Improvements in Straight Edges and Levels.
Year: 1891

page_text: • of Application, 14th Mar., 1891-Accepted, 16th May, 1891
COMPLETE SPECIFICATION.
Improvements in Straight Edges and Levels.
We. PAUL KREBS, Merchant, and Lots Ms. M
Graer
Weg 42, Berlin, Germany, do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
This invention has reference to straight edges with spirit or water levels of
the kind adapted for use both horizontally and vertically, that is to say as a
level for determining the horizontality of an object or surface, and also the per-
pendicularity of an object or surface to which it is applied. In such straight
edges according to this invention, the levelling tubes are arranged within a common
holder, so that the straight edge can be used in an easy and convenient manner
and so that the levelling tubes can be readily and accurately inserted in place
within and removed from a straight edge of any suitable length by an unskilled
person.
In straight edges with water levels of the kind mentioned as heretofore con-
structed the levelling tubes have been arranged at two separate parts of the
straight edge, and have not been capable of being readily removed and replaced,
consequently the levels are rendered practically useless by the slightest inaccuracy
in the straight edge such as would be produced by warping of the wood caused
by the levels being placed at different parts thereof, or from other cause.
These disadvantages are obviated according to this invention by arranging both
levelling tubes in one holder that is removably inserted in the straight edge near
one end thereof. Warping of the wood is thereby completely obviated, because a
continuous mass of wood can be left intact on one side of the holder, and should the
straight edge become inaccurate from any cause, the holder can be ca ily removed
therefrom and inserted in another one.
A straight edge with levels constructed according to this invention is illustrated
in the accompanying drawings.
Fig. being a front elevation; Fig. 2 a side elevation; and Fig. 3 a section on
the line of Fig. 1.
A is a portion of a straight edge formed near one end with a semi-circular hole A'
for the reception of a correspondingly formed holder B.
The straight side of the semi-circular hole A' may advantageously be arranged
at an angle of 45° to the lower side of the straight edge so that the holder will be
caused by gravity to place itself always at the same angle, even if the holder should
not exactly fit the hole A.
The holder is formed with two openings c, eat right angles to one another, in
which the levelling tubes d, d' are secured so as to be also at right angles to each
other.
Instead of using two levelling tubes, one tube may be used as indicated in dotted
lines this tube being so bent that its end portions are at right angles to each other
and have one air bubble only which can move into each portion of the tube
according to the position in which the straight edge is placed. The tubes, or the
end portions of the one tube if this be used, are protected by glass plates ca is an
opening in the narrow side of the straight edge through which the tube d can be
readily inspected to ascertain the position of the air bubble when using the straight
edge in a horizontal position.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what
we claim is :-
1. A straight edge of the kind herein referred to, provided near one end with a

page_text: removable holder B carrying two levelling tubes arranged at right angles to each
other, or a single levelling tube having its end portions bent at right angles to each
other substantially as described and shown.
2. For a straight edge of the kind referred to, a holder B constructed with two
levelling tubes d d arranged at right angles to each other, or with a single levelling
tube having its end portions bent at right angles to each other substantially as
described and shown.
Datel him 19th C 1001
P. KREBS,
By L. W., per F. B.
L. MENZ,
By L. W., per F. B.