Abstract:
A quick disconnect latching device for use in a liquid conduit coupling has two halves: a pin half and a release half. The pin half includes a casing sleeve into which a latch pin is slidably retained. The latch pin is spring biased into a retracted position within the sleeve. Latch pin dogs are located at the ends of arms extending from the latch pin to interact with a catch within the release half. A hollow nose casing is tapered to cam the arms inward when a sufficient separating axial force is applied to one or both of the pin half and the release half, so that the latch pin dogs release the catch. The amount of force required to separate the latch halves can be adjusted by varying the spring bias using an adjustment screw.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a fluid conduit coupling device that automatically uncouples with the application of a predetermined and adjustable break force. 
     BACKGROUND OF THE INVENTION 
     Uniforms and protective clothing, often referred to as PPE (Personal Protective Equipment), worn by military, rescue and maintenance personnel sometimes incorporate liquid cooling features to minimize the risk of overheating under extreme environmental conditions, for example, desert climates, fire, or high temperature industrial operations, or due to weight, density or lack of breathability, such as explosion, hazardous material or radiation shielding. There are two basic cooling approaches, active and static, each having advantages and disadvantages. Static devices, such as ice vests, do not circulate any coolant, but work on convective heat transfer. They must be worn by the user to be effective. Active cooling systems have the advantage of controlled cooling rate with the cooling liquid supplied by almost any heat sink source. The circulation function in active devices is typically provided by a pump and reservoir in a vehicle or structure that the wearer plugs into by means of a connector that seals the liquid conduit to prevent loss of coolant or introduction of air or other contaminants into the conduit during connection and release. In situations where it becomes necessary to abruptly uncouple the fluid conduits, it is desirable to provide a means for rapidly automatically disconnecting the coupling without damaging the conduits or the coupling such that rapid re-coupling cannot occur without requiring repair. Further, the act of uncoupling, even when done suddenly, should occur without fluid leakage. 
     In general, all liquid connectors have seals to control liquid loss. Simple designs have outer seals that seal while the connectors are coupled but do not prevent flow when disconnected. More complex connectors used valves to reduce or eliminate flow when the connector components are separated. A number of detachable fluid conduit coupling systems are known in the prior art. Many such devices employ spring-loaded ball-type valves that may reduce the loss of process fluid upon uncoupling. Examples of such systems are described in U.S. Pat. No. 4,105,046 of Sturgis, and U.S. Pat. No. 5,092,364 of Mullins. Systems of this type fail to provide means for preventing the introduction of contaminants such as air and ambient fluids into the process fluid upon coupling. 
     All connectors require some form of releasable locking mechanism, usually a push button or other trigger to separate the connector halves. One of the more important components of fluid conduit couplings that are used for personnel cooling is an auto release that allows the connector to be separated without the user initiating any action. Such couplings typically have a break force designed to match specifications for the particular application. 
     Most fluid coupling systems of the prior art are not adapted to allow damage-free separation of the connector ends upon the application of tensile force when a manual release mechanism has not been actuated. This can result in the loss of significant quantities of process fluid due to conduit rupturing when emergency separation becomes necessary. In situations where the process fluid is potentially dangerous, release of the fluid can pose a substantial hazard. 
     U.S. Pat. No. 6,547,284, which is incorporated herein by reference, describes a fluid conduit coupling that allows quick connection and disconnection with substantially no introduction of ambient fluids or air into the process fluid. The latch can be disconnected by activation of a manual release or by the application of a predetermined tensile force, which is determined by spring specification. One disadvantage of this device is that the spring must exert exactly the same force for each connector set in order to provide repeatable performance. Due to inherent manufacturing variations, the springs used in this connector tend to vary in force from one to another. Further, for the required disconnect force to be uniform, the spring must exert the same amount of break force at each point in the circumferential axis. However, by their very design, single helix springs are incapable of exerting the same force around the entire circumferential axis, and mere rotation of the spring, which occurs normally in this design, will produce a difference in force. In addition, the latching surfaces, with a single contact point, are located a distance from the fulcrum for latching such that the surface finish of the parts becomes critical to the amount of force required for delatching. Any change in the surface finish amplifies a change in the break force. Further, due to the use of a single contact point, an abrupt force applied perpendicular to the connector axis will cause the coupling to delatch. An additional disadvantage is that there is no means provided for adjusting the break force. 
