Patent Publication Number: US-2004042882-A1

Title: Hidden hook vehicle restraint with tab

Description:
FIELD OF THE INVENTION  
       [0001] The invention relates to vehicle restraints and, more particularly, to hidden hook vehicle restraints.  
       BACKGROUND OF THE INVENTION  
       [0002] Some loading docks are equipped with a vehicle restraint that secures a vehicle (e.g., a truck or trailer) adjacent to the loading dock during loading and unloading operations. The vehicle restraint prevents the vehicle from moving away from the loading dock during loading and unloading operations.  
       [0003] One known type of vehicle restraint includes a hook that is generally located within a pit or depression of the loading dock beneath a ramp of a dock leveler. The hook includes a generally longitudinally extending portion and a restraining portion that is substantially perpendicular to the longitudinal portion. Once a vehicle is parked adjacent to the loading dock, the hook is pivoted downwardly from a stored position to a lowered and retracted position. The hook is then extended past the forward face of the loading dock to a lowered and extended position. The hook is then pivoted upwardly to a raised and extended position where the longitudinal portion contacts the lower portion of an ICC bar of the vehicle. After contact, the hook is retracted to a restrained position where the restraining portion contacts the forward portion of the ICC bar such that the presence of a gap between the ICC bar and the restraining portion is avoided.  
       [0004] The hook is typically extended and retracted by a first hydraulic cylinder and is raised and lowered by a second hydraulic cylinder. The second hydraulic cylinder includes a spring that is located on the stem side of the piston within the cylinder. The spring biases the hook toward the raised position and allows the hook to float with the vehicle during loading and unloading operations.  
       [0005] The above-described vehicle restraints are disadvantageous because they can be manipulated out of contact with the ICC bar, thereby allowing the vehicle to be stolen from the loading dock. The hooks of the prior art vehicle restraints do not include structure that prevents the hook from being forced downward (e.g., by a pry bar). Because the restraining portion is substantially parallel with the forward face of the ICC bar, sufficient downward pressure applied to the longitudinal portion can cause the entire hook to move downward and out of contact with the ICC bar. The hook is allowed to move downwardly because of the spring within the second cylinder biasing the hook toward the raised position.  
       SUMMARY OF THE INVENTION  
       [0006] The present invention is directed to a vehicle restraint for restraining a vehicle at a loading dock. In one embodiment, the vehicle restraint includes a hook member adapted to be coupled to the loading dock. The hook member is mounted for movement toward and away from the dock face and further is mounted for movement up and down relative to the dock face. The hook member is arranged such that it will secure three sides of an ICC bar of a vehicle parked at the loading dock.  
       [0007] In one embodiment, the hook member includes a longitudinal portion, a restraining portion, and a tab. The longitudinal portion is adapted to engage a lower portion of the ICC bar, the restraining portion is adapted to engage a front portion of the ICC bar, and the tab is adapted to engage an upper portion of the ICC bar.  
       [0008] In order to provide the above-referenced movement toward and away from the dock face, the restraint can be provided with a longitudinal actuator, such as a hydraulic cylinder. In order to provide the above-referenced movement up and down movement relative to the dock face, the restraint can be provided with a vertical actuator, such as a hydraulic cylinder. To provide both movements, the longitudinal actuator can be pivotally mounted, and the vertical actuator can be designed to pivot the longitudinal actuator.  
       [0009] The above-described restraint can be utilized to perform a method of securing a vehicle having an ICC bar to a loading dock having a dock face, in accordance with the present invention. The method comprises positioning the vehicle at the loading dock, moving the hook member upward into alignment with the ICC bar (e.g., using the vertical actuator), and moving the hook member toward the dock face (e.g., using the longitudinal actuator) such that the hook member secures at least three sides of the ICC bar to thereby inhibit removal of the hook member from the ICC bar. Prior to moving the hook member into alignment with the ICC bar, it is preferred to move the hook member outward away from the dock face (e.g., by extending the hook member from a pit in the dock face). In addition, when moving the hook member upward, the hook member can move along a curved path (e.g., when the hook member is pivotally mounted).  
       [0010] In another aspect of the invention, the engagement between the hook member and the ICC bar is monitored to insure that proper engagement in maintained. This insures that the hook member maintains securement of at least three sides of the ICC bar to thereby inhibit removal of the hook member from the ICC bar. In the event that the desired engagement is not maintained, the hook member can be moved toward the ICC bar. For example, when a longitudinal actuator is being utilized, the longitudinal actuator can be actuated to move the hook member into engagement with the ICC bar. If the longitudinal actuator is a hydraulic cylinder, then the pressure of the hydraulic fluid can be monitored to insure proper engagement of the hook member with the ICC bar.  
