U.S. patent application number 11/086619 was filed with the patent office on 2006-10-05 for towed implement draft force sensor.
This patent application is currently assigned to Deere & Company, a Delaware corporation. Invention is credited to Scott Lisle Cook, Jeffrey David Dawson, Michael Dean Kollath, Peter Alan Kosmicki, Edwin Roy Kreis, Joe Lyle Schutte, Raymond Dennis Thompson, Robert James White.
Application Number | 20060219417 11/086619 |
Document ID | / |
Family ID | 36951638 |
Filed Date | 2006-10-05 |
United States Patent
Application |
20060219417 |
Kind Code |
A1 |
Thompson; Raymond Dennis ;
et al. |
October 5, 2006 |
TOWED IMPLEMENT DRAFT FORCE SENSOR
Abstract
A draft force sensor is provided for a coupling member coupled
between a towing vehicle and a towed earth engaging implement, such
as a scraper. The draft force sensor includes first and second
bores extending through the coupling member. Each bore has a
horizontal axis which extends perpendicular to a main fore-and-aft
axis of the coupling member. The second bore is positioned above
the first bore and spaced apart from the first bore. Each of the
bores is surrounded by an outer cylindrical wall. Four electrical
strain gauges are spaced apart and placed on the wall of each of
the bores. A center line bisects an axis line which extends between
the axes of the first and second bores. The axis of each bore is
spaced apart from the center line by a distance which is less than
a diameter of the bores. The strain gauges are connected
electrically in a circuit which generates a draft force signal in
response to draft forces applied to the coupling member.
Inventors: |
Thompson; Raymond Dennis;
(Waterloo, IA) ; Kosmicki; Peter Alan; (Cedar
Falls, IA) ; Dawson; Jeffrey David; (Cedar Falls,
IA) ; Cook; Scott Lisle; (Cedar Falls, IA) ;
Kreis; Edwin Roy; (Waterloo, IA) ; Kollath; Michael
Dean; (Dunkerton, IA) ; Schutte; Joe Lyle;
(Cedar Falls, IA) ; White; Robert James;
(Waterloo, IA) |
Correspondence
Address: |
DEERE & COMPANY
ONE JOHN DEERE PLACE
MOLINE
IL
61265
US
|
Assignee: |
Deere & Company, a Delaware
corporation
|
Family ID: |
36951638 |
Appl. No.: |
11/086619 |
Filed: |
March 22, 2005 |
Current U.S.
Class: |
172/7 |
Current CPC
Class: |
A01B 59/042 20130101;
G01L 5/136 20130101; A01B 63/14 20130101 |
Class at
Publication: |
172/007 |
International
Class: |
A01B 63/112 20060101
A01B063/112 |
Claims
1. A draft force sensor for a coupling member coupled between a
towing vehicle and a towed earth engaging implement, the draft
force sensor comprising: first and second bores in the coupling
member, each of the bores being surrounded by a wall, each bore
having a bore axis which extends perpendicular to a main
fore-and-aft axis of the coupling member, the second bore being
spaced apart from the first bore along a separation line which is
generally perpendicular with respect to said main fore-and-aft
axis, said separation line extending through the bore axis of both
bores; and a plurality of electrical strain gauges being spaced
apart and placed on the wall of each of the bores, the strain
gauges being connected electrically in a circuit, the circuit
generating a draft force signal in response to draft forces applied
to the coupling member.
2. The draft force sensor of claim 1, wherein: a center line
bisects an axis line which extends between the bore axes of the
first and second bores, and the bore axis of each bore being spaced
apart from the center line by a distance which is less than a
diameter of said bore.
3. The draft force sensor of claim 1, wherein: the axis line
extends vertically and perpendicular to the main fore-and-aft axis
of the coupling member.
4. The draft force sensor of claim 1, wherein: the strain gauges
are connected electrically in a bridge circuit between four nodes,
and strain gauges on opposite sides of the wall of each bore are
connected in series between an adjacent pair of the nodes.
5. The draft force sensor of claim 1, wherein: the strain gauges
are connected electrically in a bridge circuit between four nodes,
and strain gauges on top and bottom sides of the wall of each bore
are connected in series between an adjacent pair of the nodes.
6. The draft force sensor of claim 1, wherein: the first bore is
positioned above the second bore and spaced apart from the first
bore.
