Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTI(~IY
1. Field of the lnven~ n
This invention relates to vibratory concrete screeds,
and more particularly, to vibratory concrete screeds which
include a laterally translatable concrete spreading device
positioned in front of the screed blade to partially level and
distribute plastic concrete before the screed blade engages the
concrete.
2. Description of the Prior Art
A concrete screed is a device for simultaneously leveling
and fi.nishing -the entire wid-th of the surface of freshly poured
plas-tic concre-te. :[n order -to achieve greater production rates,
modern concrete screeds typically incorporate vibration generating
mechanisms for vibrating the screed blade which actually engages,
levels and finishes the upper surface of the concrete. rl'r:iangular
-truss concrete screeds incorpora-ting spaced apart front and rear
blades have become increasingly popular during -the last few years
for a number of reasons. A -triangular truss screed is strong yet
li.ght and can be assembled in a vari.e-ty of lengths from a plurality
of separate, shorter leng-th screed frame sec-tions.
Concre-te is -typically poured between opposing side forms
that also support the ends of the screed. Before the screed can be
advanced into the area of freshly poured concrete, several workers
with shovels must fill in any low places in the plastic concrete and
mus-t redistribute the concrete so that the screed blade will
initially engage -the plastic concrete surface only approximately
slightly above the concre-te surface. If the upper surface of the
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plastic concrete is not properly manually leveled and distributed,
an excess amount of concrete will come in contact with the screed
blade and will ultimately prevent further forward movement of the
screed into the unfinished concrete. 'rhese manual prefinishing
operations must be accomplished promptly to preven-t premature
setting of the freshly poured concrete before the screed finishing
operation has been completed.
The Bid-Well Division of CMI Corporation of Canton, S. Dak.
presently manufactures a spinning tube concrete finishing device
that utilizes an elevated support bridge which spans the width of an
unfinished concrete surface. See U.S. Pat. No. 4,320,9~7. A
laterally -translatable spinning tube finishing device is suspended
beneath -the elevat;ed bridge and is transla-ted from side to side
beneath the bridge by an engine driven hydraulic system that engages
and displaces a continous chain. A large horizontally oriented
dual-auger assembly is coupled to the front of the laterally
translatable spinning tube finishing device. The two coun-ter
rota-ting augers engage the upper surface of the concrete and both
level and distribute plastic concrete as the finishing unit is
translated from side to side below the support bridge. After an out
and back finishing pass has been cornp:Leted, the support bridge is
moved forward on -the concrete side forms to reposi-tion the spinning
tube finishing rollers for -the next ou-t and back finishing pass.
The Bid-Wel] roller finisher also may include a spud vibrator
attachment which can be coupled to -the la-terally translatable
finishing device in fron-t of the auger to consolidate the plastlc
concrete before contact by the augers. The bridge is supported by
four spaced apart corner roller assemblies. Each roller assembly
includes a jacking device for independently adjus-ting each of the
four corners of the support bridge. Each roller assembly can be
positioned at a variable location along the length of the suppor-t
bridge to permit the roller assemblies to engage concrete forms
having variable spacing. Hydraulic motors drive rollers coupled to
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selected ones of the roller assemblies in order to -transla-te the
Bid-Well roller finisher along the concre-te forms.
In the Bid-Well device, finishing is accomplished by
interaction of the srnooth rotating surface of the paired spinning
tubes as they are laterally translated back and forth across the
upper surface of the concrete. As explained above, a vibratory
concrete screed utilizes either a single or two spaced apar-t
vibrating blades to leve] and smoothly finish the upper surface of
the plastic concrete. The screed is continuously advanced into the
unfinished plastic concrete surface. The Bid-Well roller finisher
accomplishes its finishing operation by la-terally translating a pair
of spaced apart spinning -tubes beneath an eleva-ted bridge deck while
the bridge deck is maintained in a fixed posi-tion along the concrete
side forms.
The Miller Formless Company of McHenry, III. manufactures a
30,000 pound directiona] paver machine which includes an oscillating
screed blade and a variable height strike-off auger. This fixed
position auger is oriented parallel to the oscillating screed blade.
