Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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MOVABLE TRIPPER BELT CONVEYOR
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to belt
conveyors and, more particularly, to belt conveyors in
which a movable tripper unit for delivering the material
being conveyed to a selected one of several receiving
locations along the path of an endless belt is completely
enclosed at all times when material is being conveyed by
the belt and delivered to a selected location.
BACKGROUND OF THE INVENTION
Hansen Manufacturing Corp. Of Sioux Falls, South
Dakota, makes and sells enclosed belt conveyors under the
trademark HI ROLLERTM', in which the belt and the elements
that support it are completely enclosed in a housing,
which includes an elongated, U-shaped structure that is
usually called the "trunking" and a cover over the open
top of the trunking. The covered trunking provides a
structural support for troughing idlers, the belt and the
material being conveyed, protects the material being
conveyed by keeping out foreign substances and, in an
outside install,ation, rain and snow, and keeps dust and
any fugitive material that falls from the belt from
entering the environment. The previously known HI
ROLLER'm conveyors, which are in widespread use for
conveying various materials, especially grains, all
provide delivery at the head end or at the head end and
one or more intermediate stationary discharge units along
the conveyor upstream from the head end.
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It is common for a material that is being conveyed
by a belt conveyor to be ultimately delivered to several
locations; such as a group of storage bins or to
different locations in a single storage bin. One form of
belt conveyor that provides delivery to multiple
locations is an open traveling tripper belt conveyor, a
conveyor that is equipped with a traveling tripper that
includes a tripper and a valve. It is also well-known to
use an enclosed conveyor that discharges to a
distributor, which, in turn, delivers the material to the
several bins or locations in a single bin, or to
incorporate one or more stationary tripper units in an
.aenclosed conveyor, each of which discharges to a
different point.
Like all open belt conveyors, open traveling tripper
belt conveyors, even when installed under a cover for
weather protection, allow dust and fugitive material to
escape to the environment and require constant, costly
cleanup. Previously known enclosed belt conveyors with
fixed tripper units and enclosed belt conveyors
delivering to distributors are costly to fabricate and
install, although the cost is fully justifiable by almost
completely eliminating escape of dust and fugitive
material to the environment.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a
movable tripper belt conveyor in which the belt is fully
enclosed along its delivery and return runs. A further
object is to capture virtually all dust and spillage and
return it to the tail end of the conveyor for reloading
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onto the belt. It is also an object of the invention to
reduce the costs of operating a conveyor that delivers
product selectively to selected destinations, especially
cleanup and maintenance costs. Still another object is
to eliminate the need for a distributor or multiple fixed
trippers for delivery of material by an enclosed conveyor
to multiple points, thereby reducing the investment costs
required to provide delivery to multiple points.
The foregoing objects are attained, in accordance
with the present invention, by a movable tripper belt
conveyor that has an elongated trunking having a floor
and side walls, a tail pulley mounted in the tail end,
and a head pulley mounted in the head end. A plurality
of longitudinally spaced-apart troughing idlers are
mounted on the side walls of the trunking along the
entire length thereof between the tail pulley and the
head pulley and define an upper troughed path for an
endless conveyor belt that is trained between the tail
pulley and the head pulley. The belt returns from the
head pulley to the tail pulley in sliding contact with
the floor of the trunking. A movable tripper unit
associated with a portion of the trunking includes a
tripper that has a carriage supported for movement
longitudinally.along the trunking. Side members of the
carriage located above and laterally on both sides of the
upper path of the belt carry one or more troughing idlers
and a pair of trough-forming discs upstream from the
troughing idlers for leading the belt along an upward
bend from the upper path along an inclined path to a
discharge unit. The discharge unit has an upper bend
pulley and a valve configured and arranged to receive
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material from the belt adjacent the upper bend pulley and
discharge it selectively to one side or the other of the
movable tripper unit. A lower bend pulley carried by the
frame above the upper path and below the upper bend
pulley leads the belt from the upper bend pulley back to
the upper path. A cover received over the trunking is
configured and arranged to form with the trunking an
enclosure containing the belt, the tail pulley, the head
pulley, all of the troughing idlers and the movable
tripper unit.
The advantages of having the belt and the movable
tripping unit completely enclosed by the trunking and a
cover over the trunking are readily apparent to those
skilled in the art. Foremost among them is keeping dust
and fugitive material from entering the environment. The
present invention greatly reduces the need for costly
clean-up around the conveyor. In that regard, open
traveling tripper conveyors often require that a worker
be assigned full time to cleaning. An enclosed conveyor
also keeps foreign materials from contaminating the
material being conveyed. For example, when a facility
has several conveyors that are used for loading or
unloading various materials, it can be extremely
important to keep airborne fugitive materials or dust
from other conveyers or other equipment at the facility
from mingling with a particular commodity being conveyed.
