FR2740690A1 - Respirator mask coupling assembly - Google Patents

Abstract

The coupling assembly (A), designed to fit into the front aperture (11) of a respirator mask (2), has a generally cylindrical outer guide surface (22) which lies perpendicular to its positioning surface and fits against a front shoulder (12) in the aperture (11) on the assembly. The guide surface also has a peripheral groove containing a seal (24), e.g. toroid in shape with a circular cross-section. The assembly incorporates a respirator system (8) with at least one antechamber, an inhaler (26) and an exhalation valve (29). It can also have speech membrane (31) and/or a protective grille (32), which can form a one-piece unit with fixing elements, e.g. of a moulded synthetic material - a polyamide such as Noryl (RTM).

Description

 The invention relates to a connecting block or snout intended for a respiratory protective mask, a protective mask provided with such a connecting block, as well as a protective helmet and a diving suit comprising such a mask.

 Various types of respiratory protection masks are known.

 In particular, document FR-A-1,575,820 describes a protective mask provided with a protective compartment in the form of a connecting block.

 On the one hand, the block comprises an anteroom, a protective grid, a coupling connection as well as means for mounting an internal mask, an exhalation valve, an inspiration valve, d 'a conversation membrane.

 On the other hand, a mask body includes a front opening, of a shape complementary to that of the connection block and in which the latter is embedded, from the inside.

 Once embedded, the connection block is in abutment against a shoulder of the mask body, at the inner peripheral edge of the front opening of the latter.

 Similarly, document FR-A-2,692,793 describes a plug-in connection block, provided with a sealing ring.

 In these two documents, the front opening is in the form of a complex or left surface. In fact, the assembly of the block and the body is delicate.

 And if a sealing ring is provided, it is easily twisted, crushed or lost. This then generates leaks.

 This is all the more frequent as the block is plugged in or embedded, and therefore housed by force and without play.

 In addition, disassembly of the connection block, in particular for cleaning, is tedious, risk of damaging the mask and impairing its operation.

 According to these documents, the fittings are screwed to the bottom of the thread in the connection block. Any excessive tightening therefore alters the net and the functioning of the mask.

 The document EP-A-511 592 describes a respiratory protection mask, which can be used as a mask at ambient pressure, overpressure or in a closed circuit.

 The mask body includes an integral bayonet coupling, provided for this purpose.

 As with the previous documents, coupling risks altering the mask and its protective capacity.

 While the complex shape of the mask body is difficult to mold, for example.

 The invention therefore aims to remedy these drawbacks.

Documents US-A-1,706,602; US-A-1,777,383
US-A-2,344,718; US-A-3,457,564; US-A-3,540,442
US-A-3,545,436 US-A-3,833,935 and US-A-5,069,205 also relate to the technical field of respiratory protection masks.

 To this end and according to a first aspect, the invention relates to a connecting block or snout intended to be mounted in a front opening of a respiratory protection mask body.

 The connecting block includes breathing means; as well as removable fixing means on the mask body.

 A substantially planar front positioning face of the block is delimited externally by a generally cylindrical guide surface and the generator of which is extended along an axis substantially perpendicular to the positioning face, so that in an assembled state, the latter is in abutment against a shoulder before the opening of the mask body, while the guide surface, housed with clearance in the opening, comprises a peripheral groove for housing a seal, for example an O-ring with a circular cross section.

 According to one characteristic, the guide surface is a cylinder based on a rounded external contour, for example circular, oblong or oval.

 In one example, the base has an ovoid external contour, with a large upper radius centered on means for mounting an inspiration coupling coupling, while a small lower radius is centered on means for mounting an exhalation valve.

 According to another characteristic, the respiratory means comprise at least one anteroom; means for mounting an interior mask, an inspiration coupling connection, an exhalation valve and possibly a conversation membrane and / or a protective grid, for example so to be formed with the removable fixing means, a single piece of molded synthetic material or the like.

 According to yet another characteristic, the removable fixing means are distinct and at a distance from the guide surface and / or from the positioning face, and are for example arranged near or partly merged with means for mounting a connection d inspiration coupling.

 A feature provides that removable fixing means are essentially constituted by the means for mounting an inspiration coupling connector.

 Another characteristic provides that the means for mounting a screw-on inspiration coupling connector include a safety system capable of opposing disengagement by unscrewing the inspiration coupling connector, except when it is voluntarily disabled.

