Improvements in Pavements and in Blocks therefor.
Year: 1889

page_text: Date of Application, 5th Mar., 1889
Specification Accepted, 11th May, 1889
COMPLETE SPECIFICATION.
Improvements in Pavements and in Blocks therefor.
1, LYDIA JANE CADWELL of No. 422 Washington Boulevard in the City of Chicago
and State of Illinois United States of America, Widow and Manufacturer lo
hereby declare the nature of this invention and in what manner the same is 'to
be performed to be particularly described and ascertained in and by the following
statement:
This invention consists primarily in a pavement composed of T-shaped blocks of
iron, burned clay or other suitable material, laid in alternately reversed positions so
that they overlap each other, whereby each block of the pavement has a support
from an area of the underlying bed greatly in excess of its upper surface. The
invention further consists in the reversible T-shaped pavement block made hollow and
having the recess or recesses within it open at the sides so that both the remaining
faces of the block are available for use as the wearing surface of the pavement, said
recess being filled with sand or other suitable material for deadening the sound.
The invention further consists in the T-shaped blocks constructed with interlocking
ends for the purpose of preventing easy displacement of the blocks, and it still further
consists in providing the wearing faces of the blocks with particular forms of ribs
and grooves adapted to prevent the slipping of horses' feet thereon in all directions, and
also favorable to the extraction of the pattern or the block from the sand or mold.
In the accompanying drawings which illustrate the invention in its best form and
with all my improvements:
Figure 1 is a top view of a pavement constructed in accordance with my invention,
in which the blocks are laid end to end and with their edges in line with each
other.
-
Figure 2 is a top view of the pavement in which the blocks are offset or with
their edges out of line so that each end of each block partially overlaps two neigh-
boring blocks.
Figure 3 is a side view of one of the blocks detached from the pavement.
Figure 4 is a side view of a series of blocks in their relative positions in the
pavement and showing the manner in which the blocks interlock with each other

page_text: feature of my improvement.
Figure 5 is a transverse, vertical section of a hollow block in the line 5-5
of Figure 3.
Figure 6 is a transverse, vertical section in the line 6-6 of Figure 3.
Figure 7 is a perspective of a fragment of a block, showing more clearly the form
of the ribs upon the wearing faces of the block.
Figure is a vortical, longitudinal section of a block having internal grooves
opposite the external ribs.
A represents a single block of my pavement, said block being of broad or laterally
extended T-shape and having two opposite and parallel wearing faces a a¹ of which
the latter is shorter than, and is centrally opposite, the former. Both ends of the
block are similar and severally have three intersecting surfaces, -a², a³ and a*, of
which aand a are substantially parallel with each other and transverse to the
planes of the opposite wearing faces, and the intermediate surface a is either
horizontal or inclined at such an acute angle to the wearing faces, as shown, as
gives a bearing without a wedging action. The end of one block will therefore fit
against the end of another when the two are placed in the reversed positions shown
in Figure . In what I believe to be the best form of construction the end
surfaces a² are inclined to the working faces of the block, as indicated in several
figures of the drawing, so as to present salient angles at a³ and corresponding entering
angles at a at substantially equal distances from the planes of the working
surfaces a a. The projection a-of-one block-therefore enters the recess at a of an
adjacent block when the blocks are placed together in their proposed order, as shown
in Figure 4. By this feature of construction individual blocks are prevented from
being easily displaced vertically and the pavement as a whole is better calculated to
preserve an even surface.
.
In Figure 2 of the drawing the blocks are shown arranged with their greater
length running with the street, but obviously they may be arranged with their greater
length crosswise of the street. When the blocks are laid to break joints, half blocks
will be required to. fill out the spaces or series next the curb, whichever way the
blocks are arranged. These half blocks are not shown but will be readily
understood.
While for the general purposes of my invention ribs and grooves of any description
and arrangement may be employed on the working faces a a¹ of the blocks, I prefer
the arrangement shown most clearly in Figure 7 wherein the transverse ribs a
stop short of one edge of the block and the spaces between said ribs are closed at
one point by a lengthwise rib a8. This insures a hold for the calks of: horses' shoes!
in both directions of travel, and, in the case of east or smolded blocks, favors: the
easy withdrawal of the block or pattern sidewise from the mold. In Figure-8.the
interior surfaces of the ribbed walls are made with grooves at opposite the ribs,
which construction lightens the 'block without weakening it. These grooves are
indicated by dotted lines in Figures 1 and 2 where is also shown a .practical
distribution of vertical struts a which support the upper from the dower surface of
the block, when the latter is made hollow as indicated. The top and bottom
walls 'a a of the block may be perforated if desired, as shown in the lower-right-hand
in: Figure 2.
י
When the blocks A are made hollow, as shown, it is contemplated that they will
be filled with sand or sand and asphalt, or some other suitable material to prevent
resonance and, so far as it will do so, to add strength to the. block.
The advantages of a pavement composed of T-shaped, overlapping blocks are important
and apparent, for it is manifest that the surface of the bed or foundation which ulti-
..nately sustains the pressure applied on the top of a block is much greater than the upper
surface of said block. For example, in the case of a block A having its smaller
surface a upward, it is plain that the pressure upon said block will be distributed
over a portion of the bed equal to the larger under surface a of said: block. In the
case of a block having its larger surface a uppermost the pressure applied

page_text: to the top of the block is distributed over a portion of the bed equal to
its lower and smaller surface a' plus a considerable portion of the area of the two
adjacent blocks which the block receiving the pressure overlaps.
The pressure upon either block of the pavement being thus sustained by a more
extended area of the bed, the latter and consequently the pavement itself are more
likely to preserve the even surface originally given them.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1-A pavement composed of like T-shaped hollow blocks of metal or similar
bard material laid in alternately reversed positions and overlapping each other at
their ends, each of said blocks having its interior recess or recesses open at the side of
the block and its opposite wearing faces corrugated, whereby it may be laid either
side up, substantially as described.
2: A pavement composed of like T-shaped blocks having their contiguous ends
overlapped and interlocked against vertical displacement.
3: A pavement composed of overlapping T-shaped blocks severally having one
oblong bearing face, a shorter, centrally opposite, parallel bearing face and end faces
provided with symmetrical projections and recesses arranged to engage with those
of an adjacent block to oppose vertical displacement.
4: A reversible T-shaped paving block of metal or other hard material having
one or more laterally open recesses and provided with a filling of other material
suitable to prevent or lessen resonance of the pavement.
Signad at Chicago Illinois February 8th 1889
LYDIA JANE CADWELL.
Witnesses,
MELVILLE E. DAYTON.
Haseltine, Lake & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.