     Accordingly, the need remains for a quick-disconnect connector for fluid conduits that will automatically and reliably disengage upon application of a predetermined break force that can be adjusted by the user to meet the application The present invention is directed to such a connector. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an advantage of the present invention to provide a latch for a liquid conduit connector that allows for a quick connection and quick disconnection of the two halves of the connector where the required break force for disconnection is adjustable. 
     It is another advantage of the present invention to provide a latch for a quick release liquid conduit connector that minimizes the effects on repeatable performance that may be caused by variations in manufacture and materials. 
     A further advantage of the present invention is to provide a latch for a quick disconnect connector that eliminates the risk of unintentional disengagement of the two sides by an inadvertent external forces. 
     The quick-release connector of the present invention has two halves: a pin connector and a release connector. The pin connector includes a casing sleeve into which a latch pin is slidably retained. The latch pin is spring biased into a retracted position within the sleeve. Latch pin dogs are located at the ends of arms extending from the latch pin to interact with a catch within the release connector. A hollow nose casing is tapered to cam the arms inward when a sufficient separating axial force is applied to one or both of the pin connector and the release connector, so that the latch pin dogs release the catch. The amount of force required to separate the connector halves can be adjusted by varying the spring bias using an adjustment screw. 
     In an exemplary embodiment, the inventive quick-disconnect latch for fluid conduit connections has two halves: a pin connector and a release connector. The pin connector includes a casing sleeve having a sleeve base and a first spring flange; a latch pin is slidably disposed at least partially within the casing sleeve and includes a latch pin base and at least two latch arms extending from the base, where each latch arm has a latch pin dog extending radially away from the axial centerline of the pin. A bias spring is disposed around the casing sleeve with one end abutting the first spring flange to bias the latch pin toward the sleeve base. A screw extends axially through the sleeve base, where the screw has a head end for retaining a second spring flange and a threaded end for mating with a threaded bore formed in the latch pin base. A pin casing assembly includes a nose casing with a tapered cavity and a cylindrical base with a distal extension extending into the tapered cavity. The cylindrical base and distal extension each have channels for slidably receiving the latch arms, where the latch arms extend at least partially into the tapered cavity, and where the pin casing assembly is attached to the casing sleeve so that the latch pin slides axially relative to the pin casing assembly. The release connector includes a release housing with a release catch for cooperating with the latch pin dogs to engage the release connector and the pin connector. Adjustment of the screw controls compression of the bias spring to adjust bias force applied by the spring to establish a pre-determined axial break force so that the pin connector is separable from the release connector by applying axially separating forces that exceed the pre-determined axial break force. 
     In a preferred embodiment, the release connector includes a manual release mechanism including a release trigger disposed within the release housing and having a first camming surface. A release slide slides within the release housing and has a second camming surface for interacting with the first camming surface so that activation of the release trigger causes the release slide to move toward the pin connector, forcing the latch arms radially inward until the latch pin dogs lose contact with the release catch, releasing the pin connector from the release connector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be more clearly understood from the following detailed description of the preferred embodiments of the invention and from the attached drawings, in which: 
         FIG. 1  is an exploded perspective view of the pin half of the latch assembly. 
         FIG. 2A  is a cross sectional view of the pin half through section A-A of  FIG. 2B , which shows an end view of the insertion (distal) end of the pin half of the latch assembly. 
         FIG. 3A  is an end view of the proximal end of the pin half;  FIG. 3B  is a cross sectional view of the pin half through section B-B of  FIG. 3A . 
         FIG. 4  is an exploded perspective view of the release half of the latch assembly. 
