Patent Abstract:
A device for permitting the (preferably manual) raising of a railroad crossing pedestrian arm independently of a roadway crossing arm, comprising a hinge including a first end operable to be connected to a pedestrian gate support arm and a second end operable to be connected to a pedestrian arm; wherein the hinge permits the second end to be raised by an external force relative to a position of the first end. Some embodiments further include a brake to slow movement of a manually raised pedestrian gate to a horizontal position.

Full Description:
BACKGROUND 
       [0001]    At many roadway railroad crossings, pedestrian paths and sidewalks also cross the railroad. Gates which are raised by default and lowered when a train approaches and crosses the intersection may be provided for roadway and pedestrian safety. There may be a separate gate for the roadway and the pedestrian path. This allows a pedestrian on the railroad tracks when the gates lower to manually raise a relatively light pedestrian gate, rather than a large and heavy roadway gate, to escape. At some intersections, the roadway gate and the pedestrian gate are raised and lowered by the same gate mechanism. The same internal gearing of the gate mechanism drives both gates. Therefore, when a pedestrian manually raises the pedestrian gate, the internal gearing of the gate mechanism raises the roadway gate as well. This can create an unsafe situation wherein a railroad crossing appears to be clear to motorists when a train is approaching. Some crossings use separate gate mechanisms for the roadway and pedestrian gates, but these are more expensive than single mechanism installations. Furthermore, single mechanism installations are already in place at countless railroad crossings, and replacing them with two-mechanism systems could be cost prohibitive for many railroad operators. A pedestrian gate which can be raised and lowered independently of a roadway gate using the same gate mechanism could inexpensively improve safety at railroad crossings, particularly if such a gate is suitable for new installations and retrofits. 
     
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0002]      FIG. 1  depicts a railroad crossing gate according to an embodiment of the invention. 
           [0003]      FIG. 2  depicts a pedestrian gate support arm according to an embodiment of the invention. 
           [0004]      FIG. 3  depicts a pedestrian arm according to an embodiment of the invention. 
           [0005]      FIG. 4  depicts a hinge according to an embodiment of the invention. 
           [0006]      FIG. 5  depicts a hydraulic brake assembly according to an embodiment of the invention. 
           [0007]      FIG. 6A  depicts a pedestrian gate according to an embodiment of the invention. 
           [0008]      FIG. 6B  depicts a pedestrian gate according to an embodiment of the invention. 
           [0009]      FIG. 7  depicts a friction brake assembly according to an embodiment of the invention. 
           [0010]      FIG. 8A  depicts a pedestrian gate according to an embodiment of the invention. 
           [0011]      FIG. 8B  depicts a pedestrian gate according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    While the following embodiments are discussed in the context of railroad crossing gates, it will be understood that this is for example only, and the scope of this disclosure is not limited to the railroad field. Access control gates can be used in a wide variety of devices and fields. Furthermore, while the following embodiments may be presented for use with specific pedestrian crossing gate systems, these are also presented as examples to provide greater understanding of the disclosure to those of ordinary skill in the relevant arts. Also, while some method steps are delineated as separate steps for ease of understanding, any such steps should not be construed as necessarily distinct nor order dependent in their performance. 
         [0013]      FIG. 1  depicts a railroad crossing gate  100  in a lowered position. The example railroad crossing gate  100  includes a pole  110 , signal lights  120 , and a gate mechanism  150  to raise and lower gates  130  and  140 . The railroad crossing gate  100  may be placed at a roadway railroad crossing. When a train approaches the crossing, the railroad crossing gate  100  may signal using the signal lights  120  and lower its gates  130  and  140  to restrict traffic from crossing the tracks until the train has passed. At many crossings, at least one railroad crossing gate  100  may be placed on either side of the railroad track to restrict road traffic in both directions. At some crossings, pedestrian paths or sidewalks may run parallel to the roadway. To restrict road and sidewalk traffic, the railroad crossing gate  100  may include a separate roadway gate  130  and pedestrian gate  140 . The roadway gate  130  and pedestrian gate  140  may be raised and lowered by the same gate mechanism  150 . The pedestrian gate  140  may include a pedestrian gate support arm  200  connecting the gate  140  to the gate mechanism  150  and a pedestrian arm  300  which restricts sidewalk traffic when lowered. When raised, gates  130  and  140  may be positioned so that they do not interfere with either roadway or pedestrian traffic. 