Rotation of the auger spreads concrete along -the width of the
screed blade.
U.S. Pat. No. 4,335,976 (Morr-i.son) discloses a triangular
truss screed having an engine driven vibratory shaft which extends
along the entire ],ength of the screed for imparting vibratory motion
to the front and rear screed blades. Morrison fur-ther discloses a
hydraulically powered wi.nch system whi.ch incorporates a hydraulic
pump which is belt driven by the rotary motion of the screed
vibratory shaft. The -two spaced apart hydraulic winches are
therefore powered by a single internal combustion engine mounted on
the screed frame.
U.S. Pat. No. 3,377,933 (Dale) discloses a winch prop~lled
road laying machine having a reciprocating, rear-mounted screed and
a front-mounted spreading auger which spans the distance between the
concrete forms.
2~
U.S. Pat. No. 2,583,108 (Lewis) discloses a concrete
spreader having t~o spaced apart spreading augers ~ounted on a
carriage and laterally translatable with respect to -the machine
fra~e. A ver-tical distributing plate is mounted on the carriage
between the augers to laterally distribute plas-tic concrete.
Both the Dale and Lewis patents were cited as references
against U.S. Pat. No. 4,320,987 referred to above.
SUMMARY OF THE INVENTION
United States Patent No. 4,466,757 which issued to Allen
Engineering Corpora-tion on August 21, 1984 disc]oses a preferred
embodiment of the invention including grading means in the form
of a rotating auger. In that embodiment of the invention, the
partially levelled, redistributed plastic concrete exits the
trailing edge of the auger and is immediately intercepted by the
advancing front blade of the screed. One improvement of that
invention is disclosed and claimed herein and includes metering
means which forms a part of the grading means of the present
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` ~8120~ f
1 invention. The metering means recei~es the partially levelled
2 plastic concrete from the distributing means which forms the
3 initial portion of the grading ~eans. The metering means
4 functions to regulate the height of the charge of plastic
concrete discharged from the concrete spreading means and inter-
6 cepted by the screed blade. This improved grading means including
7 both distributing means and metering means sequentially operates
8 on the unfinished plastic concrete to feed a partially finished,
9 constant height charge of concrete to the screed blade as the
carriage means of the present invention translates the grading
11 means in first and second directions along the length of the
12 screed frame.
13
14 United States Patent No. 4,466,757 also discloses an
oscillating strike-off concrete finishing mechanism which is
16 coupled to a screed frame in front of the front screed blade.
17 The oscillating strike-off is either coupled between the concrete
lB spreading means and the front screed blade and operates as an
19 intermediate finishing device or may be coupled in a similar
position to a screed which does not include concrete spreading
21 means. The improved oscillating strike-off disclosed herein
22 includes means for adjusting the vertical spacing between the
23 oscillating strike-off blade and the screed blade. When used as
24 a concrete finishing device without the concrete spreading means
o~ the present invention, a plurality of spaced apart pneumatic
26 vibrators may be mounted directly on the oscillating strike-off
27 blade to improve the concrete finishing capabilities.
28
29 The imprDved invention disclosed herein also includes
30 ¦¦ a paving train consistlng of a primary finishing screed including
31 concrete spreading means followed in spaced apart relationship
3Z by a secondary finishing screed including an oscillating strike-of .
DESCRIPTION OF THE DRAWINGS
__ _
The invention is poin-ted out with particularity in the
appended claims. Elowever, other objects and advantages together
with the operation of the invention may be better understood by
reference to the following detailed description taken in connection
with the following illustrations, wherein:
FIG. 1 is a partial perspective view of the primary
structural elements of the vibratory concrete screed of the present
invention. For the purpose of clarity, several subsidiary
structures of the screed are not depicted in FIG. 1.
FIG. 2 is an exploded perspective view of the primary
elements of the auger and auger drive assembly.
FIG. 3 is a schema-tic diagram representation of the
hydraulic system of the concrete spreading device.