 In one embodiment, the security system, for example with ratchet, is generally arranged coaxially and / or inside a screwing hole for means for mounting the inspiration connector.

 According to one embodiment, the security system comprises a pawl, for example with displacement parallel to a so-called axial direction of screwing of the inspiration connector, and is intended to enter or leave the socket with teeth of complementary shape, integral an axial end of the inspiration fitting.

In one embodiment, the pawl of the security system comprises:
a ring gear, mounted in a screw hole of the mounting means, axially sliding between two extreme stop positions
as well as an elastic axial biasing member, such as a circular leaf spring with opposing notches, arranged so as to constantly exert on the crown, a force oriented towards an engagement position of its toothing with a toothing of the fitting. inspiration.

 Also in one embodiment, the security system comprises an unlocking mechanism, for example a finger capable of causing the disengagement of a toothing of a pawl and of the connector, the mechanism possibly being accessible exclusively using a tool as key.

 According to one characteristic, the breathing means are substantially extended in an axial direction generally parallel to a so-called axis of revolution, located in the vertical plane of symmetry of the wearer's head, inclined to the horizontal and the vertical and passing substantially through or near the middle area of the wearer's brain and the lips area, with respect to a mask in a position corresponding to a wearer with his head straight and the axis of vision horizontal.

 According to another characteristic, a plane along which the positioning face is generally extended, makes an angle of the order of 450 with the horizontal, relative to a carrier having the right head and the horizontal viewing axis.

 In one embodiment, the block is arranged so that it projects from the positioning face towards the axis of vision, in the direction of the axis of revolution.

 A feature provides that the connection block comprises means for mounting a screwable inspiration connector, provided with a polarizing device such as a rod projecting in an axial direction, inside a screwing orifice of the connection.

 According to one example, the means for mounting a fitting comprise an internal cylindrical surface with circular section, centered on an axis of the mounting means, and intended to cooperate radially with the outside of an O-ring mounted on a fitting, when the latter cooperates with the mounting means, for example by screwing.

 Yet another characteristic provides that the connection block comprises means for mounting an inspiration connector, arranged so as to open directly out of the block, in order to guide an antifogging sweeping flow from inside the mask body, and for example from his eyepiece, during inspiration.

 The block comprises in one embodiment a substantially confined or "closed" circulation circuit, separate and distinct from the means for mounting an inspiration connector.

 An example provides that the block includes means for mounting a conversation membrane, such as a screw cap.

 Another object of the invention is a respiratory protection mask comprising a connecting block as mentioned.

 According to one characteristic, the mask body is essentially constituted by an eyepiece, a transparent, curved wall, bounded by a curved outer edge, is provided with the front opening with which the connection block cooperates, the latter being housed from the inside the mask body.

 According to another characteristic, the mask comprises on the mask body, a boss provided with the front opening and in which is partially housed the connecting block, as well as a cover of shape substantially complementary to that of the boss and mounted externally. on the latter.

 In one example, the mask comprises a cover mounted externally on the mask body, with which the removable fixing means of the connection block cooperate, so that the block and the body are rigidly fixed to each other in a removable manner. , through the hood.

 An embodiment of a mask comprises a clamp limiter of the removable fixing means, such as a hood mounted on the mask body and against which a clamping piece, for example a screw-on inspiration connector, is placed in abutment axially when a predetermined maximum force is applied to the fixing means.

 Thus, any effort greater than the maximum effort is collected - not by the fixing means - by the limiter placed in abutment (for example the hood).

 Another embodiment provides a flow and moisture drainage circuit, such as a passage on the connection block and another passage substantially opposite on a hood.

 One feature provides an inner mask having a bellows, for example in crescent and facing the mask body, in order to allow a reversible elastic deformation of the inner mask, of adaptation of the latter to the morphology of a wearer of the mask.

 The mask comprises, according to one embodiment, at least one inspiration valve comprising a flexible membrane and a support. For example, the latter is mounted on an inner mask and the membrane is mounted on this support.

 A valve on each side of the inner mask is common.

 According to one characteristic, a particularity of this membrane is that it is prestressed on its support.

 Indeed, a membrane on a flat support tends, under its own weight to deform, which affects its operation and especially in terms of sealing and sealing.

 In the case which interests us, a seat of the support has a cylindrical shape, while the membrane put in place on this one also takes this cylindrical shape, which tends to stiffen the membrane (under the compressive and tensile stresses of on either side of a neutral line).

