Patent Description:
The present disclosure relates generally to breathing apparatuses, such as a self-contained breathing apparatus (SCBA), and in particular to a torque limiting and snap feedback bypass knob for a pressure regulator configured for use with an SCBA.

In the field of firefighting, rescue operations, underwater activities, and other activities that occur in dangerous or specific environments, a breathing apparatus is often required in order to permit a person to safely and continually breathe. Accordingly, such a person will don and utilize a breathing apparatus, such as an SCBA, in a variety of contaminated or other irrespirable environments or conditions.

An SCBA often includes a frame that securely holds and supports one or more air tanks, with each air tank having an air hose that supplies air or oxygen to a facemask worn by the user. In particular, the air hose provides fluid communication between the air tank and the facemask through a pressure regulator, which regulates the pressure and flow of air or oxygen to the user based on respiration demand of the user. In some examples, the regulator may be attached or attachable to the facemask.

In some designs, a diaphragm divides the pressure regulator into an inner chamber having a pressure corresponding to the pressure within the facemask and an outer chamber having a pressure corresponding to the surrounding environment. The diaphragm is coupled to an actuating mechanism which opens and closes the inlet valve. The user's respiration creates a pressure differential between the inner and outer chambers of the regulator assembly which, in turn, causes displacement of the diaphragm thereby controlling (i.e., opening and closing) the inlet valve.

The pressure regulator may have a bypass assembly that allows for air from the tank to be delivered directly to the facemask, thereby bypassing the inlet valve. A pressure regulator having a bypass assembly according to the prior art is already known from <CIT>. The bypass assembly is operable via a threaded knob between a fully open position, which bypasses the pressure regulating function of the diaphragm, and a fully closed position, which allows the regulating function of the diaphragm.

Existing bypass assemblies do not provide a positive feedback to indicate that the bypass assembly is fully closed. Furthermore, existing bypass assemblies are not configured for limiting the torque that can be applied to the threaded knob when twisting the threaded knob to the closed position. In view of these and other disadvantages of existing bypass assemblies, it is desirable to provide a pressure regulator with an improved bypass assembly.

Therefore, and generally, the present invention provides an improved pressure regulator assembly for a facemask of a self-contained breathing apparatus as defined by the independent claim <NUM> that addresses or overcomes some or all of the drawbacks associated with known pressure regulators. Preferably, the present disclosure provides an improved bypass assembly of a pressure regulator for a breathing apparatus that provides feedback to the user when the bypass assembly is in a closed position. Furthermore, the present disclosure provides an improved bypass assembly of a pressure regulator for a breathing apparatus that limits the torque that can be applied to a bypass knob when engaging the bypass assembly to the closed position.

According to the invention, provided is a bypass knob of a pressure regulator configured for use with a facemask of a breathing apparatus. The bypass knob has a first member having a first engagement surface and a second member having a second engagement surface positioned opposite the first engagement surface. At least one slot is provided on the first engagement surface of the first member, and at least one deflectable beam is provided on the second engagement surface of the second member. The at least one deflectable beam has a first end connected to the second member and a second, free end opposite the first end. The second end has a latch protruding from the second engagement surface such that the latch is receivable within the at least one slot. The first member and the second member are configured for rotating about a longitudinal axis. When the first member is rotated in a first direction about the longitudinal axis via a first rotational torque, the latch of the at least one deflectable beam may be engaged with the at least one slot to rotate the second member with the first member. When the first member is rotated in the first direction via a second rotational torque higher than the first rotational torque, the second end of the at least one deflectable beam may be deflected from a first, undeflected position to a second deflected position, whereby the latch is disengaged from the at least one slot such that the first member rotates relative to the second member.

According to the invention, the latch has an angled surface that engages a first edge or wall of the at least one slot when the latch is received within the at least one slot and when the first member is rotated in the first direction. The latch may have a normal surface opposite the angled surface. The normal surface may engage a second edge or wall of the at least one slot when the latch is received within the at least one slot and when the first member is rotated in a second direction opposite the first direction.

