass through vent valve  72 ′ while lubricant is prevented from passing through vent valve  72 ′, but vent valve  72 ′ does not include components configured to create a leaktight seal between lower portion  58  and upper portion  56 . Vent valve  72 ′ is instead sized so air is able to pass through vent valve  72 ′ but lubricant is prevented from passing through vent valve  72 ′. Sidewall  92  of valve protection chamber  76  extends from top surface  68  of actuator  38 ′ to define valve protection chamber  76 . Groove  94  extends about sidewall  92 , and retaining clip  96  is disposed within groove  94 . Plate spring  48  extends between actuator  38 ′ and alignment plate  44 , and plate spring  48  extends through valve actuation plate  80 . 
     Valve actuation plate  80  and elastic member  82  are disposed within valve protection chamber  76 . Plateau  152  extends from top surface  148  of valve actuation plate  80 . First annular recess  146  extends into actuator  38 ′ and extends about centerfill tube  40 . Second annular recess  154  extends through bottom surface  150  of valve actuation plate  80  and into plateau  152 . Elastic member  82  is disposed below valve actuation plate  80 , and a first end of elastic member is disposed in first annular recess  146  and a second end of elastic member is disposed in second annular recess  154 . Elastic member  82  biases valve actuation plate  80  away from actuator  38 ′. Retaining clip  96  abuts top surface  148  of valve actuation plate  80  and secures valve actuation plate  80  within valve protection chamber  76 . Plate retaining clip  156  extends about centerfill tube  40  and abuts a bottom surface  70  of actuator  38 ′. Plate retaining clip  156  is configured to limit the downward travel of actuator  38 ′ within housing. 
     Autofill shutoff valve  36  is disposed on top surface  54  of housing  34 . Lubricant flow path  66  extends through valve body  62 . Lubricant inlet  112  extends into valve body  62  and connects with lubricant flow path  66 . Lubricant inlet is configured to receive a supply tube and to provide lubricant from the supply tube to lubricant flow path  66 . Centerfill tube  40  extends through actuator  38 ′ and protection mechanism  78 . First end  84  of centerfill tube  40  extends through alignment plate  44  and engages shank  108  of connecting bolt  46 . Connecting bolt  46  extends through autofill shutoff valve  36 , and head  106  is disposed outside of valve body  62  while shank  108  extends through valve body  62  to engage centerfill tube  40  and secure autofill shutoff valve  36  to housing  34 . Shank  108  may include external threading and first end  84  of centerfill tube  40  may include internal threading configured to mate with the external threading on shank  108 . Lubricant ports  110  are disposed within lubricant flow path  66  and configured to receive lubricant from lubricant flow path  66 . First outlet  114  extends into valve body  62  proximate the connection of shank  108  and connecting bolt  46 , and first outlet  114  provides lubricant directly to lubricant reservoir  14  through a top portion of housing  34 . Second outlet  116  extends into valve body  62  and may receive external plumbing to allow lubricant to flow to lubricant reservoir through autofill shutoff valve  36  and the external plumbing. 
     Valve stem  64  is disposed within valve body  62  and extends through autofill shutoff valve  36 . First end  128  extends through first retaining member  118  and into upper portion  56  of lubricant reservoir  14 . Sealing portion  132  extends from valve stem  64  and is disposed proximate lubricant inlet  112 . Second end  130  extends through second retaining member  120 . Shoulder  124  extends about and is secured to valve stem  64 , and bias spring  122  surrounds valve stem  64  and is disposed between shoulder  124  and second retaining member  120 . Bulb  126  is secured to second retaining member  120  and disposed outside of autofill shutoff valve  36 . 
