Abstract: The electronic rack and mounting chassis includes a plurality of horizontal chassis members, a plurality of vertical chassis members, and a plurality of front to back chassis members. The front to back chassis members are each connectable to at least one horizontal chassis member and at least one vertical chassis member, and the front to back chassis members each comprise a hollow section extrusion.

Abstract: The electronic rack and mounting chassis includes a plurality of horizontal chassis members, a plurality of vertical chassis members, and a plurality of front to back chassis members. The front to back chassis members are each connectable to at least one horizontal chassis member and at least one vertical chassis member, and the front to back chassis members each comprise a hollow section extrusion.

Abstract: A respirator helmet (10?) or other helmet adapted to receive, by means of a plug (66) and socket arrangement (70), a pivotable bar (62) carrying a protective screen (63) such that the screen may be moved between a lowered position in front of the face of the wearer of the helmet and a raised position.

Abstract: A personalised cap (10) for use with a protective helmet is disclosed, having crown and brow portions (12, 14). The brow portion (14) is removable independently of the crown portion (10), and an alternative brow portion (14?) is provided for use when a environmental protection hood is to be worn under the helmet. An alternative crown portion (12?) also may be provided. A hood for use over a helmet and a hose for use to provide air to a respiratory mask, a mask and fittings for attaching a mask to a helmet are also disclosed. The environmental protection hood may comprise a manifold (412) having an element external to the hood, for receiving supply of services needed within the hood, and an element internal to the hood, for providing those services where required.

Abstract: An expiratory valve unit comprises a body having a plurality of outlets and valve seats, and a rotary closure member having a plurality of blades each normally biassed against a respective seat to close the outlets and being rotatable relative to said body when under pressure from user exhalate impinging the blades to open the outlets.

Abstract: A respirator helmet (10?) or other helmet adapted to receive, by means of a plug (66) and socket arrangement (70), a pivotable bar (62) carrying a protective screen (63) such that the screen may be moved between a lowered position in front of the face of the wearer of the helmet and a raised position.

Abstract: A helmet having a visor mounted on pivot posts fixed to the helmet shell includes a visor driving and latching mechanism which acts both to allow the wearer to move the visor between its lowered and raised positions and also to hold the visor in either position. The mechanism has an operating lever which is pivoted to the visor at a point spaced from the pivot post. The operating lever has a slightly elongated aperture which receives the pivot post, and a hollowed out portion which receives a cam fixed relative to the pivot post. The operating lever has a first tooth which engages a first recess in the cam to hold the visor in its lowered position, and a second tooth which engages in a second recess in the cam to hold the visor in its raised position. To move the visor from its lowered to its raised position, the wearer manually rotates the operating lever in the appropriate direction.