U.S. patent application number 09/757287 was filed with the patent office on 2002-07-11 for railway crossing guard.
This patent application is currently assigned to Energy Absorption Systems, Inc.. Invention is credited to Crowley, James D., Eckert, Bret R..
Application Number | 20020090259 09/757287 |
Document ID | / |
Family ID | 25047222 |
Filed Date | 2002-07-11 |
United States Patent
Application |
20020090259 |
Kind Code |
A1 |
Crowley, James D. ; et
al. |
July 11, 2002 |
Railway crossing guard
Abstract
A railway crossing guard includes a pivotable crossing gate and
a set of retractable barriers on the same side of a set of railroad
tracks. The pivotable crossing gate is mounted adjacent a first
traffic lane to move between a lowered position and a raised
position, and the retractable barriers are mounted in a line
oriented parallel to the traffic lanes on a median strip between
first and second traffic lanes. These retractable barriers move
between a retracted position, in which the retractable barriers are
substantially flush with the roadway, and an extended position, in
which the retractable barriers are raised above the roadway. In the
extended position, the retractable barriers are positioned to block
a vehicle in front of the lowered crossing gate from crossing the
median strip to drive around the lowered crossing gate.
Inventors: |
Crowley, James D.;
(Naperville, IL) ; Eckert, Bret R.; (Rocklin,
CA) |
Correspondence
Address: |
William A. Webb
Brinks Hofer Gilson & lione
P.O. Box 10395
Chicago
IL
60610
US
|
Assignee: |
Energy Absorption Systems,
Inc.
|
Family ID: |
25047222 |
Appl. No.: |
09/757287 |
Filed: |
January 8, 2001 |
Current U.S.
Class: |
404/6 |
Current CPC
Class: |
E01F 15/003 20130101;
E01F 13/06 20130101; E01F 9/646 20160201; E01F 13/046 20130101;
E01F 9/629 20160201; B61L 29/026 20130101; E01F 9/594 20160201;
B61L 29/04 20130101; E01F 15/006 20130101 |
Class at
Publication: |
404/6 |
International
Class: |
E01F 013/00 |
Claims
1. A railway crossing guard on a roadway comprising first and
second parallel traffic lanes separated by a median strip, said
traffic lanes crossing a set of railroad tracks, said crossing
guard comprising: a pivotable crossing gate mounted adjacent the
first traffic lane on a first side of the railroad tracks to move
between a lowered position and a raised position, said crossing
gate having a length effective to block the first traffic lane when
the crossing gate is in the lowered position; a plurality of
retractable barriers mounted on the median strip on the first side
of the railroad tracks to move between a retracted position, in
which the retractable barriers are substantially flush with the
roadway, and an extended position, in which the retractable
barriers are raised above the roadway; said retractable barriers,
when in the extended position, positioned to obstruct a vehicle
positioned in front of the lowered crossing gate from crossing the
median strip to drive around the lowered crossing gate.
2. The invention of claim 1 wherein each retractable barrier
comprises an elongated marker, a marker-receiving tube, and a motor
coupled to the marker to retract the marker into the tube and to
extend the marker out of the tube.
3. The invention of claim 2 wherein the marker is sufficiently
flexible to permit the vehicle to drive over the extended marker
without fracturing the marker.
4. The invention of claim 1 further comprising: a controller
responsive to a first command (1) to lower the crossing gate, and
(2) to extend the retractable barriers.
5. The invention of claim 1 wherein the controller is responsive to
a second command (1) to raise the crossing gate, and (2) to retract
the retractable barriers.
6. The invention of claim 1 wherein the crossing gate is disposed
substantially entirely on one side of the median strip when in the
lowered position.
7. The invention of claim 1 wherein the crossing gate blocks the
first traffic lane but not the second traffic lane in the lowered
position.
8. The invention of claim 1 wherein the plurality of retractable
barriers comprises at least three retractable barriers mounted in a
line extending along the median strip.
