Asphalt paving machine with liftable, adjustable auger mechanisms

An improved mounting arrangement for the auger and auger drive mechanism of a floating screed type asphalt paver. A drive box, pivotally mounted at the back of the paver, supports and drives the inboard ends of left side and right side augers. A cantilever beam, mounted on the drive box, extends laterally over both augers and provides outboard bearing support. Actuator means is provided for controllably pivoting the entire assembly about an axis located in front of the augers, enabling the augers to be lifted and lowered for loading/unloading operations, clearing obstructions, etc., and also enabling the auger to be adjusted vertically during paving.

BACKGROUND AND SUMMARY OF THE INVENTION 
The invention is directed generally to improvements in asphalt pavers of 
the floating screed type. In particular, the invention is directed to 
improvements in the mounting and positioning of the auger mechanisms 
typically employed with such pavers. 
In the laying of asphalt pavement roadways, it is common practice to 
utilize floating screed type paving machines. These machines typically 
include a tractor-like vehicle having an engine for propulsion and for 
material distributing functions. A material receiving hopper is provided 
at the front of the paver, arranged to receive hot asphalt materials from 
a truck, as the paving machine advances along the roadbed. Means, such as 
slat conveyors, are provided to convey the asphalt material rearward from 
the hopper and to deposit the material on the roadway, in front of the 
floating screed. 
Directly in front of the screed, there is provided a distributing auger 
mechanism, comprising left and right side augers positioned in the region 
in which the asphalt is deposited from the slat conveyors. As the machine 
advances along the prepared roadbed, the raw asphalt material is first 
deposited by the slat conveyors and then distributed laterally outward by 
the augers. The distributed material then flows under the floating screed, 
which levels, smooths and compacts the asphalt to provide a continuous, 
level pavement mat. 
Conventionally, the auger elements are mounted at the back of the paver in 
a substantially fixed position. While means typically may be provided to 
enable limited vertical adjustment of the augers, the nature of the known 
equipment is such that adjustments are rarely if ever be utilized after 
the initial setting. Historically, height adjustment of the auger 
mechanism has involved multiple manual adjustments of turnbuckles and 
bearing mounts, in some instances at locations which may be heavily coated 
with asphalt. Accordingly, adjustment of the auger height with the paver 
on the move has been altogether out of the question, and adjustment at 
other times is sufficiently complex and time consuming as to rule it out 
for most purposes. 
In accordance with the present invention, a novel and improved arrangement 
is provided for constructing and mounting the auger and auger drive 
mechanisms for limited vertical liftability and height adjustment relative 
to the tractor frame, such that the auger can be instantly and 
effortlessly raised or lowered relative to the paver. 
One of the important advantages of the mechanism of the invention resides 
in the fact that the auger may be set relatively close to the roadbed for 
normal paving operations, to achieve optimum function during paving, and 
yet may be instantly raised to clear roadbed obstructions, for example, 
such as manhole projections. In addition, for loading of the paver onto a 
low boy trailer or the like, for transportation to a new site, it is 
possible to quickly raise the auger mechanism up out of the way, providing 
sufficient clearance at the back of the paver to enable it to travel up a 
sharp incline onto the trailer bed without damaging the auger mechanism. 
Pursuant to one aspect of the invention, the new liftable auger mechanism 
includes a drive box, which is mounted centrally, at the back of the 
paver, and supports the inboard ends of each of the left and right side 
auger elements. Support for the outboard ends of the augers is provided by 
means of a laterally extending cantilever beam, which is carried by the 
drive box and extends outward over the top of the auger elements. At one 
or more outboard locations, depending upon the length of the auger 
elements, support bearings are provided, extending downward from the 
cantilever beam. 
In a preferred form of the invention, the entire auger mechanism is 
supported for limited movement by pivotal attachment of the drive box to 
the back of the paver frame. A hydraulic lift mechanism engages the 
cantilever beam at relatively widely spaced points, on opposite sides of 
the drive box, in order to pivot the assembly. The pivot axis of the drive 
box is located forwardly of the auger and generally at the same horizontal 
level, such that pivoting movement of the drive box is translated into 
generally vertical movement of the augers. 
