Abstract:
An example includes an apparatus for releasing a railroad gate in at least two directions. The example includes a primary pivot member and a secondary pivot member pivotally connected to the primary pivot member, with one end of the railroad crossing connectable to the secondary pivot member. In the example the primary pivot member is rotable around a primary pivot of the apparatus, the primary pivot member rotable in a first direction against a first spring bias and in a second direction, opposite the first direction, against a second spring bias other than the first spring bias, and 
     wherein the secondary pivot member is rotable around a secondary pivot of the apparatus, the secondary pivot member rotable in the first direction against a third spring bias other than the first spring bias and the second spring bias.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 12/001,104, filed Dec. 10, 2007, to grant as U.S. Pat. No. 8,240,618; and is related to U.S. application Ser. No. 12/944,627, filed Nov. 11, 2010, which is a continuation-in-part of U.S. application Ser. No. 12/001,104, the specifications of each of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is for a railroad gate release mechanism, and in particular, for a multiple direction railroad gate release mechanism which allows for maintaining the structural integrity of a railroad grade crossing arm when struck from one or more directions by an automotive vehicle. Although a multiple direction railroad gate release mechanism is described, the release mechanism can be used for other gates such as, but not limited to, parking lot gates, restricted access gates, road closure gates, toll gates, crowd control gates and the like. 
     2. Description of the Prior Art 
     Railroad crossing grades are protected by railroad grade crossing arms which are stored substantially in a vertical position and which are actuated by railroad gate actuators. The actuators reorient the crossing arms to a horizontal position across a railroad crossing grade. The crossing arms warn operators of vehicles of oncoming train traffic and physically place a barrier in the form of a crossing arm at both sides of the railroad crossing grade to discourage and prevent the passage of a vehicle into the railroad crossing grade. Motorists unaware of the movement of a crossing arm may impinge either the front or the back of the crossing arm to the extent that physical damage may occur whereby the crossing arm is broken or parted from the railroad gate actuator. In some situations, the motorist may physically damage a first crossing arm or may avoidingly maneuver the motor vehicle around the end of the first crossing arm whereby damaging impact with a second opposed crossing can result. Such an occurrence can compromise the safety of the railroad grade crossing in that other motorists will not be warned of impending danger due to the destruction of one or more of the crossing arms. Such occurrences will compromise safety as well as add a financial maintenance burden. 
     SUMMARY OF THE INVENTION 
     The general purpose of the present invention is to provide a multiple direction railroad gate release mechanism. 
     According to one embodiment of the present invention, there is provided a multiple direction railroad gate release mechanism for attachment between a railroad gate actuator and a crossing arm. The mechanism includes opposing channel shaped brackets which attach to the railroad gate actuator and which also serve as a mounting structure for other components. Reference is made to the multiple direction railroad gate release mechanism as deployed in a horizontal situation across a railroad crossing grade. A primary pivot arm assembly to which a secondary pivot arm assembly and a crossing arm are attached, pivotally mounts between vertically opposed top and bottom bearing support plates located on the inwardly facing surfaces of opposed channel shaped brackets. The primary pivot arm assembly is pivotable for the most part in a clockwise direction or to a lesser extent in a counterclockwise direction from a centered detent neutral position until limited by contacting limit stops. For example and illustration, the primary pivot arm assembly is pivotable 45° clockwise about a pivot pin and is pivotable 15° counterclockwise about the pivot pin. The primary pivot arm assembly is influenced by a detent and plunger arrangement which maintains a combined perpendicular relationship of the primary pivot arm assembly, the secondary pivot arm assembly and the attached crossing arm with respect to the railroad gate actuator until acted upon by outside forces. Most commonly, an outside force impinges one or more of the crossing arms when the crossing arms are deployed horizontally across both sides of a crossing grade, such as a vehicle impinging the front (approach) side of one of the crossing arms from a roadway. Such front side impingement causes the multiple direction railroad gate release mechanism, with the attached secondary pivot arm assembly and crossing arm, to pivotally overcome the influence of the detent and plunger arrangement and to swing horizontally out of the way of the oncoming impinging vehicle. Impingement from the front side of the crossing arm from a roadway can occur without functional damage to the crossing arm. Such pivotal yielding substantially reduces the possibility of breakage of the crossing arm, as little bending moment is actually applied along the crossing arm itself due to the substantially unrestricted repositioning yielding movement allowed by the multiple direction railroad gate release mechanism. Subsequent to such impingement and when the vehicle has ceased to contact the crossing arm, top and bottom spring assemblies function to return the primary pivot arm assembly of the multiple direction railroad gate release mechanism with the attached secondary pivot arm assembly and crossing arm to the detent and neutral centered position to continue to offer gated protection at the railroad crossing grade, especially for those vehicles approaching from the abutting roadway. A shock absorber allows for rapid rate pivoting of the primary pivot arm assembly and attached secondary pivot arm assembly and attached crossing arm in one direction during impingement and allows for a slower rate return of the primary pivot arm assembly and attached members in the return direction subsequent to impingement. The centering spring assembly assists in returning of the primary pivot arm assembly to the detent position in the case of a return overshoot. 
