Abstract:
A valve assembly having a base and a removable latched insert that separately contains a valve piece. The valve piece is resiliently supported to abut a seal fitted to the insert. The insert is restrained to the base with a pair of resiliently biased latch arms that radiate from the insert. Flanges at the latch arms are resiliently biased to flex and grip the base as the insert is pushed into the base. Insert removal is effected with the release of the latch arms and a lifting of the latch arms.

Description:
FIELD OF THE INVENTION 
     The present invention relates to check valves and in particular to a latched valve used to maintain a preferred suspension pressure at a prosthetic socket or interface between a limb and a prosthesis, among other applications. 
     BACKGROUND OF THE INVENTION 
     The maintenance of a negative pressure or suction in a prosthetic socket or at a related interface to thereby facilitate a desired limb suspension is typically achieved through the use of an expulsion-type check valve (e.g. auto, manual or both). Such valves are typically configured to provide a threaded base or seat. The base, in turn, normally supports a threaded valve insert that is configured to ensure a proper airtight seal. 
     Proper placement of the valve insert relative to the base requires a high degree of dexterity and hand-eye coordination, especially when used in a prosthetic limb. That is, most typically the valve base is located at the most distal aspect of a limb socket. The base is typically thermoformed or laminated into the socket. Such a location can be difficult to see, but can also present an awkward relative alignment angle to mount or detach the valve insert. 
     Because the valve threads, which exhibit a relatively fine pitch, have to line up perfectly in order for the valve insert to be set properly, the combination of poor visibility and high demands for physical dexterity typically result in difficult donning situations for individuals with sound hands and fingers. Removal of the valve can present similar challenges, as the quality of the seal is often related to how tight the insert has been screwed into the valve base. A significant amount of friction can result from overzealous tightening of the valve insert, making it extremely difficult to remove. 
     For individuals with an involved upper extremity or extremities (e.g. injured, deformed, diseased or the result of insufficient congenital development), the insertion and/or removal of the valve insert from the valve seat can prove impossible. This circumstance is particularly onerous for the debilitated user who has to periodically self-adjust the limb. 
     The foregoing difficulties have been overcome with the present valve assembly, which provides a base that is adapted to receive a mating, latched insert. The valve assembly at the coupling junction between the base and insert is particularly constructed to provide for a latched connection. The interconnection provides a sliding, sealed valve insert piece that is respectively pushed or pulled from the seat or base during mounting and removal. The connection is maintained or broken with cooperating latch arms that assure proper insert retention. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to provide a threadless valve assembly wherein a valve base or seat supports a mating, latched insert that supports a valve piece. 
     It is a further object of the invention to provide a valve assembly having a base containing a bore that accepts a slide mounted latching insert. 
     It is a further object of the invention to provide a valve assembly wherein an O&#39;ring seals a valve insert within a seat bore. 
     It is a further object of the invention to provide a resiliently biased valve piece that is sealed within the valve insert. 
     It is a further object of the invention to provide a latched interconnection between the valve base or seat and the latched insert. 
     The foregoing objects are achieved in a presently preferred construction of the invention and valve assembly, which includes a threadless valve base and a threadless valve insert. The threadless insert is pushed into the valve base by hand or using a tool or other appliance that imparts sufficient pressure on the valve insert to overcome an internal resilient tension and seal friction. 
     The valve base and valve insert include overlapping, annular flange surfaces. An O&#39;ring seals the insert within the base. A concentric, resiliently biased valve piece is retained in the insert with a second O&#39;ring. Resiliently biased latch arms are mounted to the insert and located to pivot during insert insertion and extraction. Flanged latch surfaces at the arms flex outward during insertion and spring back to a concentric, restraining alignment with the base upon traversing an interconnecting annular flange at the base. 
     During insert removal, portions of the latch arms are depressed and pivoted to disconnect the arms from the base. The insert can then be removed, which action is facilitated if the insert is independently biased with other resilient devices (e.g. springs) fitted between the insert and base. 