         [0014]    Occasionally, pedestrians using the sidewalk at a railroad crossing may find themselves on the railroad tracks when the roadway gate  130  and the pedestrian gate  140  are lowered. When a pedestrian gate  140  is placed on both sides of the railroad track to restrict entry in both directions, the pedestrian may have to manually raise one of the pedestrian gates  140  to get off the tracks before a train arrives. For railroad crossing gates  100  with single gate mechanisms  150 , manually raising the pedestrian gate  140  may also raise the roadway gate  130 , because both gates may be driven by the same internal gearing within the gate mechanism  150 . Likewise, if a pedestrian manually raises the pedestrian gate  140  while the gate mechanism  150  is lowering the gates, the lowering operation may be interrupted and both gates may be raised rather than being driven to their lowered positions. 
         [0015]    Embodiments of the invention may include a hinge on the pedestrian gate  140  to allow a pedestrian to manually raise the pedestrian gate  140  without interfering with the roadway gate  130 . A brake may also be provided so that when a pedestrian raises the pedestrian gate  140 , its descent back to its starting position may be slowed. In some embodiments of the invention, the hinge and brake may be disposed between the pedestrian gate support arm  200  and the pedestrian arm  300 . This location may allow the hinge and brake to be retrofitted into existing railroad crossing gates  100  with minimal disassembly, and it may also be compatible with new railroad crossing gate installations. 
         [0016]      FIG. 2  depicts a pedestrian gate support arm  200  according to an embodiment of the invention. The pedestrian gate support arm  200  may have an outer end  210  and an inner end  220 . The inner end  220  may connect to the gate mechanism  150 , allowing the pedestrian gate support arm  200  to be raised and lowered by the gate mechanism  150 . The outer end  210  may include one or more attachment positions ( 201  and  202  in this example) for attachment of a pedestrian arm  300  or a hinge and brake. 
         [0017]      FIG. 3  depicts a pedestrian arm  300  according to an embodiment of the invention. The pedestrian arm  300  may be of any length necessary to obstruct a pedestrian path when lowered. In many installations this length may be 12 feet or less, but larger pedestrian arms  300  are within the scope of the invention. The pedestrian arm  300  may have an inner end  310  and an outer end  320 . The inner end  310  may include one or more attachment positions ( 304  and  305  in this example) for attachment to a pedestrian gate support arm  200  or a hinge and brake. The pedestrian arm  300  may have a lower side  350  which may face the ground when the pedestrian arm  300  is in any position other than a fully open position, such as when the pedestrian arm  300  is being lowered or raised or is fully lowered. The pedestrian arm  300  may also have an upper side  360  opposite the lower side  350 . 
         [0018]      FIG. 4  depicts a hinge  400  according to an embodiment of the invention. This hinge  400  is presented as an example, but no specific hinge design is necessary, and other embodiments may use other hinges. The hinge  400  may pivot about a pivot point  403 . A first end  410  may be attached to the pedestrian gate support arm  200 , and a second end  420  may be attached to the pedestrian arm  300 . Attachment positions on the first end ( 401  and  402  in this example) may correspond to the attachment positions on the pedestrian gate support arm  200 , and attachment positions on the second end ( 404  and  405  in this example) may correspond to the attachment positions on the pedestrian arm  300 . When the hinge  400  is attached to the pedestrian gate support arm  200  and the pedestrian arm  300 , a pedestrian may lift the pedestrian arm  300  and cause the hinge  400  to rotate at its pivot point  403 . The pedestrian gate support arm  200  may continue to lower or remain lowered even as the pedestrian arm  300  is raised. Therefore, the internal operation of the gate mechanism  150  may be unaffected and the roadway gate  130  may continue to lower or remain lowered. Also, after the upward force on the pedestrian arm  300  is removed, the pedestrian arm  300  may continue to lower or proceed to its lowered state. 
         [0019]    Embodiments of the invention may provide a brake to slow the lowering of the pedestrian arm  300  after the upward force is removed. Slowing the pedestrian arm  300  may provide more time for a pedestrian to proceed through the crossing and may prevent damage or injury caused by a quickly falling pedestrian arm  300 .  FIG. 5  depicts a hydraulic cylinder brake  500  according to an embodiment of the invention. A hydraulic cylinder  510  having a cylinder body  520  and a piston rod  530  may be attached to a first bracket  502  and a second bracket  505 . These attachments may pivot to prevent bending of any part of the hydraulic cylinder  510 . In this example, the cylinder body  520  is attached to the second bracket  505  and the piston rod  530  is attached to the first bracket  502 . A piston inside the hydraulic cylinder  510  may allow the piston rod  530  to move into and out of the cylinder body  520  when the distance between the brackets  502  and  505  changes. The first bracket  502  may be attached to an attachment position or positions on the pedestrian gate support arm  200  and/or the first end  410  of the hinge  400 , and the second bracket  505  may be attached to an attachment position or positions on the pedestrian arm  300  and/or the second end  420  of the hinge  400 . 
