Abstract:
A second-stage regulator for scuba divers is disclosed that reduces considerably the inhalation effort required by the user through reduction in friction between selected components of the regulator. A flexible sleeve is sealingly connected to the regulator poppet and the baffle, and coaxially with the poppet, so as to avoid blow-by of gaseous mixture through an opening in the baffle. A tail of the poppet extends through the opening, the tail being connected to a lever of the regulator projecting into an outlet chamber thereof. The head of the poppet is or includes a ferrule with an at least partially-circular profile and abuts a selected inner portion of the inlet&#39;s intermediate chamber to allow oscillation of the poppet. The lever end of the regulator contacts a diaphragm, the diaphragm separating the outlet chamber from the external environment. The lever end has a generally arched shape with a profile such that the length of the arch between two adjacent contact points measured along the lever is generally equal to the length of the segment between the same adjacent contact points measured along the diaphragm.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to equipment for use in limited oxygen environments and, more particularly, to control devices for underwater activities or the like. 
     BACKGROUND OF THE INVENTION 
     In scuba diving, for instance, a supply of air, or of an air-oxygen mixture, is typically fed to a mouthpiece of the scuba diver from a high-pressure tank. Enroute to the diver, the air passes from a primary or first-stage pressure-reducing regulator to a second-stage regulator which, in turn, supplies the mixture to the mouthpiece, namely, when pressure within the regulator is diminished upon the diver&#39;s inhalation. 
     Second-stage regulators typically have an inlet chamber connected to an outlet of the first-stage regulator, and an outlet chamber connected to the mouthpiece of the user. The outlet chamber is separated from the external environment by an elastically deformable diaphragm. The diaphragm is joined via a lever to a poppet which closes a passage between the inlet and outlet chambers. 
     Through appropriate calibration of the first-stage regulator, the pressure inside the inlet chamber is maintained relatively constant at approximately ten bars as the pressure in the tank varies. When the user does not breathe, his or her lungs, the mouthpiece, the outlet chamber and the outside environment are generally at the same pressure. When the user inhales, on the other hand, a vacuum is created in the outlet chamber, and the diaphragm bends toward the interior of the chamber, moving the poppet, which normally closes the passage between the inlet and outlet chambers, to an open or operative position. 
     Opening the passage between the inlet and outlet chambers causes excess pressure in the outlet chamber, such that the diaphragm returns to a stowed or resting position, in turn, moving the lever and returning the poppet to a starting or stowed position at which the passage between the inlet and outlet chambers is again in a closed position. 
     In this manner, the vacuum created when the user inhales effectively controls movement of the interconnected mechanical actuating members, i.e., the diaphragm, lever and poppet. The exertion or energy required by the user, upon inhalation, must also account for the energy dissipated by friction between the mechanical members. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide an improved second-stage regulator for scuba divers that requires considerably less inhalation effort by the user than conventional second-stage regulators and, thereby, allows the user to breathe with greater ease. 
     While conventional arrangements for second-stage regulators have been found useful, substantial friction between the interconnected mechanical actuating members, e.g., the diaphragm, lever and poppet, must often be overcome, requiring considerable additional inhalation effort by the user, thus affecting his or her ease of breathing in limited oxygen environments. 
     Another object of the present invention is to provide a second-stage regulator for scuba divers that significantly reduces friction between mechanical members or components as compared to that of conventional second-stage regulators. 
     A further object of the present invention is to provide a second-stage regulator for scuba divers where the relative sliding of mutually contacting, mechanical members is virtually eliminated and replaced by rolling friction. 
     According to one aspect of the present invention, there is provided a second-stage regulator for scuba divers, the regulator including a relatively flexible sleeve, inside an intermediate chamber and coaxial to a poppet, with an airtight connection both to the poppet and a baffle around the opening, thus preventing blow-by of a gaseous mixture through an opening created by a tail of the poppet and an opening in the baffle containing the poppet, and associated dissipation of energy due to formation of tiny ice crystals. 