     Although two latch arms are symmetrically arranged to the present base, a single latch arm or other arrangements of arms can be used. A plunger-type valve piece is used to allow auto or manual expulsion of air or other gas or liquid from the limb socket, although other types and mountings of the valve piece can also be adapted to the insert. Similarly, the valve piece might be latched to the insert in a related manner with latch arms or other threadless restraints. Although the present valve assembly finds particular application with prosthetic limbs, it is to be appreciated the valve might be used in other applications. 
     Still other objects, advantages and constructions of the present invention, among various considered improvements and modifications, will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating a presently preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein similar reference callouts are used at the various figures, and wherein: 
         FIG. 1  shows a perspective view to a prosthetic limb that has been adapted to include one construction of a push valve assembly of the invention. 
         FIG. 2  shows an exploded drawing to the foregoing push valve assembly. 
         FIG. 3  shows a cross section drawing to the valve assembly at an initial insertion position or just prior to complete removal of the insert from the valve base. 
         FIG. 4  shows a cross section drawing to the valve assembly with the latch arms squeezed toward one another in preparation for full insertion or removal. 
         FIG. 5  shows a cross section drawing to the valve assembly with the latch arms latched closed to contain a concentric expulsion valve piece contained within the valve base. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. For purposes of clarity, the same reference numbers are used throughout the drawings to identify similar components. 
     Referring to  FIG. 1  a view is shown to a coupling between a limb  2  (e.g. a leg or arm) and a suitable prosthetic appliance  4 . A cutaway view is shown to a limb socket  6  at the appliance  4  and where a valve  8  constructed in accord with the subject invention is shown. The valve  8  is fitted to a socket assembly  10  that is used at the interface between the appliance  4  and an extremity of the user&#39;s limb  2 . The valve  8  is mounted to a socket piece  12  that is shaped to mate with a surgically prepared distal end of the limb extremity. A valve base  14  is typically thermoformed or laminated into the socket piece  12 . 
     A collar or harness  16  is formed to contain the socket piece  12  and shelter the distal end of the extremity. Collar  16  has suitable padding and/or has straps  18  provided to enhance the durability of the attachment. 
     Depending upon the limb and application, a principal concern is to maintain a limb to prosthesis connection that provides maximum flexibility without causing limb ulceration. Various interfaces have been developed that use padding materials such as foams, plastics, polyester and acrylic resins etc. Interfaces that incorporate air, gas or liquid buffers or cushions or combinations thereof are also frequently used. It is with respect to prosthetic devices that use gas and/or liquid buffer materials that the valve  8  of the invention finds particular application. 
     The valve  8  is particularly used at included ports to allow the filling of the socket piece  12  with a suitable gas or liquid interface material between the socket piece  12  and limb extremity. The valve  8  also serves as a check valve to prevent the uncontrolled expulsion of the interface material. 
     With attention to  FIG. 2 , the valve  8  is shown in exploded assembly. The valve  8  includes a base  20  that is designed to exhibit a suitable geometric configuration adapted to a preferred mounting of the valve  8 . Presently, the base is generally cylindrical in shape, although could exhibit a hexagonal, octagonal or other shape. 
     A bore  22  longitudinally extends through the base  20 . A ringed flange  24  projects from the base  8  and can be laminated to or thermoformed in a socket piece  12  with a variety of suitable adhesives and tapes. The diameter of the flange  24  can be varied as desired. 
     An adjoining tapered flange surface  26  is also provided that forms a “V”, “U” or other suitably shaped groove  28  relative to the flange  24 . The groove  28  accommodates valve retention within a thermoformed mounting. Suitable grooves, ridges, knurling or other types of projections and the like can be provided at the surface  26  and groove  28  to facilitate retention to the appliance  4 . 
     A third flanged surface  30  is provided that defines a groove  32  relative to the outermost portion of the flange  26 . The groove  32  contains a pair of latch arms  33  that pivot from an associated valve insert  34  to secure the insert  34  and a valve piece  36  at the insert to the bore  22 . The details of the mounting of the insert  34  and valve piece  36  are more apparent from the following description with respect to the section views at  FIGS. 3 ,  4  and  5 . The flange surfaces  26  and  30  are preferably circularly continuous although can be segmented into a number of discontinuous sections. 
