GB1329258A - Indicating devices - Google Patents

Abstract

1329258 Indicating devices AGFAGEVAERT A G 8 Sept 1970 [13 Sept 1969] 42925/70 Heading G1J An indicating device comprises a rotatable pointer 13 having its free end 14 parallel to its axis of rotation, the free end 14 being viewed through a window 4 in the housing via a reflecting surface 6 so that it appears to move laterally. In Fig.1, the reflecting surface 6 is provided on one side of a translucent prism 3 and a scale 10 is provided on the plane side 9 of the prism and viewed by reflection in surface 6. A translucent member may be provided between the scale and the pointer 14 to reduce parallax and may have a cylindrical surface adjacent the pointer of a curvature equal to or less than that of the path of the pointer 14. The scale may be cylindrical and have a curvature less than or equal to that of the path of the pointer 14 and may be provided either in front of the pointer Fig. 2 (not shown) or behind the pointer Fig. 3 (not shown), and Fig. 5. Where the curvature of the scale is less than that of the pointer path a translucent member may be interposed between the scale and the pointer Fig. 7 (not shown) to reduce parallax, the surface of the member adjacent the pointer being cylindrical and of the same curvature as the pointer path. The prism 3 may have its side adjacent the pointer 14 curved Fig.4 (not shown) a scale being fitted either on the curved surface or within the prism. In the embodiment of Fig. 5a the prism 3 has a further plane surface 50 behind which a second scale 51 is provided which may be curved or flat. The scales are removable from guide slots and may be coloured and have an illuminating device. The pointer end 14 may be of circular cross-section and may be located between the prism and its axis of rotation.