7. The draft force sensor of claim 5, wherein: each bore has a
horizontal axis which extends perpendicular to the main
fore-and-aft axis.
8. The draft force sensor of claim 1, wherein: each bore has a
horizontal axis which extends perpendicular to the main
fore-and-aft axis.
9. The draft force sensor of claim 1, wherein: each bore extends
through the coupling member.
10. In a coupling member for coupling a towed earth engaging
implement to a towing vehicle and for transmitting draft forces
along a draft force line, a draft force sensor comprising: first
and second bores in the coupling member, each of the bores being
surrounded by an outer cylindrical wall, each bore having an axis
which extends perpendicular to the draft force line, the second
bore being spaced apart from the first bore along a separation line
which is perpendicular with respect to the draft force line, said
separation line extending through the bore axis of both bores; and
a plurality of electrical strain gauges spaced apart and placed on
the wall of each of the bores, the strain gauges being connected
electrically in a bridge circuit, the bridge circuit generating a
draft force signal in response to draft forces applied to the
coupling member.
11. A draft force sensor for a scraper tongue coupled between a
towing vehicle and a towed scraper, the draft force sensor
comprising: first and second bores extending through a portion of
the tongue, each of the bores being surrounded by an outer
cylindrical wall, each bore having an axis which extends
perpendicular to a main fore-and-aft axis of the tongue, the bores
being spaced apart along a separation line which is perpendicular
to said main fore-and-aft axis, said separation line extending
through the bore axis of both bores; and a plurality of electrical
strain gauges being spaced apart and placed on the wall of each of
the bores, the strain gauges being connected electrically in a
circuit, the circuit generating a draft force signal in response to
draft forces applied to the tongue.
12. The draft force sensor of claim 11, wherein: one of the bores
is positioned directly above the other bore.
Description
BACKGROUND
[0001] The present invention relates to a draft force sensor for a
towed or drawn implement, such as a drawn scraper.
[0002] Certain commercially available drawn scrapers are pulled by
a towing vehicle, such as a tractor, and have tongue which is
coupled to the towing vehicle. Scraper draft force or load is
transmitted to the towing vehicle through the tongue. It is
believed that scraper productivity and performance can be improved
if the scraper draft force is controlled. This requires force
sensors to sense the scraper draft force.
[0003] It has been attempted to sense or measure the draft load of
a drawn scraper using load pins, load cells, and other methods.
However, a load pin at a scraper pivot will experience wear with
scraper use. The wires from a load pin would be exposed and subject
to damage. Such a draft force sensor must also be sensitive to
forces acting along a fore-and-aft direction and insensitive to
forces acting in other directions.
[0004] U.S. Pat. No. 3,246,701 discloses a tractor hitch control
system with electronic draft force sensing. Draft forces are sensed
by strain gauges mounted on the walls of bores in each of the left
and right hitch lower draft links. Such an arrangement of draft
links and sensor bores is not suitable for the coupling of an
implement such as a scraper where the implement is coupled through
a single pivot/tongue coupling. Also, with single bores in each
draft link, the strain gauges are sensitive to bending of the draft
links, rather than only to draft forces transmitted along the main
axis of the links.
SUMMARY
[0005] Accordingly, an object of this invention is to provide a
draft force sensor which is not subject to wear.
[0006] A further object of the invention is to provide such a draft
force sensor which is sensitive to forces acting along a
fore-and-aft direction and insensitive to forces acting in other
directions.
[0007] These and other objects are achieved by the present
invention, wherein a draft force sensor is provided for a coupling
member coupled between a towing vehicle and a towed earth engaging
implement, such as a scraper. The draft force sensor includes first
and second bores extending through the coupling member. Each bore
has a horizontal axis which extends perpendicular to a main
fore-and-aft axis of the coupling member. The second bore is
positioned above the first bore and spaced apart from the first
bore. Each of the bores is surrounded by an outer cylindrical wall.
Four electrical strain gauges are spaced apart and placed on the
wall of each of the bores. A center line bisects an axis line which
extends between the axes of the first
[0008] hand second bores. The axis of each bore is spaced apart
from the center line by a distance which is less than a diameter of
the bores. The strain gauges are connected electrically in a
circuit which generates a draft force signal in response to draft
forces applied to the coupling member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a simplified perspective view of a towed scraper
having a tongue for coupling to a towing vehicle;
[0010] FIG. 2 is a side elevation view of a scraper tongue
including the present invention;
[0011] FIG. 3 is an enlarged view of a portion of FIG. 2; and
[0012] FIG. 4 is a circuit diagram showing the electrical
connection of the strain gauges of FIG. 3.