     The insert  34  provides a generally cylindrical stem piece or body  38  that is sized to closely mate with the diameter of the bore  22 . An annular groove  40  contains an O&#39;ring seal  42 . The seal  42  prevents the migration of a gas or liquid contained within the socket piece  12  through the bore  22  and past the insert  34 . A pair of springs  44  depend from the body  38  and normally bias the insert  34  to an elevated condition. Although the base  20  and insert  34  are shown in cylindrical shapes, other shapes or combinations of shapes can be adapted as desired. The insert  34  might also be constructed to index to a preferred alignment with the base  20 . The springs  44  are supported at their top by recessed holes that receive and maintain the alignment of each spring  44  and are supported at their base by resting on the top edge of the valve base. 
     A port  46  is aligned to the longitudinal center of the body  38 . A stem  48  of the valve piece  36  is separately restrained to the insert  34  at a bore  50  to control liquid or gas flow through the port  46  and bore  50 . A spring  52  is supported about the stem  48  in a bore  54  and biases a circular, tapered surface  56  at a head  55  of the valve piece  36  to seal against an O&#39;ring  58  contained at a groove  60  within the bore  54 . 
     The valve piece  36  thus acts as a check valve and prevents flow through the bores  54 ,  50  and port  46 , unless the valve piece  36  is depressed from contact with the O&#39;ring seal  58 . It is to be appreciated a variety of other resilient devices and materials can be used to bias the valve piece  36 . Similarly, different seat/seal arrangements can be configured between the valve piece  36  and bore  54  to control flow through the bores  46 ,  50  and  54 . The valve piece  36  may also be mounted such that it is normally depressed against the port  46  versus being raised above the port  46 , such as with the aid of a snap ring (not shown) and spring  52  mounted to bias the stem  48  to engage the port  46 . 
     The insert  34  is restrained to the base  20  with the latch arms  33  which are mounted to pivot about pivot pins  61 . The pins  61  mount through segmented portions  62  of a flange  64  that radiates from the sidewalls of the insert  34  and nest within aligned bores  66  in the arms  33 . A torsion spring  68  is fitted around each pin  60  and between the flange  64  and arms  33 . The ends of the springs  68  are retained to induce flanges  70  in the arms  33  to pivot inward. Thus, the flanges  70  are restrained beneath the flange  30  in the base  20  and secured to the groove  32 , once the insert  34  is fully seated within the base  20 . Although two latch arms  33  are presently used, a single arm or additional arms might alternatively be incorporated into the assembly  8 . The flanges  70  might also be restrained to depressions or projections 
     In the latter regard, attention is drawn to  FIGS. 3 ,  4  and  5  and wherein the flanges  70  at the arms  33  are respectively shown in a depressed condition at  FIG. 3 , a partially flexed condition at  FIG. 4  and a seated condition at  FIG. 5 . During normal mounting, the insert  34  is merely aligned to the base  20  and the tapers at the flanges  70  and  30  induce the flange arms  33  to pivot outward, reference  FIGS. 3 and 4 . Once the insert  34  is pushed past the flange  30 , the flanges  70  spring inward and are captured in the groove  32 , reference  FIG. 5 . 
     The valve piece  36  mounts merely by suitably lubricating the piece  36  and depressing it and the spring  52  into the bore  54 . Removal of the insert  34  is effected by manually lifting up on the finger depressions  72 . A typical user of a prosthesis  4  having an air or liquid interface material is thereby now able to readily fit and make suitable adjustments to enhance the fit and comfort of the prosthesis. 
     The first O&#39;ring  42  may be located in the base or in the insert. 
     From the foregoing, it is to be appreciated the described construction of the complete valve assembly  8  is merely exemplary of a presently preferred valve. From the suggested modifications and others that might become apparent to those skilled in the art, it also is to be appreciated that the invention can be implemented in still other configurations. Still further, selected portions of the assembly might also be adapted into other valve assemblies. The scope of the invention should therefore not be construed merely to the foregoing description, but rather should be construed within the broader scope of the following claims.