U.S. patent application number 10/380984 was filed with the patent office on 2004-04-22 for step stone for a stairway and a stairway assembled therefrom.
Invention is credited to Drost, Andreas.
Application Number | 20040074167 10/380984 |
Document ID | / |
Family ID | 7946980 |
Filed Date | 2004-04-22 |
United States Patent
Application |
20040074167 |
Kind Code |
A1 |
Drost, Andreas |
April 22, 2004 |
Step stone for a stairway and a stairway assembled therefrom
Abstract
The invention relates to a step stone for a stairway comprising
an upper essentially horizontal stepping surface, a front
essentially vertical setting surface, a rear back surface, which is
located opposite the setting surface and which, with the stepping
surface, forms an upper rear edge, and comprising an underside. A
supporting section with a recess is provided in the front area of
the underside of the step stone, whereby said recess enables the
step stone to be supported on a step stone located directly
underneath in order to form a stairway. To this end, the supporting
section has a number of stepped recesses, which are offset with
respect to one another and with which the step stone can be placed
as desired onto the rear edge of the step stone located directly
underneath.
Inventors: |
Drost, Andreas; (Karlsruhe,
DE) |
Correspondence
Address: |
Lichti Lempert & Lasch
Bergwaldstr 1
Karlsruhe
D-76227
DE
|
Family ID: |
7946980 |
Appl. No.: |
10/380984 |
Filed: |
March 20, 2003 |
PCT Filed: |
September 13, 2001 |
PCT NO: |
PCT/EP01/10547 |
Current U.S.
Class: |
52/189 ;
52/608 |
Current CPC
Class: |
E04F 11/116 20130101;
E04F 11/02 20130101 |
Class at
Publication: |
052/189 ;
052/608 |
International
Class: |
E04F 011/00; E04F
019/10; E04C 002/04; E04B 005/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 2000 |
DE |
200 16 658.1 |
Claims
1. Step stone for a stairway comprising an upper substantially
horizontal stepping surface (11), a front substantially vertical
setting surface (12), a rear back surface (13) opposite to the
setting surface (12) which, together with the stepping surface
(11), forms an upper rear edge (18) and with an underside (14),
wherein a supporting section (15) is formed in the front region of
the underside (14) of the step stone (10), the supporting section
(15) having several stepped mutually displaced recesses (16) with
which the step stone (10) can optionally be disposed onto the rear
edge (18) of an underlying step stone to construct a stair way,
wherein the base point lines (16e) of the cross-sections of the
recesses (16) are disposed in a plane (A) which extends at an angle
.beta. with respect to the horizontal stepping surface (11) and
which slopes upwardly towards the front setting surface (12) of the
step stone (10), characterized in that the angle .beta. is in a
range between 25.degree. and 30.degree., wherein a further
supporting section (20) is formed in the rear region of the
underside (14) of the step stone (10) which has several stepped
recesses (21) whose base point lines (21a) are in one plane (B)
extending at an angle .beta. with respect to the horizontal
stepping surface (11) and rising towards the rear back surface (13)
of the step stone (10).
2. Step stone according to claim 1, characterized in that the angle
.beta. is between 25.degree. and 28.degree..
3. Step stone according to claim 1 or 2, characterized in that the
opening cross-sections of the recesses (16) are disposed in a plane
(X) extending at an angle .alpha. with respect to the horizontal
stepping surface (11) and sloping upwardly towards the front
setting surface (12) of the step stone (10).
4. Step stone according to claim 3, characterized in that the angle
.alpha. is between 25.degree. and 28.degree..
5. Step stone according to any one of the claims 1 through 4,
characterized in that the rear edge (18) of the step stone (10) has
a cross-section which is complementary to the cross-section of each
recess (16).
6. Step stone according to any one of the claims 1 through 5,
characterized in that each recess (16) is defined by an upper
covering surface (16a) and a rear stop surface (16b).
7. Step stone according to claim 6, characterized in that the rear
edge (18) has a rectangular cross-section and the covering surface
(16a) of each recess (16) extends substantially horizontally with
the stop surface (16b) extending substantially vertically.
