Note: Descriptions are shown in the official language in which they were submitted.
1~33301
SU~MARY OF THE I~VENTION
The present invention is directed to a paving unit and
the method of producing the unit which is made up oF a number
of individual paving blocks or stones formed of concrete or
other materials which have a setting characteristic similar to
concrete. In the unit, the paving blocks are arranged ready to
be placed on a base surface. After placement, the blocks can be
separated along their connecting surfaces.
There are many known concrete paving blocks having
various sizes and shapes. Such blocks are suitable for paving
wearing surfaces of all types, particularly vehicle roadways.
In roads used by motor vehicles, forces are effective in the
plane of the pavement especially during vehicle acceleration
and braking, but also when a vehicle is being driven around a
curve. To prevent a displacement ol the paving blocks forming
the paving surface due to such horizontal forces, the lateral
or side surfaces of the paving blocks are provided with a toothed
or denticulated arrangment so that the blocks intermesh and can-
not shift relative to one another. Accordingly, the individual
paving blocks are interconnected and form a continuous paving
surface.
When such paving blocks are used for a large pavement
surface it is disadvantageous if each block has to be placed
individually. Therefore, it has been known to connect individual
paving blocks together by means of connecting bars or webs to
form a unit of about 1 m2 in dimension. A unit of this type can
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be laid quickly and without any difficulty using a hydraulically
operated placing unit such as shown in West German Offenlegungs-
schrift 24 01 303. The connecting bars or webs form preset
breakingpoints which rupture when a vibrating device is applied
to the pavement. Unfortunately,the breaking points do not always
rupture as desired and sometimes not at the desired location.
The connecting bars are formed during the production of
the paving blocks by recesses or cutouts provided in
partitions in the formwork used for the blocks. The partitions
separate the individual blocks from one another within the form-
work. These partitions are 4 to 6 mm thick and determine the
width of the joints between the individual paving blocks within
the unit. Since the joints are relatively wide, the pavement
has an open or loosely placed appearance. Such an arxangement,
however, tends to limit the interconnection of the individual
paving blocks and restricts the effectiveness of such a composite
unit. When such an arrangement of paving blocks is used in a
heavily trafficked surface there is the danger that the
horizontal forces cannot be absorbed and the blocks shift.
Conseguently, the blocks become loose and filling the joints
between the blocks with sand does not prevent such displacement.
Loosened and displaced blocks result in expensive repairs.
When a paving unit formed of a number of paving blocks
connected together by bars is fabricated, often defective blocks
are formed and must be removed from the unit and replaced. Such
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replacement is difficult in a paving unit and it is even more
difficult if the unit is already in place in the pavement
surface, particularly if the individual paving blocks have not
separated along the preset breaking points.
The primary object of the present invention is to
provide a paving unit of the type described above having preset
separating surfaces and which permi~s fast laying of the paving
units. At the same time, however, the individual paving blocks
of the unit can be easily replaced if damaged. In addition, the
present invention encompasses the process for producing such
paving units.
In accordance with the present invention, the individual
paving blocks are arranged close to one another and are connected
together either by pressing the blocks against one another
before their material has completely set and/or by adhering the
blocks together using an adhesive material. The strength of the
connection between the individual paving blocks is sufficient
so that the paving unit can be handled and laid in place on a
base surface without affecting the integrity of the unit. In
addition, however, the strength of the connection between the
individual blocks must be less than the strength of the material
forming the blocks so that the unitbreaks apart into the
individual blocks when a vibrating device is applied without
causing any damage to the blocks.
~333~i
Further, the present invention includes the process of
producing such paving units including pressing the individual
blocks together after they have been molded and removed from
their forms. The individual paving blocks are pressed together
so that they become connected together along their lateral
surfaces. The connection of the blocks can be effected by the
material forming the blocks if it is not already set and/or by
applying an adhesive material between the lateral surfaces for
connecting them together. The connection between the bloc~s
has sufficient strength so that the unit can be handled while
maintaining its integrity, however, the strength of the
connections between the blocks must be less than that of the
material forming the blocks so that the blocks separate along
the connections when a vibrating effect`is applied without
causing any damage to the blocks.
It is appropriate to produce the individual paving
~ocks in a forming machine, however, the machine is not the
subject of this invention. The individual blocks are produced
in an arrangement suitable for forming the paving unit. The
forming machine includes a baseboard and a molding or forming
box which moves down onto the baseboard. The molding box
provides the forms for the individual blocks and the forms are
filled with concrete. After the concrete has been compacted,
the molding ~ox is lifted off and the baseboard with the
formed blocks is removed from the forming machine. The bloc~s
are checked and any faulty ones are removed and replaced with
other blocks in approximately the same stage of setting.
