Abstract:
A flatbed servicing station provides a mobile elevated workers platform with an elongated deck. The platform is selectively moved toward and away from a flatbed and has safety features for stopping movement of the platform toward the flatbed when a foreign object is detected between the platform and the flatbed. A plurality of side-by-side safety gates are provided on the side of the deck adjacent the flatbed and a guard gate is provided which is positionable across the rear of the flatbed. Safety apparatus is provided to prevent injury of personnel disposed between a platform and a flatbed being serviced.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     A workers platform is needed for servicing flatbed trucks and flatbed trailers commonly referred to as flatbeds. The servicing activity may include loading, unloading, tarping or untarping a load or inspection. A stationary workers platform has a disadvantage in that the space between the platform and a flatbed positioned alongside is often excessive which makes servicing more difficult and may impair the safety of the workers.  
       SUMMARY OF THE INVENTION  
       [0002]     A mobile elongated workers platform is provided that is shiftable lateral toward and away from a flatbed positioned alongside. Laterally shifting of the platform is effected by a power operated linear actuator. A foreign object detection apparatus is provided to halt movement of the platform toward the flatbed if an object, such as a person, is detected between the platform and the flatbed. The detection apparatus also stops movement of the platform to prevent it from contacting the flatbed. A plurality of side-by-side safety gates are provided along the side of the platform next to the flatbed and a pair of guard gates are provided that can be pivoted to a position across the rear end of the flatbed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0003]     The invention is illustrated in the accompanying drawings, in which:  
         [0004]      FIG. 1  is a top view of a pair of laterally shiftable worker platforms and a flatbed positioned there between;  
         [0005]      FIG. 2  is a view taken on the line  2 - 2  in  FIG. 1 ;  
         [0006]      FIG. 3  is a side view taken on the line  3 - 3  in  FIG. 1 ;  
         [0007]      FIG. 4  is a view taken on the line  4 - 4  in  FIG. 3 ;  
         [0008]      FIG. 5  is a section taken on line  5 - 5  in  FIG. 3 ;  
         [0009]      FIG. 6  is a side view of a safety gate taken on line  6 - 6  in  FIG. 1  with parts broken away for illustration purposes;  
         [0010]      FIG. 7  is a view taken on line  7 - 7  in  FIG. 2 ;  
         [0011]      FIG. 8  is a view taken on the line  8 - 8  in  FIG. 1  with parts broken away for illustration purposes;  
         [0012]      FIG. 9  is a section taken on line  9 - 9  in  FIG. 8 ;  
         [0013]      FIG. 10  is a section taken on line  10 - 10  in  FIG. 8 , and  
         [0014]      FIG. 11  is a schematic showing a control system for a linear actuator including a photo-electric safety sensor. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]      FIG. 1  shows a top view of a flatbed or semi trailer  16  positioned between a right side elongated elevated workers platform  18  and a left side elongated elevated workers platform  19 . The right side platform  18  has an elongated horizontal rectangular deck  22  which is slightly longer than the standard length semi trailer  16  positioned in juxtaposed parallel relation to its laterally inward side  23 . The elevated left side platform  19  likewise has an elongated horizontal rectangular deck  26  of the same length as the deck  22  of the right platform  18 . The laterally inner side  27  of the deck  26  is in juxtaposed parallel relation to the left side of the flatbed trailer  16 .  
         [0016]     As shown in  FIGS. 1, 2  and  3 , a staircase  31  is rigidly secured to the forward or front end of the deck  22  and a staircase  32  is rigidly secured to the forward or front end of the deck  26 . The staircases  31 ,  32 , which have hand rails  33 ,  34 , respectively, provide quick and safe worker access to the decks  22 ,  26  of the platforms  18 ,  19 .  