In some non-limiting embodiments or aspects, the first engagement surface and the second engagement surface may be arranged substantially perpendicular to the longitudinal axis. The first member and the second member may be arranged coaxially with the longitudinal axis. The second member may have a hollow body with a proximal end spaced apart from a distal end along the longitudinal axis, with an inner cavity extending within the hollow body between the proximal end and the distal end. The hollow body may have a radially outwardly protruding projection between the proximal end and the distal end. The second engagement surface may be defined on the projection. The projection may have at least one opening extending therethrough, and the first end of the at least one deflectable beam may be connected to a sidewall of the at least one opening. A locking ring may be positioned within a groove on an inner surface of the hollow body. The locking ring may be configured for retaining the second member in a fixed axial position relative to the first member. The locking ring may be a snap ring.

In some non-limiting embodiments or aspects, a self-contained breathing apparatus (SCBA) may have at least one air tank having at least one air hose extending therefrom, a pressure regulator assembly having a bypass assembly in fluid communication with the at least one air tank via the at least one air hose, and a facemask connected to the pressure regulator and configured for removable attachment to a head of a user. According to the invention, the bypass assembly has a bypass housing and a bypass knob. The bypass knob has a first member having a first engagement surface and a second member having a second engagement surface positioned opposite the first engagement surface. At least one slot is provided on the first engagement surface of the first member, and at least one deflectable beam is provided on the second engagement surface of the second member. The at least one deflectable beam has a first end connected to the second member and a second, free end opposite the first end. The second end has a latch protruding from the second engagement surface such that the latch is receivable within the at least one slot. The first member and the second member are configured for rotating about a longitudinal axis. When the first member is rotated in a first direction about the longitudinal axis via a first rotational torque, the latch of the at least one deflectable beam may be engaged with the at least one slot to rotate the second member with the first member. When the first member is rotated in the first direction via a second rotational torque higher than the first rotational torque, the second end of the at least one deflectable beam may be deflected from a first, undeflected position to a second deflected position, whereby the latch is disengaged from the at least one slot such that the first member rotates relative to the second member.

In some non-limiting embodiments or aspects, the bypass housing may have a bypass inlet, a bypass outlet, a fluid passage extending between the bypass inlet and the bypass outlet, and a rod configured to engage a piston of a valve assembly of the pressure regulator to regulate a passage of air from the at least one air tank through the pressure regulator. Rotation of the bypass knob may adjust a rate of air flow through the bypass assembly.

According to the invention, the pressure regulator assembly for a facemask of a self-contained breathing apparatus has a housing defining a first chamber in fluid communication with an inlet and a second chamber in fluid communication with an outlet, and a valve assembly disposed between the first chamber and the second chamber. A bypass assembly may be connected to the housing and operatively engaged with the valve assembly. The bypass assembly has a bypass housing and a bypass knob. The bypass knob has a first member having a first engagement surface and a second member having a second engagement surface positioned opposite the first engagement surface. At least one slot is provided on the first engagement surface of the first member, and at least one deflectable beam is provided on the second engagement surface of the second member. The at least one deflectable beam has a first end connected to the second member and a second, free end opposite the first end. The second end has a latch protruding from the second engagement surface such that the latch is receivable within the at least one slot. The first member and the second member are configured for rotating about a longitudinal axis. When the first member is rotated in a first direction about the longitudinal axis via a first rotational torque, the latch of the at least one deflectable beam may be engaged with the at least one slot to rotate the second member with the first member. When the first member is rotated in the first direction via a second rotational torque higher than the first rotational torque, the second end of the at least one deflectable beam may be deflected from a first, undeflected position to a second deflected position, whereby the latch is disengaged from the at least one slot such that the first member rotates relative to the second member.

Accordding to the invention, the latch has an angled surface that engages a first edge or wall of the at least one slot when the latch is received within the at least one slot and when the first member is rotated in the first direction. The latch may have a normal surface opposite the angled surface. The normal surface may engage a second edge or wall of the at least one slot when the latch is received within the at least one slot and when the first member is rotated in a second direction opposite the first direction.

These and other features and characteristics of the present disclosure, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the disclosure. Further, it is to be understood that the disclosure may assume various alternative variations and step sequences, except where expressly specified to the contrary.

As used in the specification and the claims, the singular form of "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

For purposes of the description hereinafter, the terms "end", "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and derivatives thereof shall relate to the disclosure as it is oriented in the drawing figures. However, it is to be understood that the disclosure may assume various alternative variations and step sequences, except where expressly specified to the contrary.