         [0020]      FIGS. 6A and 6B  illustrate a pedestrian gate  600  including a hinge  400  and hydraulic brake  500  according to an embodiment of the invention. Corresponding attachment positions on the pedestrian gate support arm  200  and the hinge  400  may be aligned at attachment positions  601  and  602 . The pedestrian gate support arm  200  and the hinge  400  may be attached at these attachment positions with fasteners such as screws, bolts, or other hardware; or they may be attached through welding or adhesives; or by any other technique or device. Similarly, the pedestrian arm  300  and the hinge  400  may be aligned at attachment positions  604  and  605  and attached to one another using the same or different technique or device as the pedestrian gate support arm  200  and the hinge  400 . The first bracket  502  of the hydraulic brake  500  may be attached to the pedestrian gate support arm  200  and the hinge  400  at one of the attachment positions ( 602  in this example). The first bracket  502  may be attached to the pedestrian gate support arm  200  and the hinge  400  using the same hardware joining the pedestrian gate support arm  200  and the hinge  400 , or it may be attached in a different way. The second bracket  505  of the hydraulic brake  500  may be attached to the pedestrian arm  300  and the hinge  400  at one of the attachment positions ( 605  in this example). The second bracket  505  may be attached to the pedestrian arm  300  and the hinge  400  using the same hardware joining the pedestrian arm  300  and the hinge  400 . Those of skill in the art will understand that the hydraulic brake  500  may be attached to in any number of ways, so long as opposite ends of the hydraulic brake  500  are attached on opposite sides of the pivot point  403  of the hinge  400 . For example, the hydraulic brake  500  may be attached to the hinge  400  at both ends, or to the hinge  400  at one end and either the pedestrian gate support arm  200  or the pedestrian arm  300  at the other end, or to the pedestrian gate support arm  200  at one end and the pedestrian arm  300  at the other end, etc. The hydraulic cylinder  510  of the hydraulic brake  500  may be sufficiently pressurized so that the hinge  400  does not pivot due to the forces of wind or gravity on the pedestrian arm  300  when the pedestrian gate  600  is in an open position. 
         [0021]      FIG. 6A  shows a pedestrian gate  600  that has been fully lowered by the gate mechanism  150  according to an embodiment of the invention. The pedestrian arm  300  in its lowered position may extend over a pedestrian path at a height low enough to obstruct traffic. When no force is being applied to the lower side  350  of the pedestrian arm  300  (or when no pulling force is being applied to the upper side  360 ), the piston rod  530  of the hydraulic brake  500  may be fully extended. Depending on the embodiment of the invention, a “fully extended” piston rod  530  may be extended as far as the hydraulic cylinder  510  will allow or some lesser amount dictated by a maximum open angle of the hinge  400  (180 degrees in the example of  FIG. 6A ). 
         [0022]      FIG. 6B  shows a pedestrian gate  600  that has been fully lowered by the gate mechanism  150  according to an embodiment of the invention. In  FIG. 6B , a force is being applied (or has recently been applied) to the lower side  350  (or the upper side  360 ) of the pedestrian arm  300 . This force may be a pedestrian lifting the gate, an obstacle standing in the way of the gate, or some other force. This force may cause the hinge  400  to rotate and the pedestrian arm  300  to raise. Because the hinge  400  rotates in response to this force, the pedestrian gate support arm  200  may retain its position in spite of the application of the force. Note that the pedestrian gate support arm  200  is in the same position in both  FIGS. 6A and 6B , while the pedestrian arm  300  is in a different position in each figure. When a force is applied to the pedestrian arm  300 , the pedestrian arm  300  may be raised without affecting the pedestrian gate support arm  200  at least until the piston rod  530  of the hydraulic brake  500  is fully retracted. Depending on the embodiment of the invention, a “fully retracted” piston rod  530  may be retracted as far as the hydraulic cylinder  510  will allow or some lesser amount dictated by a minimum open angle of the hinge  400 . 
