SPIRAL STAIRCASE

ESCALIER EN COLIMACON

English Abstract

A spiral staircase comprises a central supporting element (1) and a plurality
of steps (2) which are connected to the
supporting element (1) at a first end (2a), there being two types of steps
(21, 22) positioned in an alternating fashion, of which a
first type of step (21) is substantially "L"-shaped and a second type of step
(22) is substantially arrow-shaped.

French Abstract

L'invention concerne un escalier en colimaçon comportant un élément de support central (1) et une pluralité de marches (2) qui sont raccordées à l'élément de support (1) au niveau d'une première extrémité (2a), deux types de marches (21, 22) étant positionnées d'une manière alternée, un premier type de marche (21) étant sensiblement en forme de « L » et un deuxième type de marche (22) étant sensiblement en forme de flèche.

Claims

Claims
1. A spiral staircase, comprising a central supporting element (1) and a
plurality of steps (2) which are connected to the supporting element (1) at a
first
end (2a), characterised in that it comprises two types of steps (21, 22)
positioned
in an alternating fashion, wherein a first type of step (21) is substantially
"L"-
shaped and a second type of step (22) is substantially arrow-shaped. .
2. The spiral staircase according to claim 1, characterised in that the first
type
of step (21) comprises at least one projection (21a) and one recess (21b)
complementing at least one projection (22a) and one recess (22b) of the second
type of step (22).
3. The spiral staircase according to claim 1, characterised in that it
comprises
a banister (3), connected to a second end (2b) of the steps (2).
4. The spiral staircase according to claim 1 or 3, characterised in that it
comprises spacer elements (4), designed to define the riser of the steps (2).
5. The spiral staircase according to claim 1, characterised in that it
comprises
a landing (5), having an edge (5a) shaped like one of the two types of steps
(21;
22).
6. The spiral staircase according to claim 1, characterised in that the steps
(21, 22) comprise treadable portions (21c, 22c) which are separate from
portions
(21 d, 22d) that are not necessary.

Description

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Description
Spiral staircase
Technical Field
This invention relates to a spiral staircase. The widespread use of spiral
staircases, in particular for internally connecting rooms which are on
different
levels of the same building, is mainly due to the fact that they have quite
small
plan dimensions. Especially in recent decades, this has fully satisfied the
requirements of increasingly small homes.
Background Art
As is known, spiral staircases comprise a vertical central pole, along which
steps are applied, at one free end of the steps. The series of steps describes
a spiral
in space, allowing people to ascend or descend the staircase by moving around
the
pole. The free ends of the steps usually support a banister which facilitates
movements along the staircase, forming a support for users.
Being used above all when there is limited space available, it is also
undeniable that, for people of at least a normal build, the reduced width of
the
steps or, more precisely, the reduced distance between the central pole, which
is
the centre of the staircase, and the free end of the steps makes both
ascending and
descending the staircase rather difficult.
These operations are fir ther complicated by the fact that the distribution of
the steps, combined with their compact dimensions, means that in many cases
the
surface available for supporting the sole of the foot, in particular the foot
on the
inside while descending the staircase, is reduced so much that it does not
guarantee the stability needed during the movements.
It is also important to consider that the distribution of the steps in a
spiral
staircase mainly depends on the staircase plan dimensions and on the riser,
that is

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to say, the height separating two consecutive steps. Two steps which in plan
view
are separated by a round angle (360 ) must be separated in terms of height by
the
space necessary (approximately two metres) to allow a person of average height
to
pass without the risk of striking his head on the higher step. Moreover, since
the
landing covers a large angle, this situation becomes critical close to the
upper end
of the staircase.
Especially when the plan dimensions are compact, comparable to a circle
with a diameter of 130/140 centimetres, or to a square having a side of
similar
length, in the current solutions an equivalent of the riser - tread ratio is
very
different from that which can be obtained with straight ramps and also
noticeably
unfavourable for the inside foot compared with the outside foot.
Disclosure of the Invention
This invention therefore has for an aim to eliminate the above-mentioned
disadvantages.
The invention, with the characteristics described in the claims, achieves this
aim thanks to alternate positioning of two steps having different and
complementary shapes.
The main advantage of this invention is basically the fact that ascending and
descending a spiral staircase is significantly facilitated. In particular, the
surface
available for supporting the inside foot when passing from one step to another
is
increased, guaranteeing users greater stability and balance.
Moreover, the shape of the steps allows the achievement of an equivalent of
the riser - tread ratio which is practically the same for the outside foot and
the
inside foot. In addition, the shape of the landing may allow an increase in
the
number of steps, reducing the riser and achieving an equivalent of the riser -
tread
ratio which is close to that which can be achieved with straight ramps.
Finally, the structure of the invention guarantees the flexibility necessary
for covering any height, thanks to a system for adjusting the height of the
steps,
for adapting to any plan shape (circular, square, etc.) and to the direction
of

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rotation (clockwise.or anti-clockwise), for production using any material
(wood,
iron, aluminium, etc.) or colour.
Brief Description of the Drawings
Further advantages and features of the invention are more apparent in the
detailed description which follows, with reference to the accompanying
drawings,
which illustrate a preferred, non-limiting example embodiment of the
invention, in
which:
Figure 1 is a side view of the invention;
Figure 2 is a plan view of a first embodiment of the steps;
Figure 3 is a plan view of a pair of consecutive steps;
Figure 4 is a plan view of a second embodiment of the steps;
Figure 5 is a plan view of two embodiments of the landing.
Detailed Description of the Preferred Embodiments of the Invention
In accordance with the accompanying drawings, the invention relates to a
spiral staircase. It comprises a central supporting element (1) and a
plurality of
steps (2), which are connected to the supporting element (1) at a first end
(2a). In
particular, as shown in Figures 2 and 4, it comprises two types of steps (21,
22),
where a first type of step (21) is substantially "L"-shaped and a second type
of step
(22) is substantially arrow-shaped. They are positioned along the staircase
(10) in
an alternating fashion, as shown in the detail in Figure 3.
The first type of step (21) comprises at least one projection (21a) and one
recess (21b) which complement at least one projection (22a) and one recess
(22b)
of the second type of step (22). The projections (21a, 22a) and recesses (21b,
22b)
contribute to forming on the steps (21, 22) treadable portions (21 c, 22c)
which are
separate from portions (21d, 22d) that are not strictly necessary for
achieving the
advantages which the invention proposes. In this way, the "L"-shaped step (21)
provides support only for the outside foot, whilst the arrow-shaped step (22)
provides support only for the inside foot, both when a person is ascending and

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descending the staircase (10).
The staircase (10) also comprises a landing (5), having an edge (5a) shaped
like one of the two types of steps (21; 22). Obviously, depending on the shape
of
the edge (5a), anyone using the staircase (10) must begin stepping on it
starting
with the outside foot if the edge (5a) of the landing (5) is shaped like the
arrow-
shaped step (22), or with the inside foot if the edge (5a) of the landing (5)
is
shaped like the "L"-shaped step (21). In the latter case, it is possible to
increase
the number of steps (2), reducing the riser.
For a complete overview, Figure 1 also shows a banister (3), needed for
safety reasons, connected to a second end (2b) of the steps (2), and spacer
elements (4), designed to define the riser of the steps (2).
The invention described above may be modified and adapted in several ways
without thereby departing from the scope of the inventive concept. Moreover,
all
details of the invention may be substituted by technically equivalent
elements.
Obviously, in practice modifications and/or improvements are possible
which are covered by the following claims.

Representative Drawing