Desirably, the laterally extending cantilever beam is movably supported by 
the paver frame at spaced outboard locations, to provide for mechanical 
stability of the entire structure. Additionally, thrust resisting means 
may be provided respectively on the cantilever beams and paver frame, to 
assist in resisting the unbalanced sideways thrusting forces developed by 
the augers during normal paving operations. 
To advantage, the new auger mechanism is constructed as a substantially 
unitary module, which can be installed on and removed from the paver 
substantially as a single unit, greatly facilitating assembly, maintenance 
and repair operations. 
For a more complete understanding of the above and other features and 
advantages of the invention, reference should be made to the following 
detailed description of a preferred embodiment and to the accompanying 
drawings.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION 
Referring now to the drawing, and initially to FIG. 1 thereof, the 
reference numeral 10 indicates generally an asphalt paver of the floating 
screed type. The illustrated paver, utilizing large diameter, 
pneumatically tired drive wheels 19, may be of the general type described 
in the Davin U.S. Pat. No. 3,584,547 and marketed commercially by 
Blaw-Knox Construction Equipment of Mattoon, Illinois. A common 
alternative form of floating screen asphalt paver is also shown in the 
Davin U.S. Pat. No. 3,776,326, which utilizes endless tracks rather than 
pneumatically tired wheels for propulsion. The improved auger mechanism of 
the invention is utilizable to advantage in either form of paver and, 
indeed, may be useful to advantage in pavers other than floating screed 
pavers, for example. 
A paver of the type illustrated in FIG. 1 typically is provided with a 
hopper 11 in its front section, which is arranged to receive hot asphalt 
material from a dump truck located directly in front of the paver and 
typically pushed down the roadway by the paver during paving operations. 
An engine 12 provides motive power for the paver. Conventionally, conveyor 
means are provided to move the hot asphalt material from the area of the 
hopper 11 rearward, to be discharged at the back of the machine, as 
indicated at 13. Since the area being paved is usually of considerably 
greater width than the effective width of the material conveyors, and 
frequently considerably greater than the width of the paver apparatus as a 
whole, it is conventional to provide auger elements 14 at the back of the 
paver, carried slightly above the roadway surface 15. These augers are 
controllably driven in a manner to distribute the hot asphalt laterally 
outward from the central region in which the material is discharged by the 
conveyors. 
A floating screed 16 is positioned immediately behind the auger means 14 
and is connected to the paver frame by spaced towing arms 17. The towing 
arms are pivotally connected to the paver frame at tow points 18, which 
may be adjusted vertically upward and downward in accordance with known 
principles to control the attitude of the screed 16. 
In the illustrated form of the invention, a drive box 20 is pivotally 
mounted at the back of the paver 10 and serves to both mount and support 
the respective left and right side augers 21,22. The augers themselves may 
be of conventional construction, comprising internal shafts 23,23a on 
which are mounted a plurality of auger segments 24, which can be arranged 
in succession to form a more or less continuous helix. Commonly, paddle 
devices 25,26 are provided at the inboard and outboard extremities of the 
auger shafts. 
As indicated in FIG. 6, the inboard ends of the auger shafts 23,23a are 
supported in bearings 27,28 secured to spaced side plates 29,30 of the 
drive box 20. The extremities of the auger shafts 23,23a project into the 
drive box and have fixed thereto respective drive sprockets 31,32 driven 
by chains 33,34. The chains in turn are driven by hydraulic motors 35,36 
mounted at the upper rear portions of the drive box 20, as shown in FIGS. 
2 and 3, and carrying sprockets 37,38. The motors 35,36 may advantageously 
be fixed displacement hydrostatic motors, driven by variable displacement 
hydrostatic pumps (not shown) to provide variable speed operation of the 
augers, usually by means of a control responsive to the height of the pile 
of asphalt in the region of the augers. 
At the lower forward portion of the drive box 20 there are mounted bearing 
40,41, bolted or otherwise secured to the respective sidewalls 29,30 of 
the drive box. These bearings support drive shafts 42,43 for left and 
right side slat conveyors (not shown) for moving asphalt from the hopper 
10 at the front of the paver back to the area of the auger 14. As 
illustrated in FIG. 7, the outboard ends of the shafts 42,43 are supported 
by pillow blocks 44 bolted to a member 45a of the paver frame (see FIG. 3) 
immediately outboard of side plates 45 forming part of the paver tractor 
frame. Between the bearings 40,41 and the respective outboard pillow 
blocks 44, each of the conveyor drive shafts mounts a pair of spaced 
conveyor drive sprockets 46 arranged to engage chains 47 forming part of 
the slat conveyor. 