FIG. 4 is a partial perspective view showing the manner in
which a hydraulic motor is coupled to the oscillating s-trikeoff
attachment of the present invention to reciprocate the oscillating
strikeoff.
FIG. 5 is a partially cutaway, elevationa] v:Lew indicating
the manner in which the hydraulic drive motor for the carriage is
coupled to the frame of the concrete screed.
FIGS. 6-9 comprise a series of illustrations depicting the
structure and operation of the carriage directional control switch.
FIG. 10 :Lllustrates the utilization of a pneumatically
powered vibrator for imparting vibratory motion to the screed
blades.
FIG. 11 is an enlarged perspective view of one end of the
vibratory concrete screed of the present invention, particularly
illustrating the winch and its hydraulic power system and the screed
guide means.
F'IG. 12 is a plan view of the first and second units of the
screed guide means.
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FIG. 13 is a partially cutaway perspective view of a
pneumatically powered version of the oscillating strikeoff
attachment for the vibratory concrete screed of the present
invention.
FIG. 14 is a partially cutaway perspective view
particularly illustrating the manner in which the carriage is
coupled to the screed frame.
FIGS. 15A and B are partially cutaway plan views of the
carriage depicting the manner in which the concrete grading blade is
repositioned between the first and second trailing positions as a
result of reversal of the direc-tion of travel of the concrete
spreading device.
FIG. 16 is a schematic diagram representation of the
self-contained hydraulic system of the oscillating strikeoff
attachment.
FIG. 17 is a partially cutaway sectional view of the
vibratory concrete screed of the present invention.
FIG. 18 is a partially cutaway perspective view depicting
concrete spreading means of the present invention which includes
only a "V"-shaped grading blade.
FIG. 19 is a simplified plan view of the present invention
depicting concrete spreading means having a "V"-shaped grading
blade, particularly illustrating the manner in which the grading
b:Lade is displaced between first and second positions as the
direction of travel of the carriage changes.
FIG. 20 is a simplified plan view of the present invention
depicting a single fixed grading blade coupled to the front face of
the carriage.
FIG. 21 depicts the manner in which a wheel unit of the
screed guide means of the present invention can be configured to
permit a range of movement to accommodate varying spacing between
concrete forms.
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FIG. 22 illustrates the manner in which the screed guide
means of the present invention can be configured to permit the
screed to be skewed.
FIG. 23 is a simplified plan view of the present invention
depicting the manner in which the screed guide means, of the present
invention permits the screed to travel along curved concrete forms.
FIG. 24 is a partially cutaway perspective view of an
alternative embodiment of a vibratory concrete screed including a
modified concrete spreading device and a modified end support
structure.
FIG. 25 is a partially cutaway elevational view of the end
support structure oE the screed depicted in FIG. 24, particularly
illustrating the manner in which the screed guide unit can be
vertically adjusted.
FIG. 26 is an enlarged, partially cutaway perspective view
of the end support member hinge structure depicted in FIG. 25.
FIG. 27 is a partially cutaway, enlarged view of the hinge
clamp depicted in FIG. 26.
FIG. 28 is a partially cutaway sectional view of the
modified roller assembly utilized on the screed depicted in FIG. 2~.
FIG. 29 is an exploded perspective view of the lateral
adjustment device for the horizontally oriented roller depicted in
FIG. 28.
FIG. 30 is a simplifi,ed view from above of the horizontally
oriented roller support structure depicted in FIG. 28.
FIGS. 31A-D illustrate the excessive build-up of plastic
concrete on the blade of a vibxating screed which receives an
excessive charge height of plastic concrete.
FIG. 32 is a view from above of the blade spill-over
problem illustrated in FIG. 31.
8~
FIG. 33 is a view from above illustrating the metering
Imeans of the present invention coupled to the concrete spreading
¦means.
FIG. 34 illustrates the relative position of the metering
means of the present invention with respect to the front screed
blade and the distributing means of the present invention.
FIG. 35 depicts the grading means detached from the
carriage means of the present invention to illustrate structure
permitting relative vertical adjustment between the grading means
and the carriage means.
