One of the most common items to accomplish these functions is the plumb bob. The establishment of a vertical reference above an obscure datum by a surveyor or for a construction worker to transfer a datum vertically from one level to another are everyday requirements in the surveying and construction fields. This invention relates generally to plumbing devices and more particularly to plumb bobs as used in both surveying and in the construction field. In combination with a surveyor's reel a plumb bob comprising: The plumb bob of claim 19 wherein said lateral bore intersects said axial bore at an obtuse angle.Ģ1. The plumb bob of claim 15 wherein said knobbed extension further defines a lateral bore intersecting said axial bore.Ģ0. The plumb bob of claim 17 wherein said frustoconical body includes a relatively high-density metallic core and a relatively low-density frustoconical shell surrounding said metallic core.ġ9. The plumb bob of claim 16 wherein said knobbed extension further defines a lateral bore intersecting said axial bore.ġ8. Means for affixing a pointed member to said body at the smaller end thereof and coincident with said axis.ġ7.
The plumb bob of claim 15 wherein the conical portion comprises: The plumb bob of claim 10 wherein the knobbed extension defines an axial bore and further defines a lateral bore intersecting said axial bore, said knobbed extension further defining a continuous smoothly curved top portion connecting the outer surface of said extension and said bore.Ī knobbed extension at the larger end of said conical portion, said knobbed extension defining an axial bore and a continuous smoothly curved top portion connecting the outer surface of said extension and said bore.ġ6. The plumb bob of claim 12 wherein said plastic shell is a high visibility color.ġ4. The plumb bob of claim 10 wherein said plastic shell is comprised of an opaque polycarbonate.ġ3. The plumb bob of claim 10 wherein the means for affixing said pointed end includes a conical support collar, said support collar defining a first axially threaded bore.ġ2. Said plastic shell formed with a continuous smooth surfaced knobbed extension at its larger end, said extension adapted to receive a flexible support member on said axis.ġ1.
Means for affixing a pointed member to said relatively low-density frustoconical plastic shell at the smaller end thereof, coincident with said axis and Said lateral bore having a larger diameter than said axial bore.ġ0. The plumb bob of claim 1 wherein the knobbed extension defines an axial bore and further defines a lateral bore intersecting said axial bore, said knobbed extension further defining a continuous smoothly curved top portion connecting the outer surface of said extension and said bore The plumb bob of claim 1 wherein the shell and the metallic core define an axial bore.ĩ. The plumb bob of claim 6 wherein said plastic shell is a high visibility color.Ĩ. The plumb bob of claim 1 wherein said plastic shell is comprised of an opaque polycarbonate.ħ. Said flat surface forming a mating surface with said shoulder and with said shoulder defining means for resisting relative rotation of said support collar relative said shell.Ħ. The plumb bob of claim 4 wherein the frustoconical plastic shell defines a shoulder at its smaller end adjacent the threaded boss and further wherein the support collar includes a flat surface at its larger end
The plumb bob of claim 3 wherein the relatively low-density frustoconical plastic shell defines at its smaller end a threaded boss adapted to receive the second axially threaded counterbore of the conical support collar.ĥ. The plumb bob of claim 2 wherein the conical support collar defines a second axially threaded counterbore.Ĥ. The plumb bob of claim 1 wherein the means for affixing a pointed end includes a conical support collar, said support collar defining a first axially threaded bore.ģ. Said plastic shell having a continuous smooth surfaced knobbed extension at its larger end adapted to receive a flexible support member on said axis.Ģ. Means for affixing a pointed member to said relatively low-density frustoconical plastic shell at the smaller end thereof and coincident with said axis A relatively low-density frustoconical plastic shell defining an axis and surrounding said metallic core