U.S. patent application number 10/237212 was filed with the patent office on 2004-03-11 for motorized street sweeper.
This patent application is currently assigned to Tennant. Invention is credited to Engel, Gregory J., Lenzmeier, Michael H., P. Mathews, Thomas, Weidner, Archie A., Wilmo, Michael S..
Application Number | 20040045584 10/237212 |
Document ID | / |
Family ID | 31990758 |
Filed Date | 2004-03-11 |
United States Patent
Application |
20040045584 |
Kind Code |
A1 |
P. Mathews, Thomas ; et
al. |
March 11, 2004 |
Motorized street sweeper
Abstract
A street sweeper system is used in a motorized vehicle. The
sweeper utilizes a cylindrical brush rotating about a horizontal
axis that is typically perpendicular to the vehicle's direction of
motion. A conveyor belt catches debris thrown forwards and upward
by the brush and moves the debris to a hopper. A conveyor flap is
mounted on a lower edge of the conveyor to improve sweeping
performance. The conveyor lip covers a space between the lower edge
of the conveyor and the ground. A cutoff flap is located on a
forward portion of the brush to deflect debris that is passing over
the brush. A recirculation flap is located at a rear portion of the
brush to recirculate debris that has passed over the top of the
brush.
Inventors: |
P. Mathews, Thomas;
(Plymouth, MN) ; Lenzmeier, Michael H.; (North
Branch, MN) ; Weidner, Archie A.; (Minnetonka,
MN) ; Wilmo, Michael S.; (Crystal, MN) ;
Engel, Gregory J.; (Plymouth, MN) |
Correspondence
Address: |
ALTERA LAW GROUP, LLC
6500 CITY WEST PARKWAY
SUITE 100
MINNEAPOLIS
MN
55344-7704
US
|
Assignee: |
Tennant
Minneapolis
MN
|
Family ID: |
31990758 |
Appl. No.: |
10/237212 |
Filed: |
September 6, 2002 |
Current U.S.
Class: |
134/6 ; 15/82;
15/84 |
Current CPC
Class: |
E01H 1/042 20130101;
E01H 1/0854 20130101 |
Class at
Publication: |
134/006 ;
015/084; 015/082 |
International
Class: |
E01H 001/04 |
Claims
What is claimed is:
1. A sweeper for a ground surface having a front end, a back end
and a forward direction of motion, the sweeper comprising: a debris
mover comprising: an outer surface; a ground contact area defined
where the outer surface of the debris mover contacts the ground
surface; an axis of rotation, the debris mover rotating about the
axis of rotation so that the outer surface of the debris mover
moves at least in part towards the front end of the vehicle at the
ground contact area; a cutoff area on the outer surface of the
debris mover, the outer surface of the debris mover moving at least
in part upwards at the cutoff area as the debris mover rotates
about the axis of rotation; and a recirculation contact area, the
outer surface of the debris mover moving at least in part downwards
at the recirculation contact area as the debris mover rotates about
the horizontal axis; a cutoff flap mounted forward of the debris
mover, the cutoff flap having a distal end adjacent the outer
surface of the debris mover along the cutoff area so that a first
portion of the debris traveling to the cutoff area is deflected at
least in part downward; and a recirculation flap mounted behind the
debris mover, the recirculation flap proximate the recirculation
contact area so that a second portion of the debris traveling to
the recirculation contact area is deflected back into the debris
mover.
2. The sweeper of claim 1, further comprising: a debris collector
mounted forward of the debris mover; and a conveyor flap mounted
adjacent a lower edge of the debris collector, the conveyor flap
having a distal edge proximate the ground surface, the conveyor
flap substantially covering a space defined between a lower edge of
the debris collector and the ground surface.
3. The sweeper of claim 2, further comprising a ground gap defined
between the distal edge of the conveyor flap and the ground
surface.
4. The sweeper of claim 2, wherein the conveyor flap comprises a
plurality of slots at the distal edge.
5. The sweeper of claim 2, wherein at least the distal edge of the
conveyor flap is oriented an angle between 40 and 50 degrees
relative to vertical.
6. The sweeper of claim 1, wherein the cutoff area is located
between 45 degrees and 140 degrees from the ground contact
area.
7. The sweeper of claim 1, wherein at least a portion of the cutoff
flap proximate the distal tip is oriented between 10 degrees and 30
degrees relative to horizontal.
8. The sweeper of claim 1, further comprising a gap between the
distal end of the cutoff flap and the outer surface of the debris
mover.
9. The sweeper of claim 1, wherein the recirculation flap
comprises: a flexible mounting flap fixably attached to the
sweeper; an elongated blade connected to the mounting flap, an edge
of the elongated blade engaging the debris mover.