 This avoids undesirable deformations of the membrane, under its own weight.

 In one embodiment, the prestressing of the membrane is obtained by the fact that it has, at rest, a shape substantially inscribed in a cylindrical envelope with convexity facing the support.

 A third object of the invention relates to a protective helmet comprising a connection block and / or a mask as described above.

 And according to a fourth aspect, the invention relates to a protective suit comprising a connecting block and / or a mask as described above.

 The invention is not limited to these aspects and will be better understood on reading the detailed description which follows, and referring to the appended drawings, given solely by way of example.

 Figure 1 is a schematic sectional view through a vertical azimuthal median plane of a respiratory mask comprising a connecting block or snout according to the invention, shown in normal situation on the head of a wearer.

 Figure 2 is a front view, from above of an embodiment of the connecting block according to the invention, in the form of a molded plastic part.

 Figure 3 is a schematic view showing, on the one hand of a median line (on the left) a half connecting block according to the invention, provided with teeth as well as a polarization, and on the other hand of the line middle (right) a hood fitted with an unlocking mechanism.

 Figure 4 and a front view of a gear ring of a security system according to the invention.

Figure 5 is an exploded view, according to the arrow
V of Figure 4, the crown and a biasing spring (left) with a screw-in inspiration connection with teeth (right) and a gasket.

Figure 6 is a sectional view along the line
VI-VI of the connection block of FIG. 2, which is provided with concave internal shapes for guiding a ratchet toothed crown as well as a polarizing device, obtained by changing a removable core of a mold injection of a single piece of the connection block.

 And FIG. 7 is a side elevation view of an inspiration valve comprising a flexible membrane prestressed on a support with a seat in a bowl, itself designed to be mounted for example on an inner mask or half mask.

 In the figures, the reference 1 designates a mask body, here essentially composed of an eyepiece.

 To simplify the description, the body and the eyepiece are designated here by the same reference 1.

 This eyepiece 1 is specially adapted and intended for a respiratory protection mask 2.

 Such a mask 2 is, according to a typical application, intended for firefighters.

 The mask 2 also comprises a skirt 3 of generally annular shape intended to be placed around the eyepiece 1, towards the outside, by being rigidly connected to it.

 The eyepiece 1 comprises, for this purpose, on its large external peripheral free edge 4, a flange 5 forming an integral part of it, directed towards the outside of the eyepiece 1 and on which the free edge of the skirt 3 is folded .

The assembly is made rigid by a U-shaped tightening joint 6. The skirt 3 provides the sealing connection between the eyepiece 1 and the face V of a wearer
R.

 The mask 2 also includes an inner mask 7 as well as respiratory devices and / or means.

 Such a mask 2 can be integrated (FIG. 1) into a helmet 2a or a spacesuit 2b of which it then forms an integral part.

 The eyepiece 1 essentially comprises a one-piece transparent wall 9 shaped so as to fulfill the various functions of the eyepiece.

 The wall 9 is shaped by being curved with an overall concavity turned towards the face V of the wearer R, that is to say inside the eyepiece 1, while the convexity is turned towards the outside.

 The eyepiece 1, that is to say the transparent wall 9, is here made of polycarbonate. In the embodiment shown in the drawings, the wall 9 has a thickness equal to or of the order of 3 mm.

 The wall 9 is limited by the edge 4, which defines a first large rear opening 10 intended to be placed facing and in the vicinity of the face V.

Furthermore, the wall 9 has a second lower opening 11 called "front opening", with which is intended to cooperate a connecting block or snout
A, part of the respiratory system.

 The wall 9 forms around the front opening 11 an annular shoulder 12, substantially planar, intended to position the connection block A.

 The eyepiece 1 is therefore limited, downwards, by a plane P (FIG. 1) which - relative to a carrier R having the right head and a horizontal axis of vision S - makes an angle J with the horizontal ( Figure 1) of the order of 450.

This plane P includes the front opening 11 and the shoulder 12.

 The qualifiers "rear" and lower refer, like all the description, to a mask 2, as coated by a wearer R having the straight head (that is to say vertical up-down axis Z) and the axis horizontal S vision.

 Such a situation or position is subsequently called a "reference", for the convenience of description only.

 It is understood, however, that the wearer, in current use, lifts or lowers the head and / or lifts or lowers the eyes or even turns them sideways to one side or the other.