All numbers and ranges used in the specification and claims are to be understood as being modified in all instances by the term "about". By "about" is meant plus or minus twenty-five percent of the stated value, such as plus or minus ten percent of the stated value. However, this should not be considered as limiting to any analysis of the values under the doctrine of equivalents.

Unless otherwise indicated, all ranges or ratios disclosed herein are to be understood to encompass the beginning and ending values and any and all subranges or subratios subsumed therein. For example, a stated range or ratio of "<NUM> to <NUM>" should be considered to include any and all subranges or subratios between (and inclusive of) the minimum value of <NUM> and the maximum value of <NUM>; that is, all subranges or subratios beginning with a minimum value of <NUM> or more and ending with a maximum value of <NUM> or less. The ranges and/or ratios disclosed herein represent the average values over the specified range and/or ratio.

The terms "first", "second", and the like are not intended to refer to any particular order or chronology, but refer to different conditions, properties, or elements.

The term "at least" is synonymous with "greater than or equal to".

As used herein, "at least one of" is synonymous with "one or more of". For example, the phrase "at least one of A, B, and C" means any one of A, B, or C, or any combination of any two or more of A, B, or C. For example, "at least one of A, B, and C" includes one or more of A alone; or one or more B alone; or one or more of C alone; or one or more of A and one or more of B; or one or more of A and one or more of C; or one or more of B and one or more of C; or one or more of all of A, B, and C.

As used herein, the terms "parallel" or "substantially parallel" mean a relative angle as between two objects (if extended to theoretical intersection), such as elongated objects and including reference lines, that is from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, inclusive of the recited values.

As used herein, the terms "perpendicular" or "substantially perpendicular" mean a relative angle as between two objects at their real or theoretical intersection is from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, or from <NUM>° to <NUM>°, inclusive of the recited values.

As illustrated in schematic form in <FIG>, the present disclosure is directed to a pressure regulator assembly <NUM> and a bypass assembly <NUM> for use with the pressure regulator assembly <NUM>. The pressure regulator assembly <NUM> and the bypass assembly <NUM> may be configured for use with a self-contained breathing apparatus (SCBA). The SCBA includes at least one air tank (AT) configured or operable to deliver regulated air through an air hose and a breathing mask or helmet (M) configured to be worn by a user. As shown in <FIG>, the breathing mask or helmet (M) includes the pressure regulator assembly <NUM> and the bypass assembly <NUM>, which are configured to deliver air from the at least one air tank (AT) to an internal area (IA) of the breathing mask or helmet (M). The SCBA may be any SCBA available from Mine Safety Appliances Company (MSA) of Cranberry Township, Pennsylvania, such as MSA G1 SCBA.

With reference to <FIG>, the pressure regulator assembly <NUM> includes an air inlet <NUM> that is configured for receiving air from an air source, such as the air tank (AT) shown in <FIG>), and an air outlet <NUM> that is configured for delivering air to a desired destination source, such as the breathing mask or helmet (M). The pressure regulator assembly <NUM> further includes a housing <NUM> that defines an inlet chamber <NUM> in fluid communication with the air inlet <NUM>, and an outlet chamber <NUM> in fluid communication with the air outlet <NUM>. A valve assembly <NUM> is operatively positioned between the inlet chamber <NUM> and the outlet chamber <NUM>, and is configured for selectively allowing air flow in a direction from the inlet chamber <NUM> toward the outlet chamber <NUM>. The pressure regulator assembly <NUM> further includes a driving assembly <NUM> having a diaphragm <NUM> coupled to or operationally engaged with the valve assembly <NUM> in response to pressure change in the outlet chamber <NUM>.

With continued reference to <FIG>, the pressure regulator assembly <NUM> includes the bypass assembly <NUM>. In some non-limiting embodiments or aspects, the bypass assembly <NUM> is removably connectable or attachable to a suitable pressure regulator assembly <NUM>, such as with a quick connect/disconnect mechanism. The bypass assembly <NUM> may be configured to act on at least a portion of the valve assembly <NUM>, such as a piston <NUM> of the valve assembly <NUM>, to thereby allow or facilitate air flow through the valve assembly <NUM> and into the outlet chamber <NUM> and the air outlet <NUM>.

In some non-limiting embodiments or aspects, the bypass assembly <NUM> facilitates the provision of constant and adjustable air flow (through the rotation of a rotatable bypass knob, as described herein), which flushes the breathing mask or helmet (M) and removes or eliminates fog on the face-shield. Furthermore, the bypass assembly <NUM> provides an emergency air source if the valve assembly <NUM> malfunctions (e.g., cannot be opened), thereby ensuring that the user can maintain normal breathing.

