GB2166189A - Attachment device - Google Patents

Abstract

An attachment device (10) for releasably securing a breathing mask to a helmet of an aviator comprises a receiver assemblage (11) adapted for attachment to the helmet and a pin (12) adapted for attachment to a breathing mask harness. The receiver assemblage has a receiver body (15) on which locking members (24) are pivotally mounted. A cavity (23) in the receiver body houses a spring (26) for resiliently urging the locking members towards automatic engagement with an indentation (28) on the mask harness pin when it is inserted into the receiver body. The locking members are provided with profiled surfaces (29) projecting externally of the receiver body for application of a manual force to rotate the locking members in opposition to the spring for release of the mask harness pin. <IMAGE>

Description

DESCRIPTION Attachment device This invention relates to attachment devices and is particularly concerned with an attachment device for releasably securing a breathing mask to the helmet of an aviator.

There are many problems to be overcome in providing satisfactory attachment of a breathing mask to the helmet of an aviator, including the continuance of engagement of the mask harness to the helmet under extreme operational conditions, for instance as occur during ejection of the aviator from his aircraft, when he is subjected to the blast effect of the slipstream as he emerges from the protection of the aircraft structure. In overcoming this and other problems inherent to a fully operational mask attachment device the designer must remain within the requirements of robustness, simplicity, compactness and ease of use as well as within financial restraints imposed by the cost accountant.

GBA-2,065,816 discloses a locking device which is suitable for attachment of an aviator's breathing mask to his helmet. The device comprises a pin having a series of axially displaced detents and a receiver which contains a resilient locking means.

The detents are provided by truncated cones spaced along the length of the pin whilst the locking means is in the form of a locking spring having two arms acting transversely of the longitudinal axis of the pin. Movement of the spring arms into and out of engagement with the pin detents is achieved by way of a slide incorporated in the receiver.

In the preferred form for use as an aviator's maskto-helmet attachment device, the locking spring is secured to the slide and is of such preformed shape that the relative spacing of the two spring arms in their free positions is that which provides engagement of the detents when the pin is inserted into the receiver, whilst the free end of each arm is ramped and hooked for cooperation with an associated peg. The ramping of the spring arms is intended to cause the spring, when spread into the unlocked position, to bear on the pegs and so be urged to slide down these to return to the engaged position. In this device the slide and spring comprising the locking means move transversely to the longitudinal axis of the mask harness pin.

It is an object of the present invention to provide an attachment device that is of simple yet robust construction whilst being highly efficient in use and for which the procurement cost is reasonable.

According to the present invention an attachment device for releasably securing a breathing mask to a helment of an aviator includes a pin adapted for attachment to a mask harness and a receiver assemblage adapted for attachment to the helmet, the receiver assemblage comprising a receiver body, locking members pivotally mounted on the receiver body, means for resiliently urging the locking members to rotate towards a position for automatic engagement with an indentation on the mask harness pin when inserted into the receiver body, means for limiting rotation of the locking members about their pivots under the action of a force urging withdrawal of the mask harness pin from the receiver body when it is engaged by the locking members so that at least a major portion of a reaction force is provided by the pivots, means for applying a manual force to the locking members to rotate them in opposition to the resilient means for release of the mask harness pin when it is engaged, and means for assisting alignment of the receiver assemblage with a mask harness to which the mask harness pin is attached.

Preferably the receiver body includes two spaced apart walls between which the locking members are pivoted. The walls and the locking members may be shaped so as to guide the free end of the mask harness pin towards a position of engagement with the locking members. The resilient means may comprise a spring housed within the receiver body.

The means for applying a manual force to the locking members may comprise profiled portions projecting externally of the receiver body appropriate to receiving a manually applied force for their rotation in disengagement of the pin.

The means for assisting alignment of the receiver assemblage with the mask harness may be provided by hinged attachment of the receiver body to an anchorage of the receiver assemblage, the anchorage part being adapted for pivotal attachment to the helmet so as to be rotatable about a pivot axis which is normal to the axis of the hinged attachment.

The receiver body may house further resilient means arranged to contact the end of the mask harness pin when engaged in the receiver body and to apply a force tending to eject the mask harness pin from the receiver body.