In some embodiments of the present invention, the
cover may be an inverted U-shaped or box-shaped rigid
trunking cover that is coextensive with at least the
portion of the trunking along which the movable tripper
unit travels, the trunking cover having a top wall and
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side walls, and the lower edges of side walls of the
trunking cover being joined to the upper edges of the
side walls of the trunking in sealed relation. The
inverted U-shaped trunking cover may extend the full
length of the conveyor. Alternatively, the cover for the
trunking may include cover panels attached to the upper
edges of the side walls of the trunking along at least a
portion of the trunking between the tail end and the
rearward-most end of the portion of the trunking along
which the movable tripper unit travels. Preferably, the
trunking cover has a plurality of delivery chutes
attached to each of the side walls at each delivery
position. The valve of the movable tripper unit may be a
basket valve that is movable to communicate selectively
with an inlet opening to the delivery chutes on either
side of the movable tripper unit.
The tripper of the movable tripper unit may include
a pair of spaced-apart discs engaging the upper surface
of the belt at a location between the upper path and the
discharge unit, each disc engaging a band of the belt
proximate to a juncture between a medial portion and
inclined side portions so as to maintain the side
portions inclined with respect to the medial portion.
Usually, the tripper will also have at least one
troughing idler.
In other embodiments of the present invention, the
movable tripper unit has side walls, the lower edge
portions of which engage upper portions of the side walls
of the trunking in sliding sealed relation, and the cover
in at least the portion of the conveyor along which the
movable tripper unit moves includes a flexible web, which
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is supported in sealed relation on the upper edges of the
side walls of the trunking and is picked up and guided
over the top of the movable tripper unit by guide rolls
carried by the movable tripper unit. Preferably, the
movable tripper unit has a rigid cover that travels with
it and forms, along with the flexible web, the trunking
cover for the delivery section of the conveyor. The
movable tripper unit may have dual interlocked rack and
pinion gates for discharge to chutes affixed to the side
walls of the cover. The movable tripper unit may be
supported for movement along the trunking in various
ways, such as by rails extending longitudinally on the
.bottom of the movable tripper unit which roll along the
troughing idlers or by rollers mounted on the sides of
the frame of the movable tripper unit which run on the
conveyor trunking or on rails located generally laterally
and outside of the trunking. A discharge chute is
attached to each side wall of the frame of the movable
tripper unit and moves with the movable tripper unit
among the delivery stations.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present
invention and additional preferred features, and the
advantages thereof, reference may be made to the
following written description of exemplary embodiments,
taken in conjunction with the accompanying drawings, in
which:
Fig. 1 is a side elevational view, which is
generally schematic in form, of a first embodiment,
portions being broken away and several sections of the
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trunking cover being removed to reveal the movable
tripper unit;
Fig. 2 is a schematic pictorial view of a portion
adjacent the tail end of the embodiment of Fig. 1;
Fig. 3 is a schematic pictorial view of the
discharge section of the first embodiment, some of the
sections of the trunking cover being removed to reveal
the movable tripper unit;
Fig. 4 is an enlargement of a portion of Fig. 1;
Fig. 5 is a generally schematic side elevational
view of the movable tripper unit of the first embodiment
with the near side wall of the trunking cover cut away;
Fig. 6 is a generally schematic side elevational
view of a second embodiment of the present invention; and
Fig. 7 is a schematic head end view of the movable
tripper unit of the embodiment of Fig. 6.
DESCRIPTION OF THE EMBODIMENTS
An exemplary embodiment of the present invention and
its advantages are best understood by referring to
FIGURES 1 to 7 of the drawings, like numerals being used
for like and corresponding parts of the various FIGURES.
The teachings of the present specification and the
drawings may be used to advantage in enclosed movable
tripper belt conveyors of various configurations.
A movable tripper belt conveyor in which the present
invention is useful, as embodied in the one shown in
Figs. 1 to 5, has an elongated trunking 10 that extends
the entire length of the conveyor from a tail end 10T to
head end 10E. The trunking 10 is a U-shaped support
structure that is fabricated from steel sheet or plate
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and supports all components of the conveyor other than
bearings for tail and head pulleys and a drive motor and
transmission at the head end. The trunking 10 also forms
the lower and side walls of an enclosure that protects
the material being conveyed from the environment and the
environment from the material. Ordinarily and as shown,
the trunking of enclosed belt conveyors is of modular
construction, consisting of rectangular sections lOS that
are bolted together end to end along end flanges lOf. The
trunking 10 is covered along the entire length of the
conveyor.