With continued reference to <FIG>, the bypass assembly <NUM> includes a bypass housing <NUM> defining a bypass inlet <NUM>, a bypass outlet <NUM>, and a fluid passage <NUM> between the bypass inlet <NUM> and the bypass outlet <NUM>. The bypass assembly <NUM> further includes a rod <NUM> positioned in the fluid passage <NUM>. The rod <NUM> is movable within the fluid passage <NUM> by way of a threaded screw <NUM> formed at an end of the rod <NUM> that is engaged with a threaded portion of the bypass housing <NUM>. The rod <NUM> is configured to selectively seal off the bypass outlet <NUM>, thereby regulating the air flow to the valve assembly <NUM>. In particular, the rod <NUM> is configured to move relative to the piston <NUM> of the valve assembly <NUM> to allow disengagement of the piston <NUM> from a sealing member <NUM> due to air in the fluid passage <NUM> acting on the piston <NUM>.

With continued reference to <FIG>, the bypass assembly <NUM> includes a rotatable bypass knob <NUM> operatively connected or coupled to the threaded screw <NUM> of the rod <NUM>. The bypass knob <NUM> is rotatable about its longitudinal axis <NUM>, which may be coaxial with a longitudinal axis of the rod <NUM>. In particular, the bypass knob <NUM> is rotatable in a first direction (e.g., a counter-clockwise direction) and a second direction (e.g., a clockwise direction) about the longitudinal axis <NUM>. Rotation of the bypass knob <NUM> in the first direction rotates the threaded screw <NUM>, thereby urging the rod <NUM> in a direction toward the piston of the valve assembly <NUM> (shown by arrow A) to prevent disengagement of the piston <NUM> from a sealing member <NUM> due to air in the fluid passage <NUM> acting on the piston <NUM>. Conversely, when the bypass knob <NUM> is rotated in the second direction, the rod <NUM> is urged in a direction away from the piston <NUM> of the valve assembly <NUM> (shown by arrow B) to allow disengagement of the piston <NUM> from the sealing member <NUM> due to air in the fluid passage <NUM> acting on the piston <NUM>. The bypass knob <NUM> provides the user with the ability to adjust (or tune) the amount of air flow based upon the rotation of the bypass knob <NUM> in the first direction or second direction.

With reference to <FIG>, the bypass knob <NUM> is shown separately from the bypass assembly <NUM>. As shown in <FIG>, the bypass knob <NUM> has a first member <NUM> and a second member <NUM> received within at least a portion of the first member <NUM>. A locking ring <NUM> retains the second member <NUM> in a fixed axial position relative to the first member <NUM>, as described herein. The first member <NUM> and the second member <NUM> are arranged coaxially along the longitudinal axis <NUM>. The longitudinal axis <NUM> represents the longitudinal axis of the first member <NUM> and the second member <NUM> of the bypass knob <NUM>. In some non-limiting embodiments or aspects, the locking ring <NUM> may be a snap ring that is removably connectable to at least a portion of the first member <NUM>.

With continued reference to <FIG>, the first member <NUM> has a proximal end <NUM> positioned opposite a distal end <NUM> in a direction along the longitudinal axis <NUM>. As used herein, the proximal end <NUM> is an end of the first member <NUM> that is closest to the bypass housing <NUM>, while the distal end <NUM> refers to an end of the first member <NUM> that is furthest away from the bypass housing <NUM> when the first member <NUM> is installed on the bypass housing <NUM> (see <FIG>).