FIG. 36 illustrates the grading means of the present
,/
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1 invention including both distributing means and metering means
2 and its relative position with respect to a front screed blade
3 having both forward and rear facing blade sections.
FIG. 37 illustrates the grading means of the present
6 invention including both distributing means and metering means
7 with an oscillating strike-off positioned between the grading
8 means and the screed blade.
FIG. 38 illustrates the improved oscillating strike-off
11 includiny vertical strike-off blade adjustment means and a
12 plurality of pneumatic vibrators coupled to the strike-off blade.
13
14 FIG. 39 is a sectional view of the oscillating strike-
off support structure depicted in FIG. 38, taken along section
16 line 39-39, particularly illustrating the structure which couples
17 ¦the oscillating strike-off blade to the screed.
18
lg FIG. 40 represents a sectional view of the oscillating
strike-off illustrated in FIG. 38, particularly depicting the
21 roller structure which maintains a predetermined fixed spacing
22 between the oscillating strike-off blade and the screed blade.
23
24 FIG. 41 depicts a paver train comprising a primary
finishing screed including concrete spreading means followed
26 in spaced apart relationship by a secondary finishing screed
27 including an oscillating strike-off system.
28
29 FIG. 42 represents a view from above of the paver train
depicted in FIG. 41.
31
32 ...
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1 DESCRIP~ION C)F' 'rHE PREFERR~D EM~3ODIMENT
3 In order to better illustrate the advantages of the
4 invention and its contributions of the artl a preferred hardware
embodiment of the invention will now be described in detail.
7 The preferred embodiment of the initial version of the
invention is fully disclosed in ~nited States Patent No. 4,466,
9 757 and illustrated in prior art Figs. ] to 30. In certain
circumstances, that initial embodiment of the invention encountered
11 blade spill over problerns of the type illustrated in FIGS. 31
12 and 32. In the embodiment of the invention as illustrated in
13 FIGS. 1 and 17, the trailing edge of auger 84 was immovably
14 secured to carriage 76 precluding relative vertical adjustments
between the trailing edge of auger 84 and front screed blade 16.
16 As the screed advanced forward into an area of unfinished plastic
17 concrete, concrete could spill over the top of screed blade 16
18 disturbing the finished concrete surface designated by reference
19 number 300 as illustrated in FIG. 31D.
ZO
21 In order to overcome this problem, the structure il-
2 lustrated in FIGS. 33-35 has been created. The grading means
23 302 of the present invention has now been improved to incorporate
24 distributing means and metering means. In the depicted preferred
embodiment of the invention, the distributing means takes the
26 form of an auger 304 and the metering means takes the form of a
27 plow 306. Plow 306 inclucles a horizontally oriented, continuous
29 lower surface 308 joining together a pair of wedge-shaped end
sections 310 which each include a vertically oriented cutting
edge 312. Plow 306 is coupled to the horizontally oriented lower
31 surface of chain box 314 which houses the drive chain coupling
auger drive motor 92 to auger 304.
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1 ¦ To optimize operation of the metering means of the
2 ¦ present invention,vertical adjustment means is provided to
3 ¦ permit precise adjustment of the spacing between the lower
4 ¦ surface 308 of plow 306 and the horizontally oriented surface
5 ¦ 316 of front screed blade 16. The inner face 318 of auger
6 ¦ support bracket 320 includes four spaced-apart, vertically
7 ¦ oriented oval apertures 322 which may be mated with either an
8 ¦upper group 324 or a lower group 326 of apertures in the face
9 ¦of auger carriage 76. A set of four bolts (not shown) are
10 ¦inserted through vertically oriented channels 328, through each
11 ¦of the oval apertures 322 and into either the upper or lower group
12 ¦of apertures 324 or 326 as necessary to achieve the desired
13 ¦spacing between the lower surface 308 of plow 306 and the upper
14 ¦surface 316 of front screed blade 316. When the appropriate
15 ¦vertical spacing has been achieved, each of the four spaced
16 ¦apart mounting bolts is tightened to maintain auger support
17 ¦bracket 320, auger 304 and plow 306 in the desired vertical
18 position. For example, for low slump concrete including one and
19 one half inch stones, the spacing between the lower surface 308
of plow 306 and the upper surface 316 of blade 16 might be ad-
21 justed to approximately one and one quarter inches. For higher
22 slump concrete, the distance between the plow and the screed blade
Z3 is typically decreased. The particular plow/screed blade vertical
24 spacing which optimizes performance of the present invention with
Z5 any particular type of plastic concrete can be readily determined
26 by persons of ordinary sklll in the art.
