Abstract:
A forklift may include (a) a mast; (b) forks which are substantially perpendicular to the mast; (c) a load backrest adjacent to the mast, the load backrest and the forks are coupled and moveable along a longitudinal direction of the mast; and (d) a height measuring component determining a location of the forks relative to the mast.

Description:
PRIORITY CLAIM 
       [0001]    This application claims the priority to the U.S. Provisional Application Ser. No. 60/982,019, entitled “Forklift Height Indicator Using RFID,” filed Oct. 23, 2007. The specification of the above-identified application is incorporated herewith by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to a forklift height indicator. Specifically, the height of forks that are raised and lowered may be determined using sensing components. 
       BACKGROUND 
       [0003]    A forklift may be used in a variety of environments. The forklift may assist users in moving heavy loads and placing the loads in different locations including areas that are elevated. The elevations of the areas may be different, depending on a variety of factors such as a quality of supports. In certain environments, the loads are stacked on top of one another on a common rack. Furthermore, safety policies may be instituted regarding placement of loads such as when the loads are stacked, the forklift is idle, etc. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention relates to a forklift and, in particular, to a forklift height indicator. The forklift may include (a) a mast; (b) forks which are substantially perpendicular to the mast; (c) a load backrest adjacent to the mast, the load backrest and the forks are coupled and moveable along a longitudinal direction of the mast; and (d) a height measuring component determining a location of the forks relative to the mast. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  shows an exemplary forklift according to a first and a second exemplary embodiment of the present invention. 
           [0006]      FIG. 2  shows an exemplary forklift according to a third exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0007]    The exemplary embodiments of the present invention may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The exemplary embodiments of the present invention describe a forklift equipped with sensing components to indicate a height of forks. According to the exemplary embodiments of the present invention, the sensing components may include at least one of a radio frequency identification (RFID) sensor, a barcode reader, and a sonic sensor. The forklift, the forks, the RFID sensor, the barcode reader, and the sonic sensor will be discussed in more detail below. Those skilled in the art will understand that other types of sensing components may also be used and may be substituted for the described sensing components. 
         [0008]      FIG. 1  shows an exemplary forklift  100  according to a first and a second exemplary embodiment of the present invention. The forklift  100  may be used in any environment in which loads, in particular heavy loads, are transported. The forklift  100  offers movement of the loads in all three dimensions. The forklift  100  may include components such as a mast  105 , forks  110 , and a load backrest (LBR)  115 . It should be noted that other components may be included such as a seat in which a user is disposed, controls to operate the forklift  100 , wheels to move the forklift  100 , an engine, etc. 
         [0009]    The mast  105  may be a vertical assembly disposed on a front end of the forklift  100 . The mast  105  may be responsible for moving the loads in a vertical direction. Furthermore, the mast  105  may enable the loads to be tilted. The mast  105  may be, for example, hydraulically operated using one or more cylinders and interlocking rails for lifting/lowering operations and lateral stability. In another example, the mast  105  may be operated with a hydraulic motor providing motive power. 
         [0010]    The forks  110  may be two or more flat metal plates extending in a substantially perpendicular direction away from the mast  105 . The forks  110  may be attached to a carriage. The carriage may be coupled to the mast  105  using, for example, chains or direct attachment to the hydraulic cylinder. The carriage may be the component that is moved along the mast in a direction d. The forks  110  may be coupled to the carriage using, for example, hooks/latches or a shaft mount. Each front end of the forks  110  may be tapered for ease of insertion into the load. The forks  110  may be inserted into or underneath the load, usually on a pallet or skid, so that the load may be picked up. 
         [0011]    The LBR  115  may be included in the forklift  100  to prevent the load from shifting backward, especially when the load is raised to a height greater than the mast  105 . The LBR  115  may be disposed in a substantially similar location as the carriage. That is, a bottom edge of the LBR  115  may be substantially similar to a bottom edge of the carriage which coincides with the coupling area of the forks  110 . 