With reference to <FIG> and <FIG>, the first member <NUM> has a first hollow body <NUM> with a first inner cavity <NUM> (shown in <FIG>) shaped and sized to receive at least a portion of the second member <NUM>, as described herein. The first body <NUM> may have a central opening <NUM> at the distal end <NUM> that opens into the first inner cavity <NUM>. In some non-limiting embodiments or aspects, the first body <NUM> has a flange <NUM> that protrudes in a radially outward direction relative to the first body <NUM>. The first body <NUM> may have a substantially circular cross-sectional shape having a first diameter, while the flange <NUM> may have a substantially circular cross-sectional shape having a second diameter different from the first diameter. In some non-limiting embodiments or aspects, the first body <NUM> and the flange <NUM> may be monolithically formed together. In other embodiments or aspects, the first body <NUM> and the flange <NUM> may be formed separately and may be removably or non-removably connected together. The first body <NUM> and the flange <NUM> may have a substantially cylindrical form such that the diameters of the first body <NUM> and the flange <NUM> are constant along the longitudinal length of the first body <NUM> and the flange <NUM>. In some non-limiting embodiments or aspects, the first body <NUM> and the flange <NUM> may have a substantially conical form such that the diameters of the first body <NUM> and the flange <NUM> increase or decrease along the longitudinal length of the first body <NUM> and the flange <NUM>. In some non-limiting embodiments or aspects, the first body <NUM> and the flange <NUM> may have any other geometric shape, such as a square, oval, or a polygonal cross-sectional shape.

With continued reference to <FIG> and <FIG>, the first member <NUM> has at least one gripping member <NUM> connected to the first body <NUM> and/or the flange <NUM>. The at least one gripping member <NUM> protrudes from the first body <NUM> and/or the flange <NUM> in a direction radially away from the longitudinal axis <NUM>. A plurality of gripping members <NUM> may be provided with equal or unequal angular spacing between adjacent gripping members <NUM> about the longitudinal axis <NUM>. Each gripping member <NUM> is configured for providing a gripping surface such that the first member <NUM> can be easily rotated about the longitudinal axis <NUM>, even while wearing gloves. In some embodiments, at least one surface of the at least one gripping member <NUM> may have a textured coating or a textured surface (not shown) for increasing the grip between the user's fingers and the first member <NUM>.

With reference to <FIG>, an inner surface <NUM> of the flange <NUM> has a groove <NUM> that extends into the flange <NUM>. In some non-limiting embodiments or aspects, the groove <NUM> is continuous and extends circumferentially around the entire inner surface <NUM> of the flange <NUM>. In other embodiments or aspects, the groove <NUM> may extend around a portion of the inner surface <NUM> of the flange <NUM>. The groove <NUM> is configured to receive at least a portion of the locking ring <NUM> (shown in <FIG>). In this manner, once at least a portion of the locking ring <NUM> is inserted into the groove <NUM>, the locking ring <NUM> prevents the second member <NUM> from separating from the first member <NUM>.

With continued reference to <FIG>, the first member <NUM> has a first engagement surface <NUM> that is arranged substantially perpendicular to the longitudinal axis <NUM>. In some non-limiting embodiments or aspects, the first engagement surface <NUM> may be planar. The first engagement surface <NUM> is configured to engage at least a portion of the second member <NUM>, as described herein. In some non-limiting embodiments or aspects, the first engagement surface <NUM> has at least one slot <NUM>. In some non-limiting embodiments or aspects, the first engagement surface may have a plurality of slots <NUM> spaced apart from each other in a circumferential direction about the longitudinal axis <NUM>. Each of the slots <NUM> is configured for receiving at least one latch of the second member <NUM>. The slots <NUM> may have equal or unequal angular separation therebetween in a direction about the longitudinal axis <NUM>. All of the slots <NUM> may have an identical shape. In some non-limiting embodiments or aspects, at least some of the slots <NUM> may have a shape that is different from other slots <NUM>, with each of the slots <NUM> being configured to receive the at least one latch of the second member <NUM>. With reference to <FIG>, the slots <NUM> may have a length L and a width W, each of which is slightly larger than the width and length of the at least one latch of the second member <NUM>. The slots <NUM> also have a depth D that is configured to receive the at least one latch of the second member <NUM>, as described herein.

Referring to <FIG>, the second member <NUM> has a second hollow body <NUM> having a second inner cavity <NUM> extending therethrough between a proximal end <NUM> and a distal end <NUM> in a direction along the longitudinal axis <NUM>. As used herein, the proximal end <NUM> is an end of the second member <NUM> that is closest to the bypass housing <NUM>, while the distal end <NUM> refers to an end of the second member <NUM> that is furthest away from the bypass housing <NUM> when the second member <NUM> is installed on the bypass housing <NUM>. The second body <NUM>, at its distal end <NUM> is sized and shaped to be received within the first inner cavity <NUM> of the first member <NUM>. The second body <NUM> may have a substantially circular cross-sectional shape and may have a substantially cylindrical form such that the diameter of the second body <NUM> is substantially constant along the longitudinal length of the second body <NUM>. In some non-limiting embodiments or aspects, the second body <NUM> may have a substantially conical form such that the diameter of the second body <NUM> increases or decreases along the longitudinal length of the second body <NUM>. In some non-limiting embodiments or aspects, the second body <NUM> may have any other geometric shape, such as a square, oval, or a polygonal cross-sectional shape that is configured to be received within the first inner cavity <NUM> of the first member <NUM>.

