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Патент USA US2405428

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LOAD TRANSFERENCE UNIT
Filed Aug. 14, 1945
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Patented Aug. 6, `l 946
2,495,428
UNITED STATES PATENT GFFICE
_ 2,405,428
LOAD TRANSFERENCE UNIT _
J ames H. Jacobson, Chicago, Ill.
Application August 14, 1943, Serial No. 498,660
2 Claims. (Cl. 94-17)
.
l
The load transference unit of the present in
vention is designed primarily for use in the con
Fig. 4 is a modification showing the provision of
anchoring members.
struction of concrete highways, for the purpose
of connecting the ends of adjoining road slabs,
Each unit member in the form shown is formed
from plate material cut or stamped to afford a flat
body portion I0 having spaced arms I I extending
upwardly therefrom to afford a gap I 2, the base of
a manner as to prevent vertical displacement
which is afforded by the middle edge section I3 of
under the pressure of a rolling load on a highway,
the body I0.
runway or the like.
With the opposed unit members aligned as in
Before discussing the mechanical details of the 10 Fig. 1, the edges I3 afford support for a ñat dowel
present invention it is proper to point out that
bar I4, the middle portion of which bridges the
the term “load transference unit” refers to the
'gap across the joint between the concrete slabs
means employed for interconnecting the adjacent
I5 of a road or similar structure which present
ends of concrete road slabs across the gap» pro
their ñat vertical faces I6 in opposed relation to
vided for expansion and contraction and which
one another.
and transmitting load stresses across the gaps
between the adjacent faces of the slabs in such
unit includes members which are movable hori
zontally to accommodate the advance and re
Each of the unit members is provided with a
rearwardly extending foot Il struck backwardly
from one edge of the body portion to provide
supporting contact with the surface of the sub
vertical displacement of either of the slabs'with 20 grade, while the opposite edge is extended down
respect to the other. In such an arrangement
wardly in the form of a pointed spike I8 which
it is of primary importance to distribute the
is driven into the subgrade as shown in Fig. 3.
stresses imposed by an approaching load, so that
The dowel bar is of a width to lie between
a considerable portion of such stress will be re
the upstanding arms I I and is preferably, though
sisted by the more distant slab, which thus serves 25 not necessarily, secured to one of the unit mem
to reinforce the near slab which receives the in
bers by a line of welding I9 and has sliding con
itial impact of the advancing load, and it is also
tact across the body of the companion member
important to provide against vibration or similar
to allow for expansion and contraction of the
concrete due to thermal changes. The outer free
movements which, unless counteracted, have a
cumulative tendency to wear away the concrete 30 end of the dowel bar is entered into a sheath
adjacent the unit members, and thus in time per
20 which is ñxedly embedded in the concrete and
mit displacement of the unit with a resulting fail
affords clearance for the in and out sliding move
ure to perform the service intended.
v
ments of the dowel bar.
The load transference unit members which are
When the unit members are embedded within
especially adapted for use with thin slabs, have
the concrete slabs as in Fig. 3, the faces of the
been designed with a view to extreme economy in
opposed members will lie iiush with the vertical
production, being in the preferred form of iden
faces of the slabs while the oppositely extending
tical stampings, which may be cut from a bar
feet will be embedded around their top faces and
of metal with little waste of material and bent
edges with their under horizontally extended
to ñnished form, ready for use, by a stamping 40 faces abutting flatwise with the subgrade.
operation, and which need not be cut or formed
While it will not ordinarily be necessary to pro
with extreme precision in order to be interñtted
vide additional anchoring means for holding the
in the intended manner for use in a road joint.
unit members in place within the concrete slabs,
It will be understood, however, that the present
nevertheless in some cases such anchors may be
cession of the slabs, and which serve in conjunc
tion with a dowel bar to bridge the gap and resist
unit need not be formed as a stamping, but may
be produced as a malleable unit or otherwise.
