Pendulum

Claim 1

A level comprising a body defining first and second pairs of opposite sides and a cylindrical opening in said body extending between and opening outwardly of said first pair of sides, said second pair of sides being adapted for selective abutting against a surface whose orientation relative to the horizontal is to be measured, a level assembly disposed in said opening, said level assembly including a sealed hollow housing having opposite sides facing outwardly of said first pair of sides, journal means carried by central portions of said housing sides, indicator means including a horizontal shaft extending between and journaled from said journal means and pointer arm means carried by and projecting outwardly from at least one side of said shaft and including outer end provided with indicator means closely adjacent and swingable about the inner surfaces of the outer peripheries of said housing sides, said housing sides including indicia spaced about said outer peripheries with which said indicator means is registrable, second arm means carried by said shaft and projecting outwardly from opposite sides thereof, the outer ends of said second arm means including float elements spaced along said second arm means in a line normal to a diametric plane of said shaft containing said indicator means, a quantity of liquid contained within said housing to a level with said float elements disposed in said liquid and buoyed up thereby with a force substantially to the weight of said indicator means, whereby the shaft ends and journal means function primarily to guide the indicator means during its oscillation rather than support of the indicator means between said housing sides, said float elements coacting with liquid to support said pointer arm means in vertical position, said housing including a pair of aligned cylindrical opposite end sections with said opposite sides of said housing closing the remote ends of said sections, the adjacent ends of said end sections being oppositely and complementary stepped and interfittingly and sealingly secured together, corresponding peripheral portions of said adjacent ends having registered notches formed therein opening toward each other and defining a port through the corresponding outer peripheral wall portion of said housing centrally intermediate its opposite ends, a puncturable resillient plug extending through said port and overlapping the inner and outer surfaces of said corresponding peripheral wall portion, said plug being constructed of a material rendering said plug repeatedly puncturable by a hollow needle and self resealable each time the needle is withdrawn, said housing being removably and rotatably received in said body opening, said body having a bore formed therein extending generally radially of said cylindrical body opening and opening outwardly of one of said second pair of sides of said body at its outer end and into said body opening at its inner end, the inner end of said bore including a diametrically enlarged counterbore, the outer end of said bore being threaded, an abutment screw threaded in said outer end of said bore and including an inner end head loosely received in said counterbore, an abutment piston disposed in said counterbore, and a compression spring interposed between said head and abutment piston, said abutment piston being projectable, at least slightly, from said counterbore into said body opening for frictional abutting engagement with the opposing outer surface portion of said housing.