U.S. patent application number 09/764760 was filed with the patent office on 2001-08-16 for device for steering a conveyor belt.
Invention is credited to Malmberg, Mats Anders.
Application Number | 20010013462 09/764760 |
Document ID | / |
Family ID | 20416863 |
Filed Date | 2001-08-16 |
United States Patent
Application |
20010013462 |
Kind Code |
A1 |
Malmberg, Mats Anders |
August 16, 2001 |
Device for steering a conveyor belt
Abstract
For steering a conveyor belt (11) and centring the same relative
to the intended path of travel of the belt, use is made of a belt
position detecting means (22, 23) and belt readjusting means (24).
The belt readjusting means (24) is a belt support roller (24) which
is adapted to engage and roll against the belt and which is
pivotable relative to the belt. According to the invention, the
belt position detecting means (22, 23) and the belt support roller
(24) are arranged on a roller cradle (21) which is connected with a
frame (29) by means of inclined links (30) for pivoting and setting
the belt support roller (24) in a pivoting position, in which the
belt support roller by engaging the belt exerts a readjustment
force thereon.
Inventors: |
Malmberg, Mats Anders;
(Trelleborg, SE) |
Correspondence
Address: |
Jeffrey D. Shewchuk
THE KINNEY & LANGE BUILDING
312 South Third Street
Minneapolis
MN
55415-1002
US
|
Family ID: |
20416863 |
Appl. No.: |
09/764760 |
Filed: |
January 16, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09764760 |
Jan 16, 2001 |
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PCT/SEOO/01081 |
May 26, 2000 |
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Current U.S.
Class: |
198/836.3 |
Current CPC
Class: |
B65G 39/16 20130101 |
Class at
Publication: |
198/836.3 |
International
Class: |
B65G 015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 3, 1999 |
SE |
9903134-6 |
Claims
1. A belt steering device for adjusting the lateral position of a
conveyor belt (11) relative to an intended belt travelling path,
comprising a frame (29) and belt position detecting and readjusting
means (21-24; 36, 37), which have at least one belt support roller
(24; 36, 37) being arranged for pivotal movement relative to the
frame and engaging the belt, and which have belt position detecting
means (22, 23) operatively connected with the belt support roller
and intended for pivoting and setting the belt roller (24; 36, 37)
in a pivoting position, in which the belt roller by its engagement
with the belt exerts a readjustment force thereon, characterised in
that the belt support roller (24; 36, 37) and the belt position
detecting means (22, 23) are arranged on a roller cradle (21), that
the roller cradle is pivotally connected with the frame (29) by
means of at least one inclined link (30) on each side of the
intended path of travel of the conveyor belt, that the inclined
links (30) are at one end articulated to the stand (29) by means of
a first pivot (31) and at their other end articulated to the roller
cradle (21) by means of a second pivot (32), the distance between
the first pivots (31) arranged on either side of the belt differing
from the distance between the second pivots (32) arranged on either
side of the belt, and that the belt position detecting means (22,
23) are attached to the roller cradle (21).
2. A belt steering device as claimed in claim 1, characterised in
that the distance between said first pivots (31) on the frame (29)
is shorter than the distance between said second pivots on the
roller cradle (21), and that the roller cradle (21) and its belt
support roller (24) are adapted to support the conveyor belt
against the side of the belt support roller facing away from said
first pivots (31) of the frame (29).
3. A belt steering device as claimed in claim 1, characterised in
that the distance between said first pivots (31) on the frame (29)
is longer than the distance between said second pivots (32) on the
roller cradle (21), and that the roller cradle (21) and its belt
support roller (24) are adapted to support the conveyor belt
against the side of the belt support roller facing said first
pivots (31) of the frame (29).
4. A belt steering device as claimed in claim 1, 2 or 3,
characterised in that the roller cradle (21) comprises belt support
rollers (36, 37) which are inclined for cupping the conveyor belt
(11).
5. A belt steering device as claimed in any one of claims 1-4,
characterised in that on each side of the intended path of travel
of the conveyor belt (11), the roller cradle (21) has two belt
position detecting means (22, 23) which are arranged at a distance
from one another, seen in the direction of travel of the conveyor
belt.
6. A belt steering device as claimed in any one of claims 1-5,
characterised in that the links (30) are inclined at an angle of
about 45.degree. to the roller cradle (21).
Description
[0001] The present invention relates to a device for steering a
conveyor belt in a belt conveyor.
[0002] A common problem when operating belt conveyors is the
tendency of the conveyor belt in operation to move laterally
relative to the intended path of travel through the conveyor.
