ANCIENT PLUMB BOB PDF

241000013987 Colletes Species 0.000 claims abstract description 30.Application granted granted Critical Publication of US5426860A publication Critical patent/US5426860A/en Anticipated expiration legal-status Critical Status Expired - Lifetime legal-status Critical Current Links Assignors: LYNN, JOHN S., GARDINER, THOMAS S., LEE, LEONARD G. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.) Filing date Publication date Application filed by Lee Valley Tools Ltd filed Critical Lee Valley Tools Ltd Priority to US08/263,757 priority Critical patent/US5426860A/en Assigned to LEE VALLEY TOOLS LTD. Original Assignee Lee Valley Tools Ltd Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.) Gardiner Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Expired - Lifetime Application number US08/263,757 Inventor Leonard G.

ANCIENT PLUMB BOB PDF

Precisely machined and balanced bobs have pointed tips, and can be made of brass, steel, or other materials, including plastic.- Google Patents US5426860A - Plumb bob assemblyĭownload PDF Info Publication number US5426860A US5426860A US08/263,757 US26375794A US5426860A US 5426860 A US5426860 A US 5426860A US 26375794 A US26375794 A US 26375794A US 5426860 A US5426860 A US 5426860A Authority US United States Prior art keywords bob cord housing assembly plumb Prior art date Legal status (The legal status is an assumption and is not a legal conclusion. (Masons prefer nylon because it stands up better over time to the dampness that comes with the trade.) At one end of the string the weight is affixed. The plumb consists of a specially designed weight and coarse string made of twisted cotton or nylon threads. In a sense, the plumb bob is the vertical equivalent of the line level. You don’t have to be a physics whiz to understand that a string suspended with a weight at the bottom will be both vertical and perpendicular to any level plane through which it passes. The plumb bob or plumb line employs the law of gravity to establish what is “plumb” (that is, what is exactly vertical, or true). As is so often the case, it isn’t how fancy the tool is, but how well you use it.

For most home toolboxes, I recommend having a single bob that weighs a few ounces. (It’s also thought that, in tandem, they used flooded ditches to determine levels.) Plumb bobs may weigh as little as an ounce or as much as several pounds, depending upon the application.

Evidence suggests that Egyptian architects used plumb bob-like tools to establish verticals in constructing the pyramids.

Ancient plumb bob