Guidance system for tracklaying tractors

A guidance system for a track laying tractor in which a furrow following device attached to the track frame senses the distance from the furrow to the tractor and signals the operator or the hydraulic steering system and consists briefly of a sight wheel mounted orthogonally to the rear sprocket, cone wheels mounted for transverse movement orthogonally to the front idler, a bar rigidly attached to the cone wheels and universally to the rear sight wheel mounting and transmittal means for transmitting the distance of the furrow to the tractor and receiver means for indicating the distance to the tractor operator.

BACKGROUND OF THE INVENTION 
On large farms many crops are cultivated and harvested by machines which 
process several rows at a time. These machines are designed to operate on 
the assumption that all of the rows are substantially evenly spaced. The 
machines which make the furrows prior to planting, make a plurality of 
nearly perfectly evenly spaced rows for each pass across the field. In 
practice, however, it is impossible to maintain the exact row spacing 
between successive passes of the machine across the field. The first row 
next to the last row of the previous pass of the machine thus has become 
known as the "guess" row because it has been impossible for even the most 
skilled tractor operator to maintain the exact spacing. Thus, when the 
operator does not keep the spacing exactly the same between the adjacent 
rows of successive passes of the furrowing and planting machines, the 
harvesting machine will either miss an entire row or depending upon the 
crop and the harvesting mechanism, it will either destroy or improperly 
harvest at least one and sometimes more rows of the particular crop. Since 
many harvesting machines are automatically steered by mechanisms which 
have sensors which contact the crop, as for example, Schmidt, U.S. Pat. 
No. 3,326,319, an inattentive operator can and often does destroy a great 
quantity of crops because the machine does not take into consideration the 
uneven row spacing in the "guess row". 
The problem of spacing crop rows is discussed in Hunsicker, U.S. Pat. No. 
2,827,704 granted Mar. 25, 1958 and the patent teaches a visual sighting 
mechanism attached to the tractor. 
Bakehouse, U.S. Pat. No. 3,028,678 granted Apr. 10, 1962 also is concerned 
with spacing and uses a cross bar attached to the tractor with chains 
reaching to the ground to assist the operator in visually sighting the 
previous row. 
The first automatic furrow following device for a wheeled tractor found by 
Applicant in the prior art is Blachet, U.S. Pat. No. 3,548,966 granted 
Dec. 22, 1970. Blachet discloses a single wheel device mounted on the 
front end of a wheeled tractor. 
There are many sophisticated devices in the prior art for following a guide 
wire such as Amos, U.S. Pat. No. 3,258,082 granted June 28, 1966, see also 
Ruoff, U.S. Pat. No. 4,131,176 granted Dec. 26, 1978 in which a sensor 
moves the wheel of the vehicle in relation to a fixed guide rail. 
A very sophisticated guidance system is shown in Hobday, U.S. Pat. No. 
3,679,019 granted July 25, 1972 in which a wheeled vehicle follows a 
buried wire. 
All of the previously cited references relate to wheeled tractors and 
vehicles. Crawler type vehicles are also automatically steered but all of 
those found by Applicant follow a guide-wire. The earliest track laying, 
guide-wire following machine found by Applicant is Flom, U.S. Pat. No. 
3,181,441 granted May 4, 1965. The latest track laying guide-wire 
following apparatus found by Applicant is Dale, U.S. Pat. No. 3,905,715 
granted Sept. 16, 1975. 
A furrow following wheeled plow is shown in Sieling, U.S. Pat. No. 
3,123,148 granted Mar. 3, 1964. This device is designed to straighten out 
successive furrows even though the straightening process would change the 
spacing between adjacent furrows. The Sieling plow cuts only a single 
furrow with each pass across a field. 
A furrow following device is shown in Burvee, U.S. Pat. No. 3,765,501 
granted Oct. 16, 1973. Burvee discloses a device for a wheeled tractor and 
connects the furrow following device to the mid-point of the frame of the 
tractor. The furrow following device has only a single point of contact 
with the furrow; mainly a cone wheel spaced from the front wheel of the 
tractor. 
