Patent Publication Number: US-11047099-B2

Title: Pass blocking apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Applications No. 2018-172159, filed on Sep. 14, 2018, and No. 2019-089958, filed on May 10, 2019, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The invention relates to a pass blocking apparatus for blocking vehicle traffic or the like, in particular, a pass blocking apparatus including a blocking bar which is vertically swung between an open position and a closed position. 
     BACKGROUND ART 
     For example, JP2011-058333A discloses a pass blocking apparatus (gate bar apparatus) which is located at an electronic toll collection (ETC) lane of a freeway. This pass blocking apparatus is provided for the following purpose. When a blocking bar, which has been horizontally swung to an evacuation position due to vehicle contact or other reasons, returns in a horizontally-swung manner to a closed position by means of a biasing force (for example, as disclosed in JP2000-043729A), a driver has, by this return motion, a feeling that the blocking bar is coming toward the driver (an image of a door shut in the driver&#39;s face). The pass blocking apparatus disclosed in JP2011-058333A is intended to provide a mechanism for avoiding this situation in such a manner that the blocking bar is prevented from returning to the closed position by means of the biasing force. The pass blocking apparatus ( 1 ) of JP2011-058333A, for this purpose, comprises a vertically swingable blocking bar ( 6 ), a hinge connection unit ( 3   b - 3   f ) for connecting the blocking bar ( 6 ) to a driving shaft ( 3   a ), a biasing unit ( 10 ), and a resistance unit ( 20 ). The blocking bar ( 6 ) extends perpendicularly to the axis of the driving shaft ( 3   a ) and is vertically swung by rotation of the driving shaft ( 3   a ). The hinge connection unit ( 3   b - 3   f ) permits the blocking bar ( 6 ) to be horizontally swung to an evacuation position. The biasing unit ( 10 ) applies a biasing force to the blocking bar ( 6 ) for swinging the blocking bar ( 6 ) toward the evacuation position. The resistance unit ( 20 ) provides the blocking bar ( 6 ) with a resistance force for holding the blocking bar ( 6 ) in a closed position against the biasing force. 
     In this pass blocking apparatus ( 1 ), the blocking bar ( 6 ) is biased toward the evacuation position, and therefore the blocking bar ( 6 ), which has been horizontally swung due to vehicle contact or other reasons, is prevented from bouncing back. This is because the biasing force is applied in the opposite direction to that of JP2000-043729A. Since the blocking bar ( 6 ) is normally held in a vertical swing mode by means of the resistance force by the resistance unit ( 20 ), when a force more than the resistance force is applied to the blocking bar ( 6 ), the blocking bar ( 6 ) is released and automatically swung to the evacuation position by means of the biasing force. In this way, the biasing force is not used for the return of the blocking bar ( 6 ) to the closed position, and the problem above is solved by this mechanism. 
     A specific example of this pass blocking apparatus is shown in  FIGS. 1-5B  attached hereto. The illustrated pass blocking apparatus  1  comprises a blocking bar driving device  3 , a control unit  4 , and a blocking bar return device  5 , which all are housed in a box-like housing  2  covering the whole. These blocking bar driving device  3 , control unit  4  and blocking bar return device  5  can be installed by use of columnar supports and frames inside the housing  2 . The blocking bar driving device  3  comprises a motor for rotating a driving shaft  3   a  (refer to JP2011-058333A). The blocking bar return device  5  comprises a motor for moving forward and backward a reciprocal arm  5   f  (refer to JP2011-058333A). The control unit  4  is an electrical control unit for controlling the motors of the blocking bar device  3  and blocking bar return device  5 . 
     The blocking bar  6  is attached via a bar holder  3   b  such that the blocking bar  6  extends perpendicularly to the axis of the driving shaft  3   a . This blocking bar  6  can be vertically swung by rotation of the driving shaft  3  between an open position (upright state, shown by the dotted line in  FIG. 1A ) and a closed position (transverse state, shown by the solid line in  FIG. 1A ). The bar holder  3   b  is attached in hinge connection to the driving shaft  3   a  (a hinge connection unit  3   c - 3   f ), and this permits the blocking bar  6  attached to the bar holder  3   b  to be horizontally swung by about 90 degrees to evacuate to an evacuation position (shown by the dotted line in  FIG. 1B ) when a vehicle collides with the blocking bar  6  in the closed position. 
     For the swing of the blocking bar  6  to the evacuation position, the pass blocking apparatus  1  has a biasing unit  10  and a resistance unit  20 .  FIG. 2  shows the configuration of the biasing unit  10  and resistance unit  20 .  FIG. 2A  is a plan view,  FIG. 2B  is a cross-sectional view along the line B-B, and  FIG. 2C  is a cross-sectional view along the line B-B′. 
