[0001] This patent application for an industrial utility model concerns a square for use
in the building trade for hooking and stretching the reference string used by bricklayers
for levelling planes.
[0002] The invention was designed and produced to resolve a very important problem for those
in the building trade, in a technical and practical manner, once and for all; this
involves the problem that bricklayers have when building a wall in stretching a horizontal
string as reference so that they can build the wall correctly.
[0003] A well built wall must obviously have perfectly aligned horizontal and vertical rows
of bricks; to achieve this, up to now, bricklayers have always used, and continue
to use successfully, a string which they stretch and tighten horizontally as reference
for the positioning of the bricks of the first row.
[0004] Obviously when the first horizontal row of bricks has been completed, the bricklayer
has to move the string up as reference for the next row of bricks.
[0005] This means that in the case of a wall consisting of many horizontal rows, the reference
string must be moved continuously upwards as the wall is built.
[0006] The very fact that the string needs to be moved continuously is the practical difficulty
that this invention has been designed to overcome; in fact, to date, since no specific
tool was available for positioning and moving the reference string up, the majority
of bricklayers generally used two simple wooden poles - placed upright at the longitudinal
ends of the wall to be constructed - on which the ends of the string were tied, and
then stretched.
[0007] Obviously, every time the next row of bricks was to be built, the bricklayer has
to loosen the two ends of the string from the wooden poles and then knot them again
at a higher level.
[0008] Although there is nothing difficult in this, it is however intricate and above all
can lead to inaccurate alignment of the string which may at times compromise the precision
of the wall quite significantly.
[0009] As mentioned, the square according to the invention was designed to hook the ends
of the above string, efficiently and to ensure that the string is well tightened and
easy to move along the wall that is being built.
[0010] It is therefore proposed as a specific operating tool which can overcome all those
practical problems and risks related to the use of the traditional methods for stretching
and aligning the string; the square according to the invention is a cheap and simple
to use tool which allows workers to save time while guaranteeing accurate results
and is something which operators in this sector have never had to date.
[0011] The first point to specify is that in order to stretch the string perfectly, a pair
of these squares positioned opposite to each other, must be used. The squares have
a particular shape which makes it possible to"hook" them to the two bricks on the
opposite ends of the first horizontal row, between which all the other bricks will
be laid, following the reference string alignment.
[0012] The square according to the invention has a transverse "L" shaped cross-section which
makes it possible to couple the same, with its internal sides perfectly straight,
to a standard brick at the 90° angle between the front and side faces of the brick.
[0013] This square is fitted on the brick so that the internal side of the longer leg terminates
against the front surface of the brick - so as to act as a string guide - while the
internal side of the shorter leg terminates against the side surface of the brick,
so as to act as the string stretching and hooking device of the item, to the brick.
[0014] In this regard it should be noted that the particular characteristic of the item
according to the invention is that no specific fixing method is necessary to secure
it to the end bricks of the wall in that it is the tension of the string between the
two squares that attracts and secures them firmly against the respective sides of
the wall without any risk whatsoever of becoming accidentally unhooked and falling.
[0015] On the other hand, since these squares are not secured to the sides of the wall,
it is extremely easy to unhook them from the same - simply by pulling and lengthening
the string - so that they can slide upwards, and then stretching the string at a higher
level.
[0016] For major clarity the description of the invention continues with reference to the
enclosed drawings, which are intended for illustrative purposes only and not in a
limiting sense, where:
- figure 1 is a front view of a wall on which a pair of opposing squares according
to the invention, have been placed;
- figure 2 is an axonometric representation of the invention with the end of the string
hooked;
- figure 3 is an axonometric illustration of the square ccording to the invention
hooked to a brick.
[0017] With reference to figure 2, the square (1) according to the invention consists of
a prismatic block with an "L" shaped profile having a flat (2) leg which is longer,
projecting from an almost cubic body (3) which is in fact the shorter and thicker
leg of the "L" shaped structure.
[0018] The internal face (2a) of the flat leg (2) has a longitudinal centre groove (2b)
along the inside of the cubic body (3) which consequently has a deep slot (3a) at
the centre the same being is coplanar to the above groove (2b).
[0019] The reference string and guide (F) can be hooked to the square (1) by fitting the
end inside the slot (3a). It is then rotated and taken outside the flat leg (3a) and
wound several times around the same at the internal angle of the square (1) which
has a circular notch (4) for this purpose, which holds and houses the turns of the
string (F).
[0020] It should be noted that the groove (2b) on the internal face (2a) of the flat leg
(2) must be just slightly deeper than the diameter of the string (F) so that the latter
does not touch the external face of the bricks.
[0021] With reference to figure 3, it should be remembered that the notch (4) on the internal
angle of the square (1) must be deep enough to house the turns of the string (F) so
that the latter do not prevent the sharp angle of the brick from fitting into right
angle of the square (1) perfectly.