     Additional protection of the crossing arm is afforded in the opposite direction with respect to a vehicle on the actual crossing grade, i.e., a vehicle on the tracks which approaches and impinges the back side of the crossing arm. The secondary pivot arm assembly is pivotally mounted to the primary pivot arm assembly and extends outwardly therefrom to accommodate attachment of the crossing arm to offer relief from a crossing arm back side impingement. The secondary pivot arm assembly pivots in a counterclockwise direction about a pivot pin located near the end of the primary pivot arm assembly. Top and bottom spring assemblies function to return the secondary pivot arm assembly and maintain the combined perpendicular relationship of the primary pivot arm assembly, the secondary pivot arm assembly, and the attached crossing arm with respect to the railroad gate actuator. 
     One significant aspect and feature of the present invention is a multiple direction railroad gate release mechanism which is secured between the mount arms of a railroad gate actuator and a crossing arm. 
     Another significant aspect and feature of the present invention is a multiple direction railroad gate release mechanism which, when impinged, releasably allows a breakaway positioning in two directions of a crossing arm from a normal and detent position in order to prevent damage to the crossing arm. 
     Another significant aspect and feature of the present invention is a multiple direction railroad gate release mechanism which allows the return positioning of a crossing arm to a normal and detent position subsequent to a breakaway positioning caused by impingement. 
     Still another significant aspect and feature of the present invention is a multiple direction railroad gate release mechanism which offers grade crossing protection subsequent to crossing arm impingement. 
     Still another significant aspect and feature of the present invention is a multiple direction railroad gate release mechanism having a secondary pivot arm assembly pivotally attached to a primary pivot arm assembly where the secondary pivot arm assembly can operate in concert with the primary pivot arm assembly or can operate independently of the primary pivot arm assembly. 
     Yet another significant aspect and feature of the present invention is the use of cables attached to the primary pivot arm assembly which are influenced by springs in spring assemblies which springs are compressed during impingement with the front side of a crossing arm and which are used to subsequently power the return of the primary pivot arm assembly, attached secondary pivot arm assembly and attached crossing arm assembly to an original neutral and detent position. 
     A further significant aspect and feature of the present invention is the use of a shock absorber which allows rapid deployment of the primary pivot arm assembly having an attached secondary pivot assembly and attached crossing arm during frontal crossing arm impingement and which allows return of the primary pivot arm assembly having the attached secondary pivot arm assembly and crossing arm at a slower rate subsequent to impingement, whereby the slower return rate reduces the possibility of a return overshoot of the primary pivot arm assembly, attached secondary pivot arm assembly and attached crossing arm assembly. 
     Yet another significant aspect and feature of the present invention is the use of swing stops which limit the travel of the primary pivot arm assembly in clockwise and counterclockwise rotational movements in order to prevent overstressing or other damage to the cables used in the associated spring assemblies. 
     Yet another significant aspect and feature of the present invention is the use of stop plates or other structure which limit the travel of the secondary pivot arm assembly in a counterclockwise rotational movement in order to prevent overstressing or other damage to the cables used in the associated spring assemblies. 
     A still further significant aspect and feature of the present invention is the use of a centering spring assembly which urges the primary pivot arm assembly into a normal and detent position when a returning primary crossing arm assembly, attached secondary pivot arm assembly, and attached crossing arm assembly overshoot a neutral detent position. 
     Having thus described an embodiment of the present invention and having set forth significant aspects and features thereof, it is the principal object of the present invention to provide a multiple direction railroad gate release mechanism. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein: 
         FIG. 1  illustrates the use of a multiple direction railroad gate release mechanism, the present invention, wherein a railroad gate actuator is shown in the actuated position to position the multiple direction railroad gate release mechanism and the attached crossing arm in a horizontal position; 
         FIG. 2  is a right side isometric view of the multiple direction railroad gate release mechanism, the present invention, along with portions of mount arms and a crossing arm which are associated therewith in use; 
         FIG. 3  is a right side isometric view of the multiple direction railroad gate release mechanism with a top bracket removed; 
         FIG. 4  is an exploded isometric view of the components of the invention shown in  FIG. 2 ; 
         FIG. 5  is left side isometric view of the multiple direction railroad gate release mechanism; 
         FIG. 6  is an exploded isometric view of the components of the invention shown in  FIG. 5 ; 
         FIG. 7  is an isometric view of the primary and secondary arm assemblies and other closely associated components; 
         FIG. 8  is a rear isometric view of the multiple direction railroad gate release mechanism; 
         FIG. 9  is a top view of the multiple direction railroad gate release mechanism in partial cutaway showing its normal detent position when in use to deploy an attached crossing arm attached thereto; 
         FIG. 10  is a top view of the multiple direction railroad gate release mechanism in partial cutaway illustrating the mode of operation of the multiple direction railroad gate release mechanism when an attached crossing arm is forcibly impinged from the front side; and, 
         FIG. 11  is a top view of the multiple direction railroad gate release mechanism in partial cutaway and best illustrates the mode of operation of the multiple direction railroad gate release mechanism when an attached crossing arm is forcibly impinged from the back side. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows the use of the multiple direction railroad gate release mechanism  10  of the present invention. A railroad gate actuator  12  is shown in the actuated position to position the multiple direction railroad gate release mechanism  10  and attached crossing arm  14  in a horizontal position. The multiple direction railroad gate release mechanism  10  is mounted between the ends of the mount arms  16   a  and  16   b  ( FIG. 2 ) and the crossing arm  14  is mounted to the multiple direction railroad gate release mechanism  10 . 