27
28 In operation, the metering means of the present invention,
29 including both plow 306 and the above-described vertical adjust-
~0 ment means, is translated back and forth along the length of the
31 screed and as illustrated in FIGS. 33 and 34 intercepts and moves
32 plastic concrete forward into the trailing edge of auger 304.
12~1~01
1 The rotating blade of auger 304 intercepts and moves the plastic
2 concrete forward and laterally redistributes it to produce a
3 substantially level surface. In addition, the metering means
4 of the present invention regulates the charge height of plastic
concrete fed to the advancing screed blade 16 by stripping off
6 and moving forward excess height plastic concrete into the
7 trailing edge of auger 30~. The elevation of the lower surface
8 308 of plow 30~ determines the charge height of the plastic
9 concrete fed to screed blade 16. The interrelated operation
of the distributing means and metering means of the present
11 invention feeds a partially finished, constant height charge of
12 concrete to screed blade 16 as the carriage 76 translates the
13 grading means of the present invention back and forth along the
14 length of the screed frame as the screed simultaneously advances
into the unfinished plastic concrete.
16
17 FIG. 34 depicts the concrete spreading means of the
18 present invention operating in connection with a single forward-
19 facing screed blade 16. As indicated, the spacing between the
lower surface 308 of plow 306 and the upper surface 316 of screed
21 blade 16 may be made quite small. In FIG. 36, screed blade l6
22 includes both forward facing and rear facing L-shaped blade
23 elements while the spacing between the lower surface 308 of
24 plow 306 and the upper surface 316 of blade 16 has been increased
to a distance slightly less than the concrete stone size. The
Z6 rear edge of plow 306 is situated approximately halfway between
227 the front and rear edges of the front L-shaped section of
screed blade 16. In FIG. 37, screed blade 16 includes only a
29 single, rear facing L-shaped blade section and an oscillating
strike-off 330 has been coupled to the screed frame between
31 the rear surface of plow 306 and the front surface of screed
32 blade 16. In the particular embodiment illustrated in FIG. 37,
lZB5~01
1 the lower blade surface o~ oscillating strike-off 330 is positioned
2 slightly above the lower surface of screed blade 16 znd approxi-
3 mately even with the lower surface 308 of plow 306. In operation,
4 the laterally reciprocating motion of oscillating strike-off 330
accomplishes an intermediate consolidating and finishing operation
6 on the partially finished plastic concrete discharged from the
7 trailing edge of the grading means of the present invention before
8 the plastic concrete is intercePted by screed blade 16. The
9 differential elevation between the lower surface of oscillating
strike-off blade 330 and the lower surface of screed blade 16
11 ay be controlled to regulate the height of the charge of plastic
12 concrete fed to screed blade 16. In practice, the lower surface
13 of the blade of oscillating strike-off 330 will typically be
14 adjusted to be even with the lower surface of screed blade 16
or as high as approximately 3/8 of an inch above the lower surface
16 ¦f screed blade 16. Proper adjustment of the oscillating strike-
17 ¦off 330/screed blade 16 height differential can be regulated
18 by a person of ordinary skill in the art to achieve the desired
19 concrete finishing characteristics.
21 Referring now to FIGS. 38-40, screed 332 includes an
22 oscillating strike-off 330 having both a plurality of pneumatically
23 powered, high frequency air vibrators 334 as well as vertical blad~
24 adjustment means 336 for controlling the height differential
2~ between the lower surface 338 of the oscillating strike-off 330
26 and the lower surface of screed blade 16. ~IGS. 38 and 39 il-
27 lustrate the structure of vertical blade adjustment means 336.