     The biasing unit  10  is disposed on the outer surface of a pivot support  3   d  to apply a biasing force to the blocking bar  6  for swinging the blocking bar  6  toward the evacuation position. A hinge pivot  3   e  of this illustrated example is provided with a grasping projection  3   e - a  on its top end. The grasping projection  3   e - a  has a slit for grasping the inner end  11   a  of a flat spiral spring  11 . The outer end  11   b  of the flat spiral spring  11  is fixed by means of screwing, clamping or other methods to the inside wall of a cover  12  which is provided for housing the grasping projection  3   e - a  and the flat spiral spring  11 . The cover  12  is fixed to the pivot support  3   d  by means of four bolts  13 , and this fixation results in fixing the outer end  11   b  of the flat spiral spring  11  to the pivot support  3   d . Consequently, the flat spiral spring  11  provides constantly the biasing force for swinging the hinge pivot  3   e  in one direction (i.e., the direction toward the evacuation position to which the blocking bar  6  is swung). 
     The resistance unit  20  provides a resistance force for holding the blocking bar  6  in the closed position against the biasing force by the biasing unit  10 . As shown in  FIG. 2C , the resistance unit  20  comprises a plunger  21 , a coil spring  22 , and a stud bolt  23  with a hexagon socket for adjusting the resistance force. The plunger  21  and the coil spring  22  are inserted into a through hole formed in the pivot support  3   d , and then the stud bolt  23  is clenched thereinto. When the blocking bar  6  is in the vertically-swingable mode as shown by the solid line in  FIG. 1 , the head of the plunger  21  is engaged with a concave  3   c - a  formed on the surface of the base  3   c  of the bar holder  3   b . Consequently, it is required to release the engagement of the plunger  22  and the concave  3   c - a  against the coil spring  22  when the blocking bar  6  starts to swing horizontally from the closed position. The resilient force by the coil spring  22  therefore acts as the resistance force that holds normally the blocking bar  6  in the vertically-swingable mode. 
     When a vehicle contacts with the blocking bar  6 , a force exceeding the resistance force by the resistance unit  20  is applied to the blocking bar  6 . The blocking bar  6  is thereby swung, and this swing causes the engagement of the plunger  21  and the concave  3   c - a  to be released ( FIG. 2A ). Since the hold by the resistance unit  20  is thereby cancelled, the blocking bar  6  is horizontally swung to the evacuation position depending on the biasing force by the biasing unit  10  ( FIG. 2A ). This means that the blocking bar  6  does not bounce back to the closed position because of the bias toward the evacuation position that is applied by means of the biasing unit  10 . Conversely, when a force exceeding the resistance force causes the hold by the resistance unit  20  to be cancelled, the blocking bar  6  starts to swing and then swings automatically to the evacuation position depending on the biasing force. 
       FIGS. 3-5  show the operation of the pass blocking apparatus  1  for returning the blocking bar  6  from the evacuation position to the open position. The blocking bar  6  in the evacuation position is upward swung and pushed back by means of the blocking bar return device  5 . For this operation, the reciprocal arm  5   f  of the blocking bar return device  5  extends to a position under the pivot support  3   d  of the driving shaft  3   a . In another example, the blocking bar return device  5  can be mounted on the bottom of a base frame  1   b , i.e., under the blocking bar driving device  3 . 
     When the blocking bar  6  is horizontally swung from the closed position to the evacuation position due to vehicle contact or other reasons ( FIG. 3 ), a sensor detects this swing motion and a lamp  2   a  ( FIG. 1 ) is turned on. When a switch  2   b  ( FIG. 1 ) is then operated, the blocking bar driving device  3  rotates the driving shaft  3   a  to the position corresponding to the open position of the blocking bar  6  ( FIG. 4 ). In particular, for the purpose of returning upward the bar holder  3   b  toward the open position, the blocking bar driving device  3  rotates clockwise the driving shaft  3   a  by an angle of about 90 degrees. At this position, the hinge connection base  3   c  and the pivot support  3   d  can be folded upward. 
     According to this rotation of the driving shaft  3   a , the orientation of a projection  31 , which is projected diagonally backward from the hinge connection base  3   c , is changed from a lateral direction to a downward direction, and then the projection  31  is positioned at the engageable position with the reciprocal arm  5   f . In this manner, after the rotation of the driving shaft  3   a  to the position corresponding to the open position of the blocking bar  6 , while the motor  5   b  of the blocking bar return device  5  moves the reciprocal arm  5   f  forward, the reciprocal arm  5   f  is in contact with the projection  31  and pushes out the projection  31  according to the forward motion ( FIG. 5 ). The bar holder  3   b  is thereby swung upward to the open position, and at the same time, the blocking bar  6  in the evacuation position is pushed back in the vertically-swingable mode and returned to the open position by means of the forward motion of the reciprocal arm  5   f . In this way, the blocking bar  6  is upward swung from the evacuation position and returned to the open position, and after this return, the blocking bar  6  is vertically swung to the closed position according to a normal swing operation. The feeling that the blocking bar  6  is coming toward a vehicle is avoided by this operation. 