       FIG. 2  is a right side isometric view of the multiple direction railroad gate release mechanism  10  of the present invention showing its connecting relationship between mount arms  16   a  and  16   b  of the railroad gate actuator  12  and the crossing arm  14 . Top and bottom mounting brackets  18  and  20  in the form of channels accommodate attachment of the mount arms  16   a  and  16   b . The crossing arm  14  is secured over and about a secondary pivot arm assembly  58  of the multiple direction railroad gate release mechanism  10 , each of which is shown in a horizontal position, such as for stopping traffic at a railroad grade crossing. 
     Multiple views of the invention are included for a full understanding of the present invention including isometric views, exploded isometric views, and isometric views of several components generally shown in a horizontal orientation as deployed across a crossing grade.  FIG. 3  is a right side isometric view of the multiple direction railroad gate release mechanism  10  with a top bracket  18  ( FIG. 2 ) removed for the purpose of clarity.  FIG. 4  is an exploded isometric view of the components of the invention shown in  FIG. 2 .  FIG. 5  is left side isometric view of the multiple direction railroad gate release mechanism to  10 .  FIG. 6  is an exploded isometric view of the components of the invention shown in  FIG. 5 . With respect to the above figures, the invention is further described. In the invention, a plurality of nuts, bolts, and lock washers are secured through a plurality of holes in a plurality of diverse components as is common practice in the art and as are shown or indicated in engagement or alignment wherever practicable or suitable in the accompanying illustrated figures. 
     Partial or fully visible components of the multiple direction railroad gate release mechanism  10  include opposing top and bottom mounting brackets  18  and  20  in the form of a channel, each having a plurality of mounting holes  22   a - 22   n  used in the attachment of mount arms  16   a  and  16   b  of the railroad gate actuator  12 , as well as other holes and features for mounting other components thereto. Opposed top and bottom bearing support plates  24  and  26  are preferably aligned with recessed surfaces on the inwardly facing surfaces of the top and bottom mounting brackets  18  and  20  are suitably secured thereto; one such recessed surface  28  is shown in  FIG. 4 . The top bearing support plate  24  includes a circular recess  30  opening downwardly for the fixed accommodation of a top bearing assembly  32 . The top bearing support plate  24  also includes a hole  34  for the fixed accommodation of a stop pin  36  having of a greater vertical dimension than the thickness dimension of the top bearing support plate  24 . The bottom portion of such a top stop pin  36  extends downwardly a short distance beyond the bottom surface of the top bearing support plate  24 . Also, the bottom bearing support plate  26  includes a circular recess  38  opening upwardly for the fixed accommodation of a bottom bearing assembly  40 . The bottom bearing support plate  26  also includes a hole  44  for the protected accommodation of a bottom stop pin  46  having of a greater vertical dimension than the thickness dimension of the bottom bearing support plate  26 . The top portion of such a bottom stop pin  46  extends upwardly a short distance beyond the top surface of the bottom bearing support plate  26 . The bottom stop pin  46  includes a vertically aligned central bore  48 , thus enabling the accommodation of a replaceable protective shear pin  50 , the latter of which extends vertically and upwardly through the bottom mounting bracket  20 . The protective shear pin  50  extends further to align coaxially and indirectly through the hole  44  and coaxially and directly into the central bore  48  of the bottom stop pin  46 . The top portion of the replaceable shear pin  50  extends upwardly beyond the top surface of the bottom stop pin  46  to engage a hole  51  in a bottom swing plate  62 . The replaceable shear pin  50  is secured to the bottom of the bottom mounting plate  20  by means of a moveable retainer plate  52 . A connection between the top bearing support plate  24  and the bottom bearing support plate  26  is provided by a vertically oriented pivot pin  54  extending therebetween. Opposed ends of the vertically oriented pivot pin  54  are aligned within and extend between the top bearing assembly  32  and the bottom bearing assembly  40  and functions as support for a primary pivot arm assembly  56  described later in detail. A secondary pivot arm assembly  58  is pivotally supported by and extends outwardly from the primary pivot arm assembly  56 . The pivot pin  54  extends through and is secured to the structure of the primary pivot arm assembly  56 . 