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In the next production step, the individual blocks are
connected to form a paving unit. The just formed blocks, whose
concrete has not yet completely set, are transported on the base-
board to a hydraulic pressure device in which the blocks are
pressed together from all sides with a measured pressure. Accord-
ingly, the bonding strength of the setting concrete connects the
blocks into a planar or plate-shaped paving unit which can be
easily handled during storage, transport and placement. The
degree to which the concrete can be allowed to set before the
blocks are pressed together, the amount of pressure applied,
and the curing period after pressing for achieving the final
set all depend on the type and quality of the cement used in
the concrete and on the shape of the blocks.
If the bond afforded by the concrete is not sufficient,
an adhesive may also be placed into the space between the lateral
surfaces o~ the blocks. Further, it is possible to join the
blocks together using only an adhesive. Accordingly, the blocks
after they have reach their final set can still be combined into
a paving unit. Moreover, the blocks can be connected to a base
mat or mesh member during connection or after they have been
joined together.
. .
After the paving blocks have been assembled together as
a paving unit, the unit is subsequently processed, for instance
in a known manner in a steam chamber, then dried and placed in
storage.
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Depending on the size of the base board used in the
forming machine, paving uni~s having dimensions of 60 x 60 cm,
60 x 90 cm, or 90 x 120 cm can be produced.
At the construction site, the paving units are unloaded
in the immediate vicinity in which they are to be set in place.
With a device, such a placing fork, one paving unit at a time can
be grasped at ~wo points located on opposite sides and then
placed individually on a base surface. To afford a proper grip
for the placing fork, two or more blocks can be left out along
one side of each paving unit. These missing blocks can then be
inserted after the unit has been set in place.
Subse~uently, using a vibrating device, vibration can
be applied to the units already set in place. Due to the
vibration effect, the paving unit separates along the connection
surfaces, since the strength along the connection surfaces is
less than that of the individual paving blocks. Accordingly,
damage to the paving blocks can be avoided. After the vibration
effect, the paving blocks are separate from one another and
located closely together on a sand layer. A portion of the
lateral surfaces of the paving blocks along which the connection
is effected are in contact while other portions are disposed in
diverging relationship. The diverging or tapering surfaces
along the side or lateral surfaces of the blocks are formed when
the blocks are produced in the forming machine. The sand
layer forming the base surface rises upwardly into the diverging
surfaces of the ~locks so that the adjacent blocks form a
downwardly facing wedge-shaped cavity. Due to this setting
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operation, after the vibrating effect, the individual blocks sit
firmly in the sand layer forming the base surface.
In addition, the blocks may also have tapering lateral
surfaces extending downwardly from the top surface toward the
contacting portions of the lateral surfaces. These tapering or
chamfered upper edges of the blocks ensure that during vibrating
and separation of the paving unit no visible edges of the blocks
are damaged.
The paving unït embodying the present invention permits,
compared to a manual placement or setting operation of 150 to
200 m2 requiring five men working nine hours, a two to three
fold production increase using only two men. The other workers
prepare the base surface and make the joints. The joints are
completed with loose stones to the required width, or the units
are separated with a chisel to the required dimensions. The
joints are filled with sand and washed somewhat. The pavement
can then be driven on immediately.
The paving unit and the manner in which it is produced
is not limited to certain shapes of paving blocks. In principle,
all shapes of blocks can be used. The arrangement of the blocks
in the finished paving surface is very favorable, because the
blocks lie closely together without any open joints between them.
Even when heavy vehicles turn on such a surface, the horizontal
~forces are safely absorbed and the blocks are not displaced from
their original arrangement.
~33301
The various features of novelty which characterize the
invention are pointed out with particularity in the claims
annexed to and forming a part of this disclosure. For a better
understanding of the invention, its operating advantages and
specific objects attained by its use, reference should be had
to the accompanying drawings and descriptive matter in which
there are illustrated and described preferred embodiments of the
invention.
BRIEF DESCRIPTION OF THE DRAWING
.
In the drawing:
Fig. 1 is a plan view of a paving unit made up of
H-shaped concrete paving blocks;
Fig. 2 is an enlarged cross-sectional view taken along
line II-II in Fig. l;
- Fig. 3 is a plan-view of another paving unit formed of
H-shaped, concrete paving blocks with the opposite end lateral
surfaces of the blocks disposed at an oblique angle to the
othe~ lateral surfaces of the blocks;
Fig. 4 is a plan view of a paving unit of concrete
paving blocks in which each individual block consists of three
hexagonal elements; and
Fig. 5 is an enlarged cross-sectional view taken along
the line V-V in Fig. 4.