     SUMMARY 
     The pass blocking apparatus described above has the merit as mentioned above with respect to the return of the blocking bar from the evacuation position. However, for example, in the situation that a number of vehicles are bumper-to-bumper on ETC lanes due to a traffic jam, the pass blocking apparatus still has room for improvement. In particular, there is a potential for improvement with respect to the situation that in bumper-to-bumper traffic a truck passes through an ETC gate following a sedan. 
     In this case, the blocking bar is vertically swung from the open position to the closed position after the sedan (followed by the truck) passes through the ETC gate, and subsequently, this blocking bar starts to vertically swing from the closed position to the open position for permitting the following truck to pass through the ETC gate. In this situation, since there is only a slight distance between two vehicles due to the traffic jam, the truck may already reach the blocking bar. Its front face therefore lies close to the blocking bar which is swung for permitting the truck to pass through the ETC gate. Consequently, this swung blocking bar is stopped by contact with the side view mirrors of the truck, because the side view mirrors (especially, the left side mirror) of the truck is in general projected forward. This causes damage to the blocking bar. 
     The invention is directed to this problem, and intended to provide a mechanism for permitting the intentional release of the blocking bar from the closed position to the evacuation position as necessary. 
     In an aspect of the invention, a pass blocking apparatus is provided. This pass blocking apparatus comprises 
     a blocking bar extending perpendicularly to the axis of a driving shaft, the blocking bar being vertically swung by rotation of the driving shaft; 
     a hinge connection unit for connecting the blocking bar to the driving shaft, the hinge connection unit permitting the blocking bar to be horizontally swung from a closed position to an evacuation position; 
     a biasing unit for applying a biasing force to the blocking bar, wherein the blocking bar can be swung toward the evacuation position depending on the biasing force; and 
     a resistance unit for providing a resistance force for holding the blocking bar in the closed position against the biasing force, 
     wherein the resistance unit includes an electromagnetic device and a magnetic material, and is configured to generate the resistance force from a magnetic force by the electromagnetic device that attracts the magnetic material, 
     wherein the pass blocking apparatus further comprises a control unit which is configured to control electricity to the electromagnetic device. 
     The pass blocking apparatus according to the invention may include a power supply component which is capable of supplying electrical power at different levels to the electromagnetic device. The resistance force can be adjusted by means of the power switching of the power supply component. 
     The control unit may be configured to supply electrical power with reversed polarity to the electromagnetic device when controlling the electricity to the electromagnetic device in order to cancel the resistance force. In this embodiment, the power supply component is further configured to supply the electrical power with reversed polarity to the electromagnetic device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a back view (in relation to a driver) of a pair of pass blocking apparatuses which are installed at an ETC lane, according to an embodiment of the invention; 
         FIG. 1B  is a top view of the pair of pass blocking apparatuses as shown in  FIG. 1A ; 
         FIGS. 2A-2C  show the details of a connection between a driving shaft and a blocking bar; 
         FIGS. 3A and 3B  show the swing motion of the blocking bar to an evacuation position, with regard to a method for returning the blocking bar from an evacuation position to an open position; 
         FIGS. 4A and 4B  show the rotation of the driving shaft to the position corresponding to the open position of the blocking bar, with regard to the method for returning the blocking bar from an evacuation position to an open position; 
         FIGS. 5A and 5B  show the return of the blocking bar from the evacuation position to the open position, with regard to the method for returning the blocking bar from an evacuation position to an open position; 
         FIGS. 6A and 6B  show a resistance unit according to an embodiment of the invention; 
         FIG. 7  is a partially disassembled view of a biasing unit (flat spiral spring type) according to an embodiment of the invention; 
         FIG. 8  shows a control unit for controlling the resistance unit, according to an embodiment of the invention; 
         FIG. 9  shows a jumping-out mechanism in a release step by the resistance unit as shown in  FIG. 6 . 
         FIGS. 10A-10C  show a series of steps for returning the released blocking bar. 
         FIGS. 11A and 11B  show wiring to the resistance unit. 
         FIG. 12A  shows the pass blocking apparatus in a closed state, which is installed on an island beside an ETC lane. 
         FIG. 12B  shows the pass blocking apparatus of  FIG. 12A  in an open state. 