The material to be conveyed is delivered through a
belt loader 14L near the tail end lOT of the conveyor to
an endless belt 14, which is supported along an upper
delivery run of the belt within the trunking 10 by spool-
like, spaced-apart troughing idlers 16, the shafts of
which are supported by bearings 12 mounted outside of the
side walls of the trunking. Other types of troughing
idlers may be substituted for the spool-type shown in the
drawings. U.S. Patent No. 6,044,965 entitled TROUGHING
IDLERS FOR BELT CONVEYORS describes and shows troughing
idlers that may be used to advantage in movable tripper
conveyers according to the present invention. The
troughing idlers are provided along the entire length of
the conveyor.
A drive pulley (not shown) at the head end 10E,
which is driven by a motor through a transmission 21,
pulls the belt along the upper run and reverses the belt
to the return run. The belt returns to the tail end by
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sliding along the floor of the trunking, which is lined
with ultra high molecular weight polyethylene sheets. By
sliding along the trunking floor along the return run,
the belt sweeps dust and spillage back to the tail end,
where it is reloaded onto the upper, delivery run by a
reloader (not shown). The self-cleaning and reloading
features provide considerable savings in operating costs,
especially clean-up costs, and by reducing down time for
cleaning. The closed system eliminates spillage and
reduces the escape of dust to a negligible amount.
Figs. 1 and 3 to 5 show part of the discharge region
of a first embodiment of a conveyor, according to the
present invention, which is a region located between and
above several bins (or sections of one or more large
bins). In order to enclose a movable tripper unit
(described below) that rides along the top of the
trunking 10, an inverted U-shaped trunking cover 28 fits
over the top of the part of the trunking along which the
movable tripper unit moves. The trunking cover 28 has
side walls 24, which mate with the top edges of the
trunking, and a top wall 26 and form with the trunking
along the discharge section of the conveyor a dust-tight
enclosure for the movable tripper unit. The trunking
cover 28 may, as shown, be made up of sections joined end
to end. Each of the bins or bin sections is served by an
inclined chute 22. Each chute 22 is connected in sealed
relation to the side wall 24 of the trunking cover 28.
The conveyor may include a portion running from the tail
end to the discharge section and a portion running from
the discharge section to the head end, which portions may
be covered by cover panels 30 attached to the top edges
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of the trunking 10. The trunking cover has, of course,
end walls (not shown). The trunking, the cover panels 30
(if provided), and the trunking cover 28 thus form a
fully enclosed housing for the belt, the troughing
idlers, and the movable tripper unit.
The movable tripper unit 40 consists of a traveling
tripper 42 (parts 46 to 58 described below) and a valve
44. A framework 46 of the tripper 42 extends from
adjacent the disks 48 to beyond the valve 44. Parts of
the framework are removed in the drawings to show the
internal parts of the tripper and valve. The framework
has rails (not shown) on its underside that ride on the
troughing idlers 16, which do not support the belt along
the tripper, the belt having been picked up from the
troughing idlers 16 by the tripper 42, and are,
therefore, available to support the tripper itself. The
belt 14 passes under a pair of spaced part discs 48,
which engage the upper surface of the belt along the
junctures of the medial portion and the sloping sides and
maintain the trough shape of the belt along a portion of
the belt path between the point where it is picked up
from the main upper run along the troughing idlers 16 and
the first of two tripper troughing idlers 50 and 52, thus
forming an up-bend in the belt 14. The belt runs from
the second idler 52 to an upper bend pulley 54 and then
to a lower bend pulley 56. The material being conveyed
is delivered from the belt at the upper bend pulley 54
into a discharge duct 58, which feeds the material to the
valve 44, which in the embodiment is a basket valve. The
basket valve 44 is movable to provide left or right
delivery to the chutes 22 on either side of the conveyor.
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The empty belt runs from the lower bend pulley 56 back to
the main upper run to the head end 10E.
The movable tripper unit 40 is moved along the
discharge section of the conveyor by an endless cable
(not shown), the upper run of which is supported by
pulleys attached to the top wall 26 of the trunking cover
28. The lower run is connected to the frame of the
tripper 42. The movable tripper unit stops at any
selected delivery station and discharges material to a
selected right or left chute 22 at the selected station.
The trunking 10, the cover panels 30, the trunking
cover 28 and the chutes 22 provide a completely enclosed
material conveying path from the tail end to the head end
of the conveyor, which prevents escape of dust and
fugitive material to the environment and excludes
environmental foreign materials from the conveyor. If
desirable or necessary, cross-venting between bins
through the chutes 22 and the covered trunking 10 can be
prevented by providing top-pivoted, self-closing gates
(not shown) on each chute. Each chute 22 may also have
an explosion relief door downstream, with respect to the
gate, from the trunking.
