Building blocks

A shaped hollow building block suitable for lining bank slopes at the ground water level has a face wall in the form of a shield standing perpendicularly to a base wall, includes on both sides a margin projecting relative to side walls and has a height greater than that of the side walls. The side walls and the base wall jointly form an elongate trough in a direction normal to the face wall. The shaped block includes two compartments separated by a transverse wall extending parallel to the face wall in the trough and includes reinforcing walls projecting outwardly from the side walls. A building block for walls which are laid in courses without mortar and can be stabilized by planting, has a face wall, two domed side walls, and a base wall having rounded transition sections to the face wall and to the side walls. The block includes at least two curved dividing walls bounding a central space and two outer spaces between the side walls, with the upper edges of the face wall, of the side walls and of the dividing walls lying at least approximately in one plane.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to building and landscaping materials and, 
more specifically, to blocks for building walls and to shaped hollow 
blocks for lining bank slopes. 
2. Disclosure Statement Under 37 CFR 1.56(a) 
This disclosure statement is made pursuant to the duty of disclosure 
imposed by law and formulated in 37 CFR 1.56(a). No representation is 
hereby made that information thus disclosed in fact constitutes prior art, 
inasmuch as 37 CFR 1.56(a) relies on a materiality concept which depends 
on uncertain and inevitably subjective elements of substantial likelihood 
and reasonableness, and inasmuch as a growing attitude appears to require 
citation of material which might lead to a discovery of pertinent material 
though not necessarily being of itself pertinent. Also, the following 
comments contain conclusions and observations which have only been drawn 
or become apparent after conception of the subject invention or which 
contrast the subject invention or its merits against the background of 
developments subsequent in time or priority. 
Shaped blocks for building dry walls or walls without mortar, for building 
retaining walls or revetment walls and for stabilizing slopes as 
protection against erosion damage or slides are known. Such shaped blocks 
are frequently laid in courses in an open form of construction, so that 
the intervening spaces, resembling the berms in terraced lining, can be 
grassed over. In this direction, a new approach was marked by a bank block 
according to German Patent Publication No. 25 37 408. 
This shaped block is a box-shaped precast concrete block, open towards the 
rear and having a front wall, two side walls and a base. The two side 
walls are extended, by a small amount, to below the base, so that channels 
are formed in the base, on both sides, such that shaped blocks laid in 
courses engage into each other by means of an indentation produced 
thereby. In this way, a type of gravity wall is produced, having the dead 
weight of the blocks and the weight of the earth material, filled into the 
void space, as weight per unit area. 
In the case of the shaped blocks described, disadvantages result from the 
indentation, due, on the one hand, to a high weight of the blocks, of 
about 50 kilograms (kg): this high weight resulting from the dimensions 
between the channels, such dimensions being necessary for convex or 
concave wall curvatures, and, on the other hand, to the requirement for a 
large number of shaped blocks per unit area of wall. Thus, for example, 
eight blocks are required per square meter (m.sup.2) of wall and a 
steepest wall slope of 3:1 and a smallest radius of curvature of 
approximately 2 meters (m) can, respectively, be achieved. 
It has become evident that, for many cases, particularly in the case of 
terracing the ground surrounding detached houses, where slopes of 1 m to 2 
m at the most are to be reinforced, these known shaped blocks were too 
expensive and, moreover, insufficiently versatile for many applications. 
Also, slope blocks of that type cannot be used well for lining bank slopes 
in the region of the ground water level, because they cannot anywhere form 
a closure against the undisturbed earth or against dumped earth or fill. 
Experiments and tests were also carried out with a thickened base, to 
increase the weight, without depressions in the base for forming sealing 
interlocks between side walls and base, and additionally, with a 
transverse wall parallel to the face wall and with external wing-like side 
interlocks on the side walls. Compared to conventional lining using 
naturally broken stone, slope blocks of this type are, of course, 
significantly more expensive; they can, however, be grassed over from the 
water line in a simple manner, whilst below the water line the depressions 
can be filled with large pebbles in order thereby to increase the weight 
of the slope blocks. Experience, however, has shown that all these above 
measures together do not suffice to give the natural appearance to a 
watercourse having curved and straight places, because adequate closure 
against the earth is not ensured when the blocks are laid in courses on 
each other at an angle, and there is accordingly a danger of washout. 
SUMMARY OF THE INVENTION 
It is a general object of this invention to overcome the disadvantages and 
satisfy the needs expressed or implicit in the above disclosure statement 
or in other parts hereof. 
It is a germane object of this invention to provide improved walls and to 
stabilize slopes. 