         FIG. 5  is a cross sectional view of the release half. 
         FIG. 6  is a cross sectional view of the release half in the disconnect position. 
         FIG. 7  is a perspective view of the pin half of the latch assembly as applied to a liquid/gas connector. 
         FIG. 8  is a perspective view of the release half of the latch assembly as applied to a liquid/gas connector. 
         FIGS. 9   a - 9   e  are diagrams showing operation of the inventive connector, where  FIG. 9   a  shows the connector halves separate and aligned;  FIG. 9   b  shows the connector engaged;  FIG. 9   c  shows the application of initial outward force causing the latch pin dogs to begin to retract;  FIG. 9   d  shows application of increased outward force, causing further retraction of the latch pin dogs; and  FIG. 9   e  shows full retraction of the latch pin dogs to allow disengagement of the connector halves. 
         FIG. 10  is a cross sectional view of the pin and release halves of the latch as connected. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As illustrated in  FIGS. 1 ,  4 ,  9   a - 9   e , and  10 , the quick-disconnect latch assembly has two halves: a pin half  10  and a release half  300 . 
     Referring to  FIG. 1 , pin half  10  is an assembly comprising a nose pin casing  80 , a nose screw  90 , a front pin casing  100 , a solid dowel pin  120 , a latch pin  150  with latch pin dogs  156 , a pin casing sleeve  130 , a bumper washer  160 , a pin spring washer  40 , a pin tension screw  20 , and a latch pin spring  50 . Release half  300 , illustrated in  FIGS. 4-6 , comprises the following components: a release catch  310 , a release slide  320 , a release housing  330 , a release wedge  340 , a push button  350 , and a push button spring  360 . 
     As illustrated in  FIGS. 2A and 3B , nose pin casing  80  has a distal end  83  and a proximal end  84  dimensioned to fit concentrically over distal end  103  of front pin casing  100 . Nose pin casing  80  is generally cylindrical with distal end  83  tapered so that its exterior is generally frusto-conical. Distal end  83  has a bore  81  formed along its axial centerline  60  with a diameter adapted to receive a nose screw  90 . Bore  81  is further countersunk so that the head of nose screw  90  fits flush with the flat end surface of nose pin casing  80 . Proximal end  84  of casing  80  is hollow, forming a frusto-conical cavity having a first inner diameter near the distal end tapering to a larger, second inner diameter at its open end. The surface of the frusto-conical cavity defines a release surface  82  that interacts with latch pin dogs  156  to force dogs  156  radially inward when latch pin  150  is forced into nose pin casing  80 . The outer diameter of distal end  83  of nose pin casing  80  is smaller than the inner diameters of release catch  310  and release slide  320  (shown in  FIGS. 5 and 6 ), allowing release half  300  to be removed without nose pin casing  80  contacting release catch  310 . 
     As illustrated in  FIGS. 1 ,  2 A and  3 B, front pin casing  100  is generally cylindrical with a proximal section  102  and distal end extension  103 . Two axially-extending channels  110  (seen in  FIG. 1 ) are formed on diametrically opposite sides of front pin casing  100 , with each channel  110  having a depth and a width dimensioned to slidably receive latch pin arms  153 . Channels  110  are of sufficient depth that the distal ends of latch pin arms  153  will not touch the bottom of channels  110  during the release process. Distal end extension  103  has a diameter smaller than that of proximal section  102  so that it fits within the cavity of nose pin casing  80 . Channels  104  extend the entire length of front pin casing  100 , including extension  103 , but increase in depth so that extension  103  tapers slightly axially inward. A bore  108  is formed in extension  103  along axial centerline  60  and is threaded to mate with nose screw  90  to secure nose pin casing  80  to front pin casing  100 . 