10. The sweeper of claim 1, wherein the recirculation contact area
is located between 40 degrees and 80 degrees from the ground
contact area.
11. The sweeper of claim 1, wherein the debris mover comprises a
brush having bristles.
12. The sweeper of claim 11, wherein a distal end of the
recirculation flap extends substantially within the bristles of the
brush.
13. A method of street sweeping of a debris from a ground surface,
comprising: moving a conveyance in a forward direction on the
ground surface; rotating a debris mover of the conveyance to move
the debris at least in part forward of the debris mover; catching
the debris on a debris collector facing the debris mover to collect
the debris; deflecting back a first portion of the debris thrown
into a space defined between a lower edge of the debris collector
and the ground surface to recirculate the first portion of the
debris back into the debris mover; deflecting downwards a second
portion of the debris that passes upwards along a forward portion
of the debris mover to recirculate the second portion of the debris
back into the debris mover; and deflecting forwards a third portion
of debris that passes downwards along a rear portion of the debris
mover to recirculate the third portion of debris back into the
debris mover.
14. The method of claim 13, further comprising drawing a vacuum to
move an airborne dust from a space surrounding the debris mover to
collect the airborne dust.
15. The method of claim 14, further comprising blocking the
airborne dust at the forward portion of the debris mover to prevent
escape of the airborne dust therethrough.
16. The method of claim 14, further comprising blocking the
airborne dust at the rear portion of the debris mover to prevent
escape of the airborne dust therethrough.
17. The method of claim 14, further comprising blocking the
airborne dust at the space defined between a lower edge of the
collector and the ground surface to prevent escape of the airborne
dust therethrough.
18. A mobile sweeping system for removing a debris from a ground
surface, the sweeping system having a forward direction of motion
and a sweeping width, the sweeping system further comprising: a
debris moving means moving a debris at least in part forwards
across the sweeping width; a debris collecting means catching the
debris moved by the debris moving means; a deflecting means
covering at least part of a collector clearance space defined
between a lower edge of the debris collecting means and the ground
surface, the deflecting means deflecting a first portion of the
debris moved by the debris moving means into the collector
clearance space back to the debris moving means; a cutoff means
adjacent to a forward portion of the debris moving means where an
outer surface of the debris moving means is moving at least in part
upwards, the cutoff means deflecting downwards a second portion of
the debris passing upwards along the outer surface of the debris
moving means; and a recirculation means proximate a back portion of
the debris moving means where the outer surface of the debris
moving means is moving at least in part downwards and forwards, the
recirculation means deflecting a third portion of the debris
passing over and behind the debris moving means back to the debris
moving means.
19. The sweeping system of claim 18, wherein the deflecting means
comprises a distal edge adjacent the ground surface and a
substantially flexible portion along the distal edge.
20. The sweeping system of claim 19, wherein the substantially
flexible portion comprises a plurality of slots along the distal
edge.
21. The sweeping system of claim 18, further comprising a gap
between the cutoff means and the outer surface of the debris moving
means.
22. The sweeping system of claim 18, further comprising a flexible
mounting means resiliently coupling the recirculation means to the
sweeping system.
23. The sweeping system of claim 18, wherein a distal portion of
the recirculation means substantially penetrates beneath the outer
surface of the debris moving means.
24. The sweeping system of claim 18, wherein the deflecting means
causes a restriction of a flow through the collector clearance
space, the restriction of flow preventing release of a portion of
an airborne dust therethrough.
25. The sweeping system of claim 18, further comprising housing
means encompassing a rear portion of the debris moving means and
wherein the recirculation means causes an air restriction between
the debris moving means and the housing means, the air restriction
preventing release of a portion of an airborne dust of the debris
therethrough.
26. The sweeping system of claim 18, wherein the cutoff means forms
an air restriction between the debris moving means and the debris
collecting means, the restriction preventing release of a portion
of an airborne dust of the debris therethrough.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to motorized street sweeping
vehicles.
BACKGROUND OF THE INVENTION
[0002] Automated street sweeping vehicles are essential equipment
for commercial and government organizations. The vehicles are used
for cleaning debris from roadways, walkways, parking lots, runways,
and many other ground surfaces.
[0003] For streets and highways, large sweepers are primarily used.
The large sweepers are motorized (typically diesel powered) and can
be custom-made or built upon a commercial truck chassis. The large
sweepers typically include large main brushes which direct debris
onto a paddled conveyor that moves the debris into a large-capacity
debris hopper. The large hoppers allow the sweepers to cover
greater distances without the need for emptying the hopper. The
large brushes allow the sweeper to pick up larger debris (e.g.
rocks, tire treads, wood pieces), thus avoiding the need for
multiple passes of the sweeper or manual retrieval of the
debris.
