Mobile conveyor including alignment system

An articulated apparatus including a first section having first and second ends, and a length between the first and second ends; a second section having first and second ends, and a length between the first and second ends; a joint connecting the second end of the first section to the first end of the second section for pivotal movement about a first axis; and a cylinder/piston assembly having a piston connected to the first section and movable with the first conveyor section, and having a cylinder mounted to the second section and movable with the second section, the piston being slidably received in the cylinder, and a transmitter and a receiver capable of determining the location of the piston in the cylinder, the transmitter and receiver being located within the cylinder.

TECHNICAL FIELD 
This invention relates to articulated mobile conveyors. More particularly, 
the invention relates to an articulated mobile conveyor including a system 
for aligning articulated sections of the mobile conveyor with one another. 
BACKGROUND OF THE INVENTION 
Articulated mobile conveyors are used for various purposes, such as in 
mining, or in agricultural harvesting. For example, the conveyors can be 
used for excavating, stacking, or reclaiming material such as ore, coal, 
granite, clay, salt, potash, or other bulk material. The mobile conveyors 
include articulated sections. The sections are joined to one another 
using, for example, ball joints. This enables rotational translation of 
one section relative to another in view of grade changes in the ground 
over which the sections lie. This also provides flexibility between 
segments when the conveyor is moved. Each section supports an endless loop 
belt which transports material over the length of the conveyor. Each 
section is separately movable relative to the ground and includes, for 
example, wheels or tracks in contact with the ground below the section. 
Each section has its own drive motor for moving the section relative to 
the ground. Thus, the entire conveyor can be moved or transported, such as 
when it is desired to harvest or mine in a different location, or when it 
is desired to transversely move the conveyor as material is stripped away 
from the surface of the earth or is moved from large storage piles. For 
examples of such articulated mobile conveyor, see the following patents 
which are incorporated herein by reference: U.S. Pat. No. 4,206,840 to 
Hanson; U.S. Pat. No. 4,031,997 to Nelson; and U.S. Pat. No. 3,361,248 to 
Daymon. 
While moving the conveyor relative to the ground, it may be desirable to 
longitudinally align two or more adjacent sections. See, for example, U.S. 
Pat. No. 3,422,949 to Bankauf. Bankauf discloses a guide follower which, 
upon too much misalignment, activates a hydraulic system to cause 
steerable wheels to turn. 
After moving the conveyor, it may be desirable to align two or more 
adjacent sections relative to one another such that the endless belts 
extend along a straight line in a common vertical plane, such as for 
better belt training from one section to the next. Prior art mechanisms 
typically employ a series of pulleys and cables connected to each 
adjoining section for determining when precise longitudinal alignment has 
been reached. U.S. Pat. No. 3,897,640 to Swisher, Jr. et al. discloses a 
conveyor including an alignment switch and a sensor connected to the 
alignment switch for correctingly moving the conveyor to maintain the 
position of the conveyor at a predetermined alignment position, and is 
incorporated herein by reference.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
This disclosure of the invention is submitted in furtherance of the 
constitutional purposes of the U.S. Patent Laws "to promote the progress 
of science and useful arts" (Article 1, Section 8). 
The invention provides an articulated mobile conveyor which is movable 
relative to the ground, the conveyor comprising a first conveyor section 
including a frame having first and second ends, and a length between the 
first and second ends, the frame being supported from the ground for 
movement relative to the ground in at least a direction transverse to the 
length; a second conveyor section including a frame having first and 
second ends, and a length between the first and second ends, the frame of 
the second conveyor section being supported from the ground for movement 
relative to the ground in at least a direction transverse to the length of 
the second conveyor section; a joint connecting the second end of the 
first conveyor section to the first end of the second conveyor section for 
pivotal movement about a first axis; and a cylinder/piston assembly having 
a piston connected to the first conveyor section and movable with the 
first conveyor section, having a cylinder mounted to the second conveyor 
section and movable with the second conveyor section, the piston being 
slidably received in the cylinder, and a transmitter and a receiver 
capable of determining the location of the piston in the cylinder, the 
transmitter and receiver being located within the cylinder. 