Further objects and details will appear from the
description of the invention in conjunction with
the accompanying drawing, wherein
Figure 1 is a perspective view of identical com
panion unit members in their assembled relation;
, desirable and in Fig. 4 I have shown upper middle
and lower anchors 2|, 22, and 23 which enter
deeply into the body of concrete and assist in
anchoring the unit members against displace
ment. The upper anchors are formed by striking
50 back the upper ends of the arms II while the
lower anchor is formed by striking up the end of
Fig. 2 is a face view of one of the unit members;
the foot I'I. The middle anchor is formed by
Fig. 3 is an edge View of the assembled unit em
striking back a tongue cut free from the arms I I.
bedded in the faces of opposed concrete slabs on
One or more of such supplemental anchoring
opposite sides of a road joint; and
55 devices or others of similar character may be em
2,405,428
3
ployed without otherwise modifying the struc
ture or mode of operation of the device.
In use properly spaced unit members are
driven into the subgrade until the feet make con
tact with the surface and thus afford stops for
ensuring that companion members will stand at
the same level so that the dowel bar, which is
preferably connected with one of the members
4
tended horizontally to provide a ilat faced foot
underlying the concrete and contacting the sub
grade, a dowel bar bridging the space between
the slabs and the unit members and supported
between the spaced arms, and rigidly secured to
one of the unit members, and having its ends
extended backwardly therefrom and into the
respective slabs, one end portion of the dowel bar
will nt properly within the other.
having a slidable contact with the other of said
The free end of the dowel bar will be capped 10 unit members, and a sheath loosely arranged on
with the sheath 20 which extends beyond the end
said dowel bar end portion and located beyond
of the bar, so that space will be aiîorded within
the adjacent unit member and positionable on
the concrete for the free sliding movements of
the dowel bar independently of said adjacent unit
the bar. With the unit members thus staked in
member.
position, and the dowel bar in place and with 15
2. In combination with concrete pavement
suitable forms or spacers employed to provide
slabs presenting opposed edge faces on opposite
the intended gap between the slabs, the concrete
sides of a gap, a load transference unit compris
will be poured and compacted and built up to a
ing oppositely facing unit members each formed
level above the tops of the arms H, and if an
of plate material adapted to afford great resist
choring wings or flanges of the; character shown 20
ance to load stresses, and having a body and
in Fig. 4 are employed, the same will be embedded
spaced upwardly extending arms in the plane
deeply within the body of the concrete.
of the body and presenting their exposed faces
The device is one which combines great
ilush with the edge faces of said opposed concrete
strength through its resistance to stresses, with
tensile strength in resistance to shear. It may 25 slabs, the upper terminals of the arms being
extended outward horizontally to provide upper
be readily installed by simply driving-it into the
anchors and the body of each unit member being
earth to any desired height of dowel bar and still
in part extended to provide a downwardly pro
function correctly While the dowel bar itself is
jecting spike entering into the subgrade and in
held in place rigidly and at the same time is free
to move horizontally. Although the form shown 30 part extended horizontally to provide a flat faced
foot underlying the concrete and contacting the
is one which combines extreme simplicity with
subgrade, the terminal of the foot being extended
cheapness in production, it is obvious that
upwardly to provide a lower anchor, a middle
changes in the shape or proportions of the con
anchor rigid with and extending outward hori
stituent parts may be made without departing
zontally from the body at the lower end of the
35
from the spirit of the invention.
space between said arms, a ñat relatively broad
I claim:
dowel bar presenting its flat upper and lower faces
l. In combination with concrete pavement
in horizontal planes and rigidly secured to one of
slabs presenting opposed edge faces on opposite
the unit members and bridging the space be
sides of a gap, a load transference unit comprise
tween the unit members and supported between
40
ing oppositely facing unit members each formed
the spaced arms and having its ends extended
of plate material adapted to afford great resist
backwardly therefrom into the respective slabs,
ance to load stresses, and having a body and
spaced, upwardly extending arms in the plane
of thebody and presenting their exposed faces
one end portion of the dowel bar having a slidable
contact with the other of said unit members, and
a sheath loosely arranged on said dowel bar end
ilush with the edge faces of said opposed concrete 45 portion and located beyond the adjacent unit
slabs, the body of each unit member being in part
extended to provide a downwardly projecting
spike entered into the subgrade and in part ex
member and positionable on the dowel bar inde
pendently of said adjacent unit member.
JAMES H. JACOBSON.
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