[0004] Although effective, such street sweepers often miss a
certain percentage of the debris, even when the sweeper passes
directly over the debris. In some cases, the debris bounces around
between the brush and conveyor, and can be ejected out from
underneath the vehicle. At other times, the debris bounces over the
top of the brush and is passed over.
[0005] During operation, such sweepers can also generate a dust
cloud when sweeping. In some cases, suction is used on side brushes
and on the conveyor to control this dust. Regardless, a significant
amount of dust is ejected into the atmosphere during sweeping.
Besides being a nuisance, the dust is a source of particulate air
pollution. In some localities particulate air pollution is a major
problem, and municipalities are under government mandates to reduce
particulate air pollution.
[0006] What is needed is a sweeper that can pick up a higher
percentage of road debris, especially large items. Further, the
sweeper should reduce the amount of dust ejected into the air. The
present invention fulfills these and other needs, and addresses
other deficiencies of prior art implementations.
SUMMARY OF THE INVENTION
[0007] To overcome the limitations in the prior art described
above, and to overcome other limitations that will become apparent
upon reading and understanding the present specification, the
present invention discloses a sweeper for a ground surface. The
sweeper has a front end, a back end and a forward direction of
motion. The sweeper includes a debris mover with an outer surface,
a ground contact area, an axis of rotation, a cutoff area, and a
recirculation contact area. The ground contact area is defined
where the outer surface of the debris mover contacts the ground
surface The debris mover rotates about the axis of rotation so that
the outer surface of the debris mover moves at least in part
towards the front end of the vehicle at the ground contact area.
The outer surface of the debris mover moves at least in part
upwards at the cutoff area as the debris mover rotates about the
axis of rotation. The outer surface of the debris mover moves at
least in part downwards at the recirculation contact area as the
debris mover rotates about the horizontal axis.
[0008] The sweeper also includes a cutoff flap and a recirculation
flap. The cutoff flap is mounted forward of the debris mover. The
cutoff flap has a distal end adjacent the outer surface of the
debris mover along the cutoff area so that a first portion of the
debris traveling to the cutoff area is deflected at least in part
downward. The recirculation flap is mounted behind the debris
mover. The recirculation flap engages the recirculation contact
area so that a second portion of the debris traveling to the
recirculation contact area is deflected back into the brush.
[0009] The sweeper may include debris collector mounted forward of
the debris mover and a conveyor flap mounted adjacent a lower edge
of the debris collector. The conveyor flap has a distal edge
proximate the ground surface. The conveyor flap substantially coves
a space defined between a lower edge of the debris collector and
the ground surface. A ground gap may be included between the distal
edge of the conveyor flap and the ground surface. The conveyor flap
may include a plurality of slots at the distal edge. In one
arrangement, the distal edge of the conveyor flap is oriented an
angle between 40 and 50 degrees relative to vertical.
[0010] The sweeper may be configured so that the cutoff area is
located between 45 degrees and 140 degrees from the ground contact
area. Also, at least a portion of the cutoff flap proximate the
distal tip may be oriented between 10 degrees and 30 degrees
relative to horizontal. A gap between the distal end of the cutoff
flap and the outer surface of the debris mover may be included.
[0011] In one configuration, the recirculation flap includes a
flexible mounting flap fixably attached to the sweeper. An
elongated blade is connected to the mounting flap. An edge of the
elongated blade engages the debris mover. In one arrangement, the
recirculation contact area is located between 40 degrees and 80
degrees from the ground contact area. The debris mover may include
a brush having bristles. A distal end of the recirculation flap may
extend substantially within the bristles of the brush.
[0012] In another embodiment of the present invention, a method of
street sweeping of a debris from a ground surface involves moving a
conveyance in a forward direction on the ground surface. A debris
mover of the conveyance is rotated to move the debris at least in
part forward of the debris mover. The debris is caught on a debris
collector facing the debris mover to collect the debris. A first
portion of the debris thrown into a space defined between a lower
edge of the debris collector and the ground surface is deflected
back to recirculate the first portion of the debris back into the
debris mover. A second portion of the debris that passes upwards
along a forward portion of the debris mover is deflected downwards
to recirculate the second portion of the debris back into the
debris mover. A third portion of debris that passes downwards along
a rear portion of the debris mover is deflected forwards to
recirculate the third portion of debris back into the debris
mover.
[0013] The method may involve drawing a vacuum to move airborne
dust from a space surrounding the brush to collect the airborne
dust. The method may also involve blocking the airborne dust at the
forward portion of the debris mover to prevent escape of the
airborne dust therethrough. The airborne dust can also be blocked
at the rear portion of the debris mover to prevent escape of the
airborne dust therethrough. The airborne dust can further be
blocked at the space defined between a lower edge of the collector
and the ground surface to prevent escape of the airborne dust
therethrough.