     In accordance with another aspect of the present invention, a second-stage regulator for scuba divers is provided in which a head of the poppet is inside a ferrule of substantially rectangular cross-section, the section of which that is in a median longitudinal plane (that also includes the lever) additionally having at least a part with a circular profile abutting an inner wall of the intermediate chamber, enabling the poppet to oscillate in the longitudinal plane. In this manner, an end of the lever that is attached to the tail of the poppet moves integrally with the tail, with negligible sliding, and any friction induced is only of a rolling type as a circular profile of the ferrule turns against the inner wall. 
     According to a further aspect of the present invention, a second-stage regulator for scuba divers is provided, wherein the end of the lever that is in contact with a rigid plate, associated with the diaphragm, and separating the external environment from the regulator&#39;s outlet chambers, has an arched shape following a profile such that the arch extending between two adjacent points of contact measured along the lever is generally equal to the length of the segment between the same adjacent points of contact measured along the rigid plate, such that the resistance generated upon relative movement between the members is substantially of the rolling friction. 
     In accordance with still another aspect of the present invention, there is provided a second-stage regulator for scuba divers, which comprises a regulator body with an inlet conduit for connecting to a first-stage regulator that delivers a breathable gaseous mixture at a relatively constant pressure, an outlet conduit for connection to a user&#39;s mouthpiece, and an opening blocked by a deformable diaphragm. The inlet conduit forms an inlet chamber and an intermediate chamber separated by a valve seat, against which a head of a poppet movable within the intermediate chamber is elastically biased. A tail of the poppet projects into an outlet chamber through an opening in a baffle that separates the intermediate chamber from the outlet chamber, and is connected to one end of a lever hinged to the baffle. The other end of the lever rests against the diaphragm so that a vacuum generated upon the user&#39;s inhalation causes the diaphragm inside the outlet chamber to flex inwardly and the lever to rotate, with consequential displacement of the poppet that, when lifted away from the valve seat, allows passage of the gaseous mixture from the inlet chamber, through the intermediate chamber and a passage between the intermediate chamber and the outlet chamber, to the outlet chamber. Inside the intermediate chamber, and coaxial to the poppet, a flexible sleeve is coupled by an airtight connection to the poppet and to the baffle about the opening in the baffle, the width of the poppet tail being substantially less than that of the opening so as to provide clearance for movement of the tail transversely to the opening of the baffle. 
     According to yet another aspect of the present invention, second-stage regulator for scuba divers is provided. The regulator comprises a regulator body with an inlet conduit for connecting to a first-stage regulator that delivers a breathable gaseous mixture at a relatively constant pressure, an outlet conduit for connection to a user&#39;s mouthpiece, and an opening blocked by a deformable diaphragm. The inlet conduit forms an inlet chamber and an intermediate chamber separated by a valve seat, against which a head of a poppet movable within the intermediate chamber is elastically biased. A tail of the poppet projects into an outlet chamber through an opening in a baffle that separates the intermediate chamber from the outlet chamber, and is connected to one end of a lever hinged to the baffle. The other end of the lever rests against the diaphragm so that a vacuum generated upon the user&#39;s inhalation causes the diaphragm inside the outlet chamber to flex inwardly and rotation of the lever, with a consequent displacement of the poppet that, when lifted away from the valve seat, allows passage of the gaseous mixture from the inlet chamber, through the intermediate chamber and a passage between the inlet chamber and the outlet chamber, to the outlet chamber. The head of the poppet is inside a ferrule of substantially rectangular cross section, the cross section of the ferrule being in a median longitudinal plane of the second-stage regulator. Such plane also includes the lever, having an at least partially-circular profile abutting an inside wall of the intermediate chamber, enabling the poppet to oscillate in the longitudinal plane. 