One aspect of the invention provides an articulated mobile conveyor which 
is movable relative to the ground, the conveyor comprising a first 
conveyor section including first and second ends, means for conveying 
material between the first and second ends, means for moving the section 
relative to the ground, and a length between the first and second ends; a 
second conveyor section including first and second ends, means for 
conveying material between the first and second ends of the second 
conveyor section, means for moving the second section relative to the 
ground, and a length between the first and second ends of the second 
conveyor section; means connecting the second end of the first conveyor to 
the first end of the second conveyor for pivotal movement about a first 
axis; and means for aligning the first conveyor section with the second 
conveyor section, such that the length of the first conveyor section is 
parallel to the length of the second conveyor section, the aligning means 
including a cylinder/piston assembly having a piston supported by the 
first conveyor section, and a cylinder supported by the second conveyor 
section, the piston being slidably received in the cylinder, and the 
aligning means further including means, including a transmitter, for 
determining the location of the piston in the cylinder. 
Another aspect of the invention provides an articulated conveyor comprising 
a first conveyor section including first and second ends; a second 
conveyor section including first and second ends; a joint connecting the 
second end of the first conveyor section to the first end of the second 
conveyor section; and an aligner selectively aligning the first conveyor 
section with the second conveyor section, the aligner including an 
ultrasonic transmitter. 
Another aspect of the invention provides an articulated apparatus 
comprising a first section having first and second ends, and a length 
between the first and second ends; a second section having first and 
second ends, and a length between the first and second ends; a joint 
connecting the second end of the first section to the first end of the 
second section for pivotal movement about a first axis; and a 
cylinder/piston assembly having a piston connected to the first section 
and movable with the first conveyor section, and having a cylinder mounted 
to the second section and movable with the second section, the piston 
being slidably received in the cylinder, and a transmitter and a receiver 
capable of determining the location of the piston in the cylinder, the 
transmitter and receiver being located within the cylinder. 
Another aspect of the invention provides an apparatus for measuring length, 
the apparatus comprising a cylinder; a piston slidably received in the 
cylinder; an ultrasonic transmitter in the cylinder; and an ultrasonic 
receiver in the cylinder, the receiver cooperating with the transmitter to 
determine the location of the piston in the cylinder. 
Shown in the various figures is an articulated mobile conveyor 10 which 
embodies the invention. The conveyor 10 includes a first conveyor section 
12. The first conveyor section 12 includes a frame 14 having first and 
second ends 16 and 18, and a length L1 between the first and second ends 
16 and 18. The frame 14 is supported from the ground 20 for movement 
relative to the ground 20 in at least a direction transverse to the length 
of the first conveyor section 12. More particularly, in the illustrated 
embodiment, the first conveyor section 12 comprises wheels 22 supporting 
the frame 14 from the ground 20, and a motors 24 selectively driving the 
wheels 22 to move the conveyor section 12 over the ground 20. The wheels 
22 are preferably steerable. Endless tracks or other arrangements can be 
employed instead of the wheels 22. 
The conveyor 10 further includes a second conveyor section 26 which is 
similar to the first conveyor section 12. The second conveyor section 26 
includes a frame 28 having first and second ends 30 and 32, and a length 
L2 between the first and second ends. The frame of the second conveyor 
section 26 is supported from the ground 20 for movement relative to the 
ground 20 in at least a direction transverse to the length L2 of the 
second conveyor section 26. More particularly, in the illustrated 
embodiment, the second conveyor section 26 comprises wheels 34 supporting 
the frame 28 from the ground 20, and a motor 36 selectively driving the 
wheels 34 to move the conveyor section 26 over the ground 20. The conveyor 
10 further includes additional conveyor sections (not shown). 
