Patent Publication Number: US-9415983-B2

Title: Crash prevention system for a storage and retrieval machine

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit to U.S. Provisional Patent Application Ser. No. 61/738,138 filed on Dec. 17, 2012, and is herein incorporated by reference it its entirety. 
    
    
     FIELD 
     The present document relates generally to a crash prevention system and in particular to a laser crash prevention system for a storage and retrieval machine. 
     BACKGROUND 
     In distribution centers, the use of automated Storage and Retrieval Machines (SRM) to handle palletized unit loads in a warehouse setting is well known. In a typical facility, the palletized unit loads are stored on one side of a lane by an SRM which typically has a multi-story crane that moves along each lane of the warehouse. The SRM includes an automated forklift apparatus that moves along the length of the crane and moves the various palletized unit loads around the warehouse. Typically, the SRM may store palletized unit loads on one side of a lane having multiple stories of storage space and then retrieved and positioned by the SRM on the opposite side of the lane for distribution of the palletized unit load. In this storage and distribution process, the SRM travels back and forth along the lane either storing or retrieving palletized unit loads from different levels of the warehouse. It is quite common for the pallet and/or the unit load to become repositioned or poorly staged during the storage and retrieval process due to mechanical machine failure or from human intervention in which the pallet or unit load is brought into direct interference with the travel path of the SRM, thereby resulting in the SRM colliding with the pallet or unit load during the normal travel cycle and operation of the SRM. Such collisions can cause severe damage to the SRM. As such, there is a need for a crash prevention system that prevents collisions between the SRM and the obstruction. 
     SUMMARY 
     In one embodiment, a vehicle, such as a storage and retrieval machine, includes a crash prevention system comprising a sensor apparatus for generating at least one laser beam that forms a detection pattern for detecting an obstruction in the path of the vehicle. A processor in operative communication with a controller generates a fault condition that terminates movement of the vehicle upon detection of the obstruction by the sensor apparatus. In some embodiments, the vehicle includes a crane mast in which the crash prevention system is mounted for providing a detection pattern that is parallel relative to the longitudinal axis of the crane mast and offset by a predetermined distance such that any obstruction originating from one side of the path is detected by the detection pattern generated by the sensor apparatus. A user interface is in operative communication with the processor for displaying data related to fault conditions and location of obstructions that resulted in the fault conditions. 
     In some embodiments, the crash prevention system may include a pair of sensor apparatuses with each sensor apparatus positioned on opposite sides of the vehicle for generating at least one laser beam for forming a detection pattern for detecting an obstruction originating from either side of the path being followed by the vehicle. 
     In some embodiments, the crash prevention system may include a single sensor apparatus arrangement or a dual sensor apparatus arrangement in which each sensor apparatus generates a pair of laser beams emitted at opposite directions, such as 180 degrees relative to each other, for forming a detection zone on either one side of the vehicle (e.g., single sensor arrangement) or both sides of the vehicle (e.g., dual sensor arrangement). 
     Additional objectives, advantages and novel features will be set forth in the description which follows or will become apparent to those skilled in the art upon examination of the drawings and detailed description which follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is simplified block diagram of the crash prevention system and the storage and retrieval machine; 
         FIG. 2  is a simplified illustration showing the travel of the various storage and retrieval machines in a warehouse setting; 
         FIG. 3  is a simplified illustration of the storage and retrieval machine showing the operation of the crash prevention system 
         FIG. 4  is a side view of the storage and retrieval machine showing the operation of the crash prevention system including the detection zone established by the crash prevention system; 
         FIG. 5  is a front view of the storage and retrieval machine; 
         FIG. 6  is a picture showing the sensor apparatus for the crash prevention system; 
         FIG. 7  is a picture showing the sensor apparatus engaged to the rotating member driven by a motor through a pulley arrangement; 
         FIG. 8  is side view of a mounting plate used to engage the sensor apparatus to the storage and retrieval machine; 
         FIG. 9  is a front view of the mounting plate; 
         FIG. 10  is a top view of the mounting plate; 
         FIG. 11  is an isometric view of the mounting plate; 
         FIG. 12  is an isometric view of a rope guide; 
         FIG. 13  is a top view of the rope guide engaged to the mounting plate; 
         FIG. 14  is a simplified illustration of the sensor apparatus; 
         FIG. 15  is a front view of the sensor apparatus; and 
     
    
    