DETAILED DESCRIPTION
[0013] Referring to FIG. 1, a towed earth working implement 10,
such as a scraper includes a tongue 12 with an arm 13 and a hitch
pivot member 14 for connecting to a towing vehicle (not shown),
such as a tractor. The tongue will transmit draft forces from the
towed implement 10 to the towing vehicle generally along a
fore-and-aft longitudinal axis of the tongue 12.
[0014] As best seen in FIG. 2, the pivot member 14 has body 16 with
a vertically smaller front end 18 and a vertically larger rear end
20. A plurality of bolt holes 22 are formed in the rear end 20 for
bolting to the arm 13. A hollow cylinder 24 is fixed to front end
18 for receiving a coupling or pivot pin (not shown). A pair of
identical sensor bores 26 and 28 with diameter D extend through the
front end portion of the pivot member 14. Each of the first and
second bores 26, 28 has an axis which extends perpendicular to a
main fore-and-aft axis of the pivot member 14, and the bores are
spaced apart from each other along a line which is generally
perpendicular with respect to the main fore-and-aft axis. A
Y-shaped groove 29 is ground into the surface of the pivot member
14 to connect the bores 26, 28 with the aft end of the pivot member
14.
[0015] Although other orientations are possible, the pivot member
14 preferably has a vertical orientation. In this case, the bores
26, 28 have horizontally extending axes, and bore 26 is positioned
directly above the bore 28. The bores 26, 28 are surrounded by
cylindrical walls 30, 32, respectively.
[0016] As best seen in FIG. 3, a plurality, preferably four, strain
gauges 40, 42, 44, 46 are mounted on wall 30 of bore 26, and four
strain gauges 50, 52, 54, 56 are mounted on wall 32 of bore 28.
Also, as best seen in FIG. 3, strain gauges 40, 42, 44, 46 are
positioned at 9, 12, 3 and 6 o'clock orientations, respectively, on
wall 30, and strain gauges 50, 52, 54, 56 are positioned at 9, 12,
3 and 6 o'clock orientations, respectively, on wall 32.
[0017] A center line 34 (which is parallel to the line through
which draft forces are transmitted) bisects an axis line 36 which
extends between the axes of the bores 26, 28. The axis of each bore
is spaced apart from the center line by a distance d which is less
than the diameter D of the bores 26, 28. For example, if the bores
have a diameter D of 50 millimeters, it was found that a distance d
of 40 millimeters results in optimum performance.
[0018] Referring now to FIG. 4, the strain gauges 40-56 are
connected electrically in a bridge circuit 70 between circuit nodes
60, 62, 64 and 66. More specifically, strain gauges 40 and 44 on
opposite sides of the wall 30 of the first bore 26 are connected in
series between adjacent nodes 66 and 60. Strain gauges 42 and 46 on
the top and bottom of wall 30 are connected in series between
adjacent nodes 60 and 62. Strain gauges 50 and 54 on opposite sides
of the wall 32 of bore 28 are connected in series between adjacent
nodes 62 and 64. Strain gauges 52 and 56 on the top and bottom of
wall 32 are connected in series between adjacent nodes 64 and
66.
[0019] An excitation signal is applied to nodes 60 and 64. A sensor
signal representing draft force applied to pivot member 14 is
generated across nodes 62 and 66. Wires from the bridge circuit 70
are routed through and protected by the Y-shaped groove 29.
[0020] The resulting draft force sensor is sensitive to forces
acting along a fore-and-aft direction and insensitive to forces
acting in other directions. Using two bores doubles the signal
output with respect to what could be achieved with only a single
bore. The number and position of the bores and the arrangement of
strain gages described above maximize the fore/aft draft force
signal output while minimizing the effect of side and vertical
loads during scraper operation, and also provide a strong and
durable scraper tongue.
[0021] While the present invention has been described in
conjunction with a specific embodiment, it is understood that many
alternatives, modifications and variations will be apparent to
those skilled in the art in light of the foregoing description.
Accordingly, this invention is intended to embrace all such
alternatives, modifications and variations which fall within the
spirit and scope of the appended claims.
* * * * *