         [0012]    In addition to the above described components, according to the exemplary embodiments of the present invention, the forklift  100  may further include a reader  120  and a plurality of tags  125 - 145 . As will be explained in further detail below, according to the exemplary embodiments of the present invention, the first exemplary embodiment includes the reader  120  being an RFID reader and the tags  125 - 145  being a plurality of RFID tags. The second exemplary embodiment includes the reader  120  being a barcode reader and the tags  125 - 145  being a plurality of barcodes. 
         [0013]    According to the first exemplary embodiment of the present invention, the RFID reader  120  may be a conventional RFID reader that includes a transceiver and antenna to receive RF data, in particular from the RFID tags  125 - 145 . The RFID reader may be disposed on one of the LBR  115 , the carriage, the forks  110 , etc. As illustrated, the RFID reader may be disposed on the LBR  115  near a proximal end of the forks  110 . The RFID tags  125 - 245  may be conventional RFID tags that include an integrated circuit and antenna. For example, the RFID tags may be active RFID tags, passive RFID tags, or semi-passive RFID tags. Each RFID  125 - 145  tag may be disposed at predetermined locations along the mast  105 . As illustrated, the tag  125  may be disposed at a bottom edge of the mast  105 ; the tag  130  may be disposed at a quarter height of the mast  105 ; the tag  135  may be disposed at a half height of the mast  105 ; the tag  140  may be disposed at a three quarter height of the mast  105 ; and the tag  145  may be disposed at a top edge of the mast  105 . 
         [0014]    The disposition of the RFID reader  120  and the RFID tags  125 - 145  enable a determination of height to be made directly related to the forks  110  and indirectly related to the load placed in or on the forks  110 . As the forks  110 , the LBR  115 , the carriage, and the load are moved along the mast  105 , the RFID reader  120  may receive RF data from the RFID tags  125 - 145 . Depending on the location at which the forks  110 , the LBR  115 , the carriage, and the load are disposed on the mast  105 , a height determination may be ascertained. For example, if a particular RFID tag has been or is being read, the tag may indicate the height. 
         [0015]    Each of the RFID tags  125 - 145  may be encoded with data such that the RF data received by the RFID reader  120  indicates the height. In a first exemplary embodiment, the RFID tags  125 - 145  may transmit the corresponding height to the RFID reader  120 . The height may then be shown on a display of the forklift  100  to indicate to an operator of the forklift  100  the height at which the forks  110  are disposed. In a second exemplary embodiment, the RFID tags  125 - 145  may transmit an identity to the RFID reader  120 . The identity of each of the tags  125 - 145  may be included in a database indicating a height. Thus, when the RFID reader  120  receives the identity data from one the RFID tags  125 - 145 , the database may be referenced so that a corresponding height may be indicated. The height may be shown on the display of the forklift  100 . 
         [0016]    In a substantially similar manner as the RFID reader  120 , according to the second exemplary embodiment of the present invention, the reader  120  may be a barcode reader. The barcode reader  120  may be a conventional barcode reader that includes a scanning engine (e.g., imager based, laser based, etc.) to read the barcodes. The barcode reader  120  may also be disposed on a substantially similar position as the RFID reader such as the LBR  115 , the carriage, the forks  110 , etc. The barcodes  125 - 145  may be conventional barcodes such as one-dimensional barcodes, two-dimensional barcodes, color barcodes, etc. Each barcode  125 - 145  may be disposed at predetermined locations along the mast  105  in a substantially similar manner as the RFID tags. Also in a substantially similar manner, the barcodes  125 - 145  may be encoded with data indicating the height. Thus, when the barcode reader  120  scans one of the barcodes  125 - 145 , the data encoded therein may be decoded indicating the corresponding height or may be decoded indicating an identity of the barcode that is referenced to a database that indicates the height. 
         [0017]    It should be noted that the database that indicates the height may be stored in a variety of locations. In a first example, an on-board computer of the forklift  100  may include the database. The on-board computer may include a memory that stores the database. In another example, the forklift  100  may include a transceiver that associates an on-board computer of the forklift  100  with a network. A storage unit of network may store the database. Thus, a height determination of the forks  110  may be transmitted via the transceiver to a network component that accesses the database that indicates the height. 
