The invention relates generally to an improved gate device for preventing pedestrians and vehicular traffic from crossing railroad grades. Specifically, the present invention relates to gate devices that protect lowered railroad crossing gate arms from damage.
Railroad crossing gate arms are lowered from a vertical position to a horizontal position to block traffic from crossing railroad tracks when a train is present. When lowered to their horizontal position, gate arms can suffer damage from passing vehicles, wind pressure and vandalism. Damage frequently results in broken gate arms that sever at their point of attachment to a crossing gate assembly. Such damage risks exposing pedestrians and vehicular traffic to improperly guarded train crossings. To maintain safety and the integrity of grade crossing equipment, railroads expend substantial resources monitoring, repairing and replacing damaged crossing gates. Thus, in the first instance, it is advantageous to protect lowered gate arms from damage.
Various methods of protecting gate arms from damage were known to the prior art. Employing camblocks and ball bearings, U.S. Pat. No. 4,897,960 issued to Barvinek, et al., (hereinafter referred to as “Barvinek”) describes a mechanism designed to provide flexibility to lowered gate arms. Barvinek discloses a housing for pivotally mounting a support tube that swings a partially translucent, internally illuminated, impact-resistant gate arm away from an applied force. A camblock is mounted inside the housing, allowing the gate arm support tube, having a pair of ball bearings retained within, to rotate around a retaining pin that extends upwardly through the center of the camblock when force from a passing vehicle is applied. Downward force on the rotating gate arm support tube, applied by a coil spring mounted on the retaining pin, forces the arm to return to its original position parallel with the groove of the camblock when the force dissipates. However, Barvinek suffers from numerous problems. Relying on cam blocks and ball bearings, Barvinek is expensive to manufacture, monitor and maintain. Moreover, Barvinek cannot return a displaced gate arm to a position parallel with the groove of the camblock if the gate mechanism rises while the gate is displaced. Finally, Barvinek provides no control over the rate of gate arm return and cannot prevent gate arm over travel into the flow of traffic.
Alternatively, U.S. Pat. No. 5,469,660, issued to Tamenne, (hereinafter referred to as “Tamenne”) employs a spring and hydraulic piston system. Tamenne discloses a pivot assembly allowing a lowered gate arm to rotate away from traffic when a passing vehicle applies pressure and then to return to its original position once pressure is removed. The pivot assembly is mounted on a counter-weighted gate arm mechanism and includes springs mounted on a shuttle post assembly to return the gate arm to a position perpendicular to the flow of traffic. The pivot assembly includes a hydraulic piston to buffer the rate of gate arm return and a weight channel to counterbalance the gate mechanism's main counterweight when the gate arm is rotated away from passing traffic. However, Tamenne also suffers from numerous problems. Tamenne's hydraulic piston system, like Barvinek's camblock and ball bearing system, is expensive to manufacture, monitor and maintain. Further, Tamenne's weight channel counterbalance places an imbalanced strain on the gate arm pivot assembly, risking damage to the gate arm mechanism. Tamenne also decreases safety at crossing grades when the gate arm is displaced, because the weight channel swings from a position generally parallel with the flow of traffic to a position generally perpendicular to the flow of traffic and through an area where pedestrians may be standing. Like Bamivek, Tamenne is incapable of returning a displaced gate arm back to its normal position if the gate mechanism rises while the gate is displaced.
Finally, U.S. Pat. No. 6,327,818 B1, issued to Pease (hereinafter referred to as “Pease I”), provides a crossing gate assembly that can rotate a crossing gate arm in a single direction, toward the railroad track crossing, out of the way of a damaging force, such as that of a vehicle approaching the railroad crossing, while returning the gate to its normal position. The Pease I assembly is capable of being adjusted for installation in conditions requiring varied gate arm lengths and flexibilities, is capable of preventing excessive impact when the gate arm returns to its normal position, prevents gate arm over travel upon return from a displaced position, is capable of being adjusted for varying gate arm return force requirements, is less expensive than existing spring-based crossing guard mechanisms, and is not subject to the potential for deterioration of a cam-and-bearing based crossing gate assemblies. The Pease I assembly is limited, however, to a single direction of rotation.
Therefore, a need exists for a crossing gate assembly that can rotate a crossing gate arm out of the way of a damaging force that can come from either of two directions; in the direction of the railroad tracks or away from the railroad tracks, while safely and efficiently returning the gate to its normal position, that is capable of being adjusted for installation in conditions requiring varied gate arm lengths and flexibilities, that is capable of preventing excessive impact when the gate arm returns to its normal position, that prevents gate arm over travel upon return from a displaced position, that is capable of being adjusted for varying gate arm return force requirements, that is less expensive than existing spring-based crossing guard assemblies, and that is not subject to the potential for deterioration of a cam-and-bearing based crossing gate assemblies.