The enclosed movable tripper belt conveyor shown in
Figs. 6 and 7 is the same in principle as the conveyor of
Figs. 1 to 5. Accordingly, the same reference numerals,
but increased by 100, are used for corresponding
components, and the following description deals only with
the main differences.
Each of the troughing idlers 116, 150, 152 and 152'
consists of a horizontal roller 180, the shaft of which
is supported by bearings 180b mounted outside the side
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walls of the trunking sections 110S or the side walls
(described below) of the movable tripper unit 140; and
downwardly and inwardly sloping side rollers 182, which
are mounted on spindles that are cantilevered from the
side walls. Reference may be made to Application Ser.
No. [Attorney Docket No. 31557-2826/57]
referred to above for descriptions and drawings of
troughing idlers suitable for use in conveyors according
to the present invention.
The trunking cover 128 for the movable tripper unit
140 consists of a cover 128M over the movable tripper
unit that is fixed to the frame 146 that supports the
..components of the movable tripper unit and thus moves
with the movable tripper unit and a flexible cover belt
128B. The cover 128M includes side wall panels 126M on
each side, the lower edges of which are in sliding sealed
relation with the upper edges of the side walls of the
trunking 110, an inclined rear cover panel 1241, a top
panel 124T and a front panel 124F. Tracks 184 running
along the sides of the trunking 110 support the frame 146
for travel above the trunking 110 along the delivery
section of the conveyor.
The flexible cover belt 128B rests in sealed
relation on the top edges of the side walls of the
trunking 110 throughout the entire length of the
discharge section, i.e., the section along which the
movable tripper unit 140 travels, except for the part of
the discharge section occupied at any point in time by
the movable tripper unit 140. Belt hold-down rolls 190R
and 190F mounted on the frame 146 at opposite ends of the
lower edges of the side wall panels 126M hold the cover
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belt 128B down on the upper edges of the side walls of
the trunking 110 where the walls 126M intersect with the
top edges of the side walls of the trunking 110. Turning
rolls 192 mounted on the frame 146 lead the cover belt
128F over the top of the movable tripper unit. The cover
belt 128B encloses the trunking 110 along all portions of
the discharge section that are not occupied by the
movable tripper unit 140. The cover 128M encloses the
movable tripper unit 140 at the position it occupies,
i.e., the region where the cover belt 128B is picked up
and supported over the top the movable tripper unit.
Discharge chutes 194R and 194L are affixed to the
side wall panels 126M and move with the movable tripper
unit as it travels along the discharge section. Fig. 7
illustrates two possible arrangements of the discharge
chutes. The chute 194R is configured to discharge
material directly into an opening 0 in the top of a bin
BR. The chute 194L has a movable telescopic extension
194L' that retracts when the movable tripper unit is
moved and extends into the mouth of a chute C that leads
to the bin BL for discharge. Each of the chutes 194R and
194L has a slide gate valve 196, each of which in the
open position retracts into a pocket 198 attached to the
side panel 126M of the frame 146. The slide gate valves
are operated by rack and pinion drives 200 that are
coupled by a chain 202 so that when one gate is moved to
the closed position, the other gate is moved to an open
position. One of the pinions of the drive is coupled by
a shaft 204 having a drive sprocket 206, which is the
output of a drive motor (not shown).
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The dashed line M represents the trajectory of the
material that is ejected from the conveyor belt 114 at
the upper bend pulley 154. The material M impinges on a
front wall shared by the two chutes 194R and 194L and is
diverted to one side or the other by the slide gate valve
that is closed at the time of discharge. The material is
directed by the closed slide gate through the open slide
gate and flows through the open chute (194L in the case
shown in Fig. 7) into the bin BR or BL that it serves.
When the movable tripper unit 140 is moved from
chute to chute, the unit makes its way under the cover
belt 128B, which is diverted by the rolls 190 and 192 to
follow a path clear of the top walls 1261, 126T and 126F
of the cover 128M of the movable tripper unit. The cover
belt 128B, the trunking 110, and the cover 128M of the
movable tripper unit 140 form an enclosure for confining
the material being conveyed by the enclosed movable
tripper conveyor and protecting the material from the
environment.
It is possible, though not preferred, to omit one or
more of the inclined rear panel 1261, the top panel 126T
and the front panel 126F from the cover 128M of the
movable tripper unit 140 of Figs. 6 and 7 and have the
cover belt 128B sealed in sliding relation to the edges
of the side walls 124M where a panel or panels of the
cover 128M is omitted. The path of the belt over the top
of the movable tripper unit can, of course, vary. In
some cases, the valve of the movable tripper unit may be
of a three-way type that provides for right, left and
center delivery or pass-through delivery back to the belt
as it leads from the lower belt pulley 156 of the movable
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tripper unit 140 for conveyance by the belt to a head end
discharge.