[0014] In another embodiment of the present invention, a mobile
sweeping system is usable for removing a debris from a ground
surface. The sweeping system has a forward direction of motion and
a sweeping width. The sweeping system further includes a debris
moving means moving a debris at least in part forwards across the
sweeping width. A debris collecting means catches the debris moved
by the debris moving means. A deflecting means covers at least part
of a collector clearance space defined between a lower edge of the
debris collecting means and the ground surface. The deflecting
means deflects a first portion of the debris moved by the debris
moving means into the collector clearance space back to the debris
moving means. A cutoff means is adjacent to a forward portion of
the debris moving means where an outer surface of the debris moving
means is moving at least in part upwards. The cutoff means deflects
downwards a second portion of the debris passing upwards along the
outer surface of the debris moving means. A recirculation means
engages a back portion of the debris moving means where the outer
surface of the debris moving means is moving at least in part
downwards and forwards. The recirculation means deflects a third
portion of the debris passing over and behind the debris moving
means back to the debris moving means.
[0015] The deflecting means may include a distal edge adjacent the
ground surface and a substantially flexible portion along the
distal edge. The substantially flexible portion can include a
plurality of slots along the distal edge. A gap may be included
between the cutoff means and the outer surface of the debris moving
means. A flexible mounting means can be used to resiliently couple
the recirculation means to the sweeping system.
[0016] In one configuration, a distal portion of the recirculation
means substantially penetrates beneath the outer surface of the
debris moving means. The deflecting means can cause a restriction
of a flow through the collector clearance space. The restriction of
flow prevents release of a portion of airborne dust
therethrough.
[0017] The sweeper may further include housing means encompassing a
rear portion of the debris moving means. The recirculation means
causes an air restriction between the debris moving means and the
housing means. The air restriction thereby prevents release of a
portion of airborne dust of the debris therethrough.
[0018] The cutoff means may form an air restriction between the
debris moving means and the debris collecting means. The
restriction prevents release of a portion of airborne dust of the
debris therethrough.
[0019] The above summary of the present invention is not intended
to describe each embodiment or every implementation of the present
invention. Advantages and attainments, together with a more
complete understanding of the invention, will become apparent and
appreciated by referring to the following detailed description and
claims taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a cutaway perspective view of a street sweeper
vehicle according to an embodiment of the present invention;
[0021] FIG. 2 is a side view of the brush, conveyor and flaps
according to an embodiment of the present invention;
[0022] FIG. 3 is a side view of the brush and recirculation flap
showing geometric details according the an embodiment of the
present invention;
[0023] FIG. 4 is a perspective view of a conveyor flap according to
an embodiment of the present invention;
[0024] FIG. 5 is a perspective view of a cutoff flap according to
an embodiment of the present invention; and
[0025] FIG. 6 is a perspective view of a recirculation flap
according to an embodiment of the present invention.
[0026] While the invention is amenable to various modifications and
alternative forms, specifics thereof have been shown by way of
example in the drawings and will be described in detail herein. For
example, while the title describes a street sweeper, this refers
only to a preferred embodiment since the present invention is
applicable to all forms of debris gathering equipment. It is to be
understood, however, that the intention is not to limit the
invention to the particular embodiments described. On the contrary,
the invention is intended to cover all modifications, equivalents,
and alternatives falling within the scope of the invention as
defined by the appended claims.
DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS
[0027] In the following description of the illustrated embodiments,
references are made to the accompanying drawings which form a part
hereof, and in which is shown by way of illustration, various
embodiments in which the invention may be practiced. It is to be
understood that other embodiments may be utilized and structural
and functional changes may be made without departing from the scope
of the present invention.
[0028] Referring now to FIG. 1, a street sweeping vehicle,
generally indicated by reference numeral 100, has a front end 102
and back end 104. The front end 102 of the vehicle includes a cab
section 103 where an operator sits A debris mover, typically a
cylindrical pickup brush and generally indicated by reference
numeral 106, is mounted near the back end 104 of the vehicle 100.
The brush 106 includes bristles 108 and a hub 110. The horizontal
axis of the brush 106 is oriented substantially perpendicular to
the direction of forward motion of the vehicle 100, indicated by
the bold, straight arrow above the vehicle 100. It is appreciated,
however, that the brush 106 can be oriented skewed (i.e.
non-perpendicular to forward motion) to push debris both forwards
and sideways.
[0029] The brush 106 is powered and rotates about its axis in the
direction indicated by the bold, curved arrow. It is appreciated
that the brush 106 can be rotated opposite the direction indicated
in Fig.1, although such a rotation is likely to be less effective.