8. Step stone according to claim 6 or 7, characterized in that the
length l of the covering surface (16a) is substantially twice as
large as the height h of the stop surface (16b).
9. Step stone according to any one of the claims 6 through 8,
characterized in that a depression (17) is formed at the rear end
of the stepping surface (11) into which a nose (19) formed on the
covering surface of each recess (16) can be inserted.
10. Step stone according to claim 9, characterized in that the
depression (17) and the nose (19) have complementary
cross-sections.
11. Step stone according to claim 9 or 10, characterized in that
the depression (17) and the nose (19) have inclined sliding
surfaces (16d, 17a) and associated support surfaces (16c, 17b).
12. Step stone according to any one of the claims 1 through 11,
characterized in that it is a prefabricated concrete part.
13. Step stone according to any one of the claims 1 through 12,
characterized in that it has a constant cross-section throughout
its entire width.
14. Step stone according to any one of the claims 1 through 13,
characterized in that the side walls (22, 23) connecting the front
setting surface (12) and the rear back surface (13) do not extend
parallel to each other.
15. Step stone according to claim 14, characterized in that its
width is continuously reduced from the front setting surface (12)
to the rear back surface (13).
16. Step stone according to any one of the claims 1 through 15,
characterized in that its side walls bear projecting engagement
elements for engagement into recesses of a neighboring step
stone.
17. Stairway of step stones according to any one of the claims 1
through 16, wherein an upper step stone is supported with one of
the recesses (16) of its supporting section (15) on an underlying
step stone and several step stones are disposed next to one another
to form one step, characterized in that the step stones taper
conically from the front setting surface (12) towards the rear back
surface (13) and are disposed next to each other with a same
conical orientation to form a curved step.
18. Stairway of step stones according to any one of the claims 1
through 16, wherein an upper step stone is supported with one of
the recesses (16) of its supporting section (15) on an underlying
step stone and several step stones are disposed next to one another
to form one step, characterized in that the step stones taper
conically from the front setting surface (12) towards the rear back
surface (13) and are disposed next to each other with alternating
conical orientation to form a straight step.
19. Stairway according to claim 17 or 18, characterized in that the
step stones which are disposed next to each other are mutually
engaged via laterally projecting engagement elements.
Description
[0001] The invention concerns a step stone for a stairway
comprising an upper substantially horizontal stepping surface, a
front substantially vertical setting surface, a rear back surface
which is located opposite the setting surface and which, with the
stepping surface, forms an upper rear edge, and comprising an
underside, wherein a supporting section with a recess is provided
in the front area of the underside of the step stone, the recess
enabling the step stone to be supported on a step stone located
directly underneath in order to form a stairway. The invention also
concerns a stairway formed from such step stones.
[0002] A stairway or steps for securing a slope, which are included
in the term "stairway" below, has/have been conventionally produced
for a long time from superposed step stones or blocks. Each step
stone normally has the shape of an elongated cuboid and is made
from rock, concrete or wood and is supported with the front end of
its underside on the rear end of the upper side of the underlying
step stone. The remaining surface of the upper side of the
underlying step stone which is not covered by the upper step stone
forms the upper substantially horizontal stepping surface of this
step. The size of the stepping surface can be adjusted within
certain limits through displacement of the upwardly disposed step
stone. The front, substantially vertical setting surface and hence
the height of the step is fixed and determined by the height of the
cuboid such that different step stones must be used for stairways
of different step heights.
[0003] To ensure that the stairway is comfortable for use by a
person, the stepping size should be approximately 64 cm which
results from the sum of two times the step height plus the length
of the stepping surface. To fulfil this condition, the stepping
surface must have a certain predetermined length, since the step
height is defined by the height of the step stone. A stairway
having a predetermined slope therefore requires a certain cuboid
step stone wherein subsequent adjustment of the stairway course and
stairway slope are not possible. To be able to form different
stairway shapes, a plurality of different step stones must be
produced and stored which is demanding and expensive.
[0004] DD 145 298 discloses forming of a corbel on the underside of
a step stone and fashioning a shoulder in the form of a recess in
the front region of the underside. In this fashion, the user can
dispose the step stone onto an underlying step stone either with
the recess or the integral corbel to realize stairways with two
different stairway slopes. The step stone in accordance with DD 145
298 permits more variable use than the earlier conventional cuboid
step stone but it is suited only for two different stairway slopes.
