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Патент USA US3044205

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July 17, 1962
D. E. ATKINSON
3,044,195
GRADING SYSTEM WITH ELECTRICAL CONTACT
Filed June 20, 1960
2 Sheets-Sheet 1
I 51'
M|
INVENTOR
DUANE E. ATKINSON
ATTORNEY
July 17, 1962
D. E. ATKINSON
3,044,195
GRADING SYSTEM WITH ELECTRICAL CONTACT
Filed Jun'e 20, 1960
2 Sheets-Sheet 2
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INVENTOR
DUANE E. ATKINSON
FIG. ‘4
BY f%W/m
ATTORNEY
United States Patent 0 ICC
3,044,195
Patented July 17, 1962
1
2
3,044,195
serve as a sensing electrical pickup from the line for
guiding the grading blade.
GRADING SYSTEM WITH ELECTRICAL CONTACT
It is another object of this invention to provide a grad
ing system of the aforementioned character wherein the
Duane E. Atkinson, 102 Fey Drive, Burlingame, Calif.
Filed June 20, 1960, Ser. No. 37,369
9 Claims. (Cl. 37-143)
sensing means serves to adjust the blade.
It is still another object of this invention to provide
This invention relates generally to vehicle control sys
a grading system of the aforementioned character wherein
tems and more particularly to such systems which are
the sensing means not only controls blade adjustment but
guided by an electrical contact.
also the actual steering of the vehicle.
In leveling a road bed in preparation for paving, it is 10 These and other objects of the invention will become
necessary that the grading be even and accurate. It is
more clearly apparent upon reading the following descrip
well known that speci?cations for the paving of road beds
tion in conjunction with the accompanying drawing.
is determined from several factors, among which is the
Referring to the drawing:
?nished elevation of the paved road and the thickness of
FIGURE 1 is a perspective view of a grading vehicle
the paving. Consequently, the road bed must be below 15 in operation in accordance with the present invention;
the desired ?nished road surface at least a distance equal
FIGURE 2 is an enlarged view of a portion of FIG
to the speci?ed thickness of the paving.
URE 1 showing the novel contact apparatus in accordance
In addition, it is realized that in the actual construction
with the invention;
of the paved road, large amounts of material are em
FIGURE 3 is a schematic block diagram of an electri
ployed. If the ?nal road bed has been prepared deeper 20 cal circuit as used in accordance with one embodiment
than is required by the speci?cation, the additional thick
of the invention;
ness of the paving material to bring the road elevation
FIGURE 4 is a schematic block diagram of an electrical
circuit as used in accordance with another embodiment
up to the required elevation creates a large additional ex
pense on the contractor.
‘
By present methods, the road bed is roughly graded by 25
of the invention;
.
FIGURE 5 is a schematic diagram of still another em
‘bulldozers or other such equipment to the preliminary
bodiment of the invention wherein a radiator is utilized
level. Subsequently, a line is stretched and suspended
to electrically activate the line; and
along the road bed by surveyors. The line not only indi
FIGURE 6 is a schematic diagram of another embodi
cates the general horizontal location of the road but indi
ment of the invention wherein the invention is used to
cates, in addition, the actual level of the desired road sur 30 steer a vehicle.
'
face. Using the line as ayguide, the road bed is again
Referring
to
FIGURE
1,
a
line
11
is shown stretched
graded keeping a predetermined distance below the line
which is stretched. This operation may include digging
between the posts 13 and grounded. A grading tractor
19 is shown in operation adjacent to the line 11 in the
a trench along the line with subsequent laying of rails or
road bed 21. The tractor includes a cutting blade 23 and
it may include overall grading of the entire road surface. 35 a ?nal leveling blade 25, which are in ?xed relationship
When the rail trench alone is dug, the rails are laid and
with each other to operate at the same level. Pickups 27
serve as a guide for leveling the remainder of the road
surface.
At present, this ?nished leveling either of the rail trench
and 29 are disposed above and below the line 11, respec
tively. These pickups are a?‘ixed to but ‘insulated from
or of the entire bed is accomplished by the operator of 40 the blade, and serve to provide an electrical signal for
blade adjustment in a manner to be described hereinafter.
the-?nal grading vehicle observing the line and visually
FIGURE 2 shows a more detailed view of the pickup
keeping the proper position of the cutting blade.
arrangement. It- is seen that in addition to the pickups
More recently advances have been made in the art
27 and 29, there are also pickups 31 and 33. The pickups
wherein road leveling may be accomplished in an auto
31 and 33 are disposed approximately at right angles to
matic or semi-automatic operation. In some of these 45
operations, levers are disposed about the stretched line .1 the pickups 27 and 29‘ and all of the pickups are pivoted
about a pivot shaft 35. The upper pickups 27 and 31
and serve to contact the line and mechanically activate
are
connected together electrically. Likewise, the lower
a switch for adjusting the blade. Although such a system
pickups 29 and 33 are connected together electrically.
is de?nitely an advance in the art of road leveling, it has
All of the pickups 27, 29, 31 and 33 are spring urged
several disadvantages. The ?exing of the stretched line 50
in
a clockwise direction about the pivot shaft 35 as
is inherent in applying force to throw the switch as is the
actual movement of the arm in order to activate the
switch. Each of these de?ciencies causes an error in the
position of the blade.