     Bore  109  extends through proximal section  102  of front pin casing  100 , perpendicular to axial centerline  60  and the planes defined by channels  110 . When pin half  10  is assembled, front pin casing  100  is slidably received within pin casing sleeve  130  so that bore  109  is aligned with openings  131   a  and  131   b  in pin casing sleeve  100 . As shown in  FIG. 2A , a dowel pin  120  is inserted through opening  131   a , through bore  109 , and through opening  131   b , securing front pin casing  100  to pin casing sleeve  130 . A concentric recess  101  is formed in the base end of proximal section  102  and is dimensioned to allow distal end  25  of pin tension screw  20  to enter recess  101  without contacting proximal section  102  when the two sides of the latch are being pulled apart. 
     Still referring to  FIGS. 1 ,  2 A,  2 B and  3 B, latch pin  150  has a generally cylindrical base portion  155  with a pair of latch pin arms  153  extending away from the base portion toward the distal end of pin half  10 . Latch pin  150  is preferably formed from metal, such as 17-4 stainless steel, however, other materials will be readily apparent to those of skill in the art and may include plastics and polymers. Base portion  155  is concentric with axial centerline  60 . Threaded opening  157  is formed in the proximal end of latch pin base  155 , centered along axial centerline  60 . Two elongated latch pin arms  153  are disposed on diametrically opposite sides of axial centerline  60  and have a generally flattened inner surface that aligns with and slides axially within channels  110  of front pin casing  100 . A latch pin dog  156  is formed in the distal end of each latch pin arm  153 . Each latch pin dog  156  is wedge shaped with a tapered latch release surface  158  and a latching surface  159 . Latching surface  159  is perpendicular to axial centerline  60  and latch release surface  158  tapers outward from the distal end of latch pin arm  153  toward latch surface  159 . As shown in  FIGS. 9   a - 9   e , the distal end of each latch pin arm  153  penetrates into nose pin casing  80  to varying degrees during different stages of operation of the latch. The proximal end of each latch pin arm  153  has a notch  154  formed in its outer surface to generate a radially outward bias in the distal end of the arm, causing latch release surface  158  to be biased against release surface  82  of nose pin casing  80 . During automatic disconnection operation, latch pin  150  is moved toward nose pin casing  80 , causing latch pin dogs  156  to penetrate deeper into nose pin casing  80  where latch release surface  158  and release surface  82  cooperate to force the distal ends of latch pin arms  153  radially inward. 
     The outer diameter of latch pin base  155  is smaller that the inner diameter of pin casing sleeve  130 , allowing latch pin base  155  to slidably fit within pin casing sleeve  130 . The additional height provided by latch pin dogs  156  causes the distal end of the latch pin  150  to have an effective diameter that is larger than the inner diameter of pin casing sleeve  130  until the latch pin dogs are fully depressed. 
     Bumper washer  160  is disposed over pin tension screw  20  and within pin casing sleeve  130  between pin casing sleeve base  135  and latch pin base  155 . Bumper washer  160  is preferably formed from an elastomer or other resilient material. Latch pin base  155  is biased against bumper washer  160  by spring  50  when pin half  10  is detached from release half  300 . During the automatic release operation, when spring  50  is compressed, latch pin  150  moves away from bumper washer  160  until release occurs. Upon release, the spring tension causes pin  150  to resile, striking bumper washer  160 , which dampens the impact. 
     Pin casing sleeve  130  is generally cylindrical with a base, a center, and a distal end. The pin casing base  135  is solid with a concentric bore  137  of sufficient diameter for the pin tension screw  20  to slidably penetrate pin casing base  135  to extend into the interior of sleeve  130 . The center  136  of pin casing sleeve  130  has a cavity for receiving bumper washer  160 , latch pin base  155 , and proximal section  102  of front pin casing  100 . The base  135  and the center  136  sections have the same outer diameter. The distal end has a flange  133  with a diameter larger than that of spring  50  to support the distal end of the spring. One or more recesses  134  may be formed in the outer edge of flange  133  to facilitate attachment within a casing, such as that shown in  FIG. 7 . Bores  131   a  and  131   b  extend radially through the flange  133  at diametrically opposite locations for insertion of dowel pin  120  into base  102  of the front pin casing. 