With continued reference to <FIG>, the second body <NUM> has a projection <NUM> between the proximal end <NUM> and the distal end <NUM> that protrudes radially outward from an outer surface of the second body <NUM>. The projection <NUM> may have a second engagement surface <NUM> that is configured for positioning across from the first engagement surface <NUM> when the first member <NUM> and the second member <NUM> of the bypass knob <NUM> are assembled together (see <FIG>). In some non-limiting embodiments or aspects, the first engagement surface <NUM> and the second engagement surface <NUM> may be in direct physical contact with one another when the first member <NUM> and the second member <NUM> are assembled together (<FIG>). The projection <NUM> has at least one opening <NUM> extending therethrough. Each opening <NUM> has at least one deflectable beam <NUM> with a latch <NUM> configured for interacting with one or more of the slots <NUM> on the first member <NUM>. The latch <NUM> is sized and shaped such that it can be received within any of the slots <NUM> on the first member <NUM>.

With continued reference to <FIG>, the projection <NUM> may have a plurality of openings <NUM> spaced apart from each other at equal or unequal angular intervals about the longitudinal axis <NUM>. Each opening <NUM> may have a curved shape or a linear shape. As shown in <FIG>, each opening <NUM> has at least one deflectable beam <NUM> having a first end <NUM> connected to a sidewall <NUM> of the opening <NUM> and a second, free end <NUM> opposite the first end <NUM>. In this way, each deflectable beam <NUM> is arranged as a cantilever deflectable beam within the opening <NUM>. In some non-limiting embodiments or aspects, each opening <NUM> has one deflectable beam <NUM>. The deflectable beams <NUM> may be shaped to correspond to the shape of the openings <NUM>. For example, the deflectable beams <NUM> may have a curved shape that corresponds to the curved shape of the openings <NUM>.

With continued reference to <FIG>, the second end <NUM> of each deflectable beam <NUM> has the latch <NUM> such that the latch <NUM> protrudes axially relative to the second engagement surface <NUM> of the projection <NUM> in a direction toward the distal end <NUM> of the second member <NUM>. Each latch <NUM> has an angled surface <NUM> that is angled in a direction from the second end <NUM> toward the first end <NUM>. The angled surface <NUM> is configured for engaging a sidewall of the slots <NUM>, as described herein. In some non-limiting embodiments or aspects, an angle α of the angled surface <NUM> may be <NUM>° to <NUM>° relative to the second engagement surface <NUM>. Each latch <NUM> further has a normal surface <NUM> that is oriented substantially perpendicular to the second engagement surface <NUM>. Each deflectable beam <NUM> is configured to deflect from a first, undeflected position toward a second, deflected position in a direction of arrow C. Each deflectable beam <NUM> is deflectable from the first position toward the second position due to interaction of the latch <NUM> with the slots <NUM> and the engagement surface <NUM> of the first member <NUM> during rotation of the first member <NUM> relative to the second member <NUM>. With reference to <FIG>, the proximal end <NUM> of the second body <NUM> of the second member <NUM> has a keyed opening <NUM> configured for engaging the threaded screw <NUM> of the bypass housing <NUM> (shown in <FIG>).

Having described the structure of the bypass knob <NUM> with reference to <FIG>7C, a method of operating the bypass knob <NUM> via rotation of the bypass knob <NUM> in a first direction (i.e., in a clockwise direction about the longitudinal axis <NUM>) indicated by arrow D or a second direction (i.e., in a counterclockwise direction about the longitudinal axis <NUM>) indicated by arrow E will now be described with reference to <FIG>. Rotation of the bypass knob <NUM> is configured to operate the bypass assembly <NUM> between a closed position and an open position. For example, by rotating the bypass knob <NUM> in the first (clockwise) direction indicated by arrow D, the bypass assembly <NUM> may be operated to a closed position. Conversely, by rotating the bypass knob <NUM> in the second (counterclockwise) direction indicated by arrow E, the bypass assembly <NUM> may be operated to an open position. As described herein, the bypass knob <NUM> is configured to provide a torque limiting operation in the first direction such that the bypass knob <NUM> provides a positive feedback to the user that the bypass assembly <NUM> is closed.