Lateral displacement, i.e. displacement of the conveyor belt
transversely of its direction of travel, may cause, inter alia,
damage to the belt by the belt edges coming into contact with fixed
parts on the belt conveyor frame.
[0003] In order to solve this problem, many conveyors have been
provided with one or more support rollers which support the
conveyor belt during its return travel and which are manually
angularly adjustable relative to the intended direction of travel
of the belt. The angular orientation of these support rollers is
adjusted during the running-in of the belt conveyor to ensure that
in normal operational conditions the belt will travel through the
conveyor in a correctly centred manner. If a tendency towards
lateral displacement should arise in operation, due for instance to
elongation of the conveyor belt during operation or to dirt and
deposits accumulating on the end rollers of the conveyor manual
postadjustment of the set angular position of these support rollers
is necessary. Supplementary work is required therefor and
furthermore in many cases the conveyor must be stopped during the
adjustment work. By setting a support roller at an angle it is thus
possible to compensate for the tendency of the belt to run out of
line by moving laterally relative to its intended direction of
travel.
[0004] Moreover, devices have been suggested serving to
automatically adjust the conveyor for adaptation thereof to such
lateral motions of the conveyor belt. Such an automatic
self-adjusting or self-aligning device is shown and described in
NO-C-178853 and the corresponding PCT Publication WO9514627.
However, this prior-art device does not aim at adjusting the
position of the belt to maintain it in a centred position relative
to the centre line of the conveyor frame but at ensuring that the
support rollers are constantly directed perpendicular to the
conveyor belt, whether the conveyor belt is centred or not. This
aim is achieved by arranging for the belt side edges to travel
along edge guide rollers arranged at one end of a double-arm lever,
whose other end supports a stand in which the support roller is
mounted. This mounting stand, which in its simplest form is a
plate, is in turn pivotally connected with the double-arm lever.
When the latter pivots in response to the engagement of the guide
rollers with the belt edges, the support roller will automatically
set itself at right angles to the belt travelling direction. In
this prior-art device, return of the belt to the intended centre
line of the path of travel of the belt might be achieved as a
result of the edge guide rollers trying to push the belt back to a
centred position.
[0005] It has also been suggested that the belt be centred by
letting it travel over a support roller stand containing two belt
support rollers which are inclined and each engage a lateral edge
portion of the belt in order to cup the belt around the central
portion of the belt. This technique of achieving centring, however,
does not always give the intended result.
[0006] An improvement in relation to these prior-art devices is
described in SE-C-507733 and the corresponding WO9819943. This
device for steering a conveyor belt is capable of automatically
returning a conveyor belt to the intended central position along a
path of travel. Thus the steering device causes the conveyor belt
to move as much as possible in a centred fashion over support
rollers, drive rollers and end rollers in a belt conveyor.
[0007] This prior-art device for steering a conveyor belt starts
from the idea, known per se, of using a belt roller to compensate
for the tendency towards lateral displacement of the belt. What
differs this belt steering device from those previously known is
that the angular orientation of the support roller occurs
automatically and that the degree of obliqueness is determined by
the extent of the lateral movement of the conveyor belt relative to
the intended path of travel along the belt conveyor. For detecting
the degree of displacement of the conveyor belt relative to the
intended path, use is made of belt position detecting means which
are connected with the belt support roller via a linkage system for
pivoting in the principal plane of the belt and setting of the belt
support roller in a pivoting position, in which the belt support
roller, owing to its engagement with the belt, exerts a readjusting
force on the belt, so that the conveyor belt is steered back and is
centred relative to the intended path of travel of the belt.
According to SE-C 507733 and the corresponding WO9819943, the belt
readjusting means thus is a belt support roller which engages the
belt and rolls against the same and which is pivotable in the
principal plane of the belt, and the belt position detecting means
is connected with the belt support roller via a linkage system for
pivoting and adjusting the belt support roller in a pivotal
position, in which the belt support roller, owing to its engagement
with the belt, exerts a readjustment force on the belt.
[0008] This prior-art conveyor belt steering device functions very
well but suffers from one drawback--it functions merely in one belt
travelling direction. This means that the prior-art conveyor belt
steering device cannot be used in conveyor belt installations
having a reversible direction of travel of the conveyor belt since,
when reversing the direction of travel of the belt, the belt
position detecting means and the belt readjusting means must change
places and also the linkage system must be turned around.
[0009] An object of the invention therefore is to provide a new
conveyor belt steering device which functions well independently of
the direction of travel of the conveyor belt and which therefore
can be used also for conveyor belt installations with reversible
conveyor belts.