     Latch pin spring  50  fits over the outer surface of casing sleeve  130  where it is retained in position between flange  133  and a second flange extending from a shaft slidably and concentrically disposed within casing sleeve  130 . In the preferred embodiment, the second flange is pin spring washer  40 , which is retained at the head end of pin tension screw  20 . Pin tension screw  20  has a threaded, distal end  25 . (Note that the threads are visible only in the cross-sections shown in  FIGS. 2 ,  3  and  10 .) The head end is larger in diameter than center opening  45  in pin spring washer  40  so that the washer is securely retained on the screw. Pin tension screw  20  is of sufficient length to extend through pin casing base  135  and bumper washer  160 , allowing the threaded end  25  to screw into threaded hole  157  in latch pin base  155 . As pin tension screw  20  is screwed into latch pin base  155 , the distance between latch pin base  155  and spring washer  40  is reduced, applying compressive force to latch pin spring  50 . Tightening or loosening the pin tension screw adjusts the compressive force required to move the latch pin  150  during automatic disconnection. 
     As shown in  FIGS. 4-6 , release half  300  is an assembly comprising release catch  310 , release slide  320 , release housing  330 , and a release trigger which, in the preferred embodiment comprises release wedge  340 , push button  350 , and push button spring  360 . 
     Release housing  330  has a base portion  332  and a hollow cylindrical portion  334 . Recess  335  is formed in the outer surface of housing  330  in its upper portion near base portion  332  for retaining push button spring  360 . An opening  333  is formed through the wall of housing  330  within recess  335  for retaining release wedge  340 . Release housing  330  has an internal radius for slidably receiving release slide  320 . Alignment/attachment pins  337  extend in an axial direction from the edge of hollow portion  334  for attachment of release catch  310 . 
     Release slide  320  is cylindrical with a proximal end, a distal end, an upper portion, and a lower portion. The proximal end is generally solid, forming release slide base  322 . Angled slot  323  is formed in the upper portion of release slide base  322  with the taper running inward toward the proximal end. The angle and width of slot  323  generally matches the angle and width of release wedge  340  so that release wedge  340  is partially slidably retained within the slot, with at least a portion of the wedge contact surface  345  in contact with the contact slide surface  325 . The inner diameter of the distal end defines contact radius  327 , which interacts with latch release surface  158  of the pin half  10 . The thickness of the distal end of slide release  320  is equal to or greater than the height of catch surface  312 . The outer diameter of release slide  320  is smaller than the inner diameter of release housing  330  so that when release slide  320  is inserted into release housing  330 , it slides freely and remains floating until force is applied by release wedge  340 . 
     Release wedge  340  extends through opening  333  and into angled slot  323 . Threaded bore  347  is formed in the upper surface of release wedge  340  for attaching an activating trigger. 
     In the preferred embodiment, push button  350  is generally shaped in a “T” cross section with a head  351  and shaft  352 . Shaft  352 , which is threaded at its distal end  355 , is inserted through the upper end of push button spring  360  and screwed into threaded bore  347  of release wedge  340 . Spring  360  is a conical compression spring with a smaller diameter at its upper end and a larger diameter at its lower end. The lower end of push button spring  350  is secured by appropriate means within recess  335  of release housing  330 . The force of spring  360  biases push button  350  to its uppermost position until sufficient force is applied to depress the button. It will be readily apparent to those of skill in the art that other release trigger mechanisms may be substituted for the described trigger assembly for effecting manual release. 
     Release catch  310  is generally cylindrical with a proximal end, a distal end, an upper portion, and a lower portion. The diameter of the inner surface of the distal end is beveled outward to form tapered surface  313 . A second, larger inner diameter defines the catch surface  312  and the slide surface  314  of release catch  310 . The catch surface  312  extends radially, perpendicular to axial centerline  60 . Edge  328  of the proximal end has a plurality of bores (not shown) formed for receiving alignment pins  337 . Formed in the outer surface of release catch  310  is at least one recess  315  to facilitate attachment of the release half  300  to an external housing, such as that shown in  FIG. 8 . 