         [0023]    When the force applied in  FIG. 6B  is removed, the pedestrian arm  300  may return to its position in  FIG. 6A . The hydraulic brake  500  may slow the return of the pedestrian arm  300  to its lowering, raising, or lowered position corresponding with the position of the pedestrian gate support arm  200  and fully open hinge  400 . Pressurized fluid within the hydraulic cylinder  310  may slow the extension of the piston rod  530 , which in turn may counteract the force of gravity to reduce the acceleration rate of the pedestrian arm  300 . By slowing the return of the pedestrian arm  300 , injury or damage to a pedestrian or object under the pedestrian arm  300  may be minimized or prevented. 
         [0024]      FIG. 7  depicts a hinge  400  and friction brake  700  according to an embodiment of the invention. A friction brake  700  may be provided to slow the lowering of the pedestrian arm  300  after the upward force is removed in some embodiments. As with the hinge  400  of  FIG. 4 , the hinge  400  of  FIG. 7  may pivot about a pivot point  403 . A first end  410  may be attached to the pedestrian gate support arm  200 , and a second end  420  may be attached to the pedestrian arm  300 . Attachment positions on the first end ( 401  and  402  in this example) may correspond to the attachment positions on the pedestrian gate support arm  200 , and attachment positions on the second end ( 404  and  405  in this example) may correspond to the attachment positions on the pedestrian arm  300 . 
         [0025]    The friction brake  700  may include friction pads, such as a first friction pad  730  and a second friction pad  731  which may slow the movement of the second end  420  of the hinge  400  with respect to the first end  410  of the hinge  400  by converting the kinetic energy of the second end  420  into heat. The friction pads  730  and  731  may be made from different materials having different coefficients of friction or they may be made of the same material. An adjusting knob  710  may allow a user to adjust a force with which the friction pads  730  and  731  are pressed together. A rod  750  may be located at the pivot point  403 . This rod  750  may be rigidly attached to the second end  420  or it may be an integral part of the second end  420 . The rod  750  may pass through holes in the first end  410 , the adjusting knob  710 , and the friction pads  730  and  731 . A nut  720  may be provided to secure the second end  420 , the adjusting knob  710 , and the friction pads  730  and  731  around the rod  750 . One friction pad  731  may be attached to the rod  750 , and the other friction pad  730  may be attached to the first end  410 . A tab  740  may be disposed on the second end  420  near an edge  760  of the first end  410 . The tab  740  and edge  760  may be shaped such that the tab  740  may restrict the movement of the second end  420  about the pivot point  403  by blocking its progress in moving beyond a set position. In some embodiments the tab  740  and edge  760  may block the progress of the second end  420  in moving beyond two positions in opposite directions. The embodiment of  FIG. 7  is presented as an example, but other friction brake and hinge configurations are possible. For example, the first end  410  may be attached to the pedestrian gate support arm  200 , and the second end  420  may be attached to the pedestrian arm  300 . 
         [0026]      FIG. 8A  shows a pedestrian gate  800  that has been fully lowered by the gate mechanism  150  according to an embodiment of the invention. The pedestrian arm  300  in its lowered position may extend over a pedestrian path at a height low enough to obstruct traffic. When no force is being applied to the lower side  350  of the pedestrian arm  300  (or when no pulling force is being applied to the upper side  360 ), the hinge  400  may have a maximum open angle (180 degrees in the example of  FIG. 8A ). The pedestrian arm  300  may be held in place such that the hinge  400  does not exceed its maximum open angle by the edge  760  blocking the progress of the tab  740 . 
         [0027]      FIG. 8B  shows a pedestrian gate  800  that has been fully lowered by the gate mechanism  150  according to an embodiment of the invention. In  FIG. 8B , a force is being applied (or has recently been applied) to the lower side  350  (or the upper side  360 ) of the pedestrian arm  300 . This force may be a pedestrian lifting the gate, an obstacle standing in the way of the gate, or some other force. This force may cause the hinge  400  to rotate and the pedestrian arm  300  to raise. Because the hinge  400  rotates in response to this force, the pedestrian gate support arm  200  may retain its position in spite of the application of the force. Note that the pedestrian gate support arm  200  is in the same position in both  FIGS. 8A and 8B , while the pedestrian arm  300  is in a different position in each figure. When a force is applied to the pedestrian arm  300 , the pedestrian arm  300  may be raised without affecting the pedestrian gate support arm  200  at least until the edge  760  blocks the progress of the tab  740 . 