     In  FIG. 3A , lubricant reservoir  14  is in a refill state wherein a lubricant level within lubricant reservoir  14  is low. Lubricant is flowed to autofill shutoff valve  36  from a supply reservoir. The lubricant flows through autofill shutoff valve  36 , to centerfill tube  40 , and into lubricant reservoir  14 . A lubricant supply hose from the supply reservoir is connected to lubricant inlet  112 . The lubricant flows through lubricant inlet  112  proceeds through lubricant flow path  66  and to connecting bolt  46 . The lubricant then flows into shank  108  through lubricant ports  110 . Where lubricant reservoir  14  is centrally filled, the lubricant proceeds through shank  108  and to centerfill tube  40 . Centerfill tube  40  loads the lubricant into lower portion  58  of lubricant reservoir  14  proximate stirring assembly  42  (shown in  FIG. 1 ) and ricer plate  30  (shown in  FIG. 1 ). Alternatively, the lubricant may flow through lubricant ports  110  and proceed to second outlet  116 . Where external plumbing is connected to second outlet  116 , the lubricant may flow to the external plumbing and be provided to lubricant reservoir  14  through the external plumbing. External plumbing may supply the lubricant to lubricant reservoir  14  at any suitable location, such as through an inlet port disposed at a bottom of lubricant reservoir  14 . 
     As the lubricant level rises in lower portion  58  of housing  34 , air is displaced from lower portion  58  and to upper portion  56 . Vent valve  72 ′ allows air to vent from lower portion  58  to upper portion  56  as the lubricant fills lower portion  58 . The venting air may proceed to the atmosphere through weep hole  60  in sidewall  92 . 
     In the refill state actuator  38 ′ rests on plate retaining clip  156 , as plate retaining clip  156  defines the limit of downward travel for actuator  38 ′. While actuator  38 ′ is described as having a limited downward travel, it is understood that lubricant reservoir  14  may include a follower plate that follows the lubricant level fully or partially down lubricant reservoir  14  or may include a static seal, such as a diaphragm. The lubricant level within lower portion  58  continues to rise and the lubricant eventually reaches actuator  38 ′. Vent valve  72 ′ prevents the lubricant from flowing from lower portion  58  to upper portion  56  through actuator  38 ′. As such, actuator  38 ′ begins to rise with the rising lubricant level. 
     In  FIG. 3B  lubricant reservoir  14  is shown in a filled state where lubricant reservoir  14  is full. The rising lubricant level in lubricant reservoir  14  causes actuator  38 ′ to rise until valve actuation plate  80  encounters first end  128  of valve stem  64 . Elastic member  82  biases valve actuation plate  80  against retaining clip  96  as actuator  38 ′ rises. Elastic member  82  is sufficiently resilient to maintain valve actuation plate  80  against retaining clip  96  even as valve stem  64  is pushed from a first position (shown in  FIG. 2A ) to a second position (shown in  FIG. 2B ). In the first position, valve stem  64  allows lubricant to flow through autofill shutoff valve  36  and to lower portion  58  through centerfill tube  40 . In the second position valve stem  64  cuts off the flow of lubricant through autofill shutoff valve  36 . 
     Lubricant continues to be fed into housing  34  through autofill shutoff valve  36  and centerfill tube  40  as actuator  38 ′ rises. The rising actuator  38 ′ causes plateau  152  of valve actuation plate  80  to encounter valve stem  64  and shift valve stem  64  from the first position to the second position. As valve stem  64  shifts to the second position, first end  128  of valve stem  64  slides through first retaining member  118 . First retaining member  118  and second retaining member  120  balance valve stem  64  to minimize the force necessary to actuate autofill shutoff valve  36  to the second position, thereby reducing wear on the system and providing a more responsive and timely control of the flow of lubricant. 
     Plateau  152  abuts first end  128  of valve stem  64  and forces valve stem  64  up until sealing portion  132  is forced into a connection disposed between lubricant inlet  112  and lubricant flow path  66 . Pushing sealing portion  132  into the connection blocks the flow of lubricant through autofill shutoff valve  36 . As such, sealing portion  132  prevents additional lubricant from flowing to lubricant reservoir  14 . With the connection between lubricant inlet  112  and lubricant flow path  66  sealed, the pump that was providing lubricant to lubricant reservoir  14  may deadhead. A pressure sensor may sense the increased pressure in the supply tube to automatically cease fill operations. Alternatively, a switch may be activated by autofill shutoff valve  36  to automatically shut off the supply pump. 