Description
BACKGROUND
[0001] The present invention relates to a railway crossing guard
that provides improved security at relatively low cost.
[0002] Many approaches have been used for railway crossing guards.
One commonly-used guard includes a pivotable crossing gate
including an arm dimensioned to block a lane of traffic when the
gate is pivoted to a lowered position. See for example U.S. Pat.
5,671,563. This approach often requires two crossing gates on each
side of the railroad tracks, if both traffic lanes are to be
blocked, and is therefore costly to implement.
[0003] Another approach is to use retractable barriers, such as
those described in U.S. Pat. Nos. 5,975,792; 5,762,443; 5,425,595;
2,319,137; and Re 20,157. These retractable barriers are generally
flush with the adjacent roadway when lowered, and they can be
raised to block a lane of traffic.
[0004] On some occasions pivotable crossing gates have been used in
combination with retractable barriers. In one case, a railway
crossing guard included a pivotable crossing gate dimensioned to
block a first traffic lane, and a line of retractable barriers
positioned to block an adjacent traffic lane. This line of
retractable barriers was positioned in the plane of movement of the
pivotable crossing gate, such that a single vertical plane passing
through the retractable barriers also passed through the pivotable
crossing gate. This approach brings with it the disadvantage that
the crossing-guard appears to entirely block the roadway, by the
pivotable crossing gate for the first lane and by the retractable
barriers for the second lane. This can impede emergency vehicle
access to the adjacent railroad track.
[0005] The present invention is directed to an improved railway
crossing guard that benefits from the economies of retractable
barriers while overcoming this disadvantage of the prior art.
SUMMARY
[0006] The railway crossing guard described below includes a
pivotable crossing gate and a line of retractable barriers. The
crossing gate is mounted adjacent to a first traffic lane on a
first side of the railroad tracks to move between a lowered
position and a raised position, and this crossing gate has a length
effective to block the first traffic lane but not the second
traffic lane when the crossing gate is in the lowered position.
[0007] The retractable barriers are mounted on the median strip of
the roadway, on the same side of the railroad tracks as the
crossing gate. These retractable barriers move between a retracted
position, in which the retractable barriers are substantially flush
with the roadway, and an extended position, in which the
retractable barriers are raised above the roadway. A controller
lowers the crossing gate and extends the retractable barriers when
a train approaches the roadway. In this position, the retractable
barriers block a vehicle positioned in front of the lowered
crossing gate from crossing the median strip to drive around the
lowered crossing gate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIGS. 1 and 2 are perspective views of a first embodiment of
the railway crossing guard of this invention in a traffic-blocking
configuration (FIG. 1) and a standby configuration (FIG. 2).
[0009] FIG. 3 is a plan view of the crossing guard of FIGS. 1 and
2.
[0010] FIG. 4 is an exploded perspective view of one of the
retractable barriers of FIGS. 1 through 3.
[0011] FIG. 5 is an exploded perspective view of the marker of FIG.
4.
[0012] FIG. 6 is an exploded perspective view of a portion of the
drive mechanism of FIG. 4.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0013] Turning now to the drawings, FIGS. 1, 2 and 3 provide
overall views of a railway crossing guard 10 that incorporates a
preferred embodiment of this invention. For clarity of
illustration, FIGS. 1 and 2 show a crossing gate 30 and retractable
barriers 40 on one side only of the railroad tracks 20. The plan
view of FIG. 3 shows a preferred arrangement, in which crossing
gates 30 and retractable barriers 40 are provided on both sides of
the railroad tracks 20.
[0014] The crossing guard 10 is mounted at a roadway 12 that
includes first and second traffic lanes 14, 16 separated by a
median strip 18. The pivotable crossing gate 30 and the set of
retractable barriers 40 are positioned on the same side 22 of the
railroad tracks 20. Though only a single lane 14, 16 is shown on
each side of the median strip 18, in alternative embodiments there
may be two or more lanes on each side of the median strip.
