GB815452A - Improvements in or relating to dial instruments - Google Patents

Abstract

815,452. Indicating-apparatus. MANNING, MAXWELL & MOORE Inc. Oct. 31, 1957 [Dec. 19, 1956], No. 34015/57. Class 106 (4). [Also in Group XXXII] A dial for use in an instrument 31 wherein a pointer 33 moves over a dial plate 34 has a plurality of graduations in the form of portions 38 of turns of an open-coiled helical spring, the graduations being adjustable relative to one another and to the dial plate 34 so that any selected graduation may be adjusted accurately to register with the pointer 33 in that position which the pointer assumes in response to a corresponding accurately measured physical condition, the adjusted graduation then being releasably fixed. A circular groove 36 locates the spring 37 and in calibrating the instrument every tenth turn 38 is accurately located and clamped in succession, using clamps C arranged in arcuate slots 35. A turn 38 of the spring is gripped between depending walls 47 at the narrow end of the top 39 and the side walls are also formed with legs 45 engaging the dial plate 34 and legs 46 entering the slots 35 to prevent turning about the locking screw 42. Several modifications of the spring and locating groove are described and a wire may be threaded through the coil to prevent distortion, where it is clamped.