Within the drive box, the respective conveyor shafts 42,43 mount drive 
sprockets 48,49 driven by chains 50,51 from independent hydraulic motors 
52,53 mounted at the upper portions of upper forward portions of the drive 
box 20. As in the case of the auger drive motors 35,36, the conveyor drive 
motors 52,53 may be controllably driven by variable displacement 
hydrostatic pumps (not shown), under either automatic or manual control, 
so as to deliver paving material to the augers an appropriate rate in 
relation to its utilization in the paving process. 
To advantage, the drive box 20 is pivotally mounted at the back of the 
paver by means of a pair of saddle brackets 55,56, which are received over 
the circular flanges 57 of the inner shaft bearings 40,41 (see FIG. 7). 
The flanges 57 are of circular outline and are received within circular 
openings in the respective saddle brackets 55,56, so that relative pivotal 
movement is permitted. At their forward ends, the saddle brackets are 
provided with respective forwardly projecting flanges 58 and laterally 
outwardly projecting flanges 59. The latter are secured by bolts 60 to a 
transverse channel member 61 forming part of the machine frame, while the 
former, 58, are secured by bolts 62 to another fixed part of the machine 
frame. The arrangement is such that the entire drive box and auger 
mechanism is supported by the saddle brackets 55,56 for pivotal movement 
about the common axis of the conveyor drive shafts 42,43. 
As illustrated best in FIG. 2, the auger mechanism of the invention 
includes a horizontally disposed tubular beam 70, which extends through 
the walls of the drive box 20 and is secured thereto as by welding. The 
tubular beam extends in cantilever fashion outward over the top of the 
auger sections 21,22, approximately to the outer ends of the respective 
auger shafts 23,23a. Adjacent the outer end of the tubular beam, on each 
side, is an outboard support bearing structure 71, which includes a shaft 
bearing 72, directly supporting the auger shaft 23,23a and a mounting 
bracket 73 welded to the tubular support beam 70. The structural 
arrangement of the drive box, tubular beam and augers, as can be observed 
in FIG. 2, is of a self-contained, modular nature, which greatly 
facilitates mounting and removal of the mechanism from the tractor frame 
and thus simplifies assembly on maintenance procedures. 
As reflected in FIGS. 4 and 5, limited pivoting movement of the drive box 
20 about the axis of shafts 42,43, and hence generally vertical movement 
of the auger elements themselves, is effected by means of an hydraulic 
actuator 75 pivotally mounted at 76 to the machine frame. A rocker shaft 
77 is pivoted on the machine frame, centrally by means of a bracket 78 and 
at each end extremity in the frame side plates at 79. In its central area, 
the rocker shaft 77 mounts a lever 81, which is pivotally connected at 82 
to the actuator 75. Adjacent each of its end extremities, the shaft 77 
mounts outboard levers 83, which are joined by connecting links 84 to the 
outer end areas of the tubular support beam 70. When the actuator 75 is 
extended, the shaft 77 rotates clockwise, as viewed in FIG. 5, drawing the 
tubular beam 70 toward the back of the paver, and thus causing the entire 
mechanism, including the drive box 20, auger assembly 14 and tubular beam 
70 to pivot about the axis of the conveyor shafts 42,43. This pivoting 
action, as is evident in FIG. 5, will translate into generally vertical 
motion of the auger assembly 14. 
Stabilization of the auger and auger drive module is achieved in part by 
the attachment of the connecting links 84 to outboard ends of the tubular 
beam 70. In addition, mechanical stabilization is provided by means of 
generally arcuate slots 85, formed in the structural side plates 45 of the 
paver tractor (see FIG. 5). In general, the slots 85 are formed on a 
radius about the axis of the conveyor shafts 42,43 and serve generally to 
confine movement of the outboard ends of the tubular beam 70, while 
accommodating the desired motion thereof as a result of pivotal movement 
of the drive box. Adjacent the open outer end, the slot 85 may be provided 
with a generally horizontal surface 86 upon which the tubular beam 70 may 
directly rest when the hydraulic actuator 75 is deenergized. 