The brush 106 can rotate at varying speeds, typically in the range
of 75 to 150 rpm. The brush 106 in this example has an outer
diameter ranging from 36 to 18 inches (91 to 45 cm), the outer
diameter decreasing with wear of the bristles 108. The outer
surface of the brush 106 (i.e. at the tip of the bristles 108)
contacts the ground surface 112 at a contact surface 114. The brush
106 throws debris from the ground surface 112 to a debris collector
(in this example a conveyor), generally indicated by reference
numeral 120.
[0030] The conveyor 120 includes a belt 122 with paddles or cleats
124 mounted along an outer surface at regularly spaced intervals.
Debris is thrown by the brush 106 onto a collecting surface 123 of
the belt 122. The belt 122 rotates in a direction counter to
rotation of the broom 106 such the collecting surface 123 of the
belt 122 is moves at least in part upwards (and typically forwards
as well) away from the brush 106, as indicated by the angled arrow
located over the belt 122. The debris leaves an exit area 126 at
the top of the conveyor 120 and drops into a hopper 127.
[0031] It is well known that debris can escape the brush 106 and
conveyor 120 in various ways. In particular, the debris can be
ejected out underneath the conveyor 120 or bounce over the top of
the brush 106. In the sweeping vehicle 100 according to the present
invention, a set of flaps or plates are included to prevent debris
from escaping. These flaps include a conveyor flap 130, a cutoff
flap 140, and a recirculation flap 150.
[0032] The conveyor flap 130 is mounted adjacent a bottom edge of
the conveyor 130. The conveyor flap 130 covers at least in part a
collector clearance space 138 defined between the bottom edge and
the ground surface 112 along the width of the conveyor 120. The
conveyor flap 130 improves the sweeping performance of the sweeper
100 and helps contain dust at least within the enclosed space
between the brush 106 and conveyor 120.
[0033] Conceptually, the conveyor flap 130 is a structural element
that prevents debris thrown by the brush from colliding with a
counter rotating cleat 124 and being batted over the brush 106. The
conveyor flap 130 also serves as a device to improve the trajectory
of debris so the debris can land on the belt 122 rather than be
thrown under the conveyor 120.
[0034] The cutoff flap 140 is mounted above the conveyor flap 130
and forward of the brush 106. In this example, the cutoff flap 140
is attached to the conveyor shroud 142. It is possible to attach
the cutoff flap 140 to any structure allowing the flap 140 to be
adjacent the brush 106. The cutoff flap 140 includes a distal edge
that is adjacent the outer surface of the brush 106 at a cutoff
area 144 of the brush 106. The cutoff area 144 is located on a
portion of the brush's outer surface that is moving substantially
upwards as the brush 106 rotates.
[0035] The recirculation flap 150 is mounted behind the brush 106.
The recirculation flap 150 engages the outer surface of the brush
106 at a recirculation contact area 152 of the brush 106. The
recirculation contact area 152 is located on a portion of the
brush's outer surface that is moving substantially downwards and
forwards as the brush 106 rotates.
[0036] Conceptually, the flaps 140 and 150 are structural elements
that counteract the trajectory of debris being expelled by the
brush 106 or other debris moving device to recirculate/recollect
the debris. By forcing the debris back into the brush 106, the
debris will not be expelled until it reaches the appropriate
collection portion of the brush's rotation (e.g. at the debris
collector 120). In broad terms, the flaps 140 and 150 are
constructed to provide at least a barrier (deflector) to ejected
debris and, in the case of the recirculation flap 150, a bias
element to re-introduce the debris into the brush 106.
[0037] Turning now to FIG. 2, a side view of the sweeping system
shows the orientation of the flaps 130, 140, 150 relative to the
other parts of the vehicle 100. The brush 106 contacts the ground
at the contact surface 114 as it is being rotated in the direction
indicated by the curved arrow. If there is a large amount of
debris, the rotation of the brush 106 at the contact surface 114
may build up a "wedge" 200 of debris as the vehicle 100 moves
forward. Most of the debris is thrown upwards in a debris path 202
tangential to the brush 106 where the brush 106 contacts a top
portion of the wedge 200. This portion of the debris lands on the
belt 122 and is carried into the hopper 127.
[0038] If there is not enough debris to form a wedge 200 of
sufficient size, debris can be thrown in a path 204 that is more
parallel to the ground surface 112. The debris may shoot forward
under the conveyor's lower edge 205. The debris may collide also
with a counter-rotating cleat 124 and be batted up and over the
brush 106 where it can be left on the ground surface 112 behind the
machine 100. Also, since heavier debris (e.g. rocks from 2 cm to 5
cm in diameter) is more prone to travel along the lower path 204,
the heavier debris tends to reciprocate in a space between the
brush 106 and conveyor 120. The more that debris reciprocates
between the brush 106 and conveyor 120, the more likely it is to
batted over the brush 106 by a counter-rotating cleat 124 or be
launched in a direction (e.g. sideways, backwards) where it is
missed by the brush 106 and left on the ground surface 112.
