Patent GB-1109348-A (GB)
Title: Improvements in or relating to adjustable gauges
IPC: G01K5/70
Filed: 1966-07-08
Abstract: 1,109,348. Indicating apparatus: thermometers, pressure gauges. MOELLER INSTRUMENT CO. Inc. July 8, 1966 [July 16, 1965], No. 30843 /66. Headings G1D, G1J and G1L. A gauge in which an angular displacement of a sensing means is transmitted to a pointer moving over a scale e. g. a spiral Bourdon pressure gauge or a thermometer having a bi-metallic spiral 24 as sensing means, comprises a housing in two parts 11, 12, which parts are rotatable relative to each other about a plane oblique to the axes of the ports 11, 12 and defined by mating flanges 29, 30, the pointer 50 and scale 35 being coupled to opposite ends of the bi-metallic spiral 24 by bendable coupling springs 54, 55, so that the two housing parts may be rotated relative to each other about the flanges 29, 30 to bring the axes of these parts at an angle such that the face of the thermometer is easily readable without changing the relative positions of the pointer and scale during this rotation, the two housing parts 11, 12 being sealed together by an O-ring 58' so as to protect the gauge from the external environment. The bi-metallic spiral 24 is formed of two oppositely-handed spiral sections joined in tandem so that as temperature rises one section uncoils whilst the other coils, these effects being additive but cancelling out any tendency for there to be a change in length of the spiral. The spiral 24 is mounted in a tube 19 fixed in the housing part 11, which is provided with screw threads for mounting the thermometer in the desired position. One end of the spiral 24 is coupled by a sleeve 26 to a tubular shaft 22 rotatable in bearings 21 and secured by an end cup 23 to the outer coupling spring 55. The other end of the spiral 24 is secured to a shaft 27 passing through the shaft 22 and joined to the inner coupling spring 54 by a hub 53. By means of another hub 53 the spring 54 drives a shaft 49 carrying the pointer 50. The spring 55 is secured at its end remote from the cup 23 to a cap 47 secured in a ring 44 rotatably mounted in the housing part 12 and carrying the scale 35 and scale housing 13. A set screw 45 is provided to lock the ring 44 to the housing part 12 when desired. A clamp 31 having a set screw 57 is also provided to lock the flanges 29, 30 in an adjusted position. In use the clamp 31 is released and the housing part 12 is rotated to bring the thermometer force into an easily readable position with the shafts 27, 49 at any angle up to 90 degrees. Pins projecting from the flange 30 engage with a cam surface on the interior of the flange 29 to maintain the desired relationship between these flanges during relative rotation. The clamp 31 is tightened and the set screw 45 may be released to allow the scale housing to be rotated to bring the zero of the scale into a desired position, the screw 45 then being re-tightened. Small zeroing adjustments of the scale 35 may be made using a screw 38 actuating a lever 37 having a pin 39 which engages in a slot 40 in the scale. In an alternative embodiment the tubular shaft 22 is secured to the housing part 11 and the scale 35 is mounted so as to be rotatable in bearings in the ring 44. Zeroing adjustments are then made by rotating the coupling spring 55 at the end where it is joined to the shaft 22. Also described is a thermometer in which the two housing parts are pivotable in a single plane. In this case the joint between the two housing parts comprises two inter-engaging enlarged circular portions are on each housing part having mating teeth and secured by a clamp in their adjusted position.