An exemplary embodiment of the invention will now be described with reference to the accompanying drawing in which: Figure 1 is a sectional view of an attachment device for releasably securing an aviator's breathing mask to his helmet and, Figure 2 is a sectional view of the attachment device shown in Figure 1 as on line Il-Il.

Referring to the drawing, an attachment device 10 for releasably securing a breathing mask (not shown) to a helmet (not shown) of an aviator comprises a receiver assemblage 11 adapted for attachment to the helmet and an indented mask harness pin 12 for releasable retention in the receiver assemblage 11. The barrel of the mask harness pin 12 has an internal screw thread 13 for acceptance of a threaded mating part of a mask harness (not shown) which is normally secured to the breathing mask.

The receiver assemblage 11 comprises two parts 14 and 15 hinged together in a substantially vertical working plane. One part, the anchorage 14, is adapted for attachment to the helmet whilst the other part, the receiver body 15, includes a locking mechanism 16 arranged for engagement of the mask harness pin 12. The anchorage 14 comprises a single lug member having a through hole 17 for attachment means such as a bushed screw 17a (Figure 2) which provides for pivotal attachment of the receiver assemblage 11 to the helmet, and further provides a central socket element 18 for a hinge pin 19, the axis of which is arranged in a plane normal to the axis of the hole 17.

The receiver body 15 is a shallow open box-like structure having two major walls 22 separated by two minor walls 21 and partially closed at one end by a two-part end wall shaped to provide two outer socket elements 20 for the hinge pin 19. The two major walls 22 extend from the two-part end wall to positions beyond the limit of their separating walls 21 and are preferably shaped at their extremities, such as by a long shallow chamfer, in a manner for facilitating collection of the mask harness pin 12 when this is being offered for enagement with the locking mechanism 16. The region delineated with the major walls 22 by the minor walls 21 and the two-part end wall provides a cavity 23. The minor walls and two-part end wall are preferably of a minimum mass, consistent with acceptable strength requirements, and consequently may be relieved at their adjacent corners, as seen in Figure 1.

Two locking members 24 of the locking mechanism 16 are pivotally secured between and to the extensions of the major walls 22 in symmetry about the normal longitudinal axis of the mask harness pin when engaged. The locking members 24 are of a generally triangular shape and each presents one side 25 facing substantially squarely towards the cavity 23 when it is disengaged and free to respond to the influence of resilient means comprised by a spring 26 that is contained in the cavity 23. The spring 26 urges the locking members 24 to counter-rotate in the locking direction into abutment with the minor wails 21 at the outer end of their sides 25.The inner end of the side 25 of each locking member 24 terminates in a nub 27 and is distanced from its neighbour to an extent that enables an indentation or neck 28 of the mask harness pin 12 to be gripped by them when the engaged condition pertains. The neck 28 of the pin 12 is formed by an annular groove circumscribing the pin near the free end thereof. This free end is of conic form to facilitate mating with the receiver body 15. The corner of each locking member 24 remote from the side 25 projects beyond the periphery of the receiver body 15 and provides a local profile 29 of low mass, which may be formed substantially as a ring having a wide rim suited to enabling a manual squeezing or pinching action for disengagement and release of an engaged mask harness pin 12.Because of the triangular shape of the locking members 24, and their arrangement in the receiver 15 whereby, when disengaged from the mask harness pin 12, they are urged into abutment with the minor walls 21 at the outer ends of their sides 25, their sides joining the local profile 29 and the nub 27 of each are presented at an angle that facilitates collection of the pin 12 when engagement thereof is sought. The cavity 23 preferably houses a second spring 30 which is arranged to bear on the conic free end or nose ofthe mask harness pin 12 when engaged.

In operational use of the attachment device 10 the receiver assemblage 11, being secured to an aviator's helmet by an appropriate pivotal means such as the bushed screw 17a in the hole 17 of the anchorage 14 and itself being articulated about the hinge pin 19 which connects the anchorage 14tothe receiver body 15, permits alignment with the mask attachment point (not shown) within the permitted limits of the spatial restriction imposed by the structure of the helmet. In offering the mask harness pin 12 to the receiver body 15 it is, if not accurately aligned, guided towards the position of engagement with the nubs 27 of the locking members 24 by deflecting from the shaped sides of the extension portions of the major walls 22 and the relatively slanting faces of the outer sides of the locking members 24.The forward end of the mask harness pin when finally collected and entered bears on the two locking members and reacts the urge of the spring 26 so that the locking members contra-rotate and allow penetration of the pin to a position where it becomes engaged by the nubs 27 of the locking members gripping the neck 28. The mask harness pin 12 also, during the later stages of entry, tensions the second spring 30, when fitted, so that a light ejection load is applied to the pin while engaged.