     The primary pivot arm assembly  56  is aligned between the top and bottom bearing support plates  24  and  26 , respectively, and is mounted and pivotally secured therebetween by the pivot pin  54  which is in close intimate contact with the top bearing assembly  32  and the bottom bearing assembly  40 . The primary pivot arm assembly  56  includes, in part, opposing geometrically configured and vertically spaced top and a bottom swing plates  60  and  62 . As viewed in  FIG. 7 , one end of the top swing plate  60  is arcuate in shape and accommodates the secured mounting of opposed arcuate top and bottom cable guide plates  64  and  66 . The top and bottom cable guide plates  64  and  66  extend beyond the edge of the arcuate end of the top swing plate  60  to form an arcuate cable channel  68  therebetween. A semicircular detent  70  is formed by semicircular cutouts in each of the top and bottom cable guide plates  64  and  66 , the combination of which forms the detent  70 . The bottom swing plate  62  is made substantially similar to the top swing plate  60  and includes opposing arcuate top and bottom cable guide plates  72  and  74  to form an arcuate cable channel  76 . A semicircular detent  77  is formed by semicircular cutouts in each of the top and bottom cable guide plates  72  and  74 , the combination of which forms the detent  77 . It is noted that the cable channel  68  and the cable channel  76  are abbreviated with respect to the full arcuate length of the top cable guide plate  64 , the bottom cable guide plate  66 , the top cable guide plate  72 , and the bottom cable guide plate  74 , respectively, in order to allow room for accommodation of spring assembly structures described later in detail. Such abbreviation is provided by reducing the width, i.e, a reduction of the radius of the top cable guide plate  64 , the bottom cable guide plate  66 , the top cable guide plate  72  and the bottom cable guide plate  74 , such as representatively shown at reference  90  at the top cable guide plate  64 . A hole  78  ( FIG. 7 ) is included at the pivot axis of the primary pivot arm assembly  56  in the top swing plate  60  in opposed alignment with a hole  80  in the bottom swing plate  62  for accommodating of the opposed ends of the pivot pin  54 . The body of the pivot pin  54  is suitably secured in the holes  78  and  80  such as by weldments. The ends of the pivot pin  54  extend beyond the top and bottom surfaces of the top swing plate  60  and the bottom swing plate  62  in order to fittingly accommodate the top bearing assembly  32  and the bottom bearing assembly  40 , respectively. Another set of opposed holes is located at one end of the primary pivot arm assembly  56  including a hole  82  in the top swing plate  60  in opposed alignment with a hole  84  in the bottom swing plate  62  for accommodation of a pivot pin  86  in the form of a bolt which is secured therein by a nut  88 . The pivot pin  86  is used to pivotally secure the secondary pivot arm assembly  58  to the primary pivot arm assembly  56  using holes  82  and  84  and pivot holes  116  and  120 , each of which is shown in  FIG. 7 . Swing stops  92  and  94  are mounted in the top swing plate  60  and swing stops  96  and  98  are mounted in the bottom swing plate  62  in order to limit rotation of the primary pivot arm assembly  56  at clockwise and counterclockwise limits, as described below. Each swing stop is shouldered and protrudes through holes in the respective top or bottom swing plate  60  and  62 . The swing stops  92  and  94  protrude upwardly through and slightly beyond the top surface of the top swing plate  60  in order to impinge the top stop pin  36  mounted in and extending downwardly from the top bearing support plate  24 . The swing stops  96  and  98  protrude downwardly through and slightly beyond the bottom surface of the bottom swing plate  62  in order to impinge the bottom stop pin  46  extending from the bottom bearing support plate  26 . Swing stops  92  and  96  provide a clockwise rotation stop at approximately 45° from center, for example, and the swing stops  94  and  98  provide a counterclockwise rotation stop at approximately 15° from center, for example and illustration. Vertically aligned tabbed brace plates  102 ,  103 ,  104 ,  105  and  106  are aligned and secured between the top swing plate  60  and the bottom swing plate  62 , thereby connecting the top swing plate  60  and the bottom swing plate  62 . A vertically oriented support plate  107  connects one edge of the top swing plate  60  to a corresponding edge of the bottom swing plate  62 . The secondary pivot arm assembly  58  includes opposed horizontally aligned top and bottom bars  108  and  110 , respectively. Opposed vertically aligned and spaced plates  112  and  114  are aligned and secured between the top and bottom bars  108  and  110 . The top bar  108  includes a vertically aligned pivot hole  116  and a juxtaposed vertically aligned hole  118 , each extending through the top bar  108 . Correspondingly, the bottom bar  110  includes a vertically aligned pivot hole  120  and a juxtaposed vertically aligned hole  122 , each extending through the bottom bar  110  in alignment with the pivot hole  116  and the hole  118  of the top bar  108 . The inboard ends of the top bar  108  and the bottom bar  110  are aligned between the outboard ends of the top swing plate  60  and the bottom swing plate  62  and are pivotally connected to the pivot pin  86 . The pivot pin  86  extends through holes  82  and  84  of the top swing plate  60  and the bottom swing plate  62  and through the holes  116  and  120  of the top and bottom bars  108  and  110 , respectively. Horizontally aligned cable adapter holes  124  and  126  extend through the inboard ends of the top and bottom bars  108  and  110 , respectively. A replaceable shear pin  128  which generally prevents pivoting of the secondary pivot arm assembly  58  with respect to the primary pivot arm assembly  56 , is installed in holes  130  and  132 , respectively, at the end of the top swing plate  60  and the bottom swing plate  62  and through holes  118  and  122  in the top and bottom bars  108  and  110 . A stop bar  134  is located on the top bar  108  of the secondary pivot arm assembly  58  which is used to align the inboard end of the crossing arm  14  along the secondary pivot arm assembly  58 . 