         [0017]     As shown in  FIGS. 2 and 7 , the deck  22  of the platform  18  is supported by four longitudinally spaced support structures  41 ,  42 ,  43 ,  44 . As shown in  FIG. 7 , the support structure  41  includes a pair of vertical posts  46 ,  47  rigidly secured to the underside of the deck  22  and having wheels  48  rotatably mounted on their lower ends for rotation about laterally spaced horizontal parallel axes  51 ,  52  extending in the longitudinal direction of the platform  18 . The posts  46 ,  47  are braced by a diagonal brace  56  and a horizontal brace  57  near the wheels  48 . As shown in  FIG. 2 , posts  46 ,  47  are also braced by diagonal braces  58 ,  59 , respectfully, extending between and rigidly secured to the posts  46 ,  47  and the deck  22 . The other support structures  42 ,  43 ,  44  are built in a manner similar to or the same as that described regarding support structure  41  with wheels  48  on their lower ends. The wheels  48  run on a flat running surface support, which may be provided by a flat concrete surface  62  or by the flat laterally extending rigid runners  61  shown in  FIGS. 1, 2 ,  3 ,  4  and  7 . As shown in  FIG. 3  the stairway  32  is additionally supported by at least one wheel  48  rotatably mounted on a bracket  66  rigidly secured to the underside of the staircase  32 . In a similar manner the stairway  31  has a wheel  48  rotatably support on a bracket  67 . The workers platform  19  is a reverse image of the workers platform  18  and is provided with support structures  41 ′,  42 ′,  43 ′ and  44 ′ as shown in  FIG. 3 .  
         [0018]     As shown in  FIGS. 1 and 3 , an upstanding guard railing or guard rail  71  is provided at the laterally outer side of the deck  26  of the workers platform  19 . The guard rail  71  includes a top horizontal rail  72  and a lower or middle rail  73  which run the longitudinal length of the deck  22 . The rails  72 ,  73  are supported on vertical uprights or posts  74  rigidly secured to the deck  26 . As shown in  FIG. 4 , an upstanding guard railing or guard rail  76  is provided at the rear end of the deck  26 , which includes a top rail  77  and a bottom rail  78  attached to a post  74  and a corner post  79 .  
         [0019]     As shown in  FIGS. 1, 2  and  7 , the workers platform  18  is provided with an upstanding guard railing or guardrail  81  along the laterally outer side of the deck  22  which includes a horizontal top rail  82  and a lower horizontal rail  83 . As shown in  FIGS. 1 and 4 , an upstanding guard railing or guard rail  86  is provided at the rear end of the deck  22  which includes a top rail  87  and a bottom rail  88 .  
         [0020]     As shown in  FIGS. 1 and 2 , the laterally inner side of the deck  22  of the workers platform  18  is provided with side by side safety gates  91  pivotally mounted to posts  92 ,  92 ′. Referring also to  FIG. 6 , the gate  91  includes s U-shaped component  93  whose ends are welded to a vertical tie  94  which is pivotally connected on a vertical axis  95  to vertically spaced legs  96 ,  97  of a bracket  98  rigidly secured to a post  92 . An abutment plate  101  is secured by fasteners  102  to the U-shaped component  93  and a coil spring  103 , whose opposite ends  104  and  105  are connected to the gate  91  and the bracket  98 , biases the gate  91  to the closed position shown in  FIG. 6 , in which the abutment plate  101  abuts a post  92 ′. The gates  91  on the laterally inner side of the deck  26  of the workers platform  19  are constructed and installed in a similar manner. Thus the gates  91  on both platforms  18 ,  19  must be opened inwardly, away from the flatbed  16 , rather than outwardly toward the flatbed  16 .  