     In accordance with still a further aspect of the present invention, there is provided a second-stage regulator for scuba divers, which comprises a regulator body with an inlet conduit for connecting to a first-stage regulator that delivers a breathable gaseous mixture at a relatively constant pressure, an outlet conduit for connection to a user&#39;s mouthpiece, and an opening blocked by a deformable diaphragm. The inlet conduit forms an inlet chamber and an intermediate chamber separated by a valve seat, against which a head of a poppet movable within the intermediate chamber is elastically biased. A tail of the poppet projects into an outlet chamber through an opening in a baffle that separates the intermediate chamber from the outlet chamber, and is connected to one end of a lever hinged to the baffle. The other end of the lever rests against the diaphragm so that a vacuum generated upon the user&#39;s inhalation causes an inward flexing of the diaphragm inside the outlet chamber and rotation of the lever, with a consequent displacement of the poppet that, when lifted away from the valve seat, allows passage of the gaseous mixture from the inlet chamber, through the intermediate chamber and a passage between the intermediate chamber and the outlet chamber, to the outlet chamber. The end of the lever in contact with the diaphragm has a generally arched shape with a profile such that the length of the arch between two adjacent points of contact measured along the lever is generally equal to the length of the segment between the same two adjacent points of contact measured along the diaphragm or a rigid plate attached to the diaphragm, wherein the poppet oscillates transversely to the opening of the baffle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A specific, illustrative second-stage regulator for scuba divers, in accordance with the present invention, is described below with reference to the accompanying drawings, in which: 
         FIG. 1  is a sectional view of a conventional second-stage regulator; 
         FIG. 2  is an enlarged detail view of an actuating lever end portion of the regulator shown in  FIG. 1 ; 
         FIG. 3  is a sectional view taken along line III-III of  FIG. 2 ; 
         FIG. 4  is a perspective view of a foot of the regulator actuator lever shown in  FIG. 1 ; 
         FIG. 5  is a perspective view of a second-stage regulator for scuba divers, according to one embodiment of the present invention; 
         FIG. 6  is a sectional view taken along line VI-VI of  FIG. 5 ; 
         FIG. 7  is an enlarged view of the detail section set forth in  FIG. 6 ; 
         FIG. 8  is a partial view of an actuating lever of  FIG. 5 , controlled by movement of a diaphragm; 
         FIG. 9  is a sectional view taken along line IX-IX of  FIG. 6 ; 
         FIG. 10  is a side view of the regulator shown in  FIG. 5 ; 
         FIG. 11  is a side view of the regulator shown in  FIG. 10  with the cover in a raised position, and the diaphragm and its protection grid shown in exploded view; 
         FIG. 12  is a perspective view of the regulator shown in  FIG. 10  showing a member for locking the cover to the regulator body; 
         FIG. 13  is a side view of the locking member shown in  FIG. 12  in a closed position; and 
         FIG. 14  is an isometric view of the locking member shown in  FIG. 12 . 
     
    
    
     The same numerals are used throughout the drawing figures to designate similar elements. Still other objects and advantages of the present invention will become apparent from the following description of the preferred embodiments. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A conventional second-stage regulator D is shown, for instance, in  FIGS. 1-4 . The regulator has an inlet chamber D 1 , an intermediate chamber D 2 , and an outlet chamber D 3  connected to a user&#39;s mouthpiece D 4 . Inlet chamber D 1 , which is at the same pressure as that of the outlet of an associated first-stage regulator, is separated from the intermediate chamber by a valve seat D 5 . The valve seat supports a seal D 6  on a head D 7  of a poppet D 8 . The poppet has a tail D 9  passing loosely through a hole D 10   a  in a baffle D 10 , between the intermediate chamber and outlet chamber. Generally speaking, a purpose of the baffle is to support a spring D 11  that compresses the head of poppet D 8  against valve seat D 5 . 
     The outlet chamber is separated from the external environment by a diaphragm D 13 . An outer end D 15  of a lever D 16  abuts a thin rigid plate D 14  on an inner surface of the diaphragm. Another, inner end D 17  of the lever is hingedly connected to the baffle and supports the tail of the poppet which projects from the baffle and into outlet chamber D 3 . 
     Under balanced conditions, the outlet chamber of the second-stage regulator is at the same pressure as that of the user&#39;s lungs, which are, in turn, at the same pressure as in the external environment. When the user inhales, a vacuum is created in the outlet chamber relative to the external environment. This causes the diaphragm to flex inwardly, with associated rotation of lever D 16  in the direction of arrow F 1  (shown by a dotted line in  FIG. 2 ), and displacement of the poppet in the direction of arrow F 2 . As a result, a breathable gas mixture, under pressure, passes from inlet chamber D 1  to outlet chamber D 3 , through intermediate chamber D 2  connected to the outlet chamber by a wide passage D 18 . 
     When the mixture from the inlet chamber reaches the outlet chamber, thereby increasing the pressure in the latter, diaphragm D 13  returns to its stowed or resting position, as do lever D 16  and poppet D 8 , which once again close seat D 5 . This, in turn, causes the inlet chamber to separate from the intermediate and outlet chambers until the user inhales again. 