         [0018]    The disposition of the barcode reader  120  and the barcodes  125 - 145  also enable a determination of height to be made directly related to the forks  110  and indirectly related to the load placed in or on the forks  110 . As the forks  110 , the LBR  115 , the carriage, and the load are moved along the mast  105 , the barcode reader  120  may scan the barcodes  125 - 145 . Depending on the location at which the forks  110 , the LBR  115 , the carriage, and the load are disposed on the mast  105 , a height determination may be ascertained. 
         [0019]    It should be noted that the number of tags  125 - 145  being five is only exemplary. According to the exemplary embodiments of the present invention, the forklift  100  may include, at a minimum, two sensing tags. The forklift  100  may also include additional sensing tags if a more precise determination of height is desired or required. 
         [0020]    It should also be noted that the reader  120  is not limited to reading the tags  125 - 145 . The sensor  120  may also be configured to determine a presence of the load (e.g., by reading a tag similar to the tags  125 - 145  or by incorporating a different type of sensor such as a piezoelectric pressure sensor, an optical distance sensor, etc.), determine movement of the forklift  100  (e.g., by incorporating a MEMS sensor), determine a direction in which the forklift  100  is moving, determine what the load is, etc. The additional data ascertained by the sensor  120  may be incorporated with the height data read from the sensing tags  125 - 145 . 
         [0021]    It should further be noted that the tags  125 - 145  being RFID tags or barcodes is only exemplary. For example, in another exemplary embodiment, the tags  125 - 145  may be optical character recognition (OCR) strings. Thus, a respective reader  120  may be used to translate images of handwritten text, typewritten or printed text, etc. into machine readable text. 
         [0022]    Furthermore, it is noted that the reader  120  and the tags  125 - 145  may be permanently or removably disposed. The reader  120  may be permanently attached to one of the locations described above. The reader  120  may also be removably attached to one of those locations. For example, a port may be disposed at the location (e.g., the proximal end of forks  110 , the carriage, the LBR  115 , etc.) to receive the reader  120 . The reader  120  may subsequently be removed when a height determination is not necessary. In another example, the reader  120  may be equipped with locking mechanisms so that when unlocked, the reader  120  may be freely moved. The locking mechanism may then be locked to hold the reader  120 . The tags  125 - 145  may also be permanently attached or removably attached in a substantially similar way as the reader  120 . Furthermore, the tags  125 - 145  may be configured so that they be moved along the mast  105 . The tags  125 - 145  may be equipped with a locking mechanism that clips onto the mast  105 . The clips may be configured to enable the tags  125 - 145  to remain stationary at a point on the mast  105  but may also enable the tags  125 - 145  to be movable along the mast  105  by a sliding motion. Thus, the tags  125 - 145  may be used to determine any height at which they are disposed on the mast  105  and are not limited to the height corresponding to the predetermined locations along the mast  105 . When the tags  125 - 145  are movable, the tags  125 - 145  may be encoded with the identity data described above. Thus, when the reader  120  receives/scans the identity data, the database (that is updated when the tags  125 - 145  are moved) may indicate the corresponding height. 
         [0023]      FIG. 2  shows an exemplary forklift  100  according to a third exemplary embodiment of the present invention. The forklift  100  of the second exemplary embodiment of the present invention may be substantially similar to the forklift  100  of the first exemplary embodiment. That is, the forklift  100  may include components such as the mast  105 , the forks  110 , the LBR  115 , the seat, the controls, the wheels, the engine, etc. 
         [0024]    According to the second exemplary embodiment of the present invention, the forklift  100  may further include a sonic sensor  150 . The sonic sensor  150  may be a conventional sonic sensor (e.g., ultra sonic sensor). The sonic sensor  150  may include a transmitter that transmits a sound and a sensor that receives an echo of the sound. A travel time of the sound may be used with a frequency of the sound to determine a distance. The sonic sensor  150  may be disposed on a bottom side of the forks  110 . Specifically, the sonic sensor  150  may be oriented to face a floor in which the forklift  100  is disposed. Accordingly, when the sonic sensor  150  transmits the sound, the echo is produced upon reflecting off the floor. Thus, the distance that is determined corresponds to the height of the forks  110  and the load. 
