Patent GB-951817-A (GB)
Title: Improvements relating to flying helmets
Inventor: LOBELLE MARCEL JULES ODILON
IPC: A42B3/22
Filed: 1961-08-01
Abstract: 951,817. Flying helmets. M.L. AVIATION CO. Ltd. July 27, 1962 [Aug. 1, 1961], No. 27880/61. Heading A3V. A flyer's helmet, Fig. 1, has a visor 2 actuated and protected by a lune-shaped canopy 4, both pivoted to the helmet at 3. The canopy can be moved angularly, by the flyer, to move the visor from its open position, as shown, into a lower closed position, in which it covers and protects his face, or vice versa. Locking mechanism, controlled by a pivoted inertia lever 5, is provided to lock the visor in its open or closed position. If and when the flyer is subjected to a shock, such as might occur on being ejected from his aircraft by an ejection seat, the lever 5 moves downwards and unlocks the visor so that it closes automatically. The lever 5, Fig. 2, and a lever 16 having arms 17 and 18 are pivoted to the helmet about a pivot 15 and are connected by a tensioned spring 19 which, in the upper position of the lever 5, is above the pivot 15 and tends to move the lever 16 clockwise and keep a pawl 22, on the tip of the arm 17, in engagement with a tooth on a part-circular rack 23 on the edge of a plate 24 secured to the visor, and so lock the latter in its open position. When a shock of the afore-mentioned magnitude occurs, the lever 5 turns clockwise and extends the spring 19 and moves it below the pivot 15, so that it turns the lever anticlockwise and disengages the pawl 22 from the rack 23 and thus unlocks the visor, which closes automatically and rapidly. A pawl 25 on the arm 18 then engages a slot 26 in the plate 24 and locks the visor in its closed position. When the flyer wishes to open the visor he must first raise the lever 5 to disengage the pawl 25 from the slot 26. The canopy 4 is connected by a transverse extension 32 to a lever 30 pivoted to the helmet at 31 and connected to the visor by a pin 33, which engages the ends of a slot 34 in the plate 24. Movement of the canopy through an angle causes the visor to move, in the same angular direction, through a greater angle, e.g. through approximately twice that angle. The lever 30 is urged to the central or normal position, as shown, by a tensioned spring 40 connected to a pair of levers pivoting about the pivot 31 so as to press them against a pin 43 fixed to the helmet and a pin 44 projecting inwardly from the lever 30. The canopy comprises a pair of cams 50 and 51 co-operating with a roller 52 on the arm 17. When the flyer moves the canopy clockwise, the cam 50 engages this roller and unlocks the visor. The pin 33 then engages the right-hand end of slot 34 and moves the visor into its closed position. When the flyer releases the canopy, the spring 40 returns it to its normal position corresponding to the central position of the lever 30. When he desires to open the visor, the flyer moves the canopy anticlockwise so that the cam 51 engages the roller 52 and unlocks the visor and the pin 33 then engages the left-hand end of the slot 34 and moves the visor anticlockwise. The visor and canopy are pivoted on the other side of the helmet to a pivot comprising a helical spring under compression and a friction washer.