     Having described the structure of a plurality of components comprising the primary pivot arm assembly  56  and the secondary pivot arm assembly  58 , and parts and components closely associated therewith thereto, other components and associated structure, which influence the static and the actuated states before, during, and after impingement of a crossing arm  14  by an outside force either to the front or to the rear of a crossing arm  14 , are now described referring primarily to  FIGS. 3 ,  4 ,  5  and  6 . A vertically aligned left brace plate  136  and right brace plate  138  are mounted vertically between the top mounting bracket  18  and the bottom mounting bracket  20  such that the left brace plate  136  and right brace plate  138  serve as mounts for other components, as well as assisting in structural support for various previously described components. 
     Certain components are useful in maintaining position of as well as protecting and returning a displaced crossing arm  14  to a centered neutral position following the impingement on the front of the crossing arm  14  by an outside force. A plunger housing  140 , including a spring loaded movable round end plunger  142 , is mounted on the right brace plate  138 . The round end plunger  142  extends through an opening in the right brace plate  138  in order to engage the detent  77  in the bottom swing plate  62  of the primary pivot arm assembly  56  and to maintain the position of the primary pivot arm assembly  56  in a static and centered neutral position, whereby the crossing arm  14  is maintained in an extended horizontal position across a grade crossing. Upon a forcible impingement on the front side of the crossing arm  14 , the primary pivot arm assembly  56  is forced to rotate about the pivot pin  54  and simultaneously the top of the shear pin  50  is sheared whereby such movement drives the round end plunger  142  from the detent  77 . Subsequent to disengagement of the round end plunger  142  from the detent  77 , other forces, as provided by the operation of other components of the invention, serve to return the primary pivot arm assembly  56  to a static and centered neutral position, whereby the round end plunger  142  forcibly re-engages the detent  77 . A collection of return components is associated directly or indirectly with the left brace plate  136  including pivotally mounted top and bottom spring assemblies  144  and  146 , a shock absorber  148  having a cover  150  pivotally secured to the left brace plate  136  and a centering spring assembly  152  secured between the free ends of the top and bottom spring assemblies  144  and  146 . Cables  154  and  156  extend from the top and bottom spring assemblies  144  and  146  to engage the length of the cable channels  68  and  76 , respectively. Cable ball and washer assemblies  158  and  160  are affixed to the ends of the cables  154  and  156 , respectively, and are aligned at one end of the cable channels  68  and  76 , respectively. The ends of the cables  154  and  156  are positionally secured in the cable channels  68  and  76  by pins  162  and  164  ( FIG. 7 ) extending through the top cable guide plate  64  and the bottom cable guide plate  66  and extending through the top cable guide plate  72  and the bottom cable guide plate  74 , respectively, at a position outboard of and in close proximity to the cables  154  and  156 . A connector assembly  145  connects between the round end plunger  142  support structure and an event counter  147  which is attached to the inside surface of the right brace plate  138 . 
     Certain components are useful in protecting and returning a displaced crossing arm  14  to a centered neutral position with respect to impingement of the rear of the crossing arm  14  by an outside force. A vertically aligned bracket assembly  166  is secured to the edges of the top swing plate  60  and the bottom swing plate  62  of the primary pivot arm assembly  56  as a mount for a top and bottom spring assembly  168  and  170 . The top and bottom spring assemblies  168  and  170  are suitably secured in armular grooves  171  and  173  in the bracket assembly  166 . The ends of cables  172  and  174  ( FIG. 4 ) extend from the top and bottom spring assemblies  168  and  170  through body holes  175  and  177  in the tabbed brace plate  105  ( FIG. 7 ) and engage the cable connection holes  124  and  126  at the inboard ends of the top bar  108  and the bottom bar  110  of the secondary pivot arm assembly  58 , respectively. Cable ball and washer assemblies  176  and  178  are affixed to the ends of cables  172  and  174 , respectively, in order to retain the ends of the cables  172  and  174  within the cable connection holes  124  and  126 , respectively. 