A commercial furrow following device for wheeled tractors is made by 
electronics system division of Geosourse, Inc. of Modesto, Calif. and is 
sold under the trademark TAG. In this system, the furrow following device 
is mounted directly to the front portion of the frame of the wheeled 
tractor. 
The prior art system for making furrows with crawler tractors is as 
follows: For the initial pass, a transit is set up and stakes or bags are 
placed along the line for the tractor operator to follow. A device for 
making a "guide furrow" is attached to the rear cross bar and this becomes 
the guide for the operator on the second pass. When the operator has 
completed the first pass and has turned his crawler tractor to make the 
second pass, the tractor operator aligns a marking device on the front of 
the tractor such as the radiator cap with the previously made marking 
furrow and then sights along these two marks down the entire length of the 
field to a distant arbitrary mark such as a tree. The operator then steers 
the tractor toward the distant point and attempts to keep his eye on the 
distant point and the radiator cap or other marker on the tractor during 
the entire furrowing pass. A problem with this procedure is the operator 
can not keep his eye on the machinery to see whether or not the 
fertilizer, fungicide and other chemicals are being injected into the 
soil. Primarily, however, driver fatigue, dust, and glaring sun make it 
very difficult for drivers, using the present system to maintain the 
critical row spacing hour after hour. 
None of the prior art systems for causing a wheeled tractor to move 
parallel to a previously formed furrow are adaptable for track laying 
tractors. The reason for this is the fact that a wheeled vehicle with 
steerable front wheels moves in an arc when the front wheels are steered 
to the right or left. In contrast, a track laying vehicle pivots when it 
is steered. To add to this complication, the tractor does not pivot about 
a single point but in fact pivots about two different points. If the 
tractor is steered to the right, the pivot point lies beneath a center 
point on the right track laying mechanism. If the tractor is steered to 
the left, the pivot point lies beneath the left track laying mechanism. 
Further, the pivot point is not always at the same point beneath the track 
laying mechanism. L. L. Karafiath in his book SOIL MECHANICS FOR OFF-ROAD 
VEHICLE ENGINEERING, TRANS TECH PUBLICATIONS, T.L., 235, point 6, k, 34, 
E.N.G.I. (1978 ) at Page 443 and FIG. 399, demonstrated that the stresses 
under the track are trapezoidal at zero draw bar pull. As the draw bar 
pull gradually changes, the distribution of stress changes to an 
approximate triangle with the acute angle at the rear driving sprocket. 
Thus, it may be concluded, that the pivot point under full draw bar load 
is approximately at the center of the tread at the rear sprocket. These 
pivot points are shown in FIG. 7 of the drawings as P.sub.1 under the left 
track and P.sub.2 under the right track. 
SUMMARY OF THE INVENTION 
The present invention is a device which will closely follow a furrow made 
in a previous pass of the machine as distinguished from a special "guide 
furrow"and actuates the steering mechanism of a track laying tractor so 
that row spacing between successive passes of the machine will deviate 
less than 1 inch. 
Accuracy in row spacing is maintained row after row without guide wires or 
buried signal wires. The furrow following device and the furrow making 
machinery are attached to the upsprung track roller frame rather than the 
main frame of the tractor which is carried by springs and constantly moves 
up and down and in a rolling motion as the tractor traverses the uneven 
ground. 
Accuracy of the device is achieved by a two point contact between the 
furrow and the tractor. A sight wheel is spaced from the rear of the 
tractor and cone wheels are spaced an identical distance from the front of 
the tractor. Maintaining touching contact with the furrow by the front 
cone wheels and the rear sight wheels maintains the tractor in accurate 
parallel alignment with the furrow. Prior art devices such as Burvee, 
supra which have only a single point of contact with the furrow can not 
keep the accurate spacing because the furrow following device can be 
indicating the correct spacing distance while the tractor remains out of 
alignment with the furrow.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
The guidance system is for a track laying tractor 1 for maintaining the 
tractor at a pre-selected distance from a previously constructed ground 
furrow 2. The tractor includes a tractor roller frame 3, a rear sprocket 4 
and a front idler 6. The guidance system includes a rear mount frame 7 
attached to the rear outside portion of the track roller frame 3. A rear 
arm 8 is connected to the rear mount frame 7 and extends outwardly at 
substantially a right angle from the rear sprocket 4. A sight wheel 9 is 
mounted on the rear arm 8 and is adapted for riding in the previously 
formed furrow 2 at a selected fixed distance from the rear mount frame 7. 