28
29 A plurality of vertically oriented brackets 340 are
coupled to the vertically oriented face of screed blade 16 and
31 1 include a centrally located, vertically oriented oval aperture
32 ~ 342 for accommodating vertical adjustments of oscillating strike-
l off blade support units 344. A bolt 346 extends through the
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1 ¦various elements of support unit 344 and is secured to a vertical
2 ¦adjustment clamp 348 which interfaces with the rear surface of
3 ¦bracket 340. When bolt 346 is loosened, the rotation of bolt
4 1350 regulates the vertical position of strike-off support unit
5 1344 with respect to bracket 340 to control the relative elevation
6 ¦of the lower surface 338 of oscillating strike-off unit 330 with
7 ¦respect to the lower surface of screed blade 316.
8 l
9 ¦ As illustrated by FIGS. 38 and 40, a plurality of spaced
10 ¦apart rollers 352 are coupled by brackets 354 to the interior
11 ¦face of the blade of oscillating strike-off 330. The comparatively
12 ¦long rolling interface between rollers 35Z and the vertical face
13 ¦of screed blade 16 maintains the blade of oscillating strike-off
14 ¦330 parallel to the vertical face of screed blade 16 as the
15 ¦screed is advanced i.nto the unfinished plastic concrete.
16
17 Continuous , reciprocating motion of the oscillating
18 strike-off 330 is provided by reciprocating means in the form of
19 a dual-action pneumatic ram 356 and the associated connecting
linkage 358 depicted in FIG. 38. As illustrated in FIG. 4 of
21 United States Patent No. 4,466,757, oscillating strike-off 330
22 may also be driven by reciprocating means in the form of hydraulic
23 motor 64 and the associated reciprocation linkage depicted.
24
When the oscillating strike-off 330 is operated without
26 the concrete spreading means of the present invention as depicted
26 in FIG. 38, single or dual paired air vibrators 334 may be
coupled as shown to vibrate the blade of the oscillating strike-
29 off. When the oscillating strike-off 330 is configured as
indicated in FIG. 37 and positioned between the trailing edge of
31 plow 306 and screed blade 16, the air vibrators 334 will
32 typically be removed to minimize the space occupied by strike-off
330.
- 15 -
lZ~3lZOl
1 ¦ Referring now to FIGS. 41 and 42, a paving train con-
2 ¦sisting of a primary finishing screed 360 and a secondary finishing
3 ¦screed 366. Screed 360 includes concrete spreading means 362
4 ¦while screed 366 includes oscillating strike-off 370. Screed
5 ¦366 trails screed 360 by a predetermined time or distance
6 Ito allow the partially finished concrete existing screed 360
7 ¦to reach a semi-equilibrium condition prior to engagement by
8 ¦screed 366. Screed to screed spacing on the order of twenty to
9 ¦forty feet is typical although other spacing variations would
10 ¦be apparent to one of ordinary skill in the art.
11 I
12 ¦ It has been found that use of the disclosed two-unit
13 paving train incorporating primary and secondary screeds including
14 concrete spreading means 362 and oscillating strike-off 370 pro-
duces a superior concrete finish. Since screeds 360 and 366
16 typically include precisely controllable, hydraulically actuated
17 winches, the screed translation velocity and screed to screed
18 spacing can easily be regulated.
19
It will be apparent to those skilled in the art that
21 the disclosed vibratory concrete screed and paver train system
22 may be modified in numerous ways and may assume many embodiments
23 other than the preferred forms specifically set out and described
Z4 above. For example, various aifferent plow configurations other
than the disclosed configuration would function effectively
26 as metering means. Distributing means such as a V-shaped grading
Z7 blade or a spinning tube finisher could be used as a substitute
28 for the disclosed rotating auger distributing means. Accordingly,
29 it is intended by the appended claims to cover all such modifica-
tions of the invention which fall within the true spirit and
31 scope of the invention.
32