     Corresponding reference characters indicate corresponding respective elements among the views of the drawings. The headings used in the figures should not be interpreted to limit the scope of the claims. 
     DETAILED DESCRIPTION 
     Referring to the drawings, an embodiment of a crash prevention system is illustrated and generally indicated as  100  in  FIGS. 1-18  for use with a vehicle, such as a storage and retrieval machine  10 , in detecting obstructions and terminating movement of the storage and retrieval machine  10  to prevent a collision with the detected obstruction. As shown in  FIG. 4 , the storage and retrieval machine  10  includes a crane mast  12  operatively engaged to an automated forklift apparatus  14  that is used to store and retrieve palletized unit loads  16  from various levels in a warehouse divided by different lanes. In one arrangement, a respective storage and retrieval machine  10  travels along a particular lane for conducting the storage and retrieval operation. In one embodiment, the crash prevention system  100  includes a housing  102  ( FIG. 1 ) that is mounted to the crane mast  12  with a sensor apparatuses  106  extending from one side of the crane mast  12  for detecting obstructions originating from one side of the lane being traveled by the storage and retrieval machine  10 . In other embodiments, the crash prevention system  100  includes at least one housing  102  mounted to the crane mast  12  with a pair of sensor apparatuses  106 A and  106 B for detecting obstructions originating from both sides of the lane. In some embodiments, detection of the obstruction causes a controller  110  to generate a fault condition that terminates movement of the storage and retrieval machine  10  and prevents contact with the obstruction, such as an improperly positioned pallet or unit load that extends into the lane and in the path being traveled by the storage and retrieval machine  10 . 
     Referring to  FIG. 1 , the sensor apparatus controller  110  controls the operation of the crash prevention system  100  and is in operative communication with a motor  112  that is operatively engaged to a rotating member  104  for rotating a sensor apparatus  106  as shall be described in greater detail below. The sensor apparatus controller  110  may be in operative communication with a storage and retrieval machine (SRM) controller  105  that controls the operation of the storage and retrieval machine  10 . The crash prevention system  100  further includes a user interface  108 , such as a keyboard and display, in operative communication with the SRM controller  105  and sensor apparatus controller  110  for controlling and monitoring the operation of the crash prevention system  100 . In addition, the SRM controller  105  may receive data from the sensor apparatus controller  110  related to the number of fault conditions that occur and the locations of the storage and retrieval machine  10  when the fault conditions have occurred. 
     Referring to  FIG. 2 , in one arrangement a plurality of storage and retrieval machines, designated  10 A- 10 C, may be deployed in a warehouse setting such that each of the storage and retrieval machines  10  travels along a designated lane when performing the storage and retrieval operation. In one particular arrangement, one side of the lane may be a storage side, designated s, for storing the palletized unit loads by the storage and retrieval machine  10 , while the opposite side of the lane may be a distribution side, designated d, for unpacking and distributing the unit load by warehouse personnel when retrieved form the storage side by the storage and retrieval machine  10 . 
     As noted above, the crash prevention system  100  generates a fault condition whenever an obstruction is detected that obstructs the line of travel of the storage and retrieval machine  10 . As shown in  FIGS. 3 and 4 , in one embodiment a pair of sensor apparatuses, designated  106 A and  106 B, rotate a respective pair of laser beams  101 A/B and  101 C/D ( FIG. 3 ) in a circular detection pattern  103  for detecting any obstructions originating from either side of the lane being traveled by the storage and retrieval machine  10 . Referring to  FIG. 15 , for example, sensor apparatus  106  may include a transmitter  140  for transmitting at least one laser beam  101  and a receiver  142  for receiving the reflected laser beam  101  if an obstruction is detected. In some embodiments, the receiver  142  may include a slit  144  that allows the receiver  142  to receive only a portion of the reflected laser beam such that a narrower laser beam is detected by the receiver  142  when an obstruction has been detected by the sensor apparatus  106 . 
     In one embodiment shown in  FIG. 3 , each sensor apparatus  106 A and  106 B generates a pair of oppositely emitted laser beams  101 A/B and  101 C/D that form the respective circular detection pattern  103  as each respective sensor apparatus  106 A and  106 B is rotated such that the circular detection pattern  103  is positioned in parallel orientation relative to the longitudinal axis  900  ( FIG. 4 ) of the storage and retrieval machine  10  (e.g., path of travel) and is offset a predetermined distance from one side of the crane mast  12  of the storage and retrieval machine  10 . For example, as shown In  FIG. 3 , in one embodiment the predetermined distance may be a length  700  of about 2 feet; however the length  700  may vary to accommodate lane width and/or the particular size and dimensions of the storage and retrieval machine  10  traveling down the lane. In addition, a length  704  of about 6 inches may used to establish a gap between the sides of the automated fork apparatus  14  on the storage and retrieval machine  10  and either side of the lane with respect to detecting potential obstructions. 