The sight wheel of the furrow following device is located substantially on 
a line which orthogonally intersects the longitudinal axis of the tractor 
and the steering pivot points P.sub.1 and P.sub.2 of the tractor. A front 
mount frame 11 is attached to the front outside portion of the track 
roller frame. A front arm 12 is connected to the front mount frame 11 and 
extends outwardly from the tractor at substantially a right angle to the 
front idler. An extension arm 13 is slidably mounted coaxially on the 
distal end 14 of the front arm 12. 
Furrow following means 16 are mounted on the distal end 17 of the extension 
arm 13 and are adapted for staying within the previously formed furrow at 
the selected fixed distance. Transmittal means 18 mounted on the front arm 
are connected for measuring and transmitting the difference in distance of 
the furrow following means from the front mount frame as compared to the 
selected fixed distance of the rear sight wheel 9 from the rear mount 
frame 7. A receiver means 19 is operatively connected to the transmittal 
means for indicating the relative distance of the furrow following means 
from the front mount frame 11 and the selected fixed distance of the sight 
wheel from the rear mount frame. 
The furrow following means includes a pair of cone wheels 21 and 22. The 
cone wheels are a standard item and each has an edge 15 and 20 for riding 
in the bottom of the furrow and tapered sides 23 and 24 for riding against 
the sloped edges 26 and 27 of the furrow 2. 
The guidance system includes pushing means 28 connected to the cone wheels 
for maintaining the alignment of the cone wheels in a direction in 
alignment with the direction of the previously formed furrow. The pushing 
means consists of a push bar member 29 fixedly attached to the extension 
arm 13 at its front end and attached to the rear arm 8 by a universal 
joint 31. The cone wheels are in effect pushed by the bar. The bar 
stablizes the cone wheels in much the same manner as a long handled shovel 
would slide within a furrow if pushed from the end of the handle. A short 
push bar or a short handled shovel (if we were to carry through the 
simile), would be relatively directionally unstable. 
The extension arm 13 and the front arm 12 are coaxially and telescopically 
attached to one another as shown in FIGS. 1 and 2. Relative movment is 
about 8 inches. As shown in FIG. 4, the rear arm 8 is pivotally connected 
to the rear mount frame 7 by pin 30 and bracket 35 for movement in a 
vertical plane. 
The front arm 12 is universally connected to the front mount frame for 
movement in vertical and horizontal planes. The universal joint 34 is 
connected to end 36 of the front arm and to the front frame 11. 
Preferably there is a means provided for raising and lowering the front and 
rear arms. A hydraulic ram 37 may be connected to pin 38 and bracket 39 to 
the rear arm and by pin 33 and bracket 32 to the rear mount frame. The 
front arm 12 is raised and lowered by a hydraulic ram 41 connected to the 
front arm by a bracket 42 and pin 43. The upper end of the hydraulic ram 
is connected to the front frame by a universal joint 44 and a bracket 46. 
Where a field is rough or filled with clods of dirt, a second set of cone 
wheels gives more accurate results. An alternate form of the invention is 
shown in FIG. 8 in which the furrow following means includes a second pair 
of cone wheels 47 mounted on a second extension member 81 for following an 
adjacent furrow 48. Push bar 29" is rigidly connected to second extension 
81 and universally connected to rear arm extension 82 at universal joint 
83. All other parts of the furrow following means are identical and carry 
identical numbers as the previous form of the invention. 