 This position is only relative, the mask 2 (and / or its components) being able to occupy any other position, whether in use or out of use (storage, storage, etc.).

 Link block A is now described.

 The block A intended to be mounted in the concavity, and in particular in the front opening 11, of the body 1 of mask 2 for respiratory protection.

 The connecting block A comprises means 19 for breathing, forming part of or constituting the respiratory device 8.

 Means 20 for removable attachment to the mask body 1 are also provided.

 A substantially flat front positioning face 21 of the block A is delimited externally by a guide surface 22, generally cylindrical.

 The generator of the surface 22 visible in FIG. 6 is extended parallel to an axis 16, substantially perpendicular to the positioning face 21.

 In this way, in an assembled state, the face 21 is in abutment against the front shoulder 12 of the opening 11 of the body 1.

 The guide surface 22 is then housed with clearance in the opening 11. A draft such that the surface 22 is very slightly flared inward, and for example of the order of half a degree, is here provided.

 FIG. 2 shows that the surface 22 of the block A has a peripheral groove 23 for housing a seal 24.

 Here, the seal 24 is O-ring, of substantially circular cross section, and comprises a silicone or the like.

 This arrangement, which can be likened to an axial abutment against a plane, combined with a mounting guide with radial clearance and interposition of a seal, distinguishes the invention from built-in or plug-in assemblies.

 This optimizes the stresses between the body 1 and the block A. In particular, the latter is thus easily mounted and the seal 24 is easily placed and compressed to ensure a lasting and optimal seal.

 In FIG. 2, the guide surface 22 is a cylinder based on a rounded external contour.

 In embodiments not shown, the outline is circular or oblong.

 In the example of FIG. 2, the base has an ovoid external contour, with a large upper radius centered on mounting means 25 of an inspiration coupling connection, such as those visible in FIGS. 1 and 5 .

 A small lower radius of the contour of the surface 22 is centered on means 15 for mounting an exhalation valve 29.

 Such a structure makes it possible to optimize the ergonomics of the mask 2, the body 1 of which thus follows the "tip" of the lower face V of a wearer R.

 On the other hand, the large upper radius offers technically significant sizing, comfort and usable volume.

 As can be seen from FIGS. 1 and 2, the block A is generally in the form of a truncated cylinder with an ovoid cross section, and truncated at a bevel.

 The term "truncated" here means that the cylinder is delimited in its axial direction 16, by two intersecting planes, the intersection of which is located at an outside distance from the block A.

 Block A, substantially inscribed between two planes, one outside close to the opening 11, the other inside close to the face V of a wearer, makes it possible to obtain a particularly compact structure - not bulky - and ergonomic, as well than having excellent mechanical resistance qualities. Compared to known structures, block A does not present any zone of least resistance such as a flat and thin wall.

 In FIGS. 1 and 6, the two limit planes of block A form, with respect to each other, an angle less than 450, in particular between 400 and 200, and for example of the order of 300.

 Here, a function of block A is to integrate the breathing means 19, to allow the wearer a conversation, and to direct the flows in the mask 2, in particular to evacuate the excess moisture (fogging, etc.).

To this end, in addition to the mounting means 25, the breathing means 19 here include at least:
an anteroom 27
mounting means, generally designated at 28, intended for assembly to block A:
of the inner mask 7
of an inspiration coupling 26
an exhalation valve 29
a conversation membrane 31; and
a protective grid 32.

 Note that the mounting means 28 of the inner mask 7 include the groove 23 and in the latter, a male index intended to cooperate with a female index on the inner mask 7, in order to avoid any mounting and positioning errors of the latter. on block A.

 Certain embodiments of the invention do not include all of these elements.

 The reference 30 designates in FIG. 1 an inspiration valve, mounted on the block A via the mask 7, and therefore means 28.

 FIG. 7 illustrates an example of a valve 30.

 The mask 2 comprises, according to this embodiment, a flexible membrane 53 and a support 54 which form the valve 30.

 At the outer periphery of the support 54 is extended a peripheral groove for mounting this support 54 in an orifice of predetermined size (diameter), of the inner mask 7. The support 54 is therefore mounted by elastic stapling or "clipping" on the mask interior 7. This assembly is waterproof.

 Similarly, the membrane 53 is mounted on a central pin 55 with a peripheral groove, by "clipping".