The conveyor 10 further includes rollers 37 included in each conveyor 
section, and a material carrying flexible member 39, such as a belt, 
supported by the rollers 37 (FIG. 2). The conveyor includes an appropriate 
drive means or motor (not shown) for driving the flexible member 39 around 
a loop defined by the combined length of joined conveyor sections. The 
conveyor 10 includes a joint 38 (FIG. 2) connecting the second end 18 of 
the first conveyor section 12 to the first end 30 of the second conveyor 
section 26 for pivotal movement about an axis 40 (FIG. 3) which is a 
vertical axis if the conveyor is on even ground. In the illustrated 
embodiment, the joint 38 is a ball joint which further provides for 
pivotal movement about an axis 42 (FIG. 2) which is a horizontal axis when 
the conveyor 10 is on level ground. 
The conveyor 10 further includes an aligner or means for aligning the first 
conveyor section with the second conveyor section, such that the length of 
the first conveyor section is parallel to the length of the second 
conveyor section. While other means could be employed, the illustrated 
aligning means comprises a cylinder/piston assembly 44 having a piston 46 
connected to the first conveyor section 12 and movable with the first 
conveyor section 12 (FIG. 3). The cylinder/piston assembly 44 further has 
a cylinder 48 (FIG. 8) mounted to the second conveyor section 26 with 
mounting hardware 49 (FIG.3), and movable with the second conveyor section 
26. The conveyor 10 includes a cover 45 covering the cylinder/piston 
assembly 44, and the mounting hardware 49 includes a roller 47 supporting 
one end of the cover 45. The piston 46 is slidably received in the 
cylinder 48. The piston 46 is movable within the cylinder 48 along an axis 
50. The axis 50 extends between securing points defined by the mounting 
hardware 49 and a pivot 64 (described below in more detail). The cylinder 
48 includes an endwall 52, and the piston 46 has a head 54 which moves 
toward and away from the endwall 52 to define a variable volume chamber 56 
between the piston head 54 and the cylinder endwall 52. 
The aligning means further comprises an ultrasonic transmitter and an 
ultrasonic receiver located within the cylinder. The transmitter and 
receiver are capable of determining the location of the piston 46 in the 
cylinder 48. The transmitter is located in the chamber at the endwall 52, 
and the transmitter is mounted to transmit a signal against the piston 
head. The receiver is mounted to receive the signal after it is reflected 
from the piston head. The aligning means further comprises a timer 
connected to the transmitter and receiver. The timer calculates the amount 
of time for the signal to travel from the transmitter to the receiver, the 
signal being reflected from the piston head to the receiver. 
In one embodiment of the invention, the transmitter, receiver, and timer 
are all comprised by an integrated contactless distance measuring device 
or proximity sensor 58. In one embodiment, the integrated measurement 
device 58 is a model sold by Contaq Technologies Corporation, 15 Main 
Street, Bristol, Vt. 05443, such as the Model UDM-FL, or the "ISU Series". 
Various other integrated measurement devices could be employed. 
The cylinder/piston assembly 44 further includes sealing and bearing 
structure 92 at an end of the cylinder opposite the endwall 52. This 
structure guide the piston 46, and includes bearings 94, and an O-ring 96. 
The measuring device 58 provides a distance signal, via cable 60, which 
indicates the extent of the piston 46 within the cylinder 48, and 
therefore the extent of misalignment. The first and second conveyor 
sections 12 and 26 can then be either manually or automatically moved 
until the extent of the piston within the cylinder is equal, within 
tolerance, to a predetermined extent of the piston 46 within the cylinder 
48. The predetermined extent corresponds to the first and second conveyor 
sections 12 and 26 being aligned. In the illustrated embodiment, a 
conventional control system (not shown) moves the first and second 
conveyor sections 12 and 26 into alignment, by operating the motors 24 and 
36, based on the distance signal generated by the measuring device 58. In 
the illustrated embodiment, the control system comprises a PLC. The 
control system performs logic as illustrated in FIG. 10, that will be 
described below. 