The present invention provides a crossing gate assembly for use in a railroad track crossing gate. In one embodiment, the crossing gate assembly includes a gate arm adapter for receiving the gate arm and allowing rotation of the gate arm away from a normal operating position, either toward the railroad track crossing, or away from the railroad track crossing, approximately perpendicular to a flow of traffic upon application of a displacement force, such as that of an automobile impact. The gate arm adapter is capable of being pivotally mounted to a vertical support structure to allow the upward or downward rotation of the gate arm. A pair of return force mechanisms coupled to the gate arm adapter provides for a return of a displaced gate arm adapter to the normal operating position upon removal of the generally horizontal displacement force. In the one embodiment, the crossing gate assembly further includes a pair of latch hook assemblies that hold the gate arm adapter in its normal operating position in the absence of a displacement force. In another embodiment, the crossing gate assembly further includes a pair of drag brakes that retard a rate of return of the gate arm adapter to the normal operating position from a displaced position upon removal of the displacement force.
In another embodiment, the crossing gate assembly includes a crossing gate arm, the gate arm adapter, and a pair of return force mechanism attachment points. The gate arm adapter receives the crossing gate arm and includes a hinge pin that allows rotation of the gate arm away from the normal operating position upon application of the displacement force. The return force mechanism attachment points are opposite the hinge pin from the gate arm, and the return force mechanism attachment points, the hinge pin, and the gate arm are disposed in a generally fixed spatial relationship.
In another embodiment, the crossing gate assembly includes a pair of latch hook assemblies. Each latch hook assembly includes a pivotally levered latch that selectively restrains the gate arm adapter in its normal operating position, and a latch hook pressure mechanism that applies a leveraging force to the pivotally mounted latch to produce a pivotally levered force of the latch. Each latch hook assembly further includes a hook and drag surface that receives the pivotally levered force of the latch upon application of a displacement force to the crossing gate assembly.
The present invention can be more fully understood with reference to
In the event that a displacement force 120, e.g., that of an automobile 1 impact, is applied to the crossing gate arm 202 in a direction toward the railroad track crossing, as shown in
Automobile drivers, in an attempt to circumvent a railroad crossing gate arm 202, may follow a circuitous path 4 around the lowered crossing gate arm, as shown in FIG. 1C. In the event that a displacement force 120A, such as that of an automobile 1 impact, is applied to the crossing gate arm 202 away from the railroad track crossing, the crossing gate assembly releases the crossing gate arm 202 so that no permanent damage occurs. Once the displacement force 120A is removed, the crossing gate assembly 100 restores the crossing gate arm to a position approximately parallel to the ground, blocking vehicular traffic as shown in FIG. 1A.
As shown in
Crossing gate assembly 100 further includes a pair of return force mechanisms that each includes one or more, preferably three, spring assemblies 112, 112A. Each spring assembly 112, 112A is pivotally attached to the gate arm adapter 108 via a pair of spring assembly hinge pins 114, 114A. Spring assembly hinge pin sleeves 115, 115A fit over spring assembly hinge pin 114 acting as spacers to separate spring assembly adapters 117. Using a fastener 113, 113A through a lower sleeve 115, 115A hole and the spring assembly hinge pin 114, 114A, all parts stay in place within the top and bottom flanges of the gate arm adapter 108. Spring assemblies 112, 112A attach to the cross channels 104, 204 via mounting flanges 116, 116A using a similar pin and sleeve arrangement as just described. Spring assembly adapters 117 each provide an attachment point for the mounting of the spring assemblies 112, 112A, thereby providing for each spring assembly 112, 112A to be pivotally attached to gate arm adapter 108. In a preferred embodiment, gate arm adapter 108 is allowed to rotate about hinge pin 110 while the length of crossing gate arm 202, hinge pin 110 and spring assembly hinge pin 114 and sleeve 115 maintain a generally fixed spatial relationship throughout rotation.