This does provide sufficient coverage for the number of desired
stairway slopes required in practice such that the user still has
to work with step stones of different sizes.
[0005] DE 296 09 531 discloses a similar step stone. To further
increase the range of applications of the step stone, this
publication proposes forming, in addition to a recess in the front
lower supporting section of the step stone, a further recess on the
upper rear edge which is fashioned between the stepping surface and
the rear surface of the step stone. In this fashion, three
different stairway slopes can be obtained through cooperation of
the recesses of superposed step stones. It is relatively difficult
for a user to determine optimum abutment of the step stones for a
desired stairway slope. Moreover, the upper end of the stairway
still has a recess which is visible on the stepping surface of the
upper step and must be filled by placement of a last stone. The
height of that last stone must be precisely adjusted to the depth
of the recess to prevent undesirable unevenness. The requirement
for such a special last stone is tedious and impractical.
[0006] It is the underlying purpose of the invention to produce a
step stone of the above-mentioned type which can create several
different stairway slopes in a simple fashion. Moreover, a stairway
shall be produced from corresponding step stones which can be
easily adjusted to the existing conditions at the location of
use.
[0007] This object is achieved for a step stone in accordance with
the invention in that the front lower supporting section has
several stepped recesses with which the step stone can be
optionally disposed onto the rear edge of the underlying step
stone.
[0008] The front supporting section of an upper step stone is
supported on the rear edge of the underlying step stone such that
the rear edge engages in one of the recesses of the supporting
section. Through selection of that recess which is disposed onto
the rear edge of the underlying step stone, the user can easily
vary the orientation of superposed step stones relative to each
other. When the recess, which engages in the rear edge of the
underlying step stone, is changed, not only the size of the
stepping surface of the underlying step stone changes but also the
step height is simultaneously changed due to the stepped
arrangement of the recesses. The recesses define predetermined
relative positions of the sequential step stones wherein mutual
engagement of the rear edge of the underlying step stone with one
of the recesses of the step stone disposed thereabove provides high
positioning accuracy and guards against inadvertent displacement of
the step stones.
[0009] The opening cross-sections of the recesses are preferably
disposed in a plane which is upwardly inclined in the direction
towards the front setting surface of the step stone and extends at
an angle .alpha. with respect to the horizontal stepping surface.
The base point lines of the recess cross-sections, i.e. those
points with the largest separation from the opening cross-sections
of the recesses, can be disposed in a common plane which extends at
an angle .beta. with respect to the horizontal stepping surface and
which is upwardly inclined in the direction towards the front
setting surface of the step stone. If the stepping surface of the
underlying step stone is reduced in size through engagement in the
rear edge of the underlying step stone of a recess of the step
stone directly above which is disposed further inside the step
height is simultaneously increased.
[0010] The angle .alpha. and in particular the angle .beta. are
preferably in a range between 20.degree. and 40.degree. and
preferably in a range between 25.degree. and 30.degree.. In this
fashion, the above-mentioned requirements with respect to the
stepping size can be at least approximately maintained. To exactly
meet the mentioned condition, the following must be fulfilled:
tan .beta.=0.5, i.e. .beta.=26.565.degree..
[0011] Taking into consideration the usual tolerances for stairways
built at a building site, one can assume sufficient fulfilment of
the requirement if the angle .beta. is between 25.degree. and
28.degree.. The same is true for the angle .alpha..
[0012] To ensure good engagement between the rear edge and the
recess, the rear edge of the step stone should have a cross-section
which is complementary to the cross-section of each recess such
that the rear edge completely fills the recess when it engages
therein.