The conveyor 10 includes a support 62 connecting the piston/cylinder 
assembly 44 to the first conveyor section 12. The support 62 includes a 
pivot 64 providing for pivotal movement about an axis in the same 
horizontal plane as the joint 38. More particularly, the pivot 64 provides 
for pivotal movement about the axis 42. In the illustrated embodiment, the 
pivot 64 is a spherical joint. This enables the conveyor sections 12 and 
26 to pivot about the joint 38, and the pivot 64 thereby accommodates 
differences in terrain over which the conveyor sections 12 and 26 are 
located without impacting on the aligner. For example, if the section 12 
was raised in the view shown in FIG. 3, the pivot 64 will permit pivoting 
about the axis 42, and the cover 45 would move to the left over roller 47. 
The conveyor 10 further includes maximum out of alignment limit switches 
66. If either of these switches engages wall 70 of the cover 45 (FIG. 5), 
the control system will shut down the conveyer 10, and the belt 39 will 
not operate. As shown in FIGS. 3 and 4, the cover 45 has an end 72 which 
is fixed against movement in a horizontal direction relative to the 
support 62, by connecting hardware 74, to the support 62, and has an 
opposite end 76 which rides on roller 47 and is free to move in the 
horizontal direction. 
The conveyor 10 further includes parallel, spaced apart, tripper bridge 
assemblies 78 (FIG. 2). Each tripper bridge assembly 78 includes a hollow, 
elongated piece 80 having an end 82 connected to section 12 for rotation 
about a horizontal axis, and includes an elongated piece 84 telescopically 
received in the piece 80 and having an end 86 connected to section 26 for 
rotation about a horizontal axis. The tripper bridge assemblies 78 provide 
for axial displacement, but enhance structural integrity of the conveyor 
The conveyor 10 further includes dog legs 88. The dogs legs 88 each have 
one end connected to the section 12 and another end connected to the 
section 26 via spherical rod ends 90. The dog legs 88 are structural 
members which transmit torsion between sections 26 and 12. The allow for 
plan view deflection while maintaining torsional rigidity. 
The logic performed by the control system is shown in FIG. 10. 
In step S1, the alignment system (aligner) is initiated. After performing 
step S1, the control system proceeds to step S2. 
In step S2, the control system reads pre-set (predetermined desired) 
alignment values that indicate frame alignment and compares these 
alignment values with ultrasonic readings (readings from sensors 58 
indicating actual alignment condition). After performing step S2, the 
control system proceeds to step S3. 
In step S3, the control system determines whether any of the limit switches 
66 have been tripped. If so, the control system proceeds to step S4. If 
not, the control system proceeds to step S5. 
In step S4, the control system indicates to an operator (e.g., visually or 
audibly) that the conveyor is out of alignment by more than a maximum 
amount, and stops executing. 
In step S5, the control system determines whether the piston 46 is moving 
such that readings of the sensor 58 are increasing over the pre-set 
(initialized) values measured in step S2. If so, the control system 
proceeds to step S6. If not, the control system proceeds to step S7. 
At step S6, the control system causes the conveyor sections 12 and 26 to 
pivot right relative to one another (about axis 40), so as to move toward 
the pre-set values, until the pre-set values are reached. After performing 
step S6, alignment is complete, and the control system terminates 
alignment activity. 
In step S7, the control system determines whether the piston 46 is moving 
such that readings of the sensor 58 are decreasing over the pre-set 
(initialized) values measured in step S2. If so, the control system 
proceeds to step S8. If not, the control system proceeds to step S2. 
At step S8, the control system causes the conveyor sections 12 and 26 to 
pivot left relative to one another (about axis 40), so as to move toward 
the pre-set values, until the pre-set values are reached. After performing 
step S8, alignment is complete and the control system terminates alignment 
activity. 
Thus, a conveyor has been disclosed which includes a system for aligning 
adjacent sections without the need for a complicated mechanism, such as a 
mechanism having a series of pulleys and cables. 
In compliance with the statute, the invention has been described in 
language more or less specific as to structural and methodical features. 
It is to be understood, however, that the invention is not limited to the 
specific features shown and described, since the means herein disclosed 
comprise preferred forms of putting the invention into effect. The 
invention is, therefore, claimed in any of its forms or modifications 
within the proper scope of the appended claims appropriately interpreted 
in accordance with the doctrine of equivalents.