When displacement force 120 displaces gate arm adapter 108 from normal operating position 118 toward the railroad crossing, each spring assembly 112A provides an approximately horizontal return force on gate arm adapter 108 at spring assembly hinge pin 114A. The return force causes gate arm adapter 108 and gate arm 202 to return from a displaced position 122 back into normal operating position 118 after displacement force 120 is removed. Likewise, when displacement force 120A displaces gate arm adapter 108 from normal operating position 118 away from the railroad crossing, each spring assembly 112 provides an approximately horizontal return force on gate arm adapter 108 at spring assembly hinge pin 114. The return force causes gate arm adapter 108 and gate arm 202 to return from a displaced position 122A back into normal operating position 118 after displacement force 120A is removed. In a preferred embodiment, crossing gate assembly 100 includes an interchangeable selection of spring assemblies 112, 112A to provide more or less return force for returning longer or shorter gate arms 202 from the displaced position 122, 122A to the normal operating position 118. Spring assemblies 112, 112A preferably provide adequate return force on gate arm adapter 108 so that gate arm 202 can be returned from a displaced position 122, 122A to normal position 118 even if crossing gate assembly 100 pivots in the vertical plane about its vertical support, as if to raise gate arm 202 while the gate arm is displaced.
In a preferred embodiment, crossing gate assembly 100 further includes a shear pin 124 that is coupled between upper hinge bracket 106 as shown in
Referring now to
Latch hook assemblies 126, 126A, as shown in
Pressure transmitted by latch spring 134 through latch hook 128 to gate arm adapter 108 via wear plate 404 causes a frictional contact between latch hook 128 and hook and drag surface 406 as the gate arm adapter 108 returns from displaced position 122A to normal operating position 118 and latch hook 128 correspondingly translates across hook and drag surface 406. The frictional contact retards the return of gate arm adapter 108. By retarding the rate of return of gate arm adapter 108 from displaced position 122A under power from spring assembly 112, latch hook assembly 126 operates as a drag brake and prevents excessive impact between gate arm adapter 108 and latch hook 128A of the upper latch hook assembly 126A, thus dampening any rebound effect from engaging the opposing spring assembly 112A. One of ordinary skill in the art realizes that a variety of latch springs 134 are available to provide more or less retarding force on gate arm adapter 108 and brake plate 402 through levered latch hook 128. Upon return of gate arm assembly 108 to normal operating position 118, latch hook assembly 126 returns to the position shown in
In sum, the present invention provides a crossing gate assembly 100 that can rotate a crossing gate arm 202 out of the way of a damaging force, either toward or away from the railroad crossing, while safely and efficiently returning the gate arm to its normal operating position 118. Crossing gate assembly 100 includes latch hook assemblies 126, 126A that latch the gate arm in normal operating position 118. Crossing gate assembly 100 further includes return force mechanisms that include multiple spring assemblies 112, 112A that returns the gate arm 202 to the normal operating position after the gate arm has been displaced by a displacing force 120, 120A. By varying the number of spring assemblies 112, 112A used in the return force mechanism, or by using spring assemblies that apply a greater or lesser return force, crossing gate assembly 100 is capable of being adjusted for installation in conditions requiring varied gate arm lengths and flexibilities and is capable of being adjusted for varying gate arm return force requirements. Latch hook assemblies 126, 126A also operate as drag brakes that are capable of preventing excessive impact and rebound when gate arm 202 returns to its normal operating position from a displaced position 122, 122A.
Opposing latch hooks 128, 128A prevent gate arm over travel upon return from a displaced position 122, 122A. By employing a drag brake, as opposed to a hydraulic piston of the prior art, to retard the rate of return of the gate arm 202 from a displaced position 122, 122A, the present invention is less expensive than existing spring-based crossing guard assemblies. Furthermore, by employing a return force mechanism that includes one or more spring assemblies applying an approximately horizontal return force when crossing gate assembly 100 is in an approximately horizontal position, the potential for deterioration of a cam-and-bearing based crossing guard assembly is eliminated.
While the present invention has been particularly shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.
Number | Name | Date | Kind |
---|---|---|---|
1382534 | Oelenschlager et al. | Jun 1921 | A |
1535753 | Weiser | Apr 1925 | A |
3394498 | Reinitz et al. | Jul 1968 | A |
4219969 | Reinitz et al. | Sep 1980 | A |
4364200 | Cobb | Dec 1982 | A |
4469660 | Jones et al. | Sep 1984 | A |
4897960 | Barvinek et al. | Feb 1990 | A |
5904115 | Durbin et al. | May 1999 | A |
6327818 | Pease | Dec 2001 | B1 |
6470626 | Luetzow et al. | Oct 2002 | B2 |
6672008 | Luetzow et al. | Jan 2004 | B1 |
Number | Date | Country | |
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20040118048 A1 | Jun 2004 | US |