[0010] The invention is based on the per se known idea of using
belt position detecting means which detect the lateral position of
the conveyor belt relative to the intended path of travel of the
belt and which are operatively connected with belt readjusting
means which actuate the conveyor belt to be returned to the
intended centred position along the intended path of travel of the
belt. The novel feature of the invention is how the belt
readjusting means is designed and connected with the belt position
detecting means and how the readjustment of the conveyor belt
occurs.
[0011] That characterising the invention is stated in the
independent claim while the dependent claims define particularly
preferred embodiments of this invention.
[0012] To sum up, the invention can be considered to reside in belt
position detecting means and belt readjusting means being arranged
on a roller cradle which is connected with a frame by means of
inclined links for pivoting and setting the belt roller in a
pivoting position, in which the belt support roller is inclined to
exert, by engaging the belt, a readjustment force on the same.
[0013] The invention will be now be described in more detail with
reference to the accompanying drawings which illustrate a few
embodiments of a belt steering device according to the present
invention.
[0014] FIG. 1 is a schematic view of a belt conveyor provided with
a belt steering device according to the present invention.
[0015] FIG. 2 is an end view of a first preferred embodiment of a
belt steering device according to the present invention.
[0016] FIG. 3 is a top plan view of the belt steering device shown
in FIG. 2 in its position when the conveyor belt travels in a
centred manner along the intended path of travel through the belt
conveyor.
[0017] FIG. 4 is an end view of the belt steering device in FIG. 3
with a section through the conveyor belt.
[0018] FIG. 5 illustrates the same belt steering device as in FIG.
3 but in a position in which the belt has been displaced in one
direction relative to its intended centred position and in which
the belt support roller of the belt steering device has been
automatically inclined to return the belt to the intended centred
position.
[0019] FIG. 6 is an end view of the same belt steering device as in
FIG. 5, with a section through the conveyor belt.
[0020] FIG. 7 is a top plan view of a second preferred embodiment
of a belt steering device according to the invention in its
position when the conveyor belt travels in a centred manner along
the intended path of travel through the belt conveyor.
[0021] FIG. 8 is an end view of the same belt steering device as in
FIG. 7, with a section through the conveyor belt.
[0022] FIG. 9 illustrates the same belt steering device as in FIG.
7 but in a position in which the belt has been displaced in one
direction relative to its intended centred position and in which
the belt support roller of the belt steering device has been
automatically inclined to return the belt to the intended centred
position.
[0023] FIG. 10 is an end view of the same belt steering device as
in FIG. 9, with a section through the conveyor belt.
[0024] FIG. 11 illustrates a third embodiment which corresponds to
the embodiment according to FIGS. 2-6 but which has inclined belt
support rollers for cupping the conveyor belt.
[0025] FIG. 12 illustrates a fourth embodiment which corresponds to
the embodiment according to FIGS. 7-10 but which has inclined belt
support rollers for cupping the conveyor belt.
[0026] FIG. 1 illustrates schematically a belt conveyor 10. It
comprises an endless conveyor belt 11 which travels between end and
drive rollers 12. The belt conveyor has a loading station 13 and an
unloading station 14. To support the upper run of the conveyor belt
between the end rollers 12 there are belt support rollers 17. Also
under its return run 16, the belt is supported by means of belt
support rollers 18, which, however, can be arranged at a greater
distance from each other than the belt support rollers 17.
According to the invention, the belt conveyor is provided with an
automatic belt steering device 20, which in this embodiment is
placed along the return run 16 close to the loading end of the belt
conveyor. Within the scope of the invention, a belt conveyor can
have a plurality of such belt steering devices 20.
[0027] A preferred embodiment of the belt steering device 20 is
shown in more detail in FIGS. 2-6. The belt steering device
comprises a roller cradle 21, which supports two belt position
detecting means 22, 23 and a belt support roller 24 which is
directed essentially transversely of the intended path of the
travel of the conveyor belt (arrows 25). In the shown embodiment,
the roller cradle has two transverse bars 26. Roller holders 27 are
arranged between the bars 26 and attached thereto by means of
sleeves 28. In the shown embodiment, two belt detecting means 22
are arranged on one side of the conveyor belt and two belt
detecting means 23 on the other side of the conveyor belt, so that
the forces exerted on the roller cradle when the conveyor belt
moves in the lateral direction, are equalised. However, it is also
possible to use only one belt detecting means on each side of the
conveyor belt.
[0028] The belt position detecting means 22, 23 are in the form of
rollers which are rotatably mounted to roll against the edges of
the conveyor belt in operation.