     Although it is considered desirable that the vacuum created upon the user&#39;s inhalation require minimal respiratory effort by the user, with conventional second-stage regulators, the user must exert additional effort, upon inhaling, to account for friction that inevitably accompanies movement of the diaphragm, lever and poppet. Moreover, the vacuum to be produced by the user may not be reduced by simply increasing the dimensions of the diaphragm, as the size of the second-stage regulator is physically limited by the dimensions of those upstream and downstream of the regulator. 
     Generally speaking, friction in second-stage regulators has several causes. One is blow-by of gas mixture from intermediate chamber D 2  to outlet chamber D 3 , through an annular opening between tail D 9  of poppet D 5  and hole D 10   a  in baffle D 10 . Although most of the breathable gas mixture passes from the intermediate chamber to the outlet chamber through wide passage D 18 , a modest quantity inevitably also passes through the annular opening. Since passage of the mixture from the intermediate chamber to the outlet chamber is accompanied by expansion, and consequently cooling, the humidity of the mixture is converted to tiny ice crystals that generate friction during axial movement of the tail of the poppet. 
     Another cause of friction is rubbing of outer end D 15  of lever D 16  against the inner surface of plate D 14  applied under diaphragm D 13 , as the latter flexes into the outlet chamber under the vacuum induced by the user&#39;s inhalation. Despite the generally curved shape of the lever&#39;s outer end, the point of contact between the lever and diaphragm varies as the latter flexes. The result is sliding friction between the two that must be overcome by a portion of the vacuum created by the user. Friction is additionally caused by rubbing of an inner. end D 17  of the lever where it comes into contact with the tail of the poppet. 
     As shown in  FIGS. 2 ,  3  and  4 , the inner end of the lever typically comprises a first flange D 19 , substantially perpendicular to the inner end. At one end of the first flange is a second flange D 20 , substantially parallel to the inner end of the lever, and a third flange D 21  parallel to the first flange and facing the same direction. The profile of inner end D 17  is, therefore, shaped by the succession of flanges D 19 , D 20  and D 21 , substantially in the form of a Z. Finally, the presence of a longitudinal slot D 22  defines two branches of a resulting Z-shaped fork that fits around the tail of the poppet between a washer D 23  and the side of the baffle facing the outlet chamber, the washer being supported by a nut D 24  screwed onto a threaded end of the tail. 
     The baffle operates as a fulcrum for third flange D 21  of inner end D 17  and, as it turns, displaces washer D 23 , together with poppet D 8 , in the direction of arrow F 2 , overcoming a biasing force of spring D 11 . As the lever turns, the two branches of the third flange eventually slide against the washer and the baffle. The resulting friction must then be overcome by a portion of the vacuum generated by the user when he or she inhales. 
     Referring now to  FIGS. 5-14 , there is shown generally a specific, illustrative second-stage regulator for scuba divers, in accordance with various aspects of the present invention. According to one embodiment, illustrated generally in  FIGS. 5 and 6 , a regulator body  30  is provided, the body having an inlet conduit  31  and an outlet conduit  32 . The inlet conduit connects to a first-stage regulator that delivers a breathable gaseous mixture at a relatively constant pressure. Its interior forms an inlet chamber  1  and an intermediate chamber  2 , separated by a valve seat  5  supporting a seal  6  of a head  7  of a poppet  8 . The poppet has a tail  9  that passes relatively loosely through a hole  10   a  in a baffle  10 . The baffle separates intermediate chamber  2  from an outlet chamber  3  communicating, through outlet conduit  32 , with a mouthpiece applied thereto (not shown). Baffle  10  provides support for a spring  11  that compresses the head of the poppet against the valve seat. 
     According to one embodiment, illustrated generally in  FIGS. 5 and 6 , a regulator body  30  is provided, the body having an inlet conduit  31  and an outlet conduit  32 . The inlet conduit connects to a first-stage regulator that delivers a breathable gas mixture at a relatively constant pressure and its interior forms an inlet chamber  1  and an intermediate chamber  2 , separated by a valve seat  5  supporting seal  6  of head  7  of a poppet  8 . Tail  9  of the poppet passes relatively loosely through a hole  10   a  in a baffle  10 , which separates intermediate chamber  2  from an outlet chamber  3  communicating, through outlet conduit  32 , with a mouthpiece applied thereto (not shown). Baffle  10  provides support for a spring  11  that compresses the head of the poppet  8  against the valve seat  5 . 