With reference to <FIG>, to rotate the bypass knob <NUM> in the first (clockwise) direction, the user initially grasps the first member <NUM>, such as by engaging the one or more gripping members <NUM> with fingers, and rotates the first member <NUM> in the direction of arrow D about the longitudinal axis <NUM> of the bypass knob <NUM>. As shown in <FIG>, the first member <NUM> is engaged with the second member <NUM> such that the first engagement surface <NUM> of the first member <NUM> is positioned opposite the second engagement surface <NUM> of the second member <NUM>. In some non-limiting embodiments or aspects, the first engagement surface <NUM> and the second engagement surface <NUM> may be configured for sliding contact with each other to permit rotation of the first member <NUM> relative to the second member <NUM> when the input rotational torque on the first member <NUM> exceeds a predetermined threshold.

With reference to <FIG>, the latch <NUM> of each deflectable beam <NUM> is positioned within one of the slots <NUM> on the first engagement surface <NUM> of the first member <NUM>. The angled surface <NUM> of the latch <NUM> is positioned within the slot <NUM> such that a base portion of the angled surface <NUM> proximate to the second engagement surface <NUM> contacts a first edge or wall <NUM> of the slot <NUM>. Due to this direct physical contact between the angled surface <NUM> and the first edge or wall <NUM> of the slot <NUM>, rotation of the first member <NUM> about the longitudinal axis <NUM> also causes the second member <NUM> to rotate. Because the second member <NUM> is connected to the threaded screw <NUM> (shown in <FIG>), such rotation of the second member <NUM> also causes the threaded screw <NUM> to rotate in the first (clockwise) direction about the longitudinal axis <NUM>, thereby moving the rod <NUM> bypass assembly <NUM> toward the closed position.

With continued reference to <FIG>, as the threaded screw <NUM> of the bypass assembly <NUM> is moved toward the closed position, there is a corresponding increase in effort or rotational torque necessary to rotate the first member <NUM> in the first (clockwise direction) of arrow D. At this rotational torque, a resulting normal force that acts on the angled surface <NUM> has a downward force component that acts in a direction of arrow C. As the torque input increases, this downward force component overcomes the natural tendency of each deflectable beam <NUM> to remain in the first, undeflected position and causes each deflectable beam <NUM> to deflect from its first or undeflected position toward a second or deflected position in the direction of arrow C (<FIG>). Such movement of the deflectable beam <NUM> occurs at a predetermined torque, such as a torque that must be exerted on the first member <NUM> to move the bypass assembly to a fully closed position. As each deflectable beam <NUM> is deflected, each latch <NUM> is moved out of its respective slot <NUM> due to a sliding movement of the angled surface <NUM> relative to the first edge or wall <NUM>.

With reference to <FIG>, once each latch <NUM> is completely removed from the slot <NUM>, an upper surface <NUM> of the latch <NUM> contacts the first engagement surface <NUM> of the first member <NUM>. In this way, the first member <NUM> is effectively disengaged from the second member <NUM> such that rotation of the first member <NUM> in the first (clockwise direction) does not cause a corresponding rotation of the second member <NUM>. Instead, the first member <NUM> rotates relative to the second member <NUM>, thereby moving each latch <NUM> along the first engagement surface <NUM> until the latch <NUM> is moved to an adjacent slot <NUM>, thereby causing each deflectable beam <NUM> to deflect from the second, deflected position to the first, undeflected position.

Continued rotation of the first member <NUM> in the first (clockwise) direction of arrow D after the bypass assembly <NUM> is moved to a fully closed position causes the first member <NUM> to freely rotate relative to the second member <NUM> due to continuous "skipping" or "snapping" of the deflectable beams <NUM> from one slot <NUM> into an adjacent slot <NUM>. Such "skipping" or "snapping" of the deflectable beams <NUM> is configured to provide a positive feedback to the user that the bypass assembly <NUM> is in the fully closed position. This positive feedback may be via a tactile feedback that is felt through the first member <NUM> as the first member <NUM> is rotated relative to the second member <NUM>. Alternatively, or in addition, the positive feedback may be an auditory feedback that can be heard by the user due to continuous "skipping" or "snapping" of the deflectable beams <NUM> within the slots <NUM>.