     In some embodiments, the detection pattern  103  may have an effective detection range of about 47 feet in either the forward or backward directions relative to the storage and retrieval machine. The detection range may be varied to extend or shorten the detection pattern  103  of the sensor apparatus  106 . 
     Referring to  FIG. 5 , in one embodiment the housing  102  may be coupled to a mid point portion of the crane mast  12 . For example, a storage and retrieval machine  10  having a crane mast  12  with a length  702  of about 100 feet should have the housing  102  mounted about 50 feet or the mid point position of length  702 , especially if the detection range of the laser  101  is 47 feet in order to prevent false detections caused by the floor of the warehouse. In such an arrangement, the circular detection pattern  103  generated by the dual laser beams  101  is sufficiently wide enough to detect any obstruction that is in front or in back of the storage and retrieval machine  10 . It was found that a detection range of 47 feet for the sensor apparatus  106  was sufficient to stop the storage and retrieval machine  10  moving at a speed of 7.6 feet per second to terminate all movement and prevent contact with the obstruction after detection. 
     As shown in  FIGS. 6 and 7 , the sensor apparatus  106  is coupled to a rotating member  104  that rotates the sensor apparatus  106  about a longitudinal axis  902  defined by the rotating member  104 . In one embodiment, the controller  110  causes the motor  112  to rotate the sensor apparatus  106  at approximately 23 RPM to generate the circular detection pattern  103  formed by the rotation of dual laser beams  101  shown in  FIG. 4 . As shown, the action of the motor  112  rotates the rotating member  104  at a rate controlled by the controller  110  through a pulley system operatively engaged between the motor  112  and the rotating member  104 . In one embodiment, a cam operation occurs with the rotation of the sensor apparatus  106  such that rotation of the sensor apparatus  106  through a particular range of angles is noted by the sensor apparatus controller  110 . When the storage and retrieval machine  10  is positioned at the end of the lane and proximate the end zone of the warehouse ( FIG. 2 ), the circular detection pattern  103  will detect the presence of structural elements, such as stairs and aisles, located at the end of the warehouse; however, the sensor apparatus controller  110  is programmed to ignore the detection of any such structural elements at that particular range of angles during the cam operation by the sensor apparatus  106  when the storage and retrieval machine  10  is located proximate the end zone area of the lane. Otherwise, the processor  105  will generate a fault condition upon detection of the obstruction that will terminate the movement of the storage and retrieval machine  10 . Once the obstruction is removed, the software is reset for allowing the continued operation of the storage and retrieval machine  10 . 
     Referring to  FIGS. 8-11 , the housing  102  may be coupled to the crane mast  12  using a mounting plate  114 . In one embodiment, the mounting plate  114  includes first and second clamping bars  124  and  126  engaged to either side of a mounting plate body  122 . When engaged to the mounting plate body  122 , the first and second clamping bars  124  and  126  form a recess with the mounting plate body  122  configured to engage a portion of the crane mast  12  such that the mounting plate  114  engages the housing  102  to the crane mast  12 . In addition, first and second posts  128  and  130  extend outwardly downward from the mounting plate body  122 . The first and second posts  128  and  130  are engaged to the housing  102  to provide a supporting mechanism for the sensor apparatus controller  110  and the associated electrical components in operative communication with the sensor apparatus motor  112 , sensor apparatus  106 , and SRM controller  105 . 
     Referring to  FIGS. 12 and 13 , a rope guide  116  may also be coupled to the crane mast  12  as part of the assembly that engages the housing  102  to the crane mast  12 . The rope guide  116  prevents the wire ropes of the storage and retrieval machine  10  from interfering with the housing  102 . 
     As shown in  FIG. 14 , the crash prevention system  100  further includes a slip ring  118  in which control connections may be passed through. In one embodiment, the slip ring  118  may be a Mertac Model  630 .  FIG. 14  further illustrates the control connections and other electrical circuits and components of the crash prevention system  100 . 
     In some embodiments, the user interface  108  provides information related to the operation and monitoring of the crash prevention system  100 , such as the number faults that have occurred as well as the times that these faults happened and the locations that the faults occurred. However, other types of information may be displayed by the user interface  108 , such as the present location of the storage and retrieval machines  10 A,  10 B and  10 C, within the facility or instructions to a storage and retrieval of particular palletized loads. 
     It should be understood from the foregoing that, while particular embodiments have been illustrated and described, various modifications can be made thereto without departing from the spirit and scope of the invention as will be apparent to those skilled in the art. Such changes and modifications are within the scope and teachings of this invention as defined in the claims appended hereto.