       FIG. 7  illustrates attachment of the pin half  10  to an external housing  500  that is part of a fluid conduit connector with flow passages  502  and  504 . Pin half  10  is inserted into opening  506  of external housing  500  until recesses  134  line up with attachment pin holes  520 . Attachment pin holes  520  define chords across opening  506  so that when attachment pins  510  are inserted into attachment pin holes  520 , they capture recesses  134  and lock pin half  10  securely in place. 
     Similarly,  FIG. 8  illustrates the incorporation of the release half  300  into an external housing  600  that is part of a fluid conduit connector with flow passages  602  and  604 . Release half  300  is inserted into opening  606  of external housing  600  until recess  135  is aligned with attachment pin hole  620 . Attachment pin hole  620  define chords across opening  606  so that when attachment pins  610  are inserted into attachment pin holes  620 , they capture recesses  315  and lock release half  300  securely in place. 
       FIG. 8  also illustrates retainer cover  370 , a thin resilient material that sits over the top of push button  350  to hold it in place and protect against intrusion of contaminants. Pressing on retainer cover  370  in turn presses on push button  350  for the manual release procedure described below. 
       FIGS. 9   a - 9   e  are diagrams illustrating the sequence for connection and automatic release of the quick-disconnect latch when an external force is applied to connect and disconnect the two halves, the pin half  10  and the release half  300 .  FIG. 9   a  illustrates the pin half  10  and the release half  300  pre-connection, aligned in preparation to join the two latch halves. As the two latch halves move toward each other, tapered surface  313  contacts latch release surface  158  of latch pin dog  156  and as the pin half  10  and release half  300  are brought closer together, the latch pin arm  153  is forced radially inward toward the axial centerline. When the tapered surface  313  of the release catch  310  passes the tip of the latch pin dogs  156 , the latch pin dogs  156  spring outward, away from the axial centerline, where the latch surface  159  slides against the catch surface  312 , fully engaging the release catch  310  to the latch pin dog  156 , thus connecting the pin half  10  to the release half  300  as illustrated in  FIG. 9   b .  FIGS. 9   c  and  9   d  illustrate the automatic release of the quick-disconnect latch. An outward force, the pulling of the two halves apart, results in the release catch  310  forcing the latch pin  150  to move along the axial centerline toward and into the nose pin casing  80 . The tapered release surface  82  forces the latch pin dogs  156  to move inward toward the axial centerline until the latch pin dogs  156  fully disengage the catch as illustrated in  FIG. 9   e.    
     The manual release operation of the quick-disconnect latch can be understood with reference to  FIG. 10 . When connected, nose pin casing  80  is disposed within the interior of release slide  320  and spring  50  is in its fully extended condition (as determined by adjustment of pin tension screw  20 .) Contact radius  327  is in contact with latch release surface  158 , which pushes release slide  320  axially inward toward release housing base  332 . As a downward force is applied to depress push button  350 , release wedge  340  cams against contact slide surface  325  of release slide  320  to convert the radial force into an axial force causing release slide  320  to move away from base  332  and toward pin half  10 . Contact radius  327  cams against latch release surface  158 , converting the axial force into a radial force that drives latch pin arms  153  inward. As latch pin arms  153  continue to move toward the axial centerline, latch surfaces  159  of latch pin dogs becomes disengaged from catch surface  312  so that the two surfaces are no longer in contact with each other. At this point, the pin half  10  may be separated from the release half  300 . Once the push button is released, the latch components return to their normal positions. 
     The various components of the quick-release latch of the present invention may be formed from metal or plastic using conventional injection molding techniques or by precision machining, such as CNC machining, or by other methods known in the art. 
     While a preferred embodiment of this invention has been described above, these descriptions are given for purposes of illustration and explanation only. Variations, changes, modifications and departures from the systems and methods disclosed above may be adopted without departure from the spirit and scope of this invention.