       FIG. 8  is a rear isometric view of the elements shown in  FIG. 3 . Illustrated, in particular, is the relationship of the primary pivot arm assembly  56  with respect to the top and bottom spring assemblies  144  and  146 , the centering spring assembly  152 , and the shock absorber  148 . Similar spaced mounting brackets  180  are secured to the left brace plate  136 . One end of the shock absorber  148  is pivotally secured to the mounting brackets  180  and the other end of the shock absorber  148  is pivotally secured to spaced mounting brackets  182  on the rear of the tabbed brace plate  105  of the primary pivot arm assembly  56 , as shown in  FIG. 5 . The shock absorber  148  when moved to a compressed position allows for the rapid rotational movement of the primary pivot arm assembly  56  from and beyond the neutral detent position during impingement of the front side of the crossing arm  14 . The shock absorber  148  allows for a slower rate of movement when returning to the centered neutral position to suitably control the return rate of the primary pivot arm assembly  56  subsequent to impingement of the front side of the crossing arm  14 . The body of the centering spring assembly  152  is secured, as previously described, between the outboard ends of the top and bottom spring assemblies  144  and  146 . The free end of the centering spring assembly  152  closely juxtaposes a roller  153  mounted to the tabbed brace plate  103  by the use of spaced mounting brackets  187 . The centering spring assembly  152  is used to urge and assist the primary pivot arm assembly  56  to return to a normal and detent position if a return over shoot occurs, as described later in detail. The horizontally oriented top and bottom spring assemblies  144  and  146  are aligned and suitably secured in bores  184  and  186  in the left brace plate  136 . One end of cables  154  and  156  is secured by cable ball and washer assemblies  158  and  160  ( FIG. 4 ), as previously described. The cables  154  and  156  are aligned in the cable channels  68  and  76  of the top and bottom swing plates  60  and  62 , respectively. The other ends of the cables  154  and  156  are secured to circular plates  188  and  190  located inside of the top and bottom spring assemblies  144  and  146 . Springs  192  and  194  are located interior to the top and bottom spring assemblies  144  and  146  between the circular plates  188  and  190  and the inward facing ends  196  and  198  of the top and bottom spring assemblies  144  and  146 . Clockwise pivotal movement of the primary pivot arm assembly  56  about the pivot pin  54  also carries the attached secondary pivot arm assembly  58  in a clockwise direction as indicated by arrow  200  in a unitary clockwise movement. Such pivotal movement causes compression of the springs  192  and  194  to provide a built-up energy for subsequent spring powered action of the primary pivot arm assembly  56  (and the attached non-pivoted secondary pivot arm assembly  58 ) to return the primary pivot arm assembly  56  to its normal centered neutral detent position subsequent to frontal impingement of the crossing arm  14 . 
     As partially shown in  FIG. 8  and with understood reference to previously described figures, the relationship of the secondary pivot arm assembly  58  to the top and bottom spring assemblies  168  and  170  is now described. Springs  202  and  204  are located interior to the top and bottom spring assemblies  168  and  170  and are attached to and located between each of the circular plates  206  and  208  and the inward facing ends (not shown) of the top and bottom spring assemblies  168  and  170 . Pivotal movement of the secondary pivot arm assembly  58  in a counterclockwise direction about the pivot pin  86  as indicated by arrow  210  is caused by impingement to the rear of the crossing arm  14  resulting in shearing of the shear pin  128  and in compression of the springs  202  and  204  through the cables  172  and  174 . Such pivotal movement provides built-up energy for subsequent spring powered action by the top and bottom spring assemblies  168  and  170  to cause the secondary pivot arm assembly  58  to return to its normal position against the tabbed brace plate  105  subsequent to rearward impingement of the crossing arm  14 . 
       FIG. 9  is a top view of the multiple direction railroad gate release mechanism  10  in partial cutaway showing its normal detent centered neutral position when in use to deploy in attached crossing arm  14  (not shown) across a railroad grade crossing. The top cable guide plate  64  and underlying bottom cable guide plate  66  are shown in partial cutaway to reveal the detent  77  of the primary pivot arm assembly  56 . The portion of the top swing plate  60  located outboard of the tabbed brace plate  104  is cutaway in order to reveal and/or demonstrate the connection of the cable  172  (and the cable  174 , not shown) to the inboard ends of the top bar  108  and the bottom bar  110  (not shown) of the secondary pivot arm assembly  58 . The spring loaded round end plunger  142  forcibly and intimately engages the detent  77  of the primary pivot arm assembly  56  to maintain the neutral position of the primary pivot arm assembly  56  when the crossing arm  12  ( FIG. 2 ) is extended across a railroad crossing grade. The spring loaded round end plunger  142  has a sufficient outwardly directed force to maintain the primary pivot arm assembly  56  including the secondary pivot arm assembly  58  and the attached crossing arm  14  in the desired centered neutral detent orientation in either a raised or lowered position or positions therebetween to maintain the desired proper orientation extending across the crossing grade unless impinged from either side by a vehicle or other outside force. 
