Abstract:
A modular, electrified monorail system upon which at least one motorized trolley assembly may be propelled along. The system may incorporate a plurality of rail assemblies adapted to be coupled adjacent to one another to form a generally continuous track. Each rail assembly may make use of an electrified track adapted to provide an electrical signal from an electrical power source to at least one electrical conductor extending coextensively along the electrified track. A controller may be mounted on the electrified track. The controller may be configured to selectively apply and remove the electrical power from the electrified track to control propulsion of the motorized trolley assembly along the electrified track.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/449,295, filed on Mar. 4, 2011. The entire disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to monorail systems used in various applications, typically manufacturing and assembly operations, and more particularly to a monorail buss control system and method that can be implemented with less cost and complexity than previously developed monorail conveyor systems without sacrificing utility and efficiency of the system. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
         [0004]    Electrified monorail convey systems are often employed in assembly and manufacturing environments to move component parts from one location within an assembly environment (often a factory) to another station. Such systems generally are quieter and cleaner to operate than conveyor systems that use chains to pull part carriers along a predetermined path. However, electrified monorail conveyor systems have traditionally been fairly costly to implement, which has in some applications limited their applicability. Typical electrified monorail conveyor systems often include a plurality of tractor assemblies, sometimes referred to as “carrier” assemblies that are independently propelled along an electrified track. For simplicity these will be referred to simply as “tractor assemblies”. The tractor assemblies typically carry a part or subassembly thereon from one station of an assembly or processing facility to another station. Typically each tractor assembly has its own electronic controller that is mounted thereon, and uses control signals transmitted along one or more conductors extending along the track to control motion of its associated carrier assembly. Obviously, the need to include an electronic controller for each and every carrier assembly adds significant cost to the overall system. 
       SUMMARY 
       [0005]    In one aspect the present disclosure relates to a modular, electrified monorail system upon which at least one motorized trolley assembly may be propelled along. The system may incorporate a plurality of rail assemblies adapted to be coupled adjacent to one another to form a generally continuous track. Each rail assembly may make use of an electrified track adapted to provide an electrical signal from an electrical power source to at least one electrical conductor extending coextensively along the electrified track. A controller may be mounted on the electrified track. The controller may be configured to selectively apply and remove the electrical power from the electrified track to control propulsion of the motorized trolley assembly along the electrified track. 
         [0006]    In another aspect the present disclosure relates to a modular, electrified monorail system. The system may comprise a plurality of motorized trolley assemblies which are adapted to be propelled by electrical power. A plurality of rail assemblies may be included which are adapted to be coupled adjacent to one another to form a generally continuous track. Each rail assembly may include an electrified track adapted to provide an electrical signal from an electrical power source to at least one electrical conductor extending coextensively along the electrified track. The at least one electrical conductor may be adapted to provide the electrical signal to any one of the motorized trolleys that is present the electrified track. A controller may also be mounted on the electrified track. The controller may be configured to selectively apply and remove the electrical power from the electrified track to control propulsion of each of the motorized trolley assemblies along the electrified track. A remotely located controller may be included which is in communication with the controller located on each electrified track, for communicating with the controller on each one of the electrified tracks when to apply and remove power from its associated electrified track. 
         [0007]    In still another aspect the present disclosure may relate to a method for forming a modular electrified monorail system. The method may comprise plurality of operations including providing a plurality of motorized trolley assemblies that each may be independently propelled via electrical signals. A plurality of rail assemblies may be used which are adapted to be coupled adjacent to one another to form a generally continuous track upon which the motorized trolley assemblies may be propelled. For each rail assembly, an electrified track may be used which is adapted to provide an electrical signal from an electrical power source to at least one electrical conductor extending coextensively along the electrified track. A controller may also be used which may be mounted on the electrified track. The controller may be caused to selectively apply and remove the electrical power from the electrified track to control propulsion of the motorized trolley assembly along the electrified track. A remotely located controller may be used to communicate with each of the controllers and to inform each of the controllers specifically when to apply electrical power to its associated said electrified track, and when to remove electrical power from its associated said electrified track, to control movement of the motorized trolleys along each of the electrified tracks. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0009]      FIG. 1  is a side view of one embodiment of a modular, electrified monorail buss control rail system in accordance with the present disclosure that makes use of a plurality of modular, electrified monorail rail assemblies coupled adjacent to one another; 
           [0010]      FIG. 2  is an enlarged perspective view of one of the modular rail assemblies shown in  FIG. 1 ; 
           [0011]      FIG. 3  is a simplified cross sectional view one of the trolley assemblies of the system taken along section line  3 - 3  in  FIG. 2 ; 
           [0012]      FIG. 4  is a simplified electrical schematic diagram showing how a logic controller is electrically in communication with each of the controllers of the rail assemblies; and 
           [0013]      FIG. 5  is a diagram illustrating how movement of a trolley assembly occurs along a plurality of the rail assemblies. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
         [0015]    Referring to  FIGS. 1 and 2 , there is shown a modular, electrified, monorail system  10  that makes use of a plurality of identical electrified monorail rail assemblies  10   a ,  10   b  and  10   c . For convenience the electrified monorail rail assemblies  10   a - 10   c  will be referenced simply as “rail assemblies”  10   a - 10   c . It will also be appreciated immediately that while only three complete rail assemblies  10   a - 10   c  are shown in  FIG. 1 , that in a typical application dozens or even hundreds or more such assemblies  10  may be coupled adjacent to one another and used to form the needed path of travel through an assembly plant or processing plant where the system  10  is being employed. The path of travel may include long straight lengths as well as turns and elevation changes. Conventional track switches may also be employed in connection with the rail assemblies  10   a - 10   c  to route different components being carried along the rail assemblies  10   a - 10   c  to different assembly or processing stations within an assembly or processing plant. 
         [0016]    Since the rail assemblies  10   a - 10   c  are identical in construction, only the construction of rail assembly  10   a  will be described in detail. Rail assembly  10   a  is shown in greater detail in  