In normal operation of the paving equipment, the augers 21,22 serve to push 
asphalt laterally outward. For a variety of reasons, the momentary 
individual loading upon the left and right side augers may vary, such that 
the net side thrust of the augers may vary more or less continuously and 
may shift from side to side in terms of direction. In the illustrated form 
of the invention, this variable side thrust is partly absorbed by means of 
abutment collars 87 mounted on the tubular beam 70 at each side and 
cooperating with the frame side plates 45. Thus, the abutment collars 87 
are somewhat larger in diameter than the width of the guide slots 85, so 
that any tendency for the tubular cantilever beam to be driven to one side 
or the other by unbalanced forces from the augers 21,22, causes one or the 
other of the collars 87 to abut against the frame plate 45. This serves to 
reduce the side loads placed upon the saddle brackets 55,56, as will be 
understood. 
In typical operation, a paver must be adaptable to paving of various 
widths, from the width of the paver itself, as a typical minimum, to a 
maximum width significantly wider than the paver. For such applications, 
it has been typical practice to provide width extensions for the screed 
and auger assemblies, enabling the paving material to be spread laterally 
to a greater distance and then smoothed and flattened by the wider screed. 
In the apparatus of the present invention, extension of the auger 
mechanism is accommodated by providing for a telescoping outer section of 
the tubular beam 70. Referring particularly to FIG. 8, the reference 
numeral 90 represents a tubular beam extension arranged to slide 
internally of the main tubular beam 70. In the illustrated arrangement, 
the beam extension 90 is provided along its length with a plurality of 
spaced through openings 91, enabling the extension to be secured in a 
variety of extended position, by means of a pull pin 93 inserted in a pair 
of openings in each end of the main tubular beam 70. A pair of spaced 
annular bearing collars 92, near the inboard end of the extension 90, 
provide for a smooth sliding fit of the respective tubular membes 70,90. 
In part, the lateral extension of the tubular beam 70 serves to extend 
laterally a guard means which is provided in front of the auger elements. 
In addition, if the auger extension is great enough, it is necessary to 
provide for additional outboard bearing support. Such additional bearing 
support is illustrated in FIG. 5, where the bearing support 94, similar to 
the previously described bearing support 71, is clamped to the beam 
extension 90 by a clamping block 95 and carries a shaft bearing 96 at its 
lower end for engagement with an outboard extension of the auger shaft. 
As reflected in FIGS. 2, 3 and 8, a first guard plate 100 is welded or 
otherwise secured to the outboard portion of the main beam 70, on each 
side of the paver, providing a front guard for the outboard section of a 
minimum length auger. The inboard sections of the augers do not require a 
special guard as they are located directly behind the paver and of course 
they must be open to the discharge ends of the conveyor means carrying 
asphalt rearward from the front hopper. As shown particularly in FIG. 3, 
the inner guard plate 100 extends downward and is bent forwardly and 
slightly upward at its lower terminal end. Nested in front of the plate 
100 is a second guard plate 101, which is attached to the outer end 
extremity of the tubular beam extension 90 and extends inwardly from the 
end of the beam extension. When the beam extension is fully retracted, as 
shown in FIG. 2, its guard plate 101 simply slides over the front of the 
main guard plate 100. In any projected position of the beam extension, its 
guard plate 101 moves outwardly with it, partially overlapping with the 
main guard plate 100, until the member 90 reaches the limit of its 
extension. 
In the normal operation of the paver, the actuator 75 typically would be 
actuated to the position shown in FIG. 5, causing the auger sections 21,22 
to be generally in their lower limit positions. In this position, the 
lower extremity of the auger elements would ride a few inches above the 
prepared road surface, sufficient to avoid damaging contact of the auger 
with the road surface during normal operations. Upon meeting any 
obstruction, such as a manhole projection, the entire auger mechanism can 
be easily raised by appropriately energizing the hydraulic actuator 75, 
pivoting the entire drive box, beam assembly etc. and raising the auger 
elements themselves in a generally vertical direction. Heretofore, the 
presence of such a manhole projection in the path of the paver and 
projecting above the lower limit of the auger has represented a very 
serious obstacle to the movement of the paver. Further, in this respect, 
the performance of high quality paving requires a steady, continuous 
forward movement of the paver in order to maintain proper floatation of 
the floating screed. Any significant speed reduction, and particularly 
stoppage, can cause an undesirable variation in the pavement mat, 
involving extra expense and degradation of machine performance. 