     As valve actuation plate  80  pushes valve stem  64  upward, second end  130  of valve stem  64  extends through second retaining member  120  and projects into bulb  126 . Bulb  126  is preferably made of a translucent material, such that second end  130  is visible through bulb  126 . As such, second end  130  projecting into bulb  126  provides a visual indication to a user that lubricant reservoir  14  is full, and thus that the flow of lubricant through autofill shutoff valve  36  has been stopped. While autofill shutoff valve  36  is described as including bulb  126  for providing a visual indication, it is understood that autofill shutoff valve  36  may include a mechanism activated by second end  130  to indicate that lubricant reservoir  14  is full, such as a cycle switch. 
     When valve stem  64  rises to the second position, bias spring  122  is compressed between shoulder  124  and second retaining member  120 . Bias spring  122  remains compressed until the lubricant level in lower portion  58  drops as lubricant is dispensed from lubricant reservoir  14 . Once the lubricant level drops sufficiently, actuator  38 ′ travels downward and causes valve actuation plate  80  to disengage from valve stem  64 . As such, valve stem  64  may return to the position shown in  FIG. 3A , and bias spring  122  assists valve stem  64  in returning to the position shown in  FIG. 3A . 
     Autofill shutoff valve  36  automatically blocking the flow of lubricant when lubricant reservoir  14  is full helps prevent overfilling of lubricant reservoir  14  and helps prevent damage to various components that may occur due to overfilling. In addition, autofill shutoff valve  36  reduces potential wasting of lubricant due to the lubricant overflowing through weep hole  60  if reservoir is overfilled. 
     In  FIG. 3C  lubricant reservoir  14  is shown in an overfill state. An overfill state occurs when the lubricant level has risen beyond that required to cause autofill shutoff valve  36  to shift to the second position. The lubricant level may rise due to thermal expansion of the lubricant, due to a user manually filling the reservoir, due to other causes. When lubricant reservoir  14  experiences an overfill state, protection mechanism  78  prevents the rising actuator  38 ′ from damaging autofill shutoff valve  36 . 
     To cut off the flow of lubricant to lubricant reservoir  14  through autofill shutoff valve  36 , valve stem  64  is actuated from the first position (shown in  FIG. 2A ) to the second position (shown in  FIGS. 2B and 2C ). In the second position valve stem  64  is incapable of being displaced vertically upward due to sealing portion  132  engaging valve body  62  to seal the connection between lubricant inlet  112  and lubricant flow path  66 . As such, valve stem  64  cannot travel upward as actuator  38 ′ travels upward due to the rising lubricant level within lubricant reservoir  14 . The rising actuator  38 ′ could thus damage autofill shutoff valve  36 . 
     Protection mechanism  78  is configured to protect lubrication system  10  from overpressurization that would damage lubricant reservoir  14 . Protection mechanism  78  also prevents autofill shutoff valve  36  from being damaged by the rising actuator  38 ′. Overfill protection mechanism is configured such that valve actuation plate  80  remains static relative to sidewall  92  of housing  34  as actuator  38 ′ rises in response to an overfill event. Valve stem  64  abuts plateau  152  of overfill plate. As actuator  38 ′ rises in response to the rising level of lubricant, valve stem  64  exerts sufficient force on valve actuation plate  80  to cause elastic member  82  to compress within valve protection chamber  76 . The compression of elastic member  82  allows valve actuation plate  80  to remain static relative to valve stem  64  and sidewall  92 , thereby preventing excessive force from being transmitted to valve stem  64  and autofill shutoff valve  36 . The lubricant within lower portion  58  may continue to expand until seal  74  passes weep hole  60 . When seal  74  passes weep hole  60 , the expanding and excess lubricant may vent through weep hole  60 . 