 A special feature of this membrane 53 is that it is prestressed on its support 54.

 Indeed, a membrane on a flat support tends, under its own weight, to deform, which impairs its functioning, and especially in terms of sealing and sealing.

 Here, a seat of the support 54 has a cylindrical shape, while the membrane placed on it also takes this cylindrical shape, which tends to stiffen the membrane (under the compressive and tensile stresses on both sides). other from a neutral line).

 This avoids undesirable deformations of the membrane, under its own weight.

 The prestressing of the membrane 53 is obtained by the fact that it has, at rest, a shape substantially inscribed in a cylindrical envelope with convexity facing the support 54.

 In the examples illustrated, the block A forms with the removable fixing means 20, a one-piece piece of molded synthetic material.

 This material is here a polyamide such as Noryl, or the like.

 Furthermore, the removable fixing means 20 are distinct and at a distance from the guide surface 22.

 And this, although the latter collaborates via play, with a part of the mask body 1 in the form of a cylinder with cross section complementary to that of the surface 22.

 Here, the removable fixing means 20 are also at a distance from the positioning face 21.

 In the examples, these means 20 are arranged near or partly coincident with mounting means 25 of the inspiration coupling connector 26.

 More particularly, it is provided here that the removable fixing means 20 are essentially constituted by the mounting means 25 of the inspiration coupling connector 26.

 Note that usually, depending on the destination of a mask 2, different types of fittings 26 are necessary.

These are generally:
Thread fittings "Rd 40x1 / 7" for respiratory protective devices other than diving and insulating devices with positive demand pressure
Threaded connections "M45x3" and special or permanent fitting for self-contained breathing apparatus with compressed air designed as positive pressure insulating apparatus; and
Central thread fittings for closed circuit devices.

 An advantage of block A according to the invention consists in that, for the manufacture of a block A intended to receive one of these fittings, only a molding core corresponding to the means 26 in terms of form of means (threading, etc.), of dimensions and complementarity (presence in the absence of a polarizing key, etc.) is to be interchanged with another core corresponding to a block A for other connections. This is both simple and economical.

 In FIGS. 3 to 5 it can be seen that the mounting means 25 of the screw-on coupling coupling of inspiration 26 comprise a safety system 33.

 The security system 33 is capable, except when it is voluntarily deactivated, of opposing disengagement (here by unscrewing) from the inspiration coupling connector 26.

 In the illustrated embodiments, the security system 33 is generally arranged coaxially and inside an orifice 34. The orifice 34 allows the inspiration connector 26 to be screwed in, and therefore forms part of the mounting means 25 .

 Also, the security system 33 illustrated comprises a pawl 35.

 The pawl 35 is here in displacement parallel to the axial direction 16 of screwing in the inspiration connector 26.

 This axial movement is intended to bring in or out of engagement with a toothing 36 of complementary shape integral with an axial end of the inspiration connector, another toothing 37 integral with the block A.

The pawl 35 of the security system 33 of FIG. 5 comprises:
a crown 38 with teeth 37, mounted in the screw hole 34, with axial sliding between two extreme stop positions
and an elastic member 39 for axial stress.

 Here, the member 39 is a circular leaf spring with opposing notches, arranged so as to constantly exert on the crown 38, a force oriented towards an engagement position of its teeth 37 with the teeth 36 of the inspiration fitting. 26.

 In use, the spring 39 is mounted at the bottom of the orifice 34.

 And the crown 38 is guided in the axial direction 16 in this orifice 34, by two axial tabs 40.

 Each of these legs 40 has an oblong opening 41 capable of cooperating with a stud 42 integral with the interior of the orifice 34. When the crown 38 slides, a stud 42 guides the edges of a corresponding slot 41 .

 The legs 40 project symmetrically from the crown 38, in the axial direction, from the external periphery of the crown 38, in a direction opposite to the teeth 37.

 Also the illustrated embodiment provides that the security system 33 includes an unlocking or deactivation mechanism 43.

 This mechanism 43 mainly comprises here an external peripheral toothing (radially protruding and axially extended) 44 on the crown 38, as well as an additional internal peripheral toothing 45 on the body 1.

 The teeth 44 and 45 guide the crown 38 axially and make it possible to separate the teeth 36 and 37 from the pawl. Thus, the connector 36 is released in rotation and can be unscrewed.

 More particularly, the toothing 45 has come integrally with the screwing orifice 34.