         FIGS. 13A-13C  show the pass blocking apparatus which is installed on an island beside an ETC lane, in a release state  FIG. 13A , in a return start state  FIG. 13B , and in a return completion state  FIG. 13C , respectively. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 6A and 6B  shows a relevant part of a pass blocking apparatus according to an embodiment of the invention.  FIG. 6A  is a perspective view for showing the external arrangement and  FIG. 6B  is a transparent view for showing the internal arrangement inside a housing. The pass blocking apparatus  101  has the housing  102  which houses a blocking bar driving device  3 , a control unit  4 , and a blocking bar return device  105 , as in the apparatus shown in  FIGS. 1 and 3-5  (in more detail, refer to JP2011-058333A). In this embodiment, the blocking bar return device  105  is mounted on the bottom of a base frame  1   b  inside the housing  102 , i.e., arranged under the blocking bar driving device  3 . A reciprocal arm  105   f  is accordingly formed in a disk shape instead of the laterally extended form as shown in  FIGS. 3-5 . This reciprocal arm  105   f  is reciprocally moved under a driving shaft  103   a . In this embodiment, the control unit  4  is arranged with a power unit in the bottom of the housing  102  (not shown in the drawings). 
     The driving shaft  103   a  extends from the blocking bar driving device  3  within the housing  102  and projects outside the housing  102 . A bar holder  103   b  is connected in a hinged manner to the driving shaft  103   a . A blocking bar  106  is attached in a detachable manner to the bar holder  103   b . The blocking bar  106 , as illustrated in an open position, comprises an aluminum pipe covered with a urethane cover or the like which is painted in a red and white striped pattern, for example. One end of the pipe is inserted into the bar holder  103  and then fixed in the bar holder  103   a  by means of the rotary operation of a fixing lever  106   a  for screwing a fixing screw. The bar holder  103   b  includes a base  103   c  for hinge connection. 
     A hinge connection unit connects between the driving shaft  103   a  and the bar holder  103   b  as well as permitting the blocking bar  106  to be horizontally swung from a closed position to an evacuation position. The base  103   c  and a pivot support  103   d  are main components of the hinge connection unit. The base  103   c  of the bar holder  103   b  has a T-shaped cross-section, and this base  103   c  is wedged into the pivot support  103   d  having a C-shaped cross-section. The pivot support  103   d  is secured to the driving shaft  103   a . A hinge pivot  103   e  (shown in  FIG. 7 ) is secured to the base  103   a  and extends laterally (in the open position shown in  FIGS. 6 and 7 ) from the flat face part of the base  103   c  wedged into the pivot support  103   d . The hinge pivot  103   e  secured to the base  103   c  is rotatably supported by the pivot holes of the pivot support  103   d . The pivot support  103   d  has almost a square shape in the top view thereof, in which one corner  103   f  of the square shape is chamfered. The base  103   c  can be swung around the hinge pivot  103   e  in a range of about 90 degrees across the chamfered corner  103   f.    
     The blocking bar  106 , which is attached via the bar holder  103   b  and extends perpendicular to the axis of the driving shaft  103   a , is vertically swung according to the rotation of the driving shaft  103   a  between the open position (upright state, shown by the dotted line in  FIG. 1A ) and the closed position (transverse state, shown by the solid line in  FIG. 1A ). In addition, the hinged connection between the bar holder  103   b  and the driving shaft  103   a  permits the blocking bar  106  attached to the bar holder  103   b  to be horizontally swung by about 90 degrees to the evacuation position (shown by the dotted line in  FIG. 1B ) when a vehicle collides with the blocking bar  106  in the closed position. 
     For the swing of the blocking bar  106  to the evacuation position, the pass blocking apparatus  101  is provided with a biasing unit  110  and a resistance unit  120 . 
     The biasing unit  110  applies a biasing force to the blocking bar  106  for swinging the blocking bar  106  to the evacuation position. As shown in  FIG. 7 , the biasing unit  110  is housed within a housing concave  103   d - a  formed in the pivot support  103   d . As illustrated, the hinge pivot  103   e  has a grasping projection  103   e - a  on the end face. This grasping projection  103   e - a  projects into the housing concave  103   d - a . The grasping projection  103   e - a  is provided with a slit for grasping the inner end of a flat spiral spring  111  (also refer to  FIG. 2 ). The flat spiral spring  111  is housed within the housing concave  103   d - e . The housing concave  103   d - e  that has housed the flat spiral spring  111  is closed with a cover  112 . The cover  112  is provided with a flange  112   a  on the inside, which surrounds the flat spiral spring  111 . The flange  112   a  has a slit  112   b  for grasping the outer end  111   b  of the flat spiral spring  111 . The cover  112  is fixed to the pivot support  103   d  by means of four bolts  113 , and consequently, the outer end  111   b  of the flat spiral spring  111  is fixed with respect to the pivot support  103   d . This flat spiral spring  111  provides constantly a biasing force for rotating the hinge pivot  103   e  in one direction (for swinging the blocking bar  106  toward the evacuation position). In another embodiment, a coil spring may be used instead of the flat spiral spring  111 , of which one end is engaged with a projection  103   e - a  that is arranged at an offset position with respect to the pivot center, and the other end is fixed to the cover  112 . However, in view of a simple configuration, the flat spiral spring  111  is suitable for this unit. 