         [0021]     As shown in  FIGS. 3, 8 ,  9  and  10 , an electrically powered linear actuator  101  has its housing  102  pivotally connected on a horizontal axis  103  to a pair of upstanding brackets  104 , welded to a stationary actuator support  106  disposed beneath a central part  107  of the deck  26 . The actuator  101  has an extensible member  108  whose distal end is pivotally connected to a bracket  109  rigidly secured to the underside of the deck  26 . The support  106  includes a pair of legs  111 ,  112  welded at their bottoms to a base plate  113  rigidly secured to the flat concrete floor  62  by anchor bolts  63  and nuts  64 . A pair of parallel horizontal beams  116 ,  117  are welded at the underside of their mid section to the top of the legs  111 ,  112 , respectively, so as to extend in the longitudinal direction of the deck  26 . The legs  111 ,  112  are reinforced by cross braces  118 ,  119  rigidly interconnected there between. As shown in  FIGS. 8, 9  and  10 , triangular braces  121 ,  122  are welded to the leg  111  and to the beam  116  and triangular braces  123 ,  124  are welded to the leg  112  and to the beam  117 . As shown in  FIG. 8 , a vertical flange  126  of a channel  127  is welded to corresponding rearward ends of the beams  116 ,  117 . Three rollers  128  are rotatably supported on horizontal axes by the flange  126  and a flange  129  of the channel  127 . The rollers  128  are in supporting relation to the bottom of a laterally extending stringer  131  secured to and extending downward from the underside of the deck  26 . Four rollers  136  are rotatably supported on parallel vertical axes by a bracket  137  secured to and extending horizontally from the upper end of the flange  129 . The rollers  136  are in confronting or guiding relation to a vertical side of the laterally extending stringer  131 . In a like manner an upwardly open and horizontally disposed channel  141  has a flange  142  welded to the forward ends of the beams  116 ,  117  and three rollers  143  are rotatably mounted on the flange  142  and a flange  144  so as to be in supporting relation to a laterally extending stringer  146  secured to the underside of the deck  26 . A plurality of guide rollers  147 , only one of which is shown in  FIG. 8 , are rotatably mounted on laterally spaced vertical axes to a bracket  148  secured to and extending forward from the top of the flange  144 . The guide rollers  136 ,  147  in cooperation with the stringers  131 ,  146  guide the laterally movement of the workers platform  19 . The linear actuator  101  is operable to extend its extensible member  108  to the position shown by broken lines  108 ′ in  FIG. 10 , in which the workers platform  19  has been shifted laterally to a position shown by broken lines  19 ′ in which it is relatively close to the flatbed  16 . An actuator support  151 , which is a reverse image of actuator support  106 , is installed beneath the central section  152  of the deck  22  of the workers platform  18  and its linear actuator  153  is selectively operable to shift the platform  18  laterally toward and away from the flatbed  16 .  
         [0022]     A photo-electric safety system is provided for each of the workers platforms  18 ,  19 . The photo-electric system for platform  18  includes a sender or emitter  171  mounted on the staircase  31  sending upper and lower parallel light beams  173 ,  174  to a receiver  172  mounted on the platform support structure  44  as shown in  FIGS. 1 and 4 . The photo-electric system for the workers platform  19  includes a sender or emitter  176  mounted on the staircase  32  transmitting light beams  181 ,  182  to a receiver  177  mounted on the support structure  44 ′. When any one of the beams  173 ,  174 ,  181 ,  182  is interrupted or broken by the presence of an obstacle, such as a human, the power to the linear actuator is interrupted by the photo-electric receiver  172  or  177  causing a safety switch to be opened thereby disrupting the flow of electrical power to the drive motor of the associated electrical driven linear actuator  101  or  166 .  
         [0023]      FIG. 11  schematically illustrates a control system for a reversible electric motor  156  of the linear actuator  101  connected to a power source  157  by circuitry including a pair of leads  158 ,  159  with an extend switch  161  and a retract switch  162 , respectively, by which the reversible electric motor  156  may be selectively driven to extend and retract the extensible member  108 , thereby causing corresponding lateral movement of the workers platform  19 . The electric motor  156  is disposed within the actuator housing  102 . The actuator  101  has a built in retract limit switch  163  and a built in extend limit switch  164  which automatically open to interrupt power to the motor  156  at opposite ends, respectively, of the linear stroke of the extensible member  108 . A solenoid operated safety switch  166  in the extend lead  158  is opened by the receiver  177  of the left side photo-electric safety system through a lead  178  when either of the light beams  181 ,  182  is broken. A control system similar to that shown in  FIG. 11  is provided for the linear actuator  153  and the photo-electric sender  171  and receiver  172  of the right side workers platform  18 .  