 In one embodiment, the mechanism 43 comprises a finger 46 for disengagement.

 The finger 46 is capable of causing the disengagement of the toothing 44 and of the connector 26.

 In another embodiment, in order to limit the risks of involuntary operation, the mechanism 43 is accessible exclusively using a tool such as a key, designed to be introduced into the orifice 34.

 In summary, the screwing in the orifice 34 is maintained by means of the pawl whose corresponding teeth are engaged.

 By acting either on the finger 46, which therefore acts as a trigger button, or by pressure using an appropriate key inserted into the orifice 34, the loosening of the nesting of the teeth is obtained.

 It is then possible to disassemble the fitting, or an adapter, mounted in the orifice 34.

 The spring located inside the orifice also urges the mechanism so that in the absence of voluntary human intervention, the teeth are normally engaged and in the locked state.

 Note in Figure 1 or 6 that the breathing means 19 are substantially extended in the axial direction which is defined by an axis called revolution also designated at 16, located in the vertical plane of symmetry of the head of the carrier R.

 The axis 16 is inclined on the horizontal and the vertical and passes substantially in or near the projecting in the axial direction 16 as well as inside the screwing orifice 34 of the connector 26.

 The mounting means 25 of the inspiration connector are arranged so as to open directly out of the block A, in order to guide an anti-fog flow B of scanning from inside the mask body 1, and for example from its eyepiece 9, during inspiration.

 It is noted that the means for mounting the conversation membrane 31, here a screw cap, form a female thread in the face of the block A axially opposite to the face 21.

 Block A defines, from the interior mask 7 to the exterior, via the anteroom 27 and the proximity of the exhalation valve 29, a circulation circuit which is substantially closed, separate and distinct from mounting means 25 of the connector. of inspiration.

 In the mask 2, the connection block A is housed from inside the mask body 1.

 On the mask 2, we see a boss provided with the front opening 11 and in which is partially housed the connecting block A. A cover 48 of shape substantially complementary to that of the boss, is mounted externally on the latter.

The removable fixing means 20 of the connection block A cooperate with the cover 48, so that the block
A and the body 1 are rigidly fixed to each other in a removable manner, by means of the cover 48.

 The mask 2 comprises a clamp limiter of the removable fixing means 20. This is here the cover 48 mounted on the mask body 1 and against which a clamping piece - the connector 26 - comes into abutment axially when a force predetermined maximum is applied.

 This embodiment provides as a flow and drainage circuit for humidity, a passage 49 on the block A and another passage 50, substantially opposite, on the hood 48.

 In FIG. 1, the inner mask 7 has a bellows D, crescent and facing the mask body 1, in order to allow a reversible elastic deformation of the inner mask 7 for adapting the latter to the morphology of a wearer R of mask 2.

 Let us return to the eyepiece forming the major part of the body 1, where the opening 10 delimited by the collar 5 is at least partly, planar or substantially planar in particular towards the bottom of the eyepiece 1.

 Here, a flat part is notably located in a vertical plane (or close to the vertical) when the eyepiece is in the reference situation.

 Towards its upper part, the collar 5 is curved downwards, from front to back.

 We will return later to the shape of the collar 5, as well as to another way of determining it.

 Apart from the flange 5 and the shoulder 12, the wall 9 has an upper part 13 forming the usual binocular field of vision of the wearer and a lower part 14 extending the upper part down continuously, that is to say without breaking.

 However, this constructive characteristic does not exclude the presence between the parts 13 and 14 of a relief such as a hollow, or even an inflection.

The upper part 13 is of so-called spheroconical shape and generated by the displacement of an arc of a circle
C (Figure 1) rotating, on a given sector, around the axis of revolution 16.

 The latter is located in a vertical plane of symmetry of the head of the carrier R.

 The axis 16 is inclined from front to back and from bottom to top relative to the head of the carrier R in the reference situation.

 In the embodiment shown in FIG. 1, the axis 16 makes with the horizontal an angle equal to or close to 430.

 The radius of curvature of the arc of a circle C is, in the embodiment shown, of the order of 632 to 636 mm.

 Along the axis 16, the edge 4 delimits an upper end 17 of the eyepiece 1 and a lower end 18.

 Note that the eyepiece 1 once produced, for example by molding, is in certain cases subjected to a hardening and / or anti-scratch treatment.