         [0025]    The sonic sensor  150  may specifically be disposed at proximal ends of the forks  110 . As discussed above, the mast  105  may enable loads to be tilted. Consequently, distal ends of the forks  110  may be raised so that a height of the distal ends of the forks  110  is greater than proximal ends of the forks  110  where the forks  110  extend from the mast  105 . The sonic sensor  150  may determine the height of the proximal ends of the forks  110  and may also extrapolate the height of the distal ends of the forks  110  when an angle of tilting is available. As will be discussed below, the determination of both heights may be useful to the operator of the forklift  100 . 
         [0026]    It should be noted that a further sonic sensor may be disposed on the distal ends of the forks  110 . The further sonic sensor may be used to determine the height of the distal ends of the forks  110 . Thus, a further determination is not required when the sonic sensor  150  determines the height of the proximal ends of the forks  110 . In addition, the further sonic sensor disposed at the distal ends of the forks  110  may also be used to determine the height of the proximal ends to, for example, serve as a check to the height determined from the sonic sensor  150  disposed at the proximal ends. The further sonic sensor may also be used to determine a distance from the distal ends to an object disposed in front of the forklift  100 . For example, a load may be placed onto a shelf. The forklift  100  may determine the distance to the shelf via the further sonic sensor so that the operator of the forklift  100  may move the load accordingly (e.g., available space to move forward, lack of space so need to move backward, etc.). 
         [0027]    The height determination may be used for a variety of purposes. In a first example, when using RFID to place RFID tagged loads with or without pallets into RFID tagged warehouse slots, knowing the height of the forks allows for the more accurate associations of the load/pallet to the location. In particular, with multiple stacked loads, the accurate associations may be pertinent prior to, for example, placing a double stacked load/pallet on the warehouse rack. For example, a height of a load may further indicate a third dimension to a location of the load. The load may be in an elevated slot in the warehouse. Additional loads to be placed on top of, next to, etc. the load may be placed accordingly. 
         [0028]    In a second example, knowing the height of the forks  110  on the forklift  100  may be used to ensure safety policies (e.g., company based, industry based, etc.) are being followed. For example, one safety policy may relate to using the forklift  100  at certain speeds. The policy may indicate that at high speeds, the forks  110  are not to exceed a certain height. Thus, if the forks  110  are determined to be disposed beyond an acceptable height, the operator of the forklift  100  may be alerted (e.g., shown on a display, playing an audio component, etc.). The operator may then slow down, move the forks  110  to an acceptable height, etc. In another example, one safety policy may relate to the forklift  100  being unattended. The policy may indicate that when the forklift  100  is unattended, the forks  110  are not to exceed a certain height. Thus, if the forklift  100  is powered down and a determination is made that the forks  110  are at an unacceptable height, the operator may be alerted (e.g., shown on a display, playing an audio component, etc.) of this condition so that the forks  110  are moved to an acceptable height. As discussed above, the forklift  100  may further be configured with a transceiver that transmits data relating to the height of the forks  110  to a network component. The network component may determine if the forks  110  are at an acceptable height for various conditions (e.g., moving forklifts, unattended forklifts, etc.). If the forks  110  are not an the acceptable height, a command signal may be transmitted to the forklift  100  via the transceiver to alert the operator. In another example, an administrator of the network may be indicated that a particular forklift  100  has forks  110  in an unacceptable height. The operator of the forklift  100  may have a communication device on his/her person or part of the forklift  100 . The administrator may contact the operator indicating the unacceptable height. 
         [0029]    It should be noted that the exemplary embodiments using a single reader or a sonic sensor is only exemplary. The exemplary embodiments of the present invention may incorporate up to both types of readers and the sonic sensor. For example, in the first exemplary embodiment where the reader  120  is the RFID reader, the barcode reader may also be disposed on the forklift. The barcode reader may serve to provide additional data (e.g., to verify the RFID readings), different data (e.g., a different height determination), etc. Furthermore, the sonic sensor may be added to provide the various features that the sonic sensor is capable of performing. 
         [0030]    It will be apparent to those skilled in the art that various modifications may be made in the present invention, without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.