.
~
shown in FIGURE 2. A stop is employed in conjunc
tion with the spring such that the pickups 27 and 29,
in their normal position, are disposed approximately per
pendicular to the line 11. As the tractor moves from
Such errors, although small in themselves, create con 55 right to left as viewed in FIGURE 2, the pickups 27 and
siderable expense on the contractor due to the large
and 29 disposed above the below the line 11 may come
amount of materials involved in laying the paved road.
in
contact with one of the upright posts 13. Upon such
Other automatic and semi-automatic systems which have
contact the pickups 27 and 29 are urged against the
been devised include pendulums, gyroscopes, depth pres
sure gauges, visual level indications, and mercury switches. 60 spring force in a counter-clockwise direction and rotated
about the pivot 35. With this rotation, the pickups 31
Each of these has had little success due to their fragile
and 33'become disposed above and below the line 11 on
nature, expense or reliance on human judgment.
the left hand side of the posts 13. After pickups 27 and
Moreover, in the leveling of other surfaces such as beds
29 pass the post 13, the spring force about the pivot
for pipelines and drainage ditches, an accurate ?nished
surface is desirable.
'
It is, therefore, an object of this invention to provide
an improved vehicle control system.
It is a more particular object of this invention to pro
vide an improved vehicle control system wherein a
35 _ causes the pickups 27 and 29 to again be disposed
65 above
and below the line 11, respectively. The pickups
31 and 33 are again disposed approximately parallel to
the line 11.
The vertical spacing between the pickups 27 and 29,
and likewise between the pickups 31 and 33, need only
stretched electrically conductive line, indicative of the 70 to be slightly greater than the thickness of the line 11.
?nished surface, is utilized as a conductor; and sensing
Since the system works on an electrical contact principle,
means disposed on grading equipment adjacent the line
it is unnecessary to apply pressure to the line 11 or to
shearer)
the pickups 27 and 29. Merecontact is required between
one of the pickups 27 or 29 with the line 11 and de?ec
tion of the line or the pickups themselves is not neces
sary and is preferably minimized. Thus, it is seen that
there is relatively little play orerror in the system.
Referring to ‘FIGURE 3, a schematic circuit diagam
of an electrical circuit employed in one embodiment of
the invention is shown. The pickups 27 and 31 are shown
above the line 11 and the pickups 29 and 33 are shown
below the line 11.
Associated with each pair of con
tacts is a high voltage source, 35a and 35b respectively.
Since the circuits associated with each of the pairs of
contacts are identical, only the circuit associated with
the upper contact assembly will be described in detail,
it being realized that the other circuit is identical.
The pickups 27 and 31 are connected to the voltage
source 350 through a current limiting resistor 37a. The
other terminals of the high voltage source are connected
to the base ‘of the transistor 38a as an emitter follower.
The output across the resistor 39a is applied to the base
of the transistor 4% which is connected as a power am
pli?er to apply power from the battery 41 to the solenoid
42a. A stabilizing resistor 44a is provided which is con
nected between the base of the transistor 38a and ground.
A grounding means 46 grounds one terminal of the re
sistor 39a and of solenoid 42a. The grounding means
may, for example, be a probe, plow, drag or steel wheels
on the equipment. The circuit between the line 11 and
the grounding means 46 includes the resistance offered
by the ground, schematically illustrated by resistor 47.
When the probes 27 or 31 are in contact with the line
11, current will ?ow through the loop including the
ground resistance 47, power source 35a, and associated
electrical circuit. The current will be ampli?ed by the
emitter follower including the transistor 38a and will
serve to turn on the power transistor 40a to apply bat
tery voltage to the solenoid 4.2a.
Thus, it is seen that when the blade carrying the pick
ups is lower than it should be, the pickups 27 or 31 con
tact the line 11 and complete the circuit. This causes
operation of the solenoid 42a. The solenoid may con
trol the application of power to a motive means which
controls the blade position. The converse is likewise
seen if the blade carrying the pickups is higher than the
desired voltage. The lower pickups 29 or 33 will con
tact the line 11 and the electrical circuit including the
elements carrying the subscript “b” will be activated to
cause the system to lower the blade.
FIGURE 4 shows another embodiment of the inven
tion. The embodiment is similar to that shown in FIG
URE 3 and like reference numerals are applied. The
essential differences are the inclusion of A.-C. power
sources 51a and 51b in place of the D.-C. power sources
35a and 35b. Diodes 52a and 52b are provided to
rectify the signal current for application to the ampli?er
A
the radiator 57, the line 13., and the pickups 27, 29, 31
or 33-. The operation of the system would be identical
with the exception that the circuit values would have to
be adjusted to accommodate the elimination of the ground
resistance 47.
With the employment of a larger leveler than the
trench digger shown in the ?gures, such as a bulldozer
having a relatively wide blade, it would be convenient to
mount one of the sensing circuits on each side of the
blade with a lead line stretched on both sides of the
bulldozer path. Thus, not only the elevation of the blade
but the angle of inclination could be simultaneousy ad
justed.