In the form of the invention shown in FIG. 5, the transmittal means 18 for 
measuring and transmitting the difference in distance of the furrow 
following means from the front mount frame as compared to the selected 
fixed distance of the rear sight wheel from the rear mount frame consists 
of a slug 49 and coil 51 fixed to the extension arm 13 and a coil 52 fixed 
to the front arm 12. A signal generated by the amplifier 53 feeds the 
field of coil 51. As the extension arm 13 and front arm 12 moved together, 
the field in coil 52 increases thereby increasing the voltage reading on 
the meter 54. The voltage reading decreases as the extension arm and front 
arm move away from one another. By setting the voltage so that the needle 
56 is centered when the tractor is parallel to the previous furrow, when 
the tractor moves to the right, the needle will move to the right, and the 
meter will indicate left as the tractor moves in that direction. 
In the preferred form of the invention, the cone wheels 21 and 22 mounted 
on the extension arm 13 operate a hydraulic steering means on the tractor 
which automatically steers the tractor. As shown in FIGS. 1 and 6, 
extension arm 13 is telescopically mounted on front arm 12. Pin 57 mounted 
on the extension arm is inserted through slot 58 in the front arm. A rod 
59 is connected to the pin and a hydraulic spool valve 61. The spool valve 
may be any off-the-shelf item such as CVA and DCVA series control valve 
manufactured by Energy Manufacturing Co., Inc. As the spool valve rod 
moves in and out, the spool valve makes the proper connections between the 
feed line 62 to the left tractor friction or the feed line 63 to the right 
tractor friction. A high pressure feed line 64 from the tractor reservoir 
is connected to the spool valve and a return line 66 is connected to the 
tractor reservoir and the spool valve. A bypass valve 67 for automatic 
shut-off is provided when the entire furrow following assembly is raised. 
A line 68 is connected to the hydraulic ram for raising the arm. The spool 
valve carries a spring for centering the device so that neither the right 
or left feed line to the tractor frictions is activated. In this mode, the 
tractor moves in a straight line parallel to the furrow. 
In operation, the first series of furrows are made by the tractor following 
a line previously established by a transit and marked by stakes or bags. 
This first pass is made with the furrow following assembly in the raised 
position. Several furrows are made by shovels 69 mounted on the auxiliary 
cross-bar 71 which is mounted behind cross bar 72 attached to the right 
and left track roller frames by draw bars 73 and 74. Fertilizer injector 
76 is attached to auxiliary cross bars 77. Other chemicals such as 
fumigants may be injected through nozzles 78 on auxiliary cross bar 79. 
An identical furrow following device is mounted on the left side of the 
tractor as well as the right side. The mechanism is identified by numbers 
followed by a prime mark ('). 
When the operator has completed the first pass and turned his tractor, he 
lines up the tractor with the last furrow 2 made on the first pass so that 
the sight wheel 9 rides in the bottom of the furrow. The front of the 
tractor is then pivoted so that the cone wheels 21 and 22 ride in the 
forward part of the same furrow as the sight wheel. The operator then 
pivots the front of the tractor so that the needle 56 of meter 54 
indicates that the tractor is now parallel to the furrow. 
If the tractor has the automatic steering device, the cone wheels are 
positioned in the furrow and the tractor automatically positions itself 
parallel to the furrow. The tractor will automatically steer itself down 
the field and the furrows made in the second pass will be automatically 
and accurately spaced from the furrows made in the first pass. 
In the alternate form of the invention shown in FIG. 5, the operator must 
steer the tractor so that the indicator needle 56 is always in the indexed 
position which indicates that the tractor is moving parallel to the furrow 
and at the pre-selected set distance from the furrow. 
With either of the forms of the invention, the tractor moves parallel to 
the previously made furrow with a maximum deviation of about one inch. 
When the automatic steering form of the invention is used, the operator 
does not have to steer the tractor and can thus watch the making of the 
furrows and be sure that the fumigants and fertilizers are being properly 
injected while the furrows are being made. The automatic steering of the 
tractor also relieves the driver of the extreme tension and tedium of 
attempting to drive a crawler tractor over a plowed field with extreme 
alignment accuracy and often under adverse conditions such as dust, fog, 
or driving the tractor into the sun in the early morning hours or late 
evening hours. 
With the use of the automatic steering device, the spacing between furrows 
of adjacent passes can now be accurately made and harvesting machines 
which are set to harvest several evenly spaced rows of crops do not 
destroy crops because of uneven spacing of the rows.