     Protection mechanism  78  prevents lower portion  58  from being overpressurized due to excess lubricant being present in lower portion  58 . As such, overfill protection mechanism prevents damage from occurring to housing  34 , actuator  38 ′, autofill shutoff valve  36 , and other components of lubricant system  10 . In addition, protection mechanism  78  reduces lubricant waste because the lubricant in lower portion  58  is able to expand before the lubricant is vented through weep hole  60 , thereby preventing lubricant from being vented too quickly. 
       FIG. 4A  is a cross-sectional view of actuator  38  for lubricant reservoir  14  in a venting state.  FIG. 4B  is a cross-sectional view of actuator  38  for lubricant reservoir  14  in a sealing state. Lubricant reservoir  14  includes housing  34 , autofill shutoff valve  36 , actuator  38 , centerfill tube  40 , alignment plate  44 , connecting bolt  46 , and plate spring  48 . Housing  34  includes side wall  52  and top surface  54 , and side wall  52  includes weep hole  60 . Actuator  38  includes top surface  68 , bottom surface  70 , vent valve  72 , seal  74 , valve protection chamber  76 , protection mechanism  78 , and bore  158 . Valve protection chamber  76  includes sidewall  92 , groove  94 , retaining clip  96 , and first annular recess  146 . Protection mechanism  78  includes valve actuation plate  80  and elastic member  82 . Valve actuation plate  80  includes top surface  148 , bottom surface  150 , plateau  152 , and second annular recess  154 . Vent valve  72  includes ball  160 , valve seal  162 , and retaining member  164 . Retaining member  164  includes air passage  166 . Centerfill tube  40  includes plate retaining clip  156 . 
     Actuator  38  is disposed within housing  34  divides housing  34  into upper portion  56  and lower portion  58 . Weep hole  60  extends through side wall  52  to connect lubricant reservoir  14  to the atmosphere. Seal  74  extends from an outer edge of actuator  38  and engages side wall  52 . Sidewall  92  of valve protection chamber  76  extends from top surface of actuator  38  to define valve protection chamber  76 . Protection mechanism  78  is disposed within valve protection chamber  76 . Retaining clip  96  is disposed within groove  94  of sidewall  92 . Valve actuation plate  80  and elastic member  82  are disposed within valve protection chamber  76  below retaining clip  96 , with elastic member  82  disposed below valve actuation plate  80 . A first end of elastic member  82  is disposed in first annular recess  146  and a second end of elastic member  82  is disposed in second annular recess  154 . 
     Bore  158  extends through actuator  38  between top surface  68  and bottom surface  70 . Vent valve  72  is disposed within bore  158 . Valve seal  162  is disposed within bore  158  proximate top surface  68  of actuator  38 , and retaining member  164  is disposed about bore  158  proximate bottom surface  70  of actuator  38 . Ball  160  is disposed within bore  158  between valve seal  162  and retaining member  164 . Air passage  166  extend through retaining member  164 . A diameter of a lower opening of bore  158  is greater than a diameter of a top opening of bore  158 . 
     Autofill shutoff valve  36  is disposed on an exterior side of top surface  54  of housing  34 . Connecting bolt  46  extends through autofill shutoff valve  36  and engages centerfill tube  40 . Centerfill tube  40  extends through alignment plate  44 , actuator  38 , and protection mechanism  78 . Connecting bolt  46  secures autofill shutoff valve  36  to housing through the connection of connecting bolt  46  and centerfill tube  40 . Plate retaining clip  156  extends about centerfill tube  40  and defines a lower limit of travel for actuator  38 . 