[0029] The roller cradle 21 is connected with the frame stand 29 of
the conveyor belt installation by means of links 30. The links are
pivotable on a pivot 31 on the frame and a pivot 32 on the roller
cradle 21 and are inclined because the distance between the pivots
31 on the frame is greater than the distance between the pivots 32
on the roller cradle 21. The pivots 31, 32 on the roller cradle 21
are attached to a crossbar 36 with end sleeves 34, through which
the bars 26 are passed and which are attachable to the bars 26 in a
suitable position for controlling the distance between the pivots
32 and, thus, the angle of the links relative to the bars. In this
example, there are double links at each end of the roller cradle,
but in certain cases one link at each end may be sufficient.
[0030] The conveyor belt 11 travels in contact with the belt
support roller 24 on the far side of the bars 26 of the roller
cradle. A pressing force is maintained between the conveyor belt
and the belt support roller 24 due to the fact that the belt
roller, as is evident from FIG. 2, is arranged in such a position
that the conveyor belt is pressed downwards between two successive
belt support rollers 18 in the conveyor belt installation.
[0031] The function of the device is evident when comparing FIGS. 3
and 4 with FIGS. 5 and 6. In FIGS. 3 and 4, the conveyor belt 11
travels in its neutral position along the intended path of the
travel. If the conveyor belt for one reason or another should begin
to move to the left in respect of FIGS. 3 and 4, the left edge of
the conveyor belt will be caught by the belt position detecting
means or rollers 22, which consequently will be displaced to the
left (arrows 35). Since the rollers 22 are connected with the bars
26 and cannot be displaced along the same, this will cause the
roller cradle to be pivoted downwards at the left side (with
respect to FIGS. 4 and 6), so that the entire roller cradle is
inclined. The inclination causes in turn the left edge of the
conveyor belt to have a longer path of travel and thus conveyor
belt begins to move back to the starting position (the neutral
position according to FIGS. 3 and 4).
[0032] If the belt should move to the right, the effect will be the
opposite, i.e. inclination of the roller cradle in the other
direction and return of the belt from the right to the left.
[0033] Since the inclination of the belt support roller 24 occurs
in a plane which is angled to the principal plane of the conveyor
belt, this conveyor belt steering device is independent of the
direction in which the conveyor belt moves through the belt
steering device. This means that the conveyor belt steering device
will function automatically and in a correct manner also when
reversing the belt travelling direction in the conveyor belt
installation. This is in contrast to the currently best known belt
steering device as disclosed in SE-C-507733 and the corresponding
WO9819943.
[0034] The embodiment according to FIGS. 7-10 differs from the
embodiment according to FIGS. 2-6 only in respect of how the links
are angled and how the conveyor belt engages the belt support
roller 24. In this case, the conveyor belt is located on the same
side of the roller cradle as the pivots 31 on the frame 29. For a
lateral displacement of the conveyor belt 11 to be corrected and
the belt be returned to the intended neutral position, the links 32
must be inclined in opposite directions, i.e. the distance between
the pivots 31 of the frame is shorter than the distance between the
pivots 32 of the roller cradle. Otherwise, this conveyor belt
steering device works in the same manner as the steering device
according to FIGS. 2-6. However, there is one difference since, in
the steering device according to FIGS. 2-6, the conveyor belt has
been forced to travel in an arcuate form between two belt support
rollers 18 for the belt to travel with pressing force in contact
with the belt support roller 24. In the steering device according
to FIGS. 7-10, the required pressing force is achieved by the belt
being pressed by gravity against the belt support roller 24.
[0035] FIGS. 11 and 12 illustrate two more embodiments of the
invention. In these two cases, the belt support roller 24 is
replaced by two angled belt support rollers 36, 37 which bear on
opposite rim portions of the conveyor belt 11 in order to cup the
same. Consequently, also the belt position detecting means or
rollers 22, 23 have been inclined to a corresponding degree in
order to roll against the lateral edges of the cupped conveyor
belt. Also in this case, the roller cradle has two parallel bars
26, on which the various components are attachable by means of
sleeves 28, 34.
[0036] In one embodiment (not shown), the central portion of the
belt can also be supported by a belt support roller which in that
case is arranged between the two angled belt support rollers 36, 37
in FIGS. 11 and 12.
[0037] As mentioned above, the links 30 are inclined in one or the
other direction according to the side of the belt support roller
that is pressed against the conveyor belt. The degree of
inclination of the links may vary although an angle of 450 has been
selected. Both the angle and the length of the links affect the
degree of inclination of the roller cradle when the conveyor belt
is displaced laterally. A greater degree of inclination causes a
quicker return of the conveyor belt to the neutral position. A
person skilled in the art can, by simple tests, determine the
degree of inclination which is most convenient in the individual
case.
* * * * *