To release the mask harness pin from the receiver body 15 the locking members 24 are manually squeezed towards one another at their local profiles 29 which causes them to contra-rotate against the urge of the spring 26 and release their grip of the neck 28 of the pin 12 whereafter the pin is withdrawn or may be urged to eject from the receiver body 15 under the load exerted by the second spring 30.

The attachment device 10 has considerable strength and provides a positive locking action which increases its retention of the mask harness pin 12 with increasing tensioning thereof, because the locking members 24 tend towards rotating and increasing their grip on the pin 12. In gripping the mask harness pin 12 each locking member 24 behaves as a strut, which puts the tensile load that is applied to the mask harness pin 12 equally onto the two pivot pins that secure the members in the receiver 15, so that there is no bending stress in the members 24.However should wear occur, or relaxed manufacturing tolerances be allowed so that the locking members 24 fail to grip the mask harness pin 12 between them then the applied tensile load is distributed by way of the shoulder of the neck 28 bearing on the side of the nubs 27 of the two locking members 24 whereby these members are rotated about their pivot pins and, at the outer end of their sides 25, brought into abutment with the minor walls 21 of the receiver body 15. In this configuration because of a slight change in the triangulation of forces, which is limited by the chosen geometry of the locking mechanism 16, a slight bending moment is applied to the locking members 24 and because a minor proportion of the load on the pivot pins is transferred to the short walls 21 the reactant force is increased by a small acceptable amount.

One advantage of an embodiment such as above disclosed is that it provides a slim and compact mask harness attachment receiver assemblage which will fit on the inside edge of an aviator's helment without causing discomfort and which, thereby, enables existing helmets having an externally mounted anchorage related to another form of mask harness attachment to be used without the loss thereof when a mask utilising the present attachment is alternatively required to be attached.

Claims (9)

1. An attachment device for releasably securing a breathing mask to a helment of an aviator including a pin adapted for attachment to a mask harness and a receiver assemblage adapted for attachment to the helmet, the receiver assemblage comprising a receiver body, locking members pivotally mounted on the receiver body, means for resiliently urging the locking members to rotate towards a position for automatic engagement with an indentation on the mask harness pin when inserted into the receiver body, means for limiting rotation of the locking members about their pivots under the action of a force urging withdrawal of the mask harness pin from the receiver body when it is engaged by the locking members so that at least a major portion of a reaction force is provided by the pivots, means for applying a manual force to the locking members to rotate them in opposition to the resilient means for release of the mask harness pin when it is engaged, and means for assisting alignment of the receiver assemblage with a mask harness to which the mask harness pin is attached.

2. An attachment device as claimed in Claim 1, wherein the locking members are pivoted between two spaced walls of the receiver body.

3. An attachment device as claimed in Claim 2, wherein the locking members and the two spaced walls are shaped so as to guide the free end of the mask harness pin towards a position of engagement with the locking members.

4. An attachment device as claimed in any one of the preceding claims, wherein the resilient means comprises a spring housed within the receiver body.

5. An attachment device as claimed in any one of the preceding claims, wherein the means for applying a manual force to the locking members comprise profiled portions on the locking members projecting externally of the receiver body.

6. An attachment device as claimed in any one of the preceding claims, wherein the means for assisting alignment of the receiver assemblage with a mask harness is provided by hinged attachment of the receiver body to an anchorage part of the receiver assemblage, the anchorage part being adapted for pivotal attachment to the helmet so as to be rotatable about a pivot axis which is normal to axis of the hinged attachment.

7. An attachment device as claimed in any one of the preceding claims, wherein the receiver body houses further resilient means arranged to contact the end of the mask harness pin when engaged in the receiver body and to apply a load to the mask harness pin tending to eject it from the receiver body.

8. An attachment device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

9. Any new or improved features, combinations and arrangements described, shown and mentioned or any of them together or separately.