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DETAIL DESC~IPTION OF THE INVENTION
.
In Fig. 1 a paving unit l is illustrated eonsisting
of 21 individual concrete paving blocks 2. The invention does
not rely on the number or shape of the individual bloeks 2 to
guarantee a composite aetion in the transverse direction of
the unit. As illustrated, the individual bloeks 2 have an
H-shape, however, this shape of paving block is known and has
been selected only to describe a paving unit. As viewed in
Fig. l the top surface of the individual blocks forms the upper
surface while the lower surface rests on a base surfaee when
the unit is set in plaee. The lateral or side surfaees of the
bloeks are joined by eement and/or an adhesive material. It is
possible to support the bloeks on a lattieed plastie mat, not
shown, which adheres to the bottom surfaces of the bloeks. The
blocks 2 are intereonneeted together using a hydraulie pressure
device, not shown, whieh aets on the four outer peripheral sides
of the paving unit.
As shown in Fig. l, the bloeks are arranged in five rows
within the paving unit l. The upper row has two blocks missing.
As a result, two gaps 3 are formed in the upper row into which a
fork-shaped placing deviee, not s~hown, ean be inserted to grip
the unit. Such gaps are not needed on the opposite side of the
paving unit, because the plaeing fork engaged within the gaps 3
when laying a unit in position, ean fit into the gaps in a
previously plaeed unit.
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In Fig. 2, which illustrates a partial section of the
blocks 2 on a larger scale, it can be seen that the lateral
surfaces of these blocks which effect the connection, are in
contact onl~ for a portion of the height of the blocks. Below
the contacting surfaces of the blocks, the lateral surfaces
diver~e away from one another forming an inverted V-shaped
gap which is open at the bottom of the paving unit. When the
paving unit is placed on a sand layer 4 which forms the base
surface, the sand rises into the V-shaped gap when the unit is
set in place. Such an arrangement provides a firm support for the
blocks 2. Similarly,atthe upper surface 6 of the blocks 2, the
peripheral edges 7 are chamfered so that the blocks are spaced
apart above the contacting surface or joint 8 and none of the
visible edges of the blocks can be damaged during placement.
Fig. 3 shows another paving unit 1' similar to the one
illustrated in Fig. 1, however, it is made up of concrete paving
blocks 9 in which the opposite ends 10 of the lateral surfaces
are disposed at an oblique angle to the other sides of the lateral
surface. This particular shape of the block is known. Contrary
to the known manufacturing processes in which the edges of the
paving blocks are formed all in the same direction and adjacent
rows of the blocks must be turned around, in accordance with the
present invention, the individual blocks are produced in the
forming machine in the pattern as shown in the unit 1', that is,
one row of blocks have the end faces 10 sloped in one direction
while the adjacent row of blocks have the end faces 10 sloping
in the other direction. Accordingly, it is possible to produce
such paving blocks for individua] placement with the desired
facing arrangement.
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In Fig. 4, another paving unit 1'' is illustrated made
up of oblong concrete paving blocks 11 with each block consisting
of three individual hexagonally shaped elements 11', 11'', 11'''.
The three he~agonal elements form one integral block. As a
result, each individual block 11 has a denticulated lateral
surface which affords the interconnected engagement of the blocks
across the paving unit. The upper surface 13 of each block 11
has circular elevations or projections 12 so that, in the
finished pavement, the zig-zag arrangement of the joints dis-
appears to a large extent and a very attractive surface design
results. The circular projections 12 have outwardly and down-
wardly sloping lateral surfaces 14 which extend down to the
upper surface 13 of the individual elements 11', 11'', 11''' of
each block 11, note Fig. 5.
As described, a production of the paving block unit is
prefèrred in which the individual blocks are produced in the
forming machine in an arrangement corresponding to that to be
used in the paving unit~- However, the scope of the invention
includes a production arrangement in which the paving unit is
assembled from previously produced blocks which are combined by
means of an adhesive material. This second production procedure
offers the advantage that it is easier to make special arrange~
ments of the paving units in accordance with each particular
application.
While specific embodiments of the invention have been
shown and described in detail to illustrate the application of
the inventive principles, it will be understood that the invention
may be embodied otherwise without departing from such principles.
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