         [0024]     As shown in  FIGS. 2 and 7 , a pair of safety pendants  186  are pivotally connected at their upper ends to the upper ends of posts  92 ′ on a horizontal axis  184  extending in the direction of elongation of the deck  22 . The pendant  186  is biased laterally away from the deck  22  by a spring  193  to a pivotal position in which it lies between the flatbed  16  and the light beams extending between the electric eye sender  171  and the electric eye receiver  172  of the photo-electric safety system. In a similar manner a pair of pendants  196  have their upper ends pivotally connected to the upper ends of posts  197  on the workers platform  19  for pivotal movement about a longitudinally extending horizontal axis. As shown in  FIGS. 9 and 10 , if the flatbed  16  is positioned sufficiently close to the workers platform  19 , when it is in its servicing position between the workers platforms  18 ,  19 , and linear actuator  101  is actuated to move the workers platform  19  toward the flatbed as indicated by lines  19 ′ in  FIG. 10 , the pendant  196  will contact the flatbed  16  causing it to pivot to the position shown by broken lines  196 ′ in which it interrupts one or both the light beams  181 ,  182  between the sender  176  and the receiver  177  thereby stopping extension of the linear actuator  101 . Thus the pendants  186 ,  196  function to prevent the workers platforms  18 ,  19  from being extended laterally against the flatbed  16 .  
         [0025]     After the flatbed  16  is moved to its servicing position as shown in  FIG. 1 , and the workers platforms have been shifted laterally toward the flatbed as shown in  FIG. 4 , a pair of guard gates  201 ,  202  can be rotated about parallel longitudinally extending horizontal axes  203 ,  204  to their closed position, shown in  FIG. 4 , in which they extend above and across the rear end of the flatbed  16 ; thereby affording protection for workers present on the flatbed  116 . The broken lines  203 ′ show the open position for the gate  203  and the gate  204  may be rotated about the axis  204  to a similar open position, wherein it is disposed at the laterally outer side of the workers platform  18 . As shown in  FIG. 5 , a pivot connection is formed between the gate  201  and a pair of split bearing components  206 ,  207  having interiors configured to fit the guard rail  71  and cylindrically configured exterior surfaces pivotally supporting a split bearing bracket made up of a semi cylindrical member  208  welded to the gate  201  and a semi cylindrical part which is secured to the member  208  by bolts  211  and nuts  212 . The gate  201  can be slid longitudinally along the guard rail  71  to reposition the gate  201  in a fore and aft direction. When the gate  201  is pivoted upwardly from the closed position shown in  FIG. 5 , so that the keeper  216  is not engaged in any of the plurality of slots  217  in a rack  218  provided on the rail  73 , the gate may be shifted in a fore and aft direction to a new position to match deviations in the position of the rear end of the flatbed  16 . The gate  202  is connected to the rail  81  of the workers platform  18  in a similar manner and is also horizontally repositionable in a fore and aft direction. The gate  202  has a keeper  219  similar to keeper  216  which can be inserted in one of the notches or slots  221  in a rack  222  secured to rail  83 , as shown in  FIG. 2 .  
         [0026]     The herein disclosed flatbed servicing station facilitates fast safe servicing of flatbeds. The driver of the truck having or towing the flatbed need only steer the vehicle in a straight direction parallel to the platforms. The platforms can then be moved by the powered linear actuators to working positions adjacent to the flatbed. The safety system prevents injury in event a worker is between the flatbed and a platform when it is advanced toward the flatbed and also prevents the platforms from being impacted against the flatbed.