     MODE OF OPERATION 
       FIG. 10  is a top view of the multiple direction railroad gate release mechanism  10  in partial cutaway, as described in  FIG. 9 , and best illustrates the mode of operation of the multiple direction railroad gate release mechanism  10  when an attached crossing arm  14  (not shown) is forcibly impinged from the front side. Impingement of the front side of the attached crossing arm  14  by a vehicle or other object forces causes pivoting of the primary pivot arm assembly  56  in a clockwise direction, as viewed from the top, about the pivot pin  54  as shown by arrow  212 . Such forced pivoting causes a shearing of the top of the shear pin  50  and also causes forced disengagement of the spring loaded round end plunger  142  from the detent  77 , whereby the round end plunger  142  tangentially and slidingly contacts the major portion of the outer edge of the arcuate top and bottom cable guide plates  72  and  74 , respectively, of the primary pivot arm assembly  56 , thus allowing the primary pivot arm assembly  56  and attached secondary pivot arm assembly  58  to pivot unitarily, thereby preserving the integrity of the attached crossing arm  14 . During such forced unitary pivoting about the pivot pin  54 , the angular relationship of the primary pivot arm assembly  56  and attached secondary pivot arm assembly  58  is unchanged with respect to each other. Clockwise pivoting of the primary pivot arm assembly  56  and attached secondary pivot arm assembly  58  is allowed at a suitable and rapid rate and is not significantly influenced by the shock absorber  148  in order that the crossing arm  14  can be rapidly deployed without breakage. However, return of the primary pivot arm assembly  56  and attached secondary pivot arm assembly  58  to the centered neutral detent position is influenced by the shock absorber  148  which acts to allow counterclockwise return pivoting at a rate much less than that during impingement caused by the clockwise pivoting. During frontal impingement caused by the clockwise pivoting of the primary pivot arm assembly  56  and attached secondary pivot arm assembly  58 , the spring  192  in the top spring assembly  144  and the spring  194  in the bottom spring assembly  146  ( FIG. 8 ) are compressed by the movement of the cables  154  and  156 , respectively, one end of which resides in and is secured in the cable channels  68  and  76  located at the ends of the top swing plate  60  and the bottom swing plate  62 , respectively. Such spring compression provides a force to subsequently return the primary pivot arm assembly  56  and attached secondary pivot arm assembly  58  toward and into the centered neutral detent position at a controlled rate as provided by the shock absorber  148 , as previously described. Clockwise rotation is limited by impingement of the swing stop  92  of the top swing plate  60  with the top stop pin  36  of the top bearing support plate  24  as shown and by a similar impingement of the swing stop  96  of the bottom swing plate  62  with the bottom stop pin  46  of the bottom bearing support plate  26  ( FIG. 4 ). For purposes of example and demonstration, such clockwise rotation is provided at 45° but shall not be considered to be limiting to the scope of the invention. Such limitation prevents overstressing or breakage of the top and bottom cables  154  and  156  and associated components. In the case of an unintended counterclockwise return overshoot of the detent  77  beyond the spring loaded round end plunger  142 , counterclockwise motion is limited to 15° (for purposes of example and demonstration) by impingement of the swing stop  94  of the top swing plate  60  with the top stop pin  36  of the top bearing support plate  24  and by like impingement of the swing stop  98  of the bottom swing plate  62  with the bottom stop pin  46  of the bottom bearing support plate  26  ( FIG. 4 ) to prevent overstressing or breakage of the top and bottom cables  172  and  174 . In addition the centering spring assembly  152  can contact the roller  153  to urge and assist the primary pivot arm assembly  56  to return to a normal and centered neutral detent position in the event of a return overshoot, preferably prior to stopping at 15°. Such counterclockwise overshoot protection features ensure that the round end plunger  142  will maintain contact with the minor portion of the outer edge of the arcuate top and bottom cable guide plates  72  and  74 , respectively, of the primary pivot arm assembly  56 . The counterclockwise overshoot protection prevents the round end plunger  142  from disassociating with the minor portion of the outer edge of the arcuate top and bottom cable guide plates  72  and  74  and extending, for example, into the region of the cable ball and washer assembly  160 , whereby an overly directed round end plunger  142  could lock the primary pivot arm assembly  56  and attached secondary pivot arm assembly  58  in a position to one side of the neutral detent position. For purposes of example and demonstration such counterclockwise rotation is provided at a 15° angle but shall not be considered limiting to the scope of the invention. 