     The regulator body also has a relatively large opening  25  closed by a deformable diaphragm  13  that separates outlet chamber  3  from outside or external environment  12 . A lever  16  is also provided, the lever having an outer end  15  and an inner end  17 . The outer end abuts a relatively thin rigid plate  14  on an inner surface of the diaphragm, and the inner end is hingedly connected to the baffle and attached to the tail of the poppet, the tail projecting from the baffle and into the outlet chamber. The mixture flows into the outlet chamber through a passage  18 , e.g., being relatively wide. The inner end of the lever is shaped generally like a fork, as illustrated, for instance, in  FIG. 4 . 
     As shown in  FIGS. 7 and 9 , an annular opening between hole  10   a  in baffle  10  and the tail of the poppet is closed by a flexible sleeve  33 . The sleeve, for example, has a first, outer flange  34  facing the baffle, against which the sleeve is biased by spring  11  to form a seal inside a groove  10   b . At another end, sleeve  33  is provided with a second, inner flange  35  engaged with a circumferential groove  36  on a surface of poppet  8  so as to form an airtight seal. The mixture may, therefore., pass only from intermediate chamber  2  to outlet chamber  3  through wide passage  18 . This prevents “blow-by” of gaseous mixture, and associated cooling and freezing of the humidity in the fraction of the mixture that escapes, which would otherwise remain, at least partly in the form of tiny ice crystals in the annular opening. Such ice crystals may create frictional forces that act against the poppet tail and must be overcome by a portion of the vacuum created upon the user&#39;s inhalation. 
     As best seen in  FIG. 9 , the baffle, which separates the intermediate and outlet chambers from one another, includes an end of a first bushing  37 . At an end of the bushing opposite the baffle, the bushing has internal threading  38  for engagement with external threading of a second bushing  39 . The second bushing has internal threading  40  in proximity to its medial region for threaded engagement with a third bushing  41 . The end of the third bushing facing head  7  of poppet  8 , for instance, has an annular rib forming the valve seat for engagement with seal  6 . In this manner, the third bushing forms the inlet chamber inside the second bushing; the intermediate chamber being formed between the third bushing and the baffle of the first bushing. 
     Turning now to  FIGS. 6 and 9 , the head of the poppet has a ferrule  42  of rectangular cross section. The ferrule has a section in the longitudinal plane, shown in  FIG. 6 , with at least a partially-circular profile abutting the inside wall of the intermediate chamber, the inside wall also having a substantially rectangular cross section, such that the poppet may oscillate about a transverse axis C. To enable this poppet movement, the width of the ferrule, along the axis of oscillation, is narrower than the width of the intermediate chamber. Such oscillation enables washer  23  (which is suitably mounted for sliding along the tail of the poppet) to move transversely in a direction indicated by arrows F 3  (See  FIG. 7 ) together with third flange  21  on the inner end of the lever. As a result, there is no sliding movement and, hence, friction between the washer and the arms of the third flange. By so eliminating the second cause of friction in second-stage regulators, the vacuum that the user must generate when he or she inhales is reduced further. 
     According to one aspect of the present invention, a method is provided for assembling a group of operative members for a second-stage regulator (See  FIGS. 6 ,  7  and  9 ). First, flexible sleeve  33  is placed at the end of first bushing  37  with spring  11  resting on its outer flange  34 . The ferrule  42  is then mounted on poppet  8 , and tail  9  of the poppet is inserted through the spring, the sleeve and hole  10   a  in baffle  10  so as to form the end of the first bushing. Next, washer  23  is inserted on the threaded end of the tail of the poppet and nut  24  is screwed into place. Last, Z-shaped inner end  17  of lever  16  is inserted between the washer and the surface of the baffle on the side facing outlet chamber  3 . 
