GB284679A - Improvements in pressure gauges of the type using a tubular distensible element surrounded by a spring - Google Patents

Abstract

284,679. McPherson, H. L., and Weatherford, J. H. Feb. 3, 1927, [Convention date]. Pneumatic - - tyre pressure gauges. - Relates to the 'type using a tubular distensible element surrounded by a spring and consists in such element being formed as a butt-ended tube the walls of which are corrugated. A hollow cylindrical indicator 71 the upper end of which is closed slides within a casing 70 as usual, the indicator being held in any position reached by a spring ring 74. Housed within the tube 71 is a spring 75 the outer end of which is secured to a head 76 bearing against the indicator head 72. The other end of the spring is secured to a screwed washer 77 screwed into the casing 70. Between the washer 77 and an annular flanged ring 78 is clamped an annular rubber seat 79, an annular disc 81, and the flange 84 of the bag 85. The disc 81 has a hollow central extension 82 which serves to depress the tyre valve. The bag 85 is made of rubber, thin metal, celluloid or other resilient material and the walls are formed with cylindrical or spiral corrugations 86. The bag is made of such length as to come just solidly against the head 76 at that pressure normally in use, so that it is initially compressed and is under practically no tension at normal pressures. Washers 88 may be placed around the bag at the smallest diameters of the corrugations to reinforce it against lateral distortion, and these may be dished and overlap each other as shown in Fig. 6.