       [0011] Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0012]FIG. 1 is a perspective view of a loading dock partially cut away to illustrate a vehicle restraint device embodying the present invention.  
     [0013]FIG. 2 is a longitudinal section view of the vehicle restraint device shown in FIG. 1, illustrating the vehicle restraint in a stored position.  
     [0014]FIG. 3 is a view similar to FIG. 2, illustrating the vehicle restraint in a lowered and extended position.  
     [0015]FIG. 4 is a view similar to FIG. 2, illustrating the vehicle restraint in a raised and extended position.  
     [0016]FIG. 5 is a view similar to FIG. 2, illustrating the vehicle restraint in a restrained position. 
    
    
     [0017] Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The use of “consisting of” and variations thereof herein is meant to encompass only the items listed thereafter. The use of letters to identify elements of a method or process is simply for identification and is not meant to indicate that the elements should be performed in a particular order.  
     DETAILED DESCRIPTION  
     [0018]FIG. 1 illustrates a loading dock  10  that includes a dock leveler  14  and a vehicle restraint  18 . The dock leveler  14  is partially positioned in a pit or depression  22  in the loading dock  10 . The dock leveler  14  includes a ramp  26  pivotally mounted at one end to the loading dock  10  and a lip  30  pivotally connected to the other end of the ramp  26 . When a vehicle  34  is positioned adjacent the loading dock  10 , the ramp  26  is raised, the lip  30  is extended, and the ramp  26  is lowered with the lip  30  in the extended position to contact the bed of the vehicle  34  (FIG. 3). The dock leveler  14  thereby bridges the gap between the loading dock  10  and the vehicle  34  to facilitate loading and unloading of the vehicle  34 . The dock leveler  14  can be actuated by conventional methods known by those skilled in the art, such as by hydraulics, pneumatics, inflatable members, or mechanical springs.  
     [0019] With reference to FIG. 2, the vehicle restraint  18  is mounted beneath the dock leveler  14  in a second pit or depression  38  in the loading dock  10 . The vehicle restraint  18  includes a frame  42 , a hold-down cylinder assembly  46 , a hook cylinder assembly  50 , and a hydraulic power unit (not shown). The vehicle restraint  18  secures the vehicle  34  adjacent to the loading dock  10  such that the vehicle  34  is inhibited from moving away from the loading dock  10  during loading and unloading of the vehicle  34 .  
     [0020] The frame  42  includes a first set of cylinder keepers  54  for coupling the hold-down cylinder assembly  46  to the frame  42 , a second set of cylinder keepers  58  for coupling the hook cylinder assembly  50  to the frame  42 , and a bracket  62  for mounting a proximity switch  66 . The frame  42  is securely fastened to a wall of the pit  38  to support the hold-down cylinder assembly  46  and the hook cylinder assembly  50 .  
     [0021] The hold-down cylinder assembly  46  includes a hold-down cylinder  70  and a plunger rod  78  extending therefrom. The end of the plunger rod  78  includes an eyelet  82 , which couples the hold-down cylinder assembly  46  to the hook cylinder assembly  50 . The hold-down cylinder  70  is provided with two trunnions  86  that are received within the first set of cylinder keepers  54 , and a hose port  90  for connecting the hold-down cylinder  70  to the hydraulic power unit. The hold-down cylinder assembly  46  also includes a piston  92  connected to the rod  78 . The piston  92  separates the hold-down cylinder  70  into a stem side containing the rod  78  and an opposite open side. A compression spring  93  is located on the stem side within the hold-down cylinder  70 .  
     [0022] The hook cylinder assembly  50  includes a hook cylinder  94  and a plunger rod  102  extending therefrom. The hook cylinder  94  is provided with two trunnions  106  that are placed in the second set of cylinder keepers  58 , a sensing target  108  connected to one of the trunnions  106  for operation with the proximity switch  66 , and two hose ports  110  (only one shown) for connecting the hook cylinder  94  to the hydraulic power unit. The hook cylinder assembly  50  also includes a hook member  114  coupled to the plunger rod  102 , a set of plate members  118 , a track  126  longitudinally mounted to the hook cylinder  94 , and a guide rod  130  coupled to the hook member  114  and extending from the track  126 . The guide rod  130  provides additional support to the hook member  114  as the plunger rod  102  moves in and out of the cylinder  94 . The plate members  118  are coupled to the cylinder  94  to provide a mounting location for a pin  122  that extends through the eyelet  82  to couple the hold-down cylinder assembly  46  to the hook cylinder assembly  50 . The hook member  114  includes a generally longitudinally extending portion  134 , a restraining portion  138  that is substantially perpendicular to the longitudinal portion  134 , and a tab  142  that is substantially perpendicular to the retaining portion  138  and substantially parallel to the longitudinal portion  134 .  
