Level and collapsible ruler

A combination collapsible ruler and level includes a pre-stressed coilable and uncoilable spring strip ruler with a level tube mounting block mounted intermediate the strip ends. The mounting block has a foot portion which engages the supporting surface to make the spring strip self-supporting on a surface with the level tube in the proper plane. When collapsed the spring strip forms two coils which abut adjacent the level mounting block to provide for convenient handling.

BACKGROUND OF INVENTION 
The invention provides a compact collapsible ruler, level combination which 
is easily carried in a pocket. The ruler spring strip is of conventional 
construction such as that shown in U.S. Pat. No. 2,956,795 which has a 
concave, convex cross-section and is permanently stressed to form a 
plurality of convolutions or coils when collapsed. The mounting block for 
the level tube has a surface complementary to the concave side of the 
spring strip to provide a mounting surface. The mounting block can be 
fastened by bolts or the like to the strip. A foot portion on the mounting 
block is adapted to engage a supporting surface and support the spring 
strip and level tube when in use. The level tube is arranged with respect 
to the mounting block and spring strip so that a plane through the center 
of the tube and through the arc of curvature will be normal to the 
supporting surface when the strip and level are in use. 
Further objects, advantages and features of the invention will become 
apparent from the disclosure.

In the drawings FIG. 1 discloses a spring steel strip 10 which has a 
concave surface 12 and a convex surface 14. The strip 10 is permanently 
stressed so that it will form two tightly wound coils 11 and 14 when the 
strip is collapsed. The strip 10 is provided with suitable measuring 
indicia 15. 
In accordance with the invention there is provided a level tube 19 which is 
upwardly convex. The tube 19 contains the usual fluid and a bubble 17. 
Centering marks 21 are also provided on the tube 19. Means are provided 
for mounting the level tube on the strip 10. In the disclosed construction 
the mounting means comprises a block 16 which has a convex surface 18 
complementary in shape to the concave surface 12 of the strip 10 to 
provide a mounting surface. Bolts 20 extending through apertures 22 in the 
spring strip 10 and apertures 24 in the mounting block secure the block 16 
to the strip. 
The mounting block 16 has a foot portion 26 which is adapted to touch the 
supporting surface 28 and provide a free-standing ruler, level 
combination. The foot 26 is positioned so that a plane PP through the arc 
of the tube 30 and center of the tube 19 will be normal or at right angles 
to the surface 28 for accurate level readings. 
FIG. 4 shows a modified embodiment of the invention in which a mounting 
block 40 contains the horizontal level tube 19 and a vertical level tube 
42 at one end of the mounting block 40. Thus leveling of a vertical 
surface such as surface 44 can be accomplished as well as horizontal 
leveling of the surface 46.