Patent GB-222085-A (GB)
Title: Improvements in or relating to valve mechanism
IPC: B64B1/64
Filed: 1924-07-22
Abstract: 222,085. Goodrich Co., B. F., (Assignees of Gammeter, J. R., and Kmentt, W. D.). Sept. 19, 1023, [Convention date]. Safety valves for balloons and gas bags of airships &c. A disc is acted upon by spring-controlled levers in such a manner that the load remains constant or diminishes as the valve opens, means being provided for varying both the moment and the tension of the springs from outside the valve. Fig. 1 shows a valve disc 16 provided with a flexible gasket 19 which bears against a flat surface 12 on a valve frame 11. The frame 11 is secured to a flange 13 on the balloon fabric by a binding 14, the flange being stiffened bv a sinuous wire, embedded within it, which permits circumferential contraction. A rib 12<a> on the valve seating prevents ingress of air should the internal pressure in the gas chamber fall below that of the atmosphere. The disc 16 is secured to a hollow valve stem 17 which has a squared upper portion guided by the arc-shaped ends of four deeply forked levers 25 pivoted at 26 to brackets on an enclosing shell 15 secured to the frame 11. Cords 30 lie in grooves in the edges of the forked levers and are secured to the stem 17 by members 31 and are anchored to the levers at 30<a>. The lower portion of the valve stem 17 is guided by the arc-shaped ends of four levers 22 pivoted at 23 to brackets on the frame 11. These levers are preferably but not necessarily of the same length as the levers 25 so as to form a parallel motion. Cords 36 anchored at 36<a> to the levers 22 lie in grooves in the edges of the levers and are connected to members 37 carried by projections on a ring 39 capable of sliding within the stem 17 which is slotted to accommodate the projections. This ring can be raised or lowered by a screw 43 engaged by a squared shaft 45 capable of being turned by worm gear 50, 51, outside the valve, to vary its loading by adjusting the tensions of springs 32. These springs are secured to adjustable pins 64 high up at intermediate points of the upper levers 25 and are connected by cords 33 to points 34 near the ends of the levers 22 which have arc-shaped grooves to receive the cords. A dial for indicating the loading when the valve is in use at the top. bottom, or side of the gas chamber is provided on the wheel 50. The springs 32 keep both sets of cords 30, 36 taut, but since they have a greater moment upon the lower levers than upon the upper levers the disc 16 is kept normally closed. As the valve opens the springs are stretched but the moment of the springs upon the upper levers increases so that the force they exert on the valve may actually diminish. To prevent undesirable alterations in the ratio of the valve loading at the open and closed positions when the initial tension of the springs 32 is increased, means are provided for moving the pins 64 nearer to the fulcra 26 of the levers 25 when the ring 39 is moved downwards by the worm gear 50, 51. The pins 64 are mounted on carriages 65 capable of sliding in grooves 67 in the levers 25 tangent to arc struck from the points 34 on the levers 22. Links 68 connect the carriages 65 to the ends of links 59 which are guided at their upper ends in slots 63 on the levers 25 concentric with the fulcra 26, the lower ends of the links, 59 being pivoted at 60 to the levers 22. Thus, as the levers 22, 25 are separated by movement of the ring 39, the carriages 65 are moved towards the fulcra 26. Cords 16a limit the outward movement of the valve. Fig. 13 shows means for manually opening the valve and for positively closing it when necessary. A fitting 69 on the end of the shaft 45 is connected to a cord 71 led over a pulley 72 on a depending frame 73 to enable the valve to be opened by hand. A tube 74 is pivoted to the fitting 69 and is normally held in an inclined position by an elastic cord 75. A cord 77 is led over another groove in the pulley 72, a pull on the cord first drawing the tube 74 into a vertical position and then forcing the valve home. Elastic connections 79, 80 normally ensure that the cords 71, 77 are slack near the valve. A modification is described in which the whole of the valve mechanism is on the outside of the disc 16 which is mounted on the upper end of the stem 17 and seats against a ring carried by a cylindrical frame extending inwards from the envelope.