[0039] The conveyor flap 130 has been found to help reduce
collisions with counter-rotating cleats and reciprocation of debris
between the brush 106 and conveyor 120, as well as preventing
debris from being ejected underneath the conveyor 120. The conveyor
flap 130 typically includes at least a rigid mounting bracket 230
and a flexible blade or skirt 232. The mounting bracket 230
attaches adjacent to the lower edge 205 of the conveyor 120. The
mounting bracket 230 can either be attached to the conveyor 120 or
to any part of the surrounding structure. The mounting bracket 230
extends along the width of the conveyor 120 and forms a rigid
blocking member in front of and/or below the conveyor 120. The
conveyor flap 130 thereby covers the collector clearance space 138
between the ground surface 112 and the conveyor's lower edge
205.
[0040] The conveyor flap 130 may be configured so that a ground
clearance gap 234 exists between the flexible blade 232 and the
ground surface 112. The ground clearance gap 234 prevents dust and
small debris from accumulating on the flexible blade 232 and
lessens wear on the flexible blade 232. The flexible blade 232 is
compliant enough that material that is larger than the clearance
gap 234 will deflect the flexible blade 232 upwards so that debris
does not get swept forward by the flexible blade 232, thereby
allowing the debris to reach the brush 106.
[0041] It is also known that debris can be carried over the top of
the brush 106 such as in a path 240 as indicated in FIG. 2. In
prior art sweepers, this debris is usually ejected from behind the
brush 106 and therefore missed by the sweeper. By including the
cutoff flap 140, the debris is defected substantially downwards so
that the debris can be returned to the collection space 242, and
eventually be recovered at the conveyor 120.
[0042] The cutoff flap 140 in the illustrated embodiment is formed
as an elongated blade fixably attached to an angle bracket 243 and
a mounting plate 244. A retainer bracket 246 clamps the cutoff flap
140 to the mounting plate 244. The retainer bracket 246 may have an
angular cross section to further stiffen the cutoff flap 140 and
angle bracket 243.
[0043] The angle bracket 243 orients the distal end of the cutoff
flap 140 to the desired angle relative to the brush 106. The angle
bracket 243 also positions the cutoff flap 140 so that there is a
gap 248 between a distal edge 247 of the cutoff flap 140 and the
outer surface of the brush 106 (i.e. at the tip of the bristles
108). In most applications, the gap 248 is desired to reduce
vibrations and wear on the brush 106 and cutoff flap 140. In some
applications, however, it may be beneficial to allow the distal
edge 247 to touch the brush 106 (i.e. gap 248 measures zero), or
arrange the cutoff flap 140 so that the distal edge 247 protrudes
through the brush's outer surface to extend into the bristles
108.
[0044] The cutoff flap 140 is preferably made adjustable (e.g. by
using elongated mounting slots) thereby allowing the user to adjust
the gap 248 to keep it a desired value given various stages of
brush wear. The cutoff flap 140 is made from a flexible material,
such as rubber or plastic. A cutoff flap 140 using a rigid blade
may also be constructed, although the associated gap 248 would
typically need to be larger to prevent flap damage due to
deflecting large objects or inadvertent contact with the brush
106.
[0045] Debris can also be carried over the top of the brush 106 by
being embedded within the bristles of the brush 106 and therefore
missed by the cutoff flap 140. This debris can fall off the back
end of the brush 106 as it rotates. By including the recirculation
flap 150, the debris is deflected back into the bristles 108 at the
back end of the brush so that the debris can be carried forward
(recirculated) to the wedge 200 and eventually be recovered at the
conveyor 120.
[0046] The recirculation flap 150 in the illustrated embodiment
includes a flexible mounting flap 250 fixably attached to a chassis
bracket 251. The mounting flap 250 allows the recirculation flap
150 to conform to ground surface irregularities so as to prevent
breakage of the flap 150. Alternate structural elements may be used
in place of a flexible mounting flap 250 to allow conformance of
the flap 150, including spring loaded and/or slidable mounts.
However, such alternates may be more prone to damage due to chassis
movement. The flexible mounting flap 250 allows a flexible and
resilient mount that is not easily damaged even when contacting the
ground.
[0047] A rigid angle bracket 252 is coupled to the mounting flap
250 and an elongated blade 254. The angle bracket 252 can be
incorporated as part of the mounting flap 250 and/or elongated
blade 254, or be fabricated as a separate piece as shown. The angle
bracket 252 orients the elongated blade 254 so that a portion of
the blade 254 is at least touching an outer surface of the brush
106 (i.e. at the tip of the bristles 108) along the brush's width.