It is seen, therefore, that a new and improved vehice
control system is provided wherein a minimum of con
tact between the pickup and the lead line is necessary.
Consequently, de?ection of the lead line and of the
pickups themselves is held to a minimum and the blade
position is extremely accurate.
Moreover, it is apparent that the control system de
scribed may be utilized not only for levelling road beds
but for grading any surface where a grading vehicle is
used in conjunction with an adjustable blade. Other
such uses would include trench digging such as for drain
“ age ditches, pipeline beds, or cuts for poured founda
tions.
it is also apparent that the control system described
may be utilized not only for vertical adjustment of a
blade but may likewise be extended to steering of the
vehicle itself as shown in FIGURE 6. In such a system,
pickups 61 similar to those described may be arranged
in a vertical plane above the lead line 11 to provide
steering.
I claim:
1. A vehicle control system for controlling grading ap
paratus of the type which is ‘adapted to establish a graded
surface comprising a lead line disposed a predetermined
elevation above the surface to be graded, said ead line
being electrically conductive and grounded to earth, cir
cuit loop means including said lead line and earth, means
on said vehicle and coupled to said circuit loop for ener~
gizing said circuit loop means with electrical energy, the
means for energizing the circuit loop being grounded to
earth, means in said circuit loop cooperating with said lead
line and serving to derive a control signal, and means re
sponsive to said control signal serving to control the grad
ing apparatus whereby it establishes a grade which is a
predetermined level below the lead line.
2. A vehicle control system as de?ned in claim 1 where
in said means for producing the electrical signal is a direct
current source.
3. A vehicle control system as de?ned in claim 1 where
in said means for producing an electrical signal is an alter
nating current source.
4. A vehicle control system as de?ned in claim 1 where
in said circuit loop includes an electrical pickup affixed to
said blade.
stage. The ampli?er operates as previously described
5. A system as de?ned in claim 4 wherein two said cir
to activate, through earth, either one or the other of the
cuit loops are included, one of said loops being operable
solenoids which, in turn, control the blade position.
to adjust said blade in one direction and the other said
This latter embodiment has an advantage over the 60 loop being operable to adjust said blade in the other direc
embodiment shown in FIGURE 3 in that A.-C. signals
tion.
which includes the emitter follower stage and power
provide easier pickup than D.-C. pulses. The A.-'C. sig
6. A system as de?ned in claim 5 wherein each of said
pickup loops includes an electrically conductive arm, one
said arm being disposed above said lead line and one of
which might be high frequency is easy to ground. Capaci 65 said arms being disposed below said lead line.
tive coupling between the equipment frame and earth aids
7. A vehicle control system as de?ned in claim 4 where
grounding, even with poor resistive coupling. The use
in said electrical pickup comprises a ?rst pair of arms and
of A.-C. permits lower voltages, and consequently re
a second pair of arms displaced from said ?rst pair by an
duces the danger to personnel using the system.
As a variation in the use of the A.-C. ‘system, the 70 approximate right angle, said line adapted to be disposed
between said ?rst pair of arms, both of said pairs being re
grounding rods 17 may be eliminated and signal source
siliently urged about a vertical pivot shaft, a stop asso
applied to the line 11 by use of a radiator 57 located on
ciated with said arms wherein said ?rst pair maintains a
the tractor and positioned adjacent the line 11 as shown
home position approximately perpendicular to said line
in FIGURE 5; In such a manner, the circuit loop would
nals are not so much impeded by deterioration of the
line such as by rust or oxidation. In addition, the A.-C.
include the A.-C. sources 51a and 51b, the ampli?ers,
and upon contact with an obstruction said arms rotate
5
3,044,195
about said pivot shaft wherein said line becomes disposed
between said second pair of same.
8. A vehicle control system as de?ned in claim 1 to
gether with means for steering the vehicle responsive to a
second electrical signal, means disposed adjacent said
lead line in a vertical plane for deriving said second elec
trical signal, and circuit loop means including said lead
line for delivering said second signal to the means for
cluding said radiator, said lead line and one of said con
tact means when in contact with the lead line, means cou
pled to said circuit loop for energizing said circuit loop
means with electrical energy, means in said circuit loop
cooperating with said lead line and serving to receive a
control signal, and means responsive to said control sig
nal serving to control the grading apparatus whereby it
establishes a grade which is a predetermined level below
steering the vehicle.
the lead line.
9. A-vehicle control system for controlling grading ap~~ 10
paratus of the type which is adapted to establish a graded
surface comprising a lead line disposed a predetermined
elevation above the surface to be graded, said lead line
being electrically conductive, an electromagnetic radiator
' in close proximity with said lead line, a pick up arm a?ixed 15
to the grading apparatus, said pick up arm having contact
means for continuing said lead line, circuit loop means in
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,980,553
Salisbury ____________ __ Nov. 13, 1934
2,509,914
, Goodwine ____________ __ May 30, 1950
2,873,541
2,947,097
Eliason ______________ __ Feb. 17, 1959'
Toews ________________ __ Aug. 2, 1960
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