         [0028]    When the force applied in  FIG. 8B  is removed, the pedestrian arm  300  may return to its position in  FIG. 8A . The friction brake  700  may slow the return of the pedestrian arm  300  to its lowering, raising, or lowered position corresponding with the position of the pedestrian gate support arm  200  and fully open hinge  400 . Friction between friction pads  730  and  731  may counteract the force of gravity to reduce the acceleration rate of the pedestrian arm  300 . By slowing the return of the pedestrian arm  300 , injury or damage to a pedestrian or object under the pedestrian arm  300  may be minimized or prevented. 
         [0029]    In some embodiments of the invention, some or all of the components of the pedestrian gate release may be made of materials which resist corrosion and/or wear. The components may also be constructed such that the device may be operable in varying and extreme weather and temperature conditions. For example, components may be used which operate during severe temperature conditions from −40 degrees Celsius to +71 degrees Celsius, with no humidity restrictions. Components may comply with other suitable temperature and humidity requirements as conditions at installation sites may dictate. Components may be manufactured such that they do not collect water either individually or when assembled into a complete pedestrian gate release. In some embodiments, all surface edges on the pedestrian gate release may be free of burrs and sharp edges that may cause injury or damage. 
         [0030]    In some embodiments of the invention, an alarm or alarms may be added. These alarms may be triggered when the pedestrian arm  300  is lifted by a force. For example, audio alarms, strobe lights, or other indicators may be used as alarms. Audio or visual alarms may also be provided to indicate that the pedestrian arm  300  has been lifted by public authorities or because of special safety or environmental conditions. Surveillance cameras may be installed on or near the railroad crossing gate  100  to monitor the pedestrian arm  300 . The pedestrian gate  140  may also be provided with flashing lights to indicate the approach of a train. The pedestrian gate release may be equipped with warning labels to alert pedestrians of the danger of potential retraction of the pedestrian arm  300  back to its normal position after being lifted, labels specifying maximum recommended gate lengths, and/or other labels. 
         [0031]    The AREMA Manual For Railway Engineering 2010 is incorporated by reference in its entirety herein. Some embodiments of the invention may adhere fully with the AREMA Manual For Railway Engineering 2010 Part 3.2.23: Recommended Functional/Operational Guidelines for Self-Restoring Highway Rail Grade Crossing Gate Arm Devices. Fasteners, materials, and coatings used in embodiments of the invention may conform to guidelines specified in the AREMA Manual (for example, Part 1.5.10: Recommended Instructions for Painting and Protective Coatings; Part 14.6.20: Recommended Design Criteria for Bolts, Nuts, and Threads; Part 14.6.21: Recommended Design Criteria for Plain and Spring Lock Washers; Part 15.1.4: Recommended Developmental Criteria for Various Types of Steel; and/or Part 15.1.5: Recommended Developmental Criteria for Various Types of Non-Ferrous Metal and Alloys). When a pedestrian gate  140  is in its raised position, embodiments of the invention may allow it to withstand the wind forces specified in the AREMA Manual Section 3: Highway Rail Grade Crossing Warning Systems. 
         [0032]    While various embodiments have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art(s) that various changes in form and detail can be made therein without departing from the spirit and scope. In fact, after reading the above description, it will be apparent to one skilled in the relevant art(s) how to implement alternative embodiments. Thus, the present embodiments should not be limited by any of the above-described embodiments. 
         [0033]    In addition, it should be understood that any figures which highlight the functionality and advantages, are presented for example purposes only. The disclosed methodology and system are each sufficiently flexible and configurable, such that it may be utilized in ways other than that shown. 
         [0034]    Further, the purpose of the Abstract of the Disclosure is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The Abstract of the Disclosure is not intended to be limiting as to the scope of the present invention in any way. 
         [0035]    It should also be noted that the terms “a”, “an”, “the”, “said”, etc. signify “at least one” or “the at least one” in the specification, claims and drawings. 
         [0036]    Finally, it is the applicant&#39;s intent that only claims that include the express language “means for” or “step for” be interpreted under 35 U.S.C. §112, paragraph 6. Claims that do not expressly include the phrase “means for” or “step for” are not to be interpreted under 35 U.S.C. §112, paragraph 6.

Technology Classification (CPC): 8