     The resistance unit  120  provides a resistance force for holding the blocking bar  106  in the closed position against the biasing force by the biasing unit  110 . In this embodiment, the pivot support  103   d  has an elongated base board  103   d - b  extending parallel to the bar holder  103   b . The base board  103   d - b  is fixed substantially at its center to the driving shaft  103   a . An electromagnetic device  121  of the resistance unit  120  is attached to the distal end extending from the central fixed part. This means that the electromagnetic device  121  is arranged at the shaft-fixation side of the hinge connection unit. At the same time, a board-like magnetic material  122  of the resistance unit  120  is attached by use of U-shaped bolts  123  to the bar holder  103   b  positioned parallel to the base board  103   d - b , thereby facing the electromagnetic device  121 . This means that the magnetic material  122 , which is magnetically attracted to the electromagnetic device  121 , is arranged at the bar side (swing side). In another embodiment, the arrangement of the electromagnetic device  121  and the magnetic material  122  may be reversed (i.e., the electromagnetic device arranged at the bar side and the magnetic material arranged at the shaft-fixation side). Alternatively, a magnetic bar holder or a magnetic base board may be used instead of the magnetic material  122 . In an embodiment, the magnetic material  122  is made of ferrite-based or martensite-based stainless steel. The energized electromagnetic device  121  attracts magnetically the magnetic material  122 , thereby generating the resistance force against the biasing force by the biasing unit  106 . The vertical-swing mode of the blocking bar  106  is normally maintained by means of the resistance force. 
     When a vehicle collides with the blocking bar  106  in the closed position, the blocking bar  106  receives a force exceeding the resistance force by the resistance unit  120 , i.e., the magnetic force by the electromagnetic device  121 . The blocking bar  106  is released by this force from the held state by the resistance unit  120 , and then horizontally swung by about 90 degrees to the evacuation position depending on the biasing force by the biasing unit  121 . When the blocking bar  106  reaches the evacuation position in consequence of this evacuation swing, the blocking bar  106  in the evacuation position is detected by a sensor. An operator checks this sensor detection, and then operates a switch mounted on the housing  102  or a remote operation switch disposed in a waiting booth to activate the blocking bar return device  105  for returning the blocking bar  106  to the vertical-swing mode. 
     As an example, the blocking bar return device  5  as shown in  FIGS. 3-5 , which is the same as JP2011-058333A, is usable as the blocking bar return device  105 . However, in this embodiment, the blocking bar return device  105  different from the blocking bar return device  5  in the mounted position. In particular, the blocking bar return device  105  is mounted on the outside or inside of the bottom of the base frame  1   b . This means that the blocking bar return device  105  is positioned under the blocking bar driving device  103 . With respect to this arrangement, a columnar support  1   a  as shown in the drawings can be used in the case of mounting the device  105  on the bottom inside, but in the case of mounting the device  105  on the bottom outside, another columnar support or frame, which is adapted to the arrangement of the blocking bar return device  105  on the bottom of the base frame  1   b , is required instead of the illustrated columnar support  1   a . Here, the blocking bar return device  105  is described with reference to the reference numbers used in  FIGS. 3-5 . In this example of the blocking bar return device  105 , an L-shaped frame  5   a  is fixed at its side wall to the bottom of the base frame  1   b  by means of bolt fixation or welding. A motor  5   b , a pinion gear  5   c  driven by the motor  5   b , and a rack gear  5   d  moved forward and backward according to the pinion gear  5   c  are mounted on the frame  5   a  and constitute an actuator. The rack gear  5   d  of the blocking bar return device  105  is positioned under the driving shaft  103   a  (i.e., the position of the reciprocal arm  105   f  in  FIG. 6A ). In this example in which the side wall of the frame  5   a  is fixed to the bottom of the base frame  1   b , a set of all components is rotated clockwise by 90 degrees. In the illustrated example in  FIG. 6B , the blocking bar return device  105  is mounted on the inside of the bottom of the base frame  1   b . In the blocking bar return device  105  of  FIG. 6B , a set of the motor  5   b , the pinion gear  5   c  and the rack gear  5   d  is assembled in one housing. This assembled blocking bar return device  105  is mounted on the bottom inside (upper side face) and positioned under the blocking bar driving device  3 . 