[0013] In a possible embodiment of the invention, each recess is
defined by an upper covering surface and a rear stop surface, i.e.
has a triangular cross-section. The intersecting edge between the
upper covering surface and the rear stop surface thereby forms a
base point line i.e. a line in which the base points of the
individual cross-sections of the recesses are located. If the rear
edge has a rectangular cross-section (i.e. the stepping surface
merges into the rear surface of the step stone at right angles),
the covering surface of each recess should extend substantially
horizontally and the stop surface substantially vertically. To
ensure the above-mentioned step dimensions in any position of an
upper step stone relative to a lower step stone, i.e. independent
of which recess of the upper step stone is disposed onto the rear
edge of the underlying step stone, the length l of the covering
surface, i.e. its extension in the longitudinal direction of the
stairway should preferably be approximately and in particular
exactly twice the size of the height of the stop surface.
[0014] A further development of the invention may provide that a
depression is formed at the rear end of the stepping surface into
which a nose can be inserted which is formed on the covering
surface of each recess. Corresponding engagement of the nose of the
recess into the depression prevents inadvertent release of the
upper step stone from engagement with the underlying step stone
since it must initially be slightly lifted so that the nose comes
out of engagement with the depression.
[0015] The depression and the nose preferably have complementary
cross-sections such that the nose completely fills the depression
to stabilize the position of the step stones.
[0016] In a preferred embodiment of the invention the depression
and the nose each have inclined sliding surfaces and associated
stop surfaces such that an upper step stone automatically slides,
due to gravity, along the superposed sliding surfaces up to mutual
abutment of the abutment surfaces at a predetermined desired
position when its nose is inserted into the depression of the
underlying step stone.
[0017] In a further development of the invention a further
supporting section is formed in the rear region of the underside of
the step stone which has several stepped recesses with the
above-mentioned design whose base lines are in one plane which
extends at an angle .beta. with respect to the horizontal stepping
surface. The opening cross-sections of the recesses can also lie in
one plane which extends at an angle .alpha. with respect to the
horizontal stepping surface. In this fashion, the step stone can be
disposed onto an underlying step stone in two different
orientations, rotated through 180.degree. about a vertical axis.
When the step stone is turned, its rear surface is used as the
front setting surface to produce different structural possibilities
for the stairway for different setting surface and rear surface
designs.
[0018] The step stone is preferably made from concrete and is
formed as a prefabricated concrete part. In particular, it has a
constant cross-section across its entire width, i.e. transverse to
the longitudinal direction of the stairway.
[0019] To obtain a stairway of uniform width, the step stone may
have a constant width in its longitudinal direction, i.e. in the
longitudinal direction of the stairway such that the width of the
front setting surface is identical with the width of the rear back
surface. Alternatively, the side walls of the step stone connecting
the front setting surface with the rear back surface may not extend
parallel to each other such that the width of the step stone varies
in its longitudinal direction. In particular, the width of the step
stone may be continuously reduced starting from the front setting
surface towards the rear back surface thereby providing the step
stone with a conicity which permits formation of straight and also
of curved stairway steps.
[0020] To form a stairway from the above-mentioned step stones, an
upper step stone is supported with one of the recesses of its
supporting section on the rear edge of an underlying step stone as
has already been described. One step stone may thereby form one
step. However, it is also possible to provide several step stones
next to each other to form a step. The step stones preferably have
engagement elements protruding from their side walls with which
they can be brought into engagement with recesses of a neighboring
step stone. If the step stones are conically tapered starting from
the front setting surface towards the rear back surface and are
disposed next to each other with the same conical orientation, the
step is angled in the transverse direction of the stairway such
that, when several step stones are disposed next to each other, a
polygonally curved stairway step is obtained.
[0021] Alternatively, the above-mentioned conical step stones may
form a step which is straight in the transverse direction of the
stairway through disposing neighboring step stones in alternating
conical orientation.
[0022] Further details and features of the invention can be
extracted from the following description of embodiments with
reference to the enclosed drawing.
[0023] FIG. 1 shows a cross-section of a step stone in accordance
with a first embodiment;
[0024] FIG. 2 shows a perspective view of a stairway formed from
step stones of FIG. 1;
[0025] FIG. 3 shows a side view of the stairway in accordance with
FIG. 2;
[0026] FIG. 4 shows a stairway of FIG. 3 with reduced slope;
[0027] FIG. 5 shows a stairway of FIG. 3 with increased slope;
[0028] FIG. 6 shows a cross-section of a step stone in accordance
with a second embodiment;
[0029] FIG. 7 shows a cross-section of a step stone in accordance
with a third embodiment;
[0030] FIG. 8 shows a bottom view VIII of the step stone of FIG.