 In addition, a gold plating is in some embodiments applied to the outer surface of the eyepiece, in order to increase its repellency and thermal insulation qualities.

 By bringing FIGS. 1 and 5 together, it is understood that the invention makes it possible to obtain a seal at two locations by bringing an O-ring into contact against an extended surface substantially in a direction of assembly of the two parts (9 and A ; 26 and A) between which sealing is desired.

 This has already been seen for the seal 24, here an O-ring with a circular section, between the block A and the interior of the shoulder 22.

 Similarly (FIG. 5), a seal 60, here an O-ring with circular section, is mounted in a groove in the connector 26.

 And the mounting means 25 of this connector comprise an internal cylindrical surface with circular section, extended as follows, as well as centered on the axis 16, and intended to cooperate radially with the outside of the O-ring 60, when the connector 26 cooperates with the mounting means 25.

 Sealing is thus obtained even before the complete connection of the fitting 26, in a peripheral zone perpendicular to the axis 16, and independently of the complete mounting of the fitting.

 This too is a safety factor.

Claims (27)

 1. Connection block (A) or snout, intended to be mounted in a front opening (11) of a body (1) of mask (2) for respiratory protection, the connection block (A) comprising breathing means ; as well as removable fixing means on the mask body (1)  characterized in that a substantially planar front positioning face (21) of the block (A) is delimited externally by a generally cylindrical guide surface (22), the generatrix of which is extended along an axis (16) substantially perpendicular to the face positioning (21), so that in an assembled state, the latter is in abutment against a shoulder (12) before the opening (11) of the mask body (1), while the guide surface (22) , housed with clearance in the opening (11), comprises a peripheral groove (23) for housing a seal (24), for example O-ring with circular cross section.  2- block (A) according to claim 1, characterized in that the guide surface (22) is a cylinder based on a rounded external contour, for example an ovoid, with a large upper radius centered on mounting means (25) d 'a coupling coupling (26) inspiration, while a small lower radius is centered on mounting means (25) of an exhalation valve (29).  3- block (A) according to claim 1 or 2, characterized in that the respiratory means (8) comprise at least one anteroom (27); mounting means (25) for an interior mask (7), an inspiration coupling (26), an exhalation valve (29), and possibly a conversation membrane ( 31) and / or a protective grid (32), for example so as to form with the removable fixing means, a single piece (A) of molded synthetic material or the like.  4- Block (A) according to one of claims 1 to 3, characterized in that the removable fixing means (25) are distinct and at a distance from the guide surface (22) and / or from the positioning face ( 21), and are for example arranged close to or partly merged with mounting means (25) of an inspiration coupling coupling.  5- Block (A) according to one of claims 1 to 4, characterized in that removable fixing means are essentially constituted by the mounting means (25) of an inspiration coupling connector (26).  6- block (A) according to one of claims 1 to 5, characterized in that the mounting means (25) of the coupling connection (26) for example screwable inspiration, comprise a security system (33) able to oppose disengagement of the inspiration coupling, except when it is voluntarily deactivated.  7- block (A) according to claim 6, characterized in that the security system (33), for example ratchet (35), is generally arranged coaxially and / or inside an orifice (34) of screwing mounting means (25) of the inspiration fitting.  8- Block (A) according to claim 6 or 7, characterized in that the security system (33) comprises a pawl (35), for example with displacement parallel to a direction (16) called axial, for screwing the connection d inspiration (26) and intended to enter or exit from engagement with a toothing (36) of complementary shape, integral with an axial end of the inspiration connector (26).  as well as an elastic member (39) for axial stress, such as a spring with circular blades with opposing notches, arranged so as to constantly exert on the crown (38) a force oriented towards an engagement position of its teeth ( 37) with a toothing (36) of the inspiration fitting (26).  a crown (38) with teeth (37), mounted in an orifice (34) for screwing the mounting means (25), axially sliding between two extreme stop positions  9- Block (A) according to claim 8, characterized in that the pawl (35) of the security system (33) comprises:  10- Block (A) according to one of claims 6 to 9, characterized in that the security system (33) comprises an unlocking mechanism (46), for example a finger capable of causing the disengagement (37) of a toothing of a pawl (35) and of the fitting (36), the mechanism possibly being accessible exclusively using a tool such as a wrench.  