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Патент USA US2405654

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Aug- 13,_1946- -
Filed Sept; 16, 1944
~ $405,654
2- Sheets-Sheet 1
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' ‘. J23“ '5. HUN-r, .522.
Aug. 13,"'i94s.
Filed Sept. 16, 1944
zsneets-sneet' 2
Patented Aug. 13, 1946
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' 2,405,654
Jesse B, Hunt, Sn, Raleigh, N. (3..
Application September 16, 1944, Serial No. 554,466
2 Claims.
This invention relates to new and useful im
provements in, contraction joints such as are used
in the construction of concrete highways, air
(CI. 94-17)
elongated rods 3, 8, running longitudinally of the
joint. A, plurality of transversely disposed U
shaped chairs 9 are disposed transversely of the
ports, streets and other paved surfaces.
joint, the same passing under the rods 8, with
The principal object of the present invention is
the rods being welded as at E8 to the inside cor
to provide a unitary open-work frame structure
ner portions of said chairs 9.
for not only properly holding dowel rods in prop
The U-shaped chairs 9 each includes a pair
erly spaced parallel relation to the sub-grade,
of upstanding leg members i I, t2, the leg H be
but being so constructed as to spread and thus
ing somewhat taller than the leg i2 and having
compensate for the contracting action which 10 a
circular opening, or in fact, opening of any
takes place in concrete.
and denoted by numeral l3 and conforming
Another important object of the invention re
with the cross-sectional shape of a corresponding
lates to a method of installing dowel bars in con
dowel I4.
traction or dummy joints in concrete slabs in a
The dowel I4 is slipped through the opening 7
more satisfactory manner than is now had with 15 l3 and rests in a crotch in the upper end of the
present-day equipment.
Another important object of the invention is
to provide for
brought to the
bled and ready
forms with the
leg l2 where it is welded inplace as at E5.
Alluding further to the U-shaped chair 9, it
a rigid assembly which can be
can be seen that the intermediate portion of
site of the work already assem
its horizontal part is crimped or offset upwardly
to set on the sub-grade between 20 as at It in the form of an inverted V or some
end in View of affording positive
other accordion-like spreader and to afford ready
and de?nite alignment of the dowels, holding
?exibility at this point it is preferable that the
them at a set distance from the sub-grade and
chair be longitudinally slotted, as at El, through
top of the slab as well as at a positive and de?nite
said crimp l6.
space between each dowel.
It can now be seen, that the joint is placed
A further important object of the invention is
on the sub-grade 1 in the manner shown in Fig
to provide a structure of the character stated
ure 1 and the chairs will serve to maintain the
which can be easily disposed in place and which
Ill in proper parallel spaced relation with
remain in a de?nite position during the pouring
respect to the sub-grade ‘I.
of concrete.
If desired, a weakening strip 58 may be em
Other objects and advantages of the invention
in the upper portion of the concrete pave
will become apparent to the reader of the follow
ment 6 as shown in Figure 2 immediately above
ing description.
the crimp I 6 so that the concrete will crack at
In the drawings;
this point on a straight line.
Figure 1 represents a fragmentary sectional 35
It can be seen, that while the concrete is con
view through a concrete pavement showing the
tracting, there will be a transverse exertion on the
joint installed.
joint which will be taken care of by the yield
Figure’Z is a sectional view similar to that of
ability of the crimps I6 and the fact that the
Figure 1 but showing the use of a weakening
dowels I4 are slidable through the legs H.
The U-shaped chairs are formed of ?at sheet
Figure 3 is a fragmentary perspective view of
material using a minimum width of 11/2 inches
the complete contraction joint assemblage.
and when placed in position on the sub-grade act
Figure 4 is a fragmentary side elevational view
as sand plates and bearing on the sub-grade for
looking at one end of one of the U-shaped chairs.
adequately and properly supporting the entire
Figure 5 is a side elevational view looking at 45 assembly.
the opposite end of the chair shown in Figure 4.
As evident, the essence of this invention is the
Figure 6 is a sectional view through'one of the
fact that I am using a self adapting V crimp
chairs, the section being on the’ line 6-6 of
which will allow the dowel supporting chairs
Figure 4.
to spread when the concrete contracts at the
Referring to the drawings wherein like numer
plane of‘ weakness. The V crimp is shown at the
als designate like parts, it can be seen that nu
bottom of the dowel support. The plane of weak
meral 5 generally refers to the improved contrac
ness is formed as in Figure 2 by a groove in the
tion joint embedded in a concrete pavement or
of the concrete slab over the center of the
the like 6 and resting on a sub-grade 7.
dowel assembly. This groove allows the concrete
The contraction joint 5 consists of a pair of 55 slab to crack in a straight line when the contrac
tion takes place. My invention, however, has
only to do with the dowel bar and chair assembly.
each having one end secured to one end of a cor
responding chair and being slidable through the
opposite end of said chair.
While the foregoing speci?cation sets forth the
invention in speci?c terms,‘it is to be understood
2. As a component part of an assemblage of
the class described, a U-shaped chair, the hori
that numerous changes in the shape, size and ma
terials may be resorted to without departing from
the spirit and scope of the invention as claimed
Having described the invention, what is claimed
as new is:
zontal connective portion thereof being provided
withan inverted V-shaped spreader, said spread
er being of a self-adapting and accommodating
type, and a dowel rod, said rod being rigidly con
nected at one end to the upper end of one of the»
1. A contraction joint comprising an elongated
ability of said elongated structure, said dowels
vertical limbs of said chair, the remaining limb
having an aperture therein and the adjacent end
of said dowel rod sliding freely through said aper
structure including a plurality of transverse '
chairs, said elongated structure being transversely
yieldable and dowels supported by said chairs,
each of said chairs being provided with ‘an up
standing crimp to permit the transverse yield
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