As shown in FIG. 2, the elongated blade 254 may protrude beneath
the outer surface so that a tip 255 of the elongated blade 254
extends into the bristles 108. An additional skirt 222 extends from
the mounting flap 210 to close proximity with the ground. The skirt
222 could also be formed by further extending the mounting flap 210
downward.
[0048] A housing 258 typically surrounds the brush 106 and conveyor
120. It is appreciated that the spaces between the rotating brush
106 and the housing 258 are potential escape routes for airborne
dust stirred up by the brush's rotation. The conveyor clearance
space 138 is another escape route for dust. The flaps 130,140,150
substantially block portions of these spaces and thereby help
prevent the airborne dust from escaping. The conveyor flap 130
prevents dust from passing through the collector clearance space
138, the cutoff flap 140 traps dust in the collection space 242,
and the recirculation flap 150 prevents dust from passing between
the inner surface of the housing 258 and a rear portion of the
brush 106. The vehicle 100 may also include a vacuum system 150
(best seen in FIG. 1) to pull dust from inside the housing 258. The
flaps 130,140,150 create a restriction of outside air flowing into
the housing 258, and thereby help retain the dust in the housing
258 so that it can be more thoroughly removed by the vacuum system
150. Skirt 222 further contains dust and improves the effectiveness
of the vacuum system.
[0049] Turning now to FIG. 3, geometric details of the flaps are
illustrated. The conveyor flap 130 is mounted adjacent the lower
edge of the conveyor 120, typically at an angle 330 ranging between
20 degrees and 70 degrees. If a ground clearance gap 234 (seen in
FIG. 2) is included, it measures preferably between 0.75 and 1.25
inches (0.9 and 3.2 cm).
[0050] The cutoff flap 140 is mounted forward of the brush 106 so
that the distal edge 247 is adjacent the cutoff area 144. The
cutoff area 144 is preferably located at an angle 340 measuring
between 45 degrees to 140 degrees (preferably 94 degrees) from the
ground contact area 114. For a brush 106 with a nominal outer
diameter of 35.5 inches (90.2 cm), this corresponds to locating the
distal edge 247 of the cutoff flap 140 about 20.0.+-.1.0 inches
(51.0.+-.2.0 cm) above ground. The cutoff flap 140 is typically
oriented at a mounting angle 342 measuring between 10 degrees and
30 degrees from horizontal, preferably about 23.+-.1 degrees. In
this application, the gap 248 ranges from 0.0 inches to 1.0 inch
(2.50 cm) or more, preferably 0.75.+-.0.10 inches (1.91.+-.0.25
cm).
[0051] At the back end of the brush, the recirculation flap 150
contacts the brush 106 at the recirculation contact area 152. The
recirculation contact area 152 can be located anywhere the brush's
outer surface is moving at least in part downwards. Typically, the
recirculation contact area 152 located at a contact angle 350
measuring between 20 degrees to 90 degrees clockwise from the
ground contact area 114, preferably 63.+-.2 degrees. For a brush
106 with a nominal outer diameter of 35.5 inches (90 cm), this
corresponds to locating the tip 350 of the recirculation flap 150
between 4.1 and 14.7 inches (10 and 37 cm) above the ground,
preferably 6.75.+-.0.50 inches (17.1.+-.1.2 cm). The elongated
blade 254 is oriented at a mounting angle 352 which is from 0
degrees to 90 degrees from vertical, preferably 50.+-.2 degrees. It
is appreciated that the nominal brush diameter of 35.5 inches (90
cm) used in this example is that of an unworn brush 106.
[0052] The construction and attachment of the flaps 130,140, 150
can be accomplished using materials and methods well known in the
arts. Typically, the portions of the flaps 130,140,150 adjacent to
moving surfaces (e.g. the brush 106, the ground surface 112) are
formed a flexible material. In particular, two- or three-ply sheet
rubber product such as thick Goodyear Plylon.RTM. is suitable for
this application. The flaps 130, 140, 150 are typically adjustably
fastened to rigid brackets that are bolted or welded to the
structures.
[0053] FIG. 4 shows a useful configuration of the conveyor flap
130. The mounting bracket 230 can be formed from sheet metal, in
this example {fraction (3/16)} inch (4.8 mm) thick carbon steel.
The mounting bracket 230 is formed into a tubular structure which
gives it strength to resist damage yet keeps the bracket's weight
acceptably low. An equivalent strength aluminum sheet may be used
where even lower weight or corrosion resistance is desired. A
support blade 402 made of relatively thick rubber (e.g. {fraction
(3/16)} inch (4.8 mm) 3-ply rubber) may be sandwiched between the
mounting bracket 230 and flexible blade 232, extending out past the
mounting bracket 230. The support blade 402 is relatively flexible,
yet will not droop down when mounted.