     The motor  5   b  is provided with a decelerator  5   e  on its head and fixed to the frame  5   a . The output shaft of the decelerator  5   e  passes through the frame  5   a  and projects into the opposite side. The pinion gear  5   c  is attached to the projected output shaft to engage with the rack gear  5   d . The rod-like rack gear  5   d  extends parallel to the axis of the driving shaft  103   a . The disk-like reciprocal arm  105   f  ( FIG. 6 ) is attached to one end of the rack gear  5   d . The rod-like rack gear  5   d  has teeth which are formed in the longitudinal direction by cutting, and is slidably supported by two bearing blocks  5   g  which are fixed to the frame  5   a . The rack gear  5   d  can be thereby slid parallel to the axis of the driving shaft  103   a . The two bearing blocks  5   g  are separately arranged from each other. The pinion gear  5   c  engages with the rack gear  5   d  between the two bearing blocks  5   g . The rack gear  5   d  is moved forward and backward according to the reversible rotation of the pinion gear  5   c . According to this reciprocal motion of the rack gear  5   d , the reciprocal arm  105   f  attached to the rack gear  5   d  is moved forward and backward parallel to the axis of the driving shaft  103   a . In this example, there is no need to provide a guide rod  5   h  for the blocking bar return device  105 . 
     A plate  5   i  is attached to the other end of the rack gear  5   d . This plate  5   i  pushes a limit switch  5   j  mounted on the frame  5   a  in the forward-motion-end position of the rack gear  5   d . Another limit switch  5   j  is also mounted on the frame  5   a . In other words, two limit switches  5   j  are arranged at the front and rear of the frame  5   a . In the backward motion of the rack gear  5   d , the front side limit switch  5   j  is pushed by the reciprocal arm  105   f  that have been moved to the backward-motion-end position, in order to stop the motor  5   b . In other embodiments, the front side limit switch  5   j  may be omitted. In the forward motion of the rack gear  5   d , the rear side limit switch  5   j  is pushed by the plate  5   i  that have been moved to the forward-motion-end position. This action triggers the switching of the rotation direction of the motor  5   b  from the normal rotation to the reverse rotation. In other embodiments, instead of the motor  5   b , the actuator may comprise a hydraulic cylinder or a pneumatic cylinder in which the reciprocal arm is attached to its rod. 
     The reciprocal arm  105   f  moved forward according to the rack gear  5   d  is in contact with a projection  1031  which is projected diagonally backward from the hinge connection base  103   c . The projection  1031  is thereby pushed out for the swing of the bar holder  103   b . The blocking bar  106  is horizontally swung to the evacuation position due to collision with a vehicle (refer to  FIG. 3 ). After this, according to the start of the return operation, the blocking bar driving device  3  rotates the driving shaft  103   a  to the position corresponding to the open position of the blocking bar  106  (refer to  FIG. 4 ). In particular, the blocking bar driving device  3  rotates the driving shaft  103   a  clockwise by 90 degrees so that the base  103   c  and the pivot support  103   d  of the hinge connection unit are folded upward for the upward return of the bar holder  103   b  to the open position. As the result of this rotation of the driving shaft  103   a , the projection  1031  is turned from the lateral position to the downward position at which the reciprocal arm  105   f  can contact with the projection  1031 . After the rotation of the driving shaft  103   a  to the position corresponding to the open position of the blocking bar  106 , the motor  5   b  of the blocking bar return device  105  is driven in a normal-rotation mode to move forward the reciprocal arm  105   f . This moved reciprocal arm  105   f  is in contact with the projection  1031  to push out the projection  1031  ( FIG. 5 ). According to this motion, the bar holder  103   b  is upward swung to the open position. In this manner, the forward motion of the reciprocal arm  105   f  causes the blocking bar  106  in the evacuation position to be pushed back to the vertical-swing mode and returned to the open position. 
     In this return method, the blocking bar  106  is upward swung from the evacuation position to the open position, and subsequently the blocking bar  106  in the open position is vertically swung to the closed position according to the normal swing motion for closing. The feeling that the blocking bar  106  is coming toward a driver is therefore avoided. 