       FIG. 11  is a top view of the multiple direction railroad gate release mechanism  10  in partial cutaway, as described in  FIG. 9 , and best illustrates the mode of operation of the multiple direction railroad gate release mechanism  10  when an attached crossing arm  14  (now shown) is forcibly impinged from the back side. Impingement of the back side of the attached crossing arm  12  by a vehicle or other substantial object causes shearing of the shear pin  128  and pivoting of the secondary pivot arm assembly  58  in a counterclockwise direction, as viewed from the top, about the pivot pin  86  as shown by arrow  214 . During rearward impingement causing counterclockwise pivoting of the secondary pivot arm assembly  58 , the spring  202  in the top spring assembly  168  and the spring  204  in the bottom spring assembly  170  (not shown) are compressed by the movement of the cables  172  and  174 , respectively. Such a spring compression provides a force to subsequently return the secondary pivot arm assembly  58  in a clockwise rotation to intimately contact the tabbed brace plate  105  which is the normal position with respect to the primary pivot arm assembly  56 . Counterclockwise rotation is limited by impingement of the top and bottom bars  108  and  110  with the tabbed brace plate  106  which functions as a stop to prevent overstressing or breakage of the top and bottom cables  172  and  174 . Additionally, protection is provided in an articulating fashion. If the secondary pivot arm assembly  58  is positioned to invoke stoppage by the tabbed brace plate  106  and further positioned in a counterclockwise manner, additional protection is provided by counterclockwise rotation of the primary pivot arm assembly  56  until limitation by impingement of the swing stop  94  of the top swing plate  60  with the top stop pin  36  of the top bearing support plate  24  and by like impingement of the swing stop  98  of the bottom swing plate  62  with the bottom stop pin  46  of the bottom bearing support plate  26 . Thus, pivotal arm relief is provided for either the front side or rear side impingement of the attached crossing arm  14 . Shearing of the shear pin in a front impingement of the crossing arm  14  or shearing of the shear pin  128  is an indication to maintenance personnel that the crossing arm  14  has been impacted from the front or rear respectively. Crossing arm protection and function is in effect with the shear pins  50  or  128  in a sheared or un-sheared state. 
     Various modifications can be made to the present invention without departing from the apparent scope thereof. 
     PARTS LIST 
     
         
           10  multiple direction railroad gate release mechanism 
           12  railroad gate actuator 
           14  crossing arm 
           16   a - b  mount arms 
           18  top mounting bracket 
           20  bottom mounting bracket 
           22   a - n  mounting holes 
           24  top bearing support plate 
           26  bottom bearing support plate 
           28  recessed surface 
           30  circular recess 
           32  top bearing assembly 
           34  hole 
           36  top stop pin 
           38  circular recess 
           40  bottom bearing assembly 
           42  hole 
           44  hole 
           46  bottom stop pin 
           48  bore 
           50  shear pin 
           51  hole 
           52  retainer plate 
           54  pivot pin 
           56  primary pivot arm assembly 
           58  secondary pivot arm assembly 
           60  top swing plate 
           62  bottom swing plate 
           64  top cable guide plate 
           66  bottom cable guide plate 
           68  cable channel 
           70  detent 
           72  top cable guide plate 
           74  bottom cable guide plate 
           76  cable channel 
           77  detent 
           78  hole 
           80  hole 
           82  hole 
           84  hole 
           86  pivot pin 
           88  nut 
           90  reference 
           92  swing stop 
           94  swing stop 
           96  swing stop 
           98  swing stop 
           102  tabbed brace plate 
           103  tabbed brace plate 
           104  tabbed brace plate 
           105  tabbed brace plate 
           106  tabbed brace plate 
           107  support plate 
           108  top bar 
           110  bottom bar 
           112  plate 
           114  plate 
           116  pivot hole 
           118  hole 
           120  pivot hole 
           122  hole 
           124  cable connection hole 
           126  cable connection hole 
           128  shear pin 
           130  hole 
           132  hole 
           134  stop bar 
           136  left brace plate 
           138  right brace plate 
           140  plunger housing 
           142  round end plunger 
           144  top spring assembly 
           145  connector assembly 
           146  bottom spring assembly 
           147  event counter 
           148  shock absorber 
           150  cover 
           152  centering spring assembly 
           153  roller 
           154  cable 
           156  cable 
           158  cable ball and washer assembly 
           160  cable ball and washer assembly 
           162  pin 
           164  pin 
           166  bracket assembly 
           168  top spring assembly 
           170  bottom spring assembly 
           171  annular groove 
           172  cable 
           173  annular groove 
           174  cable 
           175  body hole 
           176  cable ball and washer assembly 
           177  body hole 
           178  cable ball and washer assembly 
           180  mounting brackets 
           182  mounting brackets 
           184  bore 
           186  bore 
           187  mounting bracket 
           188  circular plate 
           190  circular plate 
           192  spring 
           194  spring 
           196  end 
           198  end 
           200  arrow 
           202  spring 
           204  spring 
           206  circular plate 
           208  circular plate 
           210  arrow 
           212  arrow 
           214  arrow