[0054] In this configuration, the flexible blade 232 is mounted on
top of the support blade 402 and extends past an edge of the
support blade 301. The flexible blade 232 is formed from a
relatively compliant belted rubber, such as 1/8 inch thick (3 mm)
bias 2-ply belted sheet rubber. The flexible blade 232 may include
edge slots 404 evenly spaced along the distal edge 406 of the
conveyor flap 140. The slots 404 allow large debris that is passing
under the flap 130 to deflect only a small, local portion of the
flexible blade 232 so that the remainder of the flexible blade 232
remains substantially undeformed, and therefore the blade 232 can
continue to deflect debris back onto the brush 106. The edge slots
404 shown are substantially perpendicular to a distal edge of the
conveyor lip 408, although it is appreciated that the slots 404 can
be formed at a non-perpendicular angle relative to the distal edge
406.
[0055] The flexible blade 232 and support blade 432 are attached to
the mounting bracket 230 by fasteners 408 (e.g. bolts) and a
clamping bracket 410. The mounting bracket 230 can be mounted to
the vehicle 100 by using fasteners or by other means such as
welding. It is appreciated that the flexible blade 232 and/or
support blade 402 are removably mounted with bolts 408 at least for
maintenance purposes. It may also be desired to remove the blades
232, 402 for certain tasks such as sweeping up leaves or other
lightweight debris. More elaborate quick release methods of blade
mounting may be used, although inexpensive and reliable fasteners
such as bolts 408 are usually sufficient for assembling and
attaching the blades 232, 402. It is also appreciated the conveyor
flap 130 provides some benefit even with one or both blades 232,
402 removed.
[0056] Referring now to FIG. 5, an embodiment of a cutoff flap 140
is shown. The cutoff flap 140 is best made of two- or three-ply
sheet rubber product such as 3/8 inch (0.95 cm) thick Goodyear
Plylon.RTM. (220B {fraction (3/16)}.times.{fraction (1/16)}, Class
I). Making the cutoff flap 140 from relatively flexible rubber
helps prevent damage caused by deflecting heavy objects and
inadvertent contact with the brush 106. In another embodiment, the
cutoff flap 140 can be made of a rubber blade portion attached to a
rigid portion made of metal or some other suitable material. The
rigid portion is attachable to the mounting structures of the
vehicle 100.
[0057] The cutoff flap 140 can be attached standard fasteners that
pass through the retainer bracket 246 (seen in FIG. 2) mounting
slots 500 in the flap 140. The retainer bracket 246 can be formed
of angled sheet metal to further stiffen the mounting plate 244 and
cutoff flap 160.
[0058] Turning now to FIG. 6, an embodiment of a recirculation flap
150 is shown. The mounting flap 250 and elongated blade 254 are
typically made of two- or three-ply sheet rubber product such as
3/8 inch (0.95 cm) thick Goodyear Plylon.RTM.). Fabricating the
mounting flap 250 from relatively flexible rubber helps prevent
damage to the blade and/or vehicle caused by heavy objects and
ground surface irregularities. Further, use of sheet rubber in
fabricating the mounting flap 250 and elongated blade 254 help
provide damping of the assembly and reduce noise.
[0059] The mounting flap 250 can be attached to the chassis bracket
251 (best seen in FIG. 2) using standard fasteners through mounting
slots 600. The angle bracket 252 can be formed from sheet metal,
typically 0.08 inch to 0.12 inch thick (2.0 to 4.5 mm) carbon
steel. An equivalent strength aluminum or magnesium material may be
used where low weight or corrosion resistance is desired. The angle
bracket 252 is fastened to the mounting flap 250 and elongated
blade 254 by using fasteners 602. Any type of fastener 602 can be
used, such as bolts and/or rivets.
[0060] Although the sweeping system of the present invention has
been described in conjunction with a self propelled vehicle 100, it
is appreciated that a brush 106, conveyor 120, and flaps 130, 140,
150 can be used alone or in combination on any conveyance, such as
trailers or push sweepers. The flaps 130, 140, 150 can also be used
on smaller sweeping systems that have alternate conveyor (debris
collector) 120 embodiments, such as an auger conveyor or a suction
plenum. The flaps 130, 140, 150 can also be used in systems that do
not have a conveyor, such as systems that throw the debris directly
into a hopper.
[0061] It will, of course, be understood that various modifications
and additions can be made to the preferred embodiments discussed
hereinabove without departing from the scope of the present
invention. Accordingly, the scope of the present invention should
not be limited by the particular embodiments described above, but
should be defined only by the claims set forth below and
equivalents thereof.
* * * * *