[0015] The illustrated median strip 18 is flush with the first and
second traffic lanes 14, 16, but in general the shape and
configuration of the median strip can vary widely. At one extreme,
the median strip can simply be the central portion of the roadway
12 between the traffic lanes 14, 16, without any marking or
elevation change to distinguish the median strip 18. Alternately,
the median strip 18 may be marked, as for example with traffic lane
markings, or it may be raised in whole or in part. All of these
configurations are intended to be encompassed within the meaning of
the term "median strip". Similarly, the railroad tracks 20 can take
any suitable form, and may include more than two rails.
[0016] The pivotable crossing gate 30 can be a conventional railway
crossing gate that pivots between the lowered position shown in
FIG. 1 and the raised position shown in FIG. 2. In the lowered
position of FIG. 1, the pivotable crossing gate 30 extends across
the first traffic lane 14 but not the second traffic lane 16. For
this reason, a vehicle is physically able to bypass the pivotable
crossing gate 30 by traveling in the second traffic lane 16 toward
the railroad tack 20.
[0017] This invention can be implemented using the widest variety
of pivotable crossing gates 30, and it is not limited to the
particular form shown in the drawings. For example, the pivotable
crossing gates shown in any of the following patents can be used,
as can many alternatives to these examples: U.S. Pat. Nos.
3,994,457, 4,655,002, 4,666,108, 4,897,960, 5,442,878.
[0018] The retractable barriers 40 are moveable between an extended
position (FIG. 1), in which the barriers 40 are raised above the
roadway 12, and a retracted position (FIG. 2), in which the
retractable barriers are lowered to a point where they are flush
with the roadway 12. As shown in FIGS. 1, 2 and 3, the retractable
barriers 40 are arranged along a line extending along the median
strip 18, and they are positioned slightly upstream of the
pivotable crossing gate 30 in the anticipated direction of traffic
flow 42. In FIG. 1, the region 44 indicates schematically the
location of a first vehicle in a line of vehicles stopped in front
of the pivotable crossing gate 30. Note that the retractable
barriers 40 are positioned alongside the region 44 to prevent a
vehicle in the region 44 from crossing the median strip 18 and
bypassing the pivotable crossing gate 30 in the second traffic lane
16. When the retractable barriers 40 are retracted and the
pivotable crossing gate is raised as shown in FIG. 2, the roadway
12 is completely unobstructed and normal traffic flow (including
cross-median traffic flow) is permitted.
[0019] A wide variety of retractable barriers can be used with this
invention. By way of example, FIGS. 4 through 6 provide details of
construction for one preferred retractable barrier.
[0020] As shown in FIG. 4, the retractable barrier 40 includes a
marker 42 that is preferably sufficiently flexible to permit a
vehicle to drive over the marker 42 in the extended position
without fracturing it. The marker 42 is mounded for vertical
movement in a marker-receiving tube 43, and the position of the
marker 42 within the tube 43 is controlled by a reversible electric
motor 44. Other types of motors, including hydraulic motors, can be
used. The motor 44 is coupled to a lead screw 46 by a flexible
coupling 50, shown in greater detail in FIG. 6. The lead screw 46
threadedly engages a lead screw nut 48 that is secured in place to
an externally-threaded adapter 56. The adapter 56 includes notches
58 that slide along rails (not shown) of the tube 43 to prevent the
adapter 56 from rotating with respect to the tube 43. For this
reason, when the lead screw 46 is rotated by the motor 44, the
adapter 56 moves vertically up or down as desired within the tube
43.
[0021] As shown in FIG. 5, the marker 42 includes an
internally-threaded end piece 54 that threadedly engages the
externally-threaded adapter 56. The adapter 56 supports a magnet 60
(FIG. 6), and the tube 43 supports magnetic sensors (not shown).