As reflected in FIG. 1, the location of the auger mechanism is well behind 
the rear wheels of the paver, or behind the tracks of the paver, if a 
track laying version is being utilized. As a result, when it is time to 
load or unload the paver to or from a low boy trailer, in order to move 
the paver from one job site to another, even a slight upward tilting of 
the paver, as it begins to ascend an inclined ramp to the trailer body, 
tends to cause the augers 14 to contact the road surface. With 
conventional equipment, this has been a cause of considerable problem and 
damage to the auger mechanism. With the mechanism of the invention, 
however, all that is necessary is to energize the hydraulic actuator 75, 
lifting the augers through a full vertical stroke of five to six inches 
and clearing the augers out of harms way for loading and unloading. 
The mechanism of the invention is also highly beneficial for relatively 
higher speed, over the road travel of the paver when moving from one 
location to another in a non-paving mode. Particularly with the rubber 
tired version of the paver, which is preferred by many contractors, high 
speed movement of the paver can be accompanied by considerable bouncing on 
the pneumatic rear tires, which are purposely under inflated to provide a 
broad footprint for paving. Thus, damage to the augers is always a 
potential problem with conventional pavers moving in the travel mode. With 
the mechanism of the invention, however, a simple control operation by the 
driver raises the augers out of the way sufficiently for safe travel. 
In this respect, while as a theoretical matter it has been possible to 
raise the mounted position of an auger assembly on a paver in the past, 
the task has been so difficult and time intensive that, as a practical 
matter, a road contractor simply will not devote the time and manpower 
necessary to do the job. 
An additional benefit of the new auger and auger drive mechanism is its 
essentially modular construction. For example, in order to install the 
auger mechanism, the entire modular unit can be engaged by a forklift 
truck and brought to the back of the paver (the screed at this time having 
been dropped from the paver). The saddle brackets 55,56 are first attached 
to the paver frame, by means of the bolts 60,62. Thereafter, the 
connecting links 84 are attached and the outer pillow blocks 44, at the 
outer ends of the conveyor drive shafts 42,43, are bolted to the machine 
frame. Finally, a curved guard plate 110 (FIG. 5) is installed over and 
around each of the conveyor drive shafts 42,43 to provide guidance and 
support for the slat conveyor elements 111 as they round the sprockets 46. 
The job also can be performed without a forklift, by properly blocking the 
auger mechanism at the desired height and then backing the paver into 
position for assembly. 
Complete removal of the unit for periodic servicing and maintenance is also 
a highly simplified procedure, being essentially the reverse of that 
described for the installation. It will be noted, in this respect, that 
the side frame plates 45 of the paver are provided with rearwardly opening 
slots to receive the outer end extremities of the conveyor drive shafts. 
To advantage, the guard panel 100 depending from the tubular beam elements 
70 may be provided with openings for the mounting of a temporary support 
bracket 115 (see schematic representation in FIG. 7). Thus, during the 
initial assembly of the auger and auger drive module, the outboard ends of 
the conveyor drive shafts 42,43 may be supported in temporary support 
brackets secured by bolts 116 to the front face of the panels 100. The 
bolts 116 for temporary brackets 115 are removed when the pillow blocks 44 
are secured to the machine frame. This enables the auger/drive module to 
be handled easily, without excessive concern for damaging of the drive 
shafts and/or bearings therefor. 
The new auger and auger drive mechanism, thus not only enables 
significantly superior performance of the paving equipment in the course 
of its normal operations, but also enables significant advantages to be 
realized in assembly/disassembly operations, and substantial economies 
thereby to be realized in connection with maintenance and servicing of the 
equipment. 
It should be understood, of course, that the specific form of the invention 
herein illustrated and described is intended to be representative only, as 
certain changes may be made therein without departing from the clear 
teachings of the disclosure. Accordingly, reference should be made to the 
following appended claims in determining the full scope of the invention.