     The electromagnetic device  121  for generating the resistance force against the biasing force by the biasing unit  110  is controlled by a control component  130  (of the control unit) for controlling the electricity to the electromagnetic device  121 . Control signals, which are transmitted from a remote operation switch disposed in a booth or the like, are isolation-processed in a signal converter component  131  and then transmitted to the control component  130 . The control signals include a turn-on/off instruction on the electromagnetic device  121  and a release instruction. In the power supply system for the electromagnetic device  121 , an AC power source is electrically connected to a protective component  132  with one or more fuses, and after this fuse protection, AC-DC conversion is performed in a rectifier component  133 . A power supply component  134  generates electrical power at different levels from the DC power by the rectifier component  133 . In this embodiment, as an example, the power supply component  134  generates electrical power at four levels of 60V, 70V, 80V and 90V. These power levels are switched according to an instruction signal from a voltage switching component  135 . The voltage switching component  135  transmits the instruction signal according to a button operation, dial operation or switch operation. In this embodiment, the power supply component  134  further generates polarity-reversed (+/−reversed) electrical power with 90V (maximum voltage). This polarity-reversed electrical power is output from the power supply component  134  in response to an instruction from the control component  130 . The control component  130  in operation according to the control signal transmits a signal to an operation-state display  136  which is disposed on the housing  102  or in a booth. The operation-state display  136  informs the current operation state of the electromagnetic device  121  by means of LEDs, etc. 
     The voltage setting for the power supply component  134  by means of the voltage switching component  135  can be performed in the default settings for the pass blocking apparatus  101 . As necessary, the voltage can be switched after the determination of the default settings. In this regard, the any one of the settable voltages is set in view of wind conditions and traffic conditions at the installation location of the pass blocking apparatus  101 . According to this embodiment, the electromagnetic device  121  generates the minimum magnetic force in response to the minimum supply voltage of 60V, and generates the maximum magnetic force in response to the maximum supply voltage of 90V. Since the magnetic force by the electromagnetic device  121  that attracts the magnetic material  122  is the resistance force against the biasing force, the resistance force is regulated by means of the power switching of the power supply component  134 . 
     When receiving a control signal including a turn-on instruction, the control component  130  transmits the setup electrical power of the power supply component  134  to the electromagnetic device  121 . The electromagnetic device  121  thereby functions as the resistance unit  120  for generating the resistance force in accordance with the supply power. The control component  130  receive a control signal including a release instruction from a release switch disposed on the housing  102  or in a booth. When receiving the release instruction, the control component  130  may cut off the electricity to turn off the power supply from the power supply component  134 . Alternatively, in this embodiment, the control component  130  switches the power supply mode to a polarity-reversed-power supply mode for applying the polarity-reversed electrical power with 90V to the electromagnetic device  121 . The electromagnetic device  121 , which is operated with the polarity-reversed electrical power, generates a magnetic force with reversed N and S poles. As the result of this magnetic pole reversal, the magnetic pole of the electromagnetic device  121  that has faced the magnetic material  122  is turned to the identical pole with respect to the magnetic field of the magnetic material  122  (in this situation, N(S) pole faces N(S) pole). The magnetic material  122  thereby repels the electromagnetic device  121 . As shown in  FIG. 9 , the bar holder  103   b  and the blocking bar  106  jump out and instantly and securely released as the result of the repulsion of the magnetic material  122 . After the release, the control component  130  appropriately switches the polarity-reversed-power supply mode to the normal power supply mode with respect to the electromagnetic device  121  for the return of the blocking bar  106 . 
     As described above, the electromagnetic device  121  generates the resistance force for holding the blocking bar  106  in the closed position against the biasing force. The resistance force is cancelled as necessary by control of the electricity to the electromagnetic device  121 . The cancellation of the resistance force permits the blocking bar  106  to be swung depending on the biasing force from the closed position to the evacuation position. This means that the blocking bar  106  can be released to the evacuation position as necessary by button operation or the like. 
     The blocking bar  106 , which has been released to the evacuation position, can be returned according to the above-described return operation. In response to the return operation, the blocking bar driving device  3  rotates the driving shaft  103   a  to the position corresponding to the open position of the blocking bar  106  ( FIG. 10A ). The base  103   c  and the pivot support  103   d  of the hinge connection unit can be folded upward in this position. At the same time, the projection  1031  is directed downward by this rotation of the driving shaft  103   a , and positioned in the position contactable with the reciprocal arm  105   f . The forward-moved reciprocal arm  105   f  is in contact with the projection  1031  and pushes out the projection  1031  ( FIG. 10B ). The bar holder  103   b  is thereby swung upward. The blocking bar  106  in the evacuation position is pushed back to the vertical-swing mode according to the forward motion of the reciprocal arm  105   f  and then returned to the open position ( FIG. 100 ). 
     For example, the pass blocking apparatus  101 , which is installed at an ETC lane, vertically swings the blocking bar  106  in the normal mode between the closed position ( FIG. 2A ) and the open position ( FIG. 2B ) with respect to a passage. In contrast, all steps of the return operation of the blocking bar  106  from the evacuation position (including the case of evacuation caused by a vehicle collision) are completely performed within an island outside the passage (a booth area between passages), as shown in  FIG. 13 . There is no possibility that the blocking bar  106  in the return operation passes over the passage. The problem mentioned in the BACKGROUND ART above is also solved by this manner. 