These magnetic sensors respond to the magnet 60, thereby sensing
when the marker 42 is in the retracted (flush) position as well as
when the marker 42 is in the extended (raised) position. The
marker-receiving tube 43 includes an upper flange that supports a
annular wiper 52 that retards the introduction of road grit into
the interior of the tube 43. A waterproof cord connection provides
electrical power to and conducts sensor signals from the marker
40.
[0022] Other types of retractable markers can be used with this
invention, including for example those described in the following
U.S. Pat. Nos. 5,975,792; 5,762,443; 5,671,563; 2,319,137; and Re
20,157. This list is of course intended by way of illustration and
should not limit the scope of this invention. In some cases, the
lead screw may be replaced with a smooth rod, and the lead screw
nut may be replaced with a set of rollers that perform the function
of the lead screw nut while acting as an automatic clutch. Also,
the magnet 60 and associated sensor may be replaced by a current
sensor that monitors current drawn by the motor 44. An excessively
high motor current may be taken as an indication that the marker
has reached an extreme of travel.
[0023] Returning to FIG. 3, the crossing guard 10 also includes a
controller 70 that responds to two crossing-approach sensors 72 and
two crossing-exit sensors 74. When a train approaches the crossing,
the respective crossing-approach sensor 72 sends a first command to
the controller 70, which causes the controller 70 to lower the
pivotable crossing gate 30 and to raise the retractable markers 40
to the position of FIG. 1. After the train has crossed the roadway
12, the respective crossing-exit sensor 74 sends a second command
to the controller 70, which causes the controller 70 to raise the
pivotable crossing gate 30 and to retract the retractable barriers
40 to the position of FIG. 2. The controller 70 and the sensors 72,
74 can take any suitable form. In one example, the controller 70 is
implemented as a conventional programmable logic controller.
Alternatively, a programmable microprocessor or any alternative
structure, electrical or mechanical, can be used to achieve the
control functions described above.
[0024] To improve visibility, the crossing gate 30 preferably
includes warning lights that are activated when the crossing gate
is lowered, and the markers 42 are preferably provided with a
highly reflective coating or layer or with internal lights. As is
conventional, warning bells or other warning devices can be used to
alert the drivers of oncoming vehicles when the crossing gate 30 is
lowered.
[0025] The crossing guard 10 described above provides a number of
important advantages. First, by combining a pivotable crossing gate
with retractable barriers, the overall cost of the crossing guard
is reduced. Second, because the retractable barriers 40 are aligned
with the median strip, a waiting vehicle is blocked from crossing
the median strip to circumvent the lowered crossing gate. Third,
the traffic lane that is not blocked by the pivotable crossing gate
30 remains unobstructed, thereby providing emergency vehicle access
to the region of the railroad tracks 20 and an exit path for
vehicles on the railroad tracks. As explained above, the markers 42
are preferably flexible barriers such that a vehicle can drive over
the markers 42 when necessary. Nevertheless, they provide a visual
barrier that may undesirably obstruct access of emergency vehicles
if placed across the traffic lane opposite the crossing gate on a
given side of the railroad tracks. Alternatively, the markers 42
may form rigid barriers.
[0026] In the foregoing example, the retractable barriers are
completely flush with the roadway when retracted. Alternatively,
the retractable barriers may protrude a small distance above the
roadway surface when retracted. Such retractable barriers are
considered to be substantially flush with the roadway as this term
is used in the present specification.
[0027] The term "obstruct" is intended broadly to include physical
obstruction (as for example by a rigid retractable post or bollard)
as well as visual obstruction (as for example by a flexible
marker). Thus, the marker 42 described above obstructs a vehicle
from crossing the median strip, even though the vehicle is
physically able to drive over the marker.
[0028] The term "barrier" is intended broadly to encompass rigid
barriers and flexible barriers.
[0029] The foregoing detailed description has discussed only a few
of the many forms that this invention can take. For this reason,
this detailed description is intended by way of illustration and
not limitation. It is only the following claims, including all
equivalents, that are intended to define the scope of this
invention.
* * * * *