     [0023] When not in operation, the vehicle restraint  18  is kept in a stored position as illustrated in FIGS. 1 and 2. The vehicle restraint  19  is designed so the weight of the hook cylinder assembly  50  keeps the trunnions  86  biased against the first set of cylinder keepers  54 .  
     [0024] Referring to FIG. 3, once the vehicle  34  is in position adjacent the loading dock  10  and the dock leveler  14  is bridging the gap between the loading dock  10  and the vehicle  34 , an operator controls the hydraulic power delivered from the hydraulic power unit to the hold-down cylinder  70  and the hook cylinder  94 . The hydraulic power unit is commonly mounted on the floor of the pit  22 . Hydraulic power is delivered to the hold-down cylinder  70  and the hook cylinder  94  via hoses or lines (not shown) extending from a manifold of the hydraulic power unit to the hose ports  90  and  110 , respectively. The manifold provides hydraulic power to the respective hoses based on the operator inputs.  
     [0025] During operation, the vehicle restraint  18  moves from the stored position to a lowered and retracted position by provision of hydraulic power to extend the plunger rod  78  of the hold-down cylinder assembly  46  until the sensing target  108  contacts the proximity switch  66  (see position of sensing target  108  with respect to proximity switch  66  in FIG. 3). Once in the lowered and retracted position, the hydraulic pressure level of the hold-down cylinder  70  is maintained as hydraulic power is provided to extend the plunger rod  78  of the hook cylinder assembly  50  past the face of the loading dock  10  to a lowered and extended position.  
     [0026] Referring to FIG. 4, while maintaining the hydraulic pressure level of the hook cylinder  94 , the plunger rod  78  of the hold-down cylinder  70  retracts, thereby raising the vehicle restraint  18  to a raised and extended position. The plunger rod  102  of the hook cylinder  94  is then retracted to a restrained position, as shown in FIG. 5, where the hook member  114  is secured around three sides of the ICC bar  146  of the vehicle  34 .  
     [0027] As shown in FIG. 5, when in the restrained position, the tab  142  extends over the upper portion of the ICC bar  146 , the restraining portion  138  contacts the forward portion of the ICC bar  146 , and the longitudinal portion  134  extends under the lower portion of the ICC bar  146 . Although the spring  93  of the hold-down cylinder assembly  46  allows for vehicle float, the hook member  114  cannot be pried downward due to the tab  142  and the pressure maintained in the hook cylinder  94 . In order to manipulate the hook member  114  away from the ICC bar  146 , the hook member  114  would need to be moved longitudinally outward away from the loading dock  10  and then downward. The hydraulic pressures of the hook cylinder  94  resist any longitudinal movement of the hook member  114 .  
     [0028] A hydraulic pressure sensor is further provided to monitor the hydraulic pressure levels present in the hook cylinder  94 . The monitoring can be performed on a continuous or periodic basis. It is common for hydraulic pressure to decrease because of bleeding, vehicle movement, or tampering. When a decreased pressure level is detected, the hydraulic power unit is controlled to provide an increased pressure level to the respective cylinder. Maintenance of the pressure levels ensures that the hook member  114  maintains engagement with the ICC bar  146 . Alternative ways of monitoring proper engagement of the hook member  114  with the ICC bar  146  include use of proximity sensors, position switches, strain gages, or any other suitable device.  
     [0029] Guards (not shown) may be provided to protect the hose ports  90  and  110 , the hydraulic hoses, and the hydraulic power unit from tampering. In one embodiment, the guards may be constructed of steel and designed to allow for movement of the vehicle restraint  18  as discussed above.  
     [0030] When the vehicle is ready to leave the loading dock, the operator returns the vehicle restraint to the stored position by moving the vehicle restraint  18  in an order opposite to the operation discussed above. Therefore, the vehicle restraint  18  moves from the restrained position to the raised and extended position, to the lowered and extended position, to the lowered and retracted position, and finally to the stored position. The operation described herein represents only one method of operating the vehicle restraint  18 , and other methods of operation between the stored and restrained positions are considered to be within the scope of the invention.  
     [0031] The concepts of the present invention can be used to modify existing vehicle restraints in the field. More specifically, the hook member  114  of the present invention could be used to replace hooks that do not have a tab  142  for preventing downward movement of the hook. To facilitate removal of the old hook and replacement with the new hook, the restraint can be moved from the stored position to a lowered and extended position or a raised and extended position. The old hook can then be removed and replaced with the new hook having a tab  142 . In this manner, the performance of a vehicle restraint can be improved without the need to replace the entire vehicle restraint.  
     [0032] The foregoing description of the present invention has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and the skill or knowledge of the relevant art, are within the scope of the present invention. The embodiments described herein are further intended to explain best modes known for practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with various modifications required by the particular applications or uses of the present invention.