It is a related object of this invention to provide improved building 
blocks. 
It is also an object of this invention to produce shaped blocks of the type 
described, which are lighter and accordingly cheaper to manufacture and 
with which any shape of wall is rendered possible, from a vertical wall to 
a wall having a minimum slope of approximately 2:1 and having appropriate 
back-filling with earth, and from right-angle corners to an extended wall 
course having any desired wall curvature. 
A related object of this invention is to produce shaped hollow blocks 
capable of satisfying all requirements relevant to the lining of bank 
slopes. 
From a first aspect thereof, the subject invention resides in a shaped 
hollow building block comprising, in combination, a base wall, a face wall 
and side walls. According to the invention, the shaped building block 
includes means for dividing the inside of the building block into distinct 
compartments, one of which is open at the rear of the building block 
opposite said face wall and at the top of the building block opposite said 
base wall, and the other of which is located between said one compartment 
and said face wall and is also open at the top of the building block 
opposite said base wall, with said side walls laterally delimiting both 
said one compartment open at the rear and said other compartment between 
said one compartment and the face wall.

DESCRIPTION OF PREFERRED EMBODIMENTS 
The two embodiments of the shaped hollow block, according to the invention 
shown in FIGS. 1 and 2, each have a face wall 10 and, connecting 
therewith, a base wall 1 and two side walls 12 and 13. The face wall 10 is 
designed, preferably as a plate of semi-circular shape, in the form of a 
shield, which stands perpendicularly to the base wall 11, has on both 
sides a margin 15 projecting relative to the outside surface of the side 
walls 12 and 13, and has a height 20 greater than that of the side walls; 
projecting above the upper edges of the above mentioned side walls 12 and 
13. 
The elongate trough 16, formed jointly by the side walls 12 and 13 and the 
base wall 11 in a direction normal to the face wall 10, is subdivided into 
two approximately equal parts by means of a transverse wall 17 (FIG. 1). 
The shaped block thus includes two compartments separated by the 
transverse wall 17 extending parallel to the face wall 10 in the trough. 
In the region of the transverse wall 17, the side walls carry, on their 
outer surfaces, two reinforcing walls 18 and 19, projecting outwardly from 
the side walls and being preferably moulded-on integrally with the side 
walls. The reinforcing walls 18 and 19 preferably project from the side 
walls or are arranged with a displacement relative to each other, such 
that adjacent reinforcing walls 18 and 19 engage behind each other or 
interlock when several shaped hollow blocks are laid in courses on or are 
positioned adjacent each other. 
Each margin 15 which projects at the face surface 10 preferably is smaller 
than the corresponding lateral extension of the reinforcing walls 18 and 
19. The reinforcing walls 18 and 19, measured outwards of the side walls, 
are larger than the width of the projecting margins 15 of the face wall 
10. 
The projecting margins 15 and the reinforcing walls 18 and 19 have several 
purposes. For instance, if in the case of a slope extending rearwards, the 
shaped hollow blocks are laid with their face walls in lateral contact or 
alignment with each other, chambers are formed, on the one hand, by the 
troughs 16 and, on the other hand, by the side walls 12 and 13 and the 
reinforcing walls 18 and 19 which engage behind each other or interlock; 
applied water being trapped in these chambers and the earth behind the 
shaped hollow blocks being unable to wash out. In the case of concave 
curvatures, the face walls 10 can remain adjacent to each other and the 
reinforcing walls 18 and 19 may in effect be pulled apart until they are 
just touching each other. On the other hand, in the case of convex 
curvature, the face walls 10 can be pulled apart and the reinforcing walls 
18 and 19 remain engaged with each other. 
In addition to the above, the projecting margins 15, together with the 
reinforcing walls 18 and 19, enable the blocks to be laid loosely and thus 
enable the cost of the slope stabilization to be reduced. 
FIGS. 3, 4 and 5 show a type of layering of loosely laid shaped hollow 
blocks, in elevation, plan, and in cross-section, respectively. 
In the embodiment of FIG. 1, the transverse wall 17 is moulded-on 
integrally with the side walls. According to the second illustrative 
embodiment according to FIG. 2, the transverse wall 21 is not formed 
integrally with the side walls and the base wall, but is manufactured as a 
separate part, for the retention of which the side walls 12 and 13 
possess, inside the trough, enlarged portions 22 and 23 on their inner 
sides; such enlarged portions defining each a groove 25 standing normal or 
extending perpendicularly to the base wall 11 for the purpose of retaining 
the separate part or transverse wall 21. The advantage of such an 
embodiment is greater versatility. 