11- Block (A) according to one of claims 1 to 10, characterized in that the breathing means are substantially extended in an axial direction generally parallel to an axis (16) of revolution, located in the vertical plane of symmetry of the wearer's head, tilted horizontally and vertically and passing substantially in or near the middle area of the wearer's brain and the area of the lips, with respect to a mask (2) being in a corresponding position to a wearer with the right head and the horizontal line of sight (S).  12- Block (A) according to claim 11, characterized in that a plane (P) along which the positioning face (21) is generally extended, makes an angle (J) of the order of 450 with the horizontal , compared to a wearer with the right head and the horizontal axis of vision (S).  13- Block (A) according to claim 11 or 12, characterized in that the block (A) is arranged so that it projects from the positioning face towards the viewing axis (S), in the direction of the axis of revolution (16).  14- Block (A) according to one of claims 1 to 13, characterized in that the connecting block comprises mounting means (25) of an inspiration connector (26), provided with a polarizing device such that 'A rod projecting in an axial direction as well as inside a hole (34) for mounting the connector (26).  15- Block (A) according to one of claims 1 to 14, characterized in that mounting means (25) of a connector (26) comprise an internal cylindrical surface with circular section, centered on an axis (16) mounting means (25), and intended to cooperate radially with the outside of an O-ring (60) mounted on a fitting (26) when this fitting (26) cooperates with the mounting means (25), for example by screwing.  16- Block (A) according to one of claims 1 to 15, characterized in that the connecting block (A) comprises mounting means (25) of an inspiration connector, arranged so as to lead to the inside directly outside the block (A), in order to guide an anti-fog sweeping flow from inside the mask body (1), and for example from its eyepiece (1; 9), during inspiration.  17- Block (A) according to one of claims 1 to 16, characterized in that the block (A) comprises a substantially closed circulation circuit, separate and distinct from mounting means (25) of an inspiration fitting .  18- Block (A) according to one of claims 1 to 17, characterized in that the block (A) comprises mounting means (25) of a conversation membrane (31), such as a screw cap.  19- Mask (2) for respiratory protection comprising a connecting block (A) according to one of Claims 1 to 18, characterized in that the body (1) of the mask (2) essentially consists of an eyepiece (1 ; 9) of which a curved transparent wall bounded by a curved outer edge, is provided with the front opening (11) with which the connection block (A) cooperates, the latter (A) being housed from inside the body ( 1) mask.  20- Mask (2) according to claim 19, characterized in that it (2) comprises on the mask body (1), a boss provided with the front opening and in which is partially housed the connecting block ( A), as well as a cover (48) of shape substantially complementary to that of the boss and mounted externally on the latter.  21- Mask (2) according to claim 19 or 20, characterized in that it (2) comprises a cover (48) mounted externally on the body (1), with which cooperate the removable fixing means of the connection block ( A), so that the block (A) and the body (1) are rigidly fixed to one another in a removable manner, by means of the hood.  22- Mask (2) according to one of claims 19 to 21, characterized in that it (2) comprises a clamp limiter of the removable fixing means, such as a hood (48) mounted on the mask body and against which a clamping piece, for example an inspiration fitting (26), is placed in axial abutment when a predetermined maximum force is applied to the fixing means.  23- Mask (2) according to one of claims 19 to 22, characterized in that it (2) comprises a flow and moisture drainage circuit, such as a passage (49) on the block of connection and another passage (50) substantially opposite on a hood (48).  24- Mask (2) according to one of claims 19 to 23, characterized in that it (2) comprises an inner mask having a bellows, for example in crescent and facing the body (1), in order to allow a reversible elastic deformation of the inner mask for adapting the latter to the morphology of a wearer of the mask.  25- Mask (2) according to one of claims 19 to 23, characterized in that it (2) comprises at least one inspiration valve (54) with a flexible membrane (53) and a support, for example, the latter is mounted on an inner mask (7) and the membrane (53) is mounted on this support (54), the membrane (53) being prestressed by the fact that it (53) has, at rest, a shape substantially inscribed in a cylindrical envelope with convexity facing the support (54) having a seat of curved shape, against which the membrane comes into place.  26- helmet (2a) of protection characterized in that it (2a) comprises a connection block (A) according to one of claims 1 to 18 and / or a mask (2) according to one of claims 19 to 25.  27- Diving suit (2b) of protection characterized in that it (2a) comprises a connecting block (A) according to one of claims 1 to 18 and / or a mask (2) according to one of claims 19 to 25.