7;
[0031] FIG. 9 shows a top view of a polygonally curved stairway
step formed from several step stones in accordance with FIGS. 7 and
8;
[0032] FIG. 10 shows a perspective view of a stairway formed from
correspondingly curved stairway steps; and
[0033] FIG. 11 shows a top view of a straight stairway step formed
from several step stones in accordance with FIG. 7.
[0034] FIG. 1 shows the cross-section of a step stone 10 which
comprises an upper substantially horizontal stepping surface 11 and
a front substantially vertical setting surface 12 which joins at a
right angle. The stepping surface 11 forms a rectangular upper rear
edge 18 together with a rear substantially vertical back surface
13, which is opposite to the setting surface 12.
[0035] An underside 14 of the step stone 10 also extends
substantially horizontally and merges in its front region into the
front setting surface 12 via a supporting section 15 which extends
from the underside 14 with an upward inclination towards the
setting surface 12.
[0036] Three recesses 16, which are disposed in steps one behind
the other, are formed in the supporting section 15 and are mutually
offset both in the longitudinal direction of the step stone (from
the setting surface 12 towards the rear surface 13) as well as in
the vertical direction of the step stone (from the underside 14
towards the stepping surface 11). Each recess 16 is defined by a
horizontal covering surface 16a which extends parallel to the
stepping surface 11 and a substantially vertical stop surface 16b
which joins the rear end of the covering surface 16a. The
intersecting edge between the covering surface 16a and the stop
surface 16b defines a base point line 16e for the respective recess
16. The base point lines 16e of all recesses 16 extend
perpendicular to the plane of the drawing and are in a common plane
A which extends at an angle .beta. of approximately 26.5.degree.
with respect to the horizontal and which is upwardly inclined
towards the front setting surface 12 of the step stone 10. The
length l of the covering surface 16a, i.e. its extension in the
longitudinal direction of the stairway, is twice the size of the
height h of the stop surface 16b.
[0037] An opening cross-section of each recess 16 extends from the
front edge of the covering surface 16a, which faces the setting
surface 12, to the lower edge of the stop surface 16b facing the
underside 14. The recesses 16 are disposed such that their opening
cross-sections are in a common plane X which extends parallel to
the plane A and is therefore also inclined at an angle .alpha. of
approximately 26.5.degree. with respect to the horizontal and
slants upwardly towards the front setting surface 12 of the step
stone.
[0038] To build a stairway 22 as shown in FIG. 2, several step
stones are disposed one on top of the other, wherein one recess 16
of each step stone 10 is disposed onto the rear edge 18 of the
respectively underlying step stone and is brought into engagement
therewith. In accordance with FIG. 2, the respective central
recesses 16 are disposed onto the rear edge 18 of the underlying
step stone. Selection of another recess produces a change of the
stairway slope as shown in FIGS. 3 through 5.
[0039] FIG. 3 shows a side view of the stairway 22 in accordance
with FIG. 2. The central recess 16 is thereby disposed onto the
rear edge 18 of the underlying step stone. To form a stairway with
a smaller slope (FIG. 4) the front recess 16 can engage with the
rear edge 18 of the respectively underlying step stone. In this
fashion, each respective upper step stone is set back relative to
the underlying step stone thereby enlarging the stepping surface 11
of the underlying step stone. At the same time, the step height of
the upper step stone is reduced through the offset in height of the
recesses 16 due to the angle .beta. of the plane A and the angle
.alpha. of the plane X such that, in total, the above-mentioned
condition with regard to the stepping size is maintained.
[0040] Alternatively, the slope of the stairway can be increased by
disposing the respectively upper step stone onto the rear edge of
the underlying step stone (FIG. 5) at a further inwardly located
recess 16. In this case, the length of the stepping surface is
reduced and the respectively upper step stones are simultaneously
lifted relative to the respectively underlying step stone such that
the step height is increased with the condition for the stepping
size also being maintained in this case.
[0041] The step stone shown in FIGS. 1 through 5 has three
recesses. More recesses, in particular four or five, may be
provided to increase the range of applications of the step stone.