     By adjusting the nut, the tightness of second bushing  39 , in first bushing  37 , and the tightness of third bushing  41  in the second bushing, the user may one hand it is possible to calibrate the force with which seal  6  of the poppet is applied to valve seat  5 . Varying the degree of tightness of nut  24  also enables the user to calibrate the exact position of outer end  15  of lever  16 . 
     The assembly may be readily adjusted prior to installation in regulator body  30  using a suitable tool through inlet conduit  31  on the regulator body. As shown in  FIGS. 5 and 9 , opposing grooves  43  are formed in the outer surface of first bushing  37 , perpendicularly to the longitudinal axis of symmetry. In addition, holes  44  are formed in the inlet conduit at the same distance transversely from grooves  43  for receiving pins  45  when the grooves and holes are in alignment with one another. In this manner, the relative longitudinal position of the assembly vis-à-vis the inlet conduit is precisely defined. Finally, the assembly is secured in place by a nut  46  engaging the external threading on second bushing  39  until it abuts the end of the inlet conduit. 
     As for the third source of friction in second-stage regulators, namely, friction due to sliding motion of the rounded outer end of the lever against the plate underneath the inner surface of the diaphragm such sliding motion—and associated sliding friction—are converted, according to the present invention, to rolling motion and rolling friction, respectively. More specifically, outer end  15  of the lever has a profile such that it rolls along the underside of plate  14 , remaining generally tangential to the latter, as the diaphragm and plate flex inwardly from a stowed or resting position to maximum expansion of the diaphragm. A profile or configuration of the end of the lever for accommodating operation in this fashion is set forth, for example, in  FIG. 8 . 
     Generally speaking, to achieve rolling rather than sliding motion between the lever and plate, it is considered necessary that segment AB on the plate, coinciding with a set of points of contact between the lever and plate from the resting position to maximum extension of the diaphragm, coincide with the length of arch A′B′ on the lever, and that the tangent of B′ remain horizontal. 
     As illustrated in  FIG. 5 , regulator body  30 , for example, has an elongated shape suitable for housing diaphragm which, according to one aspect of the present invention, has an elliptical shape. This allows the transverse dimension of the regulator to be maintained within the overall dimensions of the surrounding apparatus, while increasing the surface area of the diaphragm. Such an arrangement is particularly beneficial for the user who now needs to expend much less effort and energy because the vacuum he or she must create upon inhalation decreases generally with increasing surface area of the diaphragm. Moreover, the diaphragm&#39;s elliptical shape enables the plate to remain parallel as it descends under the effect of the vacuum in the outlet chamber, action that is fundamental to proper operation of the lever and other moving parts of the regulator. 
     In traditional second-stage regulators, the diaphragm is attached to the edge of the corresponding opening by a covering frame threadably engaged with the regulator body after inserting an axially-movable control button, such that a slight amount of pressure on the button allows operation of the second-stage regulator to be checked and maintained at proper levels. With the present invention, on the other hand, as shown in  FIGS. 10 and 11 , the diaphragm and corresponding control button  47  are biased against an edge of a corresponding opening in the regulator body by a covering frame  48 . One end of the frame is hingedly connected at  49  to regulator body  30 , whereas another end is hingedly joined at  50  to a bracket  51  having a relatively long through hole  52 . Desirably, the through hole is suitable for alignment with a corresponding hole  53  in the regulator body, when the frame is in a closed position as shown in  FIG. 10 . In this position, a pin  54  with an elongated head  55  is used to lock the assembly on the regulator body  30 . 
     According to a further arrangement, shown in  FIGS. 12 ,  13  and  14 , elongated head  55  on pin  54  is, for instance, a cross member engaging a seat  56  situated at an end of a cam profile  57 . A spring  58 , for example, maintains the cross member elastically in a closed position.  FIGS. 13 and 14  illustrate members  59  and  60 , according to one arrangement, where they are integral with the regulator body, while member  61  conforms with the end of bracket  51 . Additionally, the pin has a head  54   a  with a prism-shaped cavity designed so that it may not be opened without the use of a special key. In this manner, unwanted or accidental opening of the regulator due to the release of bracket  51  and frame  48 , and resulting detachment of the diaphragm, is prevented. 
     Various modifications and alterations to the present invention may be appreciated based on a review of this disclosure. These changes and additions are intended to be within the scope and spirit of the invention as defined by the following claims.