     The power supply wiring for the electromagnetic device  121  is described with reference to  FIGS. 11A and 11B .  FIG. 11A  shows the inside of a wiring housing  140  surrounding the driving shaft  103   a .  FIG. 11B  shows the cross-sectional view thereof. 
     As shown in  FIG. 11A , a power supply cable  150  is led from the control component  130  inside the housing  102 . This power supply cable  150  is pulled out from the housing  102 , and then disposed in a loop fashion around the driving shaft  103   a  by a lap and a quarter inside the wiring housing  140  surrounding the driving shaft  103   a . The power supply cable  150  is then pulled out from the wiring housing  140  to the electromagnetic device  121 . The loop of the power supply cable  150  has a diameter wider than the diameter of the driving shaft  130   a , thereby having a margin with respect to the driving shaft  130   a . As the result of this margin, the loop of the power supply cable  150  is variable in the diameter. A plastic band is wound on the loop part inside the wiring housing  140  for effecting a spring function. This spring function provides constantly a radial-expansion force to the loop part of the power supply cable  150 . While the blocking bar  106  is swung from the open position to the closed position by about 90 degrees, the terminal of the power supply cable  150 , which extends to the electromagnetic device  121 , is pulled by about 90 degrees (shown by the dotted arrow in  FIG. 11A  that shows the power supply cable  150  at the open position). The loop of the power supply cable  150  shrinks in response to this situation. On the other hand, when the blocking bar  106  is swung from the closed position to the open position, the loop of the power supply cable  150  expands radially according to the spring function in response to this situation. In this manner, the power supply cable  150  follows the swing of the blocking bar  106  with no contact by means of the shrinkage and expansion of the loop. This effects improved endurance in the power supply cable. 
     Hereinafter, the wiring housing  140  will be described in detail with reference to  FIG. 11B . The wiring housing  140  has an annular dust-sealing member  141 , a bearing holder  142  for pressing the dust-sealing member  141 , and an annular insulation sheet  143  fixed on the surface of the bearing holder  142 , in the vicinity of the housing  102 . The bearing holder  142  holds a bearing  144  for the driving shaft  103   a . In addition, the wiring housing  140  has a cylindrical cap  145  with a central hole for the passage of the driving shaft  103   a , and an annular insulation sheet  146  fixed on the inner surface of the cap  145 , in the vicinity of the base board  103   d - b  of the pivot support  103   d . The cap  145  has a cylindrical side wall extending over the side of the bearing holder  142  for protecting against raindrops and dust. 
     The dust-sealing member  141 , the bearing holder  142  and the insulation sheet  143  are provided with holes for the passage of the power supply cable  150 . The power supply cable  150  is pulled out through the holes from the housing  102 , and then fastened once to the insulation sheet  143  by means of an appropriate fastener. A part of the power supply cable  150  extending from this fastened position is disposed around the driving shaft  103   a  by a lap and a quarter to form the loop mentioned above, and then fastened to the insulation sheet  146  by means of an appropriate fastener. A part of the power supply cable  150  extending from this fastened position is led through the hole of the insulation sheet  146  to a wiring chamber formed in the base board  103   d - b , and electrically connected to a wiring plug of the electromagnetic device  121  in the chamber. 
     The pass blocking apparatus according to the invention includes the electromagnetic device which is configured to generate the resistance force for holding the blocking bar in the closed position against the biasing force. The resistance force can be cancelled as necessary by means of the control of electricity to the electromagnetic device. The blocking bar is swung from the closed position to the evacuation position in response to the cancellation of the resistance force. This allows the blocking bar to be released as necessary to the evacuation position by means of a button operation or the like. 
     Although the embodiments of the invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention. 
     LIST OF REFERENCE NUMBERS 
     
         
           101  Pass Blocking Apparatus 
           102  Housing 
           103   a  Driving Shaft 
           103   b  Bar Holder 
           103   c  Base 
           103   d  Pivot Support 
           103   e  Hinge Pivot 
           103   d - b  Base Board 
           105  Blocking Bar Return Device 
           105   f  Reciprocal Arm 
           106  Blocking Bar 
           110  Biasing Unit 
           111  Flat Spiral Spring 
           112  Cover 
           120  Resistance Unit 
           121  Electromagnetic Device 
           122  Magnetic Material 
           130  Control Component 
           134  Power Supply Component 
           135  Voltage Switching Component 
           140  Wiring Housing 
           150  Power Supply Cable