At least three recesses should preferably be present.
[0042] FIG. 6 shows a cross-section of a step stone 10 in
accordance with a second embodiment which only differs from the
cross-section of FIG. 1 in that the rear end of the stepping
surface 11 has a depression 17 which is defined by a sliding
surface 17a extending at a downward angle from the rear edge 18 and
a support surface 17b adjacent to the front end of the sliding
surface 17a and being upwardly inclined. One nose 19 is formed on
each of the covering surfaces of the recesses 16, the nose 19
having a complementary cross-section which comprises a downwardly
inclined support surface 16c extending from the front setting
surface 12, which is parallel to the support surface 17b of the
depression 17, and an adjacent upwardly inclined sliding surface
16d which extends parallel to the sliding surface 17a of the
depression 17.
[0043] When one of the recesses 16 of the step stone is disposed on
the rear edge 18 of an underlying step stone, the nose 19 engages
completely into the depression 17 of the underlying step stone
thereby obtaining exact orientation of the step stones, disposed
one on top of the other. If the nose of the upper step stone is not
completely inserted into the depression of the underlying step
stone, the inclined sliding surfaces 17a and 16d guarantee that the
upper step stone slides with its nose 19 into the depression 17,
due to its intrinsic weight, until the support surfaces 17b and 16c
abut at the desired position.
[0044] FIG. 7 shows a further development of the cross-section of
FIG. 1. Three recesses 16 are provided in the front supporting
section 15 as described in connection with FIG. 1. The rear region
of the underside 14 of the step stone is also provided with a
further supporting section 20 which also has three stepped recesses
21 which are designed to correspond to the recesses 16 such that
the front and rear recesses are pairwise disposed at the same
level. The base lines 21a of the recesses 21 are in a common plane
B which extends at an angle .beta. with respect to the horizontal
stepping surface 11 and rises in the direction towards the rear
surface 13 of the step stone 10. The opening cross-sections of the
recesses 21 are in a common plane Y which extends at an angle
.alpha. with respect to the horizontal stepping surface 11 and
rises from the underside 14 towards the rear surface 13 of the step
stone. The design of the step stone with two supporting sections
disposed on different sides, each with several stepped recesses
permits use of the step stone 10 in different orientations, rotated
through 180.degree. about a vertical axis. The step stone 10 shown
in FIG. 7 may be disposed with a recess 16 of the front supporting
section 15 on the rear edge of the underlying step stone, wherein
the front setting surface 12 determines the height and design of
the step. Alternatively, the step stone can be disposed with one of
the recesses 21 of the rear supporting section 20 onto the rear
edge of the underlying step stone wherein the rear surface 13 of
the step stone becomes the setting surface and determines the
design and height of the step. This use of the step stone in
different orientations is particularly advantageous when the step
stone does not have a constant width i.e. in the direction
perpendicular to the plane of the drawing.
[0045] FIG. 8 shows a step stone 10 which is wider in the region of
its setting surface 12 than in the region of its rear back surface
13 wherein the width is continuously reduced from the front setting
surface 12 to the rear back surface 13 such that two side walls 22
and 23 of the step stone do not extend parallel to each other and
the step stone is strongly conically tapered in width towards its
rear end. In the embodiment shown, the step stone has an
equilateral trapezoidal outline but could also have a
non-equilateral trapezoidal profile.
[0046] One individual step can be formed from one single step
stone. It is also possible to dispose several step stones next to
each other for forming a step. If the step stones disposed next to
each other conically taper towards their rear end as mentioned
above, and are disposed next to each other with the same conical
orientation (FIG. 9), the front wider setting surfaces 12 border
and produce a polygonal curved convex shape for the front side of
the step. FIG. 10 shows a perspective view of a stairway formed
with corresponding steps.
[0047] The same conical step stones also permit formation of a step
which is straight in the transverse direction when neighboring step
stones 10 are disposed in an orientation rotated through
180.degree. (with alternating conical orientation). The front
surface of a corresponding step is formed alternately by the
setting surface 12 of a step stone and the adjacent rear surface 13
of the neighboring step stone.
* * * * *