With a rotation of the bypass knob <NUM> in the second (counterclockwise) direction indicated by arrow E, the latch <NUM> of each deflectable beam <NUM> is positioned within one of the slots <NUM> on the first engagement surface <NUM> of the first member <NUM> such that the normal surface <NUM> of the latch <NUM> contacts a second edge or wall <NUM> of the slot <NUM> that is positioned opposite the first edge or wall <NUM>. In this manner, rotation of the first member <NUM> about the longitudinal axis <NUM> in the direction of arrow E also causes the second member <NUM> to rotate due to engagement between the normal surface <NUM> of the latch <NUM> with the second edge or wall <NUM> of the slot <NUM>. Because the second member <NUM> is connected to the threaded screw <NUM> (shown in <FIG>), such rotation of the second member <NUM> also causes the threaded screw <NUM> to rotate in the second (counterclockwise) direction about the longitudinal axis <NUM>, thereby moving the rod <NUM> of the bypass assembly <NUM> toward the open position. Due to the parallel arrangement of the normal surface <NUM> and the second edge or wall <NUM>, there is no resulting force component that deflects the deflectable beams <NUM> from the slots <NUM> when the bypass knob <NUM> is rotated in the second (counterclockwise) direction indicated by arrow E.

In some non-limiting embodiments or aspects, the first member and the second member of the bypass knob may be manufactured in a molding process, such as an injection molding process, which provides a simplified part manufacture, reduces manufacturing costs, and reduces product weight.

While the bypass knob <NUM> has been described herein in terms of its use on a bypass assembly <NUM> of a pressure regulator for an SCBA, the use of the bypass knob <NUM> is not limited to such applications. For example, the bypass knob <NUM> may be used instead of any rotary-style knob where it is desired to have a positive indication that the knob is in a fully closed or a fully open position.

Claim 1:
A pressure regulator assembly (<NUM>) for a facemask (M) of a self-contained breathing apparatus, the pressure regulator assembly (<NUM>) comprising:
a housing (<NUM>) defining a first chamber in fluid communication with an inlet (<NUM>) and a second chamber (<NUM>) in fluid communication with an outlet;
a valve assembly (<NUM>) disposed between the first chamber and the second chamber (<NUM>); and
a bypass assembly (<NUM>) connected to the housing (<NUM>) and operatively engaged with the valve assembly (<NUM>), the bypass assembly (<NUM>) comprising a bypass housing (<NUM>) and a bypass knob (<NUM>), the bypass knob (<NUM>) comprising:
a first member (<NUM>) having a first engagement surface (<NUM>);
a second member (<NUM>) having a second engagement surface (<NUM>) positioned opposite the first engagement surface (<NUM>);
at least one slot (<NUM>) on the first engagement surface (<NUM>) of the first member (<NUM>); and
at least one deflectable beam (<NUM>) on the second engagement surface (<NUM>) of the second member (<NUM>), wherein the at least one deflectable beam (<NUM>) has a first end (<NUM>) connected to the second member (<NUM>) and a second, free end (<NUM>) opposite the first end (<NUM>),
wherein the second end has a latch (<NUM>) protruding from the second engagement surface (<NUM>) such that the latch (<NUM>) is receivable within the at least one slot (<NUM>),
wherein the latch (<NUM>) has an angled surface (<NUM>) that is angled in a direction from the second end (<NUM>) toward the first end (<NUM>)
wherein the first member (<NUM>) and the second member (<NUM>) are configured for rotating about a first axis (<NUM>),
wherein, when the first member (<NUM>) is rotated in a first direction (D) about the first axis (<NUM>) via a first rotational torque, the latch (<NUM>) of the at least one deflectable beam (<NUM>) is engaged with the at least one slot (<NUM>) to rotate the second member (<NUM>) with the first member (<NUM>), and wherein, when the first member (<NUM>) is rotated in the first direction (D) via a second rotational torque higher than the first rotational torque, the second end of the at least one deflectable beam (<NUM>) is deflected from a first, undeflected position to a second deflected position whereby the latch (<NUM>) is disengaged from the at least one slot (<NUM>) such that the first member (<NUM>) rotates relative to the second member (<NUM>).