In practice, the hollow blocks advantageously may be completely filled with 
earth above the normal water level, and the blocks can be provided with 
plants, whereby a biological connection with the undisturbed earth is 
forming within a short time and, despite any flood, no earth washouts are 
able to occur, inasmuch as the protection from the scouring water is 
preserved by the margins 15 which project and the greater height 20 of the 
face wall, on the one hand, and by the reinforcing walls 18 and 19, on the 
other hand. 
The embodiments of the invention shown in the drawings, that is, the shaped 
hollow blocks, are also suitable for conventional retaining walls. For 
instance, the long trough part with the reinforcing walls can be employed 
for a gravity wall, especially when the earth is loose or in cases when 
the subsoil is very moist. In this respect, the base wall 11 may have a 
thickness at least equal to that of the side walls. Alternatively and for 
larger gravity and greater rigidity, the base wall 11 may have a thickness 
at least twice as great as that of the side wall. 
A further embodiment of the invention will now be described with the aid of 
FIGS. 6 to 9. 
In the showing of FIG. 6, a shell building block 100 is represented as seen 
from an open back side or rear. The shell building block 100 comprises a 
face wall 110, a base wall 111, two side walls 112 and 113 and at least 
two dividing walls 114 and 115 bounding a central space B and two outer 
spaces A and C between the side walls 112 and 113. The base wall 111 has 
rounded transition sections to the face wall 110 and to the side walls 112 
and 113. Preferably, the face wall 110 and the two side walls 112 and 113 
are domed outwardly in a convex manner, and, in particular, in a manner 
such that they are pulled in above, below and behind, and particularly 
toward the base wall and toward a top opposite the base wall. The face 
wall 110 is also domed in a convex manner, being rounded towards the rear 
at the upper edge and at the lower edge. The transition sections between 
the base wall 111 and the side walls 112 and 113, between the base wall 
111 and the face wall 110, and between the face wall 110 and the side 
walls 112 and 113 are rounded. The side walls 112 and 113 exhibit a 
rounding towards the rear opposite the face wall. Such rounding of the 
side walls at least approximately follows a uniform curved line, which may 
be a piece of a conic section. 
The void space between or within the four walls just described is 
subdivided by the two dividing walls 114 and 115 into the three spaces A, 
B, C. The dividing walls 114 and 115 extend symmetrically with reference 
to a median plane of the face wall; this median plane standing normal to 
the base wall. 
In plan, the dividing walls 114 and 115 are curved, concave to the outside, 
and stand at least approximately normally on the base wall, such that the 
central space B has its greatest dimension in a central region thereof. 
The walls 114 and 115 can be regarded as sections of the curved surface of 
a perpendicular or right cylinder having a conic section as a base line. 
The upper edges of the face wall 110, of the side walls 112 and 113 and of 
the dividing walls 114 and 115 lie at least approximately in a common 
plane. When shell building blocks of this type are being laid in courses, 
this arrangement allows free choice of a gap between adjacent shell 
building blocks, in such a way that the upper building block always rests 
in contact with, in each case, a side wall 112 or 113 and, in the same 
way, with the corresponding dividing wall 114 or 115. 
As FIG. 7 shows, walls can be laid in courses, without mortar, in a closed 
form of construction 120, as shown on the right in FIG. 7, or in an open 
form of construction 121, as shown on the left in FIG. 7. In the case of 
an open laying in courses, the intervening spaces between two adjacent 
shell building blocks can be grassed over or planted in a known manner. 
The vertical laying in courses, shown in FIGS. 8 and 9, which can merge 
into a more gentle slope adapted to the site configuration, and the 
virtually unrestricted variation of the wall curvatures between walls of 
extended form and right-angle form, are new and advantageous features of 
these proposed shell building blocks. 
However, high walls should not be built up with such a shell building 
block, because the static strength is lacking. In the case of a length of 
50 centimeters (cm), a height of 20 cm and a depth of 25 cm, the shell 
building block, made of concrete or normal quality, possesses a weight of 
about 35 kg. However, walls of up to 1.5 m may also be erected with these 
proposed shell building blocks, depending on the bank angle. After some 
time, usually 1 to 2 years, the plant roots have penetrated so far into 
the undisturbed soil of the slope that the wall can usually be regarded as 
a unit belonging to the soil. No special arrangements need be made for the 
slope drainage, because sufficient gaps and cracks are present, both in 
the closed form of construction and in the open form of construction, for 
the slope water to flow off easily, even under heavy rain, without the 
slope being eroded.