GB1072499A - - Google Patents

Abstract

1,072,499. Spirit levels. D. E. WRIGHT. June 21, 1965 [June 25, 1964], No.26184/65. Heading G1F. A vial 8 for a spirit level comprises a body, at least part of which is transparent, formed with an elongated symmetrical bore, the central portion of the bore 12 having a greater diameter than the end portion 13 thereof, and provided with an opening to permit the introduction of a fluid into the bore, the external periphery of the body being formed with means 9 spaced equidistantly from the longitudinal axis of the bore for accurately mounting the vial upon a base 4 without adjustment. The vials are mounted in openings 6 Fig. 2 (not shown) in a web 4 by means of notches 7, the web 4 having working surfaces 3. In the embodiment illustrated the vials are formed from an extruded transparent plastics material. A pair of grooves 10 are cut in the external periphery of the vial with which the outermost points of the bubble should register. The central barrel shaped portion 12 is sealed from the exterior by a plug 14 which is sealed in position by a resinous mass 15. Due to the close fitting between the notches 7 and vial ends the vial is aligned with its bore axis parallel to the plane of the web. A pair of transparent coverplates 16 are secured to opposite sides of web 4 and over vial 8 which protect the vial and establish lateral alignment of the vial with respect to the web. A pair of spaced lips 18 on each cover-plate project into the chamber and into contact with annular recesses on the vial outer periphery so that the vial axis is positioned in alignment with the lateral mid-line of the web.