US 5,864,956 AGranted

Level line and limb line combination

OwnerDawei Donginventor

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Abstract

A combination of square alloy rulers with precisely machined planes, each ruler unit having two 1.5v batteries and two bubble levels to level in all directions. A line generator is mounted in front of a laser diode module. This basic laser line ruler unit can produce an accurate laser level line or plumb line after it is calibrated. By adjusting the calibrating knob, the laser line ruler will produce a precise level line or plumb line when the level bubbles are centered. Putting a properly aligned level line unit and a properly aligned plumb line unit together will produce a cross line in front of the combination. Adding at least one more laser line ruler, that is combining three or more line units, will produce 90.degree. lines, 45.degree. lines, and 180.degree. lines, as well as 270.degree. lines up and down or on the right and left sides by simply adjusting the position of the relevant ruler. The housing of the ruler unit is machined with accurate planes and vertical angles. Therefore, the combination of several rulers can project accurate level lines, vertical lines, 45.degree. lines, 90.degree. lines, etc. This simple, small, and unique ruler combination is affordable to the public and can be widely used in hardwood layout and cutting, carpet cutting, squaring the surfaces of any plane object, etc. in addition to its usage in construction.

Claims3

Dependent claims

A combination of laser line rulers comprising:

a plurality of generally square alloy ruler units with precisely machined planes, each said ruler unit includes a means to generate a laser line, and a means to orient and calibrate said laser line,
a housing of at least a first one of said ruler units includes a precisely machined opening in a center of a bottom side of said housing, and a housing of at least a second one of said ruler units includes a protruding post extending from a center of a top side of said housing, such that when said first ruler unit is placed on top of said second ruler unit, said post of said second ruler unit is received in said opening of said first ruler unit such that said two ruler units are perfectly aligned,
each said housing further includes top and bottom surfaces that are precisely machined so as to be parallel to each other, said housing includes at least one corner machined at a 45.degree. angle, and
at least one of said ruler units includes two bubble levels to level said ruler unit;
such that
by rotating said first ruler unit about said post of said second ruler unit and establishing a proper orientation by use of said square corners and said 45.degree. corners of said ruler units, reference crossing plumb lines are generated by said first ruler unit perpendicular to a base level line projected by said second ruler unit, said crossing plumb lines are generated in 45.degree. increments.

3 more elements

Dependencies are inferred from the claim text.