     Autofill shutoff valve  36 , connecting bolt  46 , and centerfill tube  40  form a flow path for lubricant to enter lower portion  58  of housing  34 . Lubricant enters autofill shutoff valve  36  through a lubricant inlet and flows to connecting bolt  46 . The lubricant flows through connecting bolt  46  and to centerfill tube  40 , and the lubricant flows through centerfill tube  40  and is loaded into lower portion  58  of housing  34 . The lubricant is loaded into lower portion  58  of housing  34  and the lubricant level rises until the lubricant encounters actuator  38 . Once the lubricant encounters actuator  38 , the rising lubricant level shifts actuator  38  upwards until autofill shutoff valve  36  is actuated from a first position (shown in  FIG. 3A ) to a second position (shown in  FIG. 3B ), thereby blocking the flow of lubricant to lower portion  58 . 
     In  FIG. 4A , actuator  38  is shown in a venting state, where vent valve  72  is open. Lubricant is disposed within lower portion  58  of housing  34 . As lubricant is fed to lower portion  58  the lubricant level rises within housing  34 . The rising lubricant level displaces air from lower portion  58  of housing. The air is vented from lower portion  58  to upper portion  56  through vent valve  72 . The air vents to the atmosphere from upper portion  56  through weep hole  60 . Ball  160  rests on retaining member  164  as lubricant fills lower portion. Air passage  166  through retaining member  164  allows air to pass through vent valve  72  even with ball  160  resting on retaining member  164 . Lubricant continues to fill lower portion  58  until the lubricant level reaches ball  160 . 
     In  FIG. 4B , actuator  38  is shown in a sealing state where vent valve  72  is closed. The lubricant level rises within lower portion  58  until the lubricant contacts ball  160 . Ball  160  is configured to shift with the rising level of lubricant, such as by floating on the lubricant. Ball  160  shifts from the venting position, shown in  FIG. 4A , to the sealing position, shown in  FIG. 4B . In the sealing position ball  160  contacts valve seal  162  and forms a leaktight seal through bore  158 . As such, vent valve  72  prevents lubricant from passing through bore  158  between lower portion  58  and upper portion  56 . 
     With vent valve  72  in the sealing position lubricant is prevented from flowing from lower portion  58  to upper portion  56 . The lubricant can neither flow around actuator  38  due to seal  74  nor flow through actuator  38  due to vent valve  72 . As such, the rising lubricant level shifts actuator  38  upwards within housing  34 . Actuator  38  continues to rise with the lubricant level until the flow of lubricant is cut off. 
     After the flow of lubricant to lower portion  58  is cut off, the lubricant maintains vent valve  72  in the sealing position until the lubricant level drops. As the lubricant level in lower portion  58  drops, actuator  38  shifts downwards with the dropping lubricant level. Actuator  38  continues to shift downward until actuator  38  encounters plate retaining clip  156 . Plate retaining clip  156  maintains a position of actuator  38  on centerfill tube  40  as the lubricant level continues to fall. 
     With actuator  38  supported on plate retaining clip  156  vent valve  72  shifts from the sealing position, shown in  FIG. 4B , back to the venting position, shown in  FIG. 4A . Ball  160  shifts within bore  158  to again rest on retaining member  164 . Air enters lower portion  58  as the lubricant is dispensed to fill the volume of lower portion  58  vacated by the dispensed lubricant. The air flows into upper portion  56  through weep hole  60 . From upper portion  56 , the air flows through bore  158 , around ball  160 , and through air passage  166  in retaining member  164  to enter lower portion. 
     As such, in the venting position vent valve  72  allows air to pass from lower portion  58  and to upper portion  56  as lubricant fills lower portion  58 . Vent valve  72  also allows air to pass from upper portion  56  and to lower portion  58  as lubricant is dispensed from lower portion  58 . In the sealing position vent valve  72  prevents lubricant from flowing from lower portion  58  to upper portion  56 , and vent valve  72  creates a leaktight seal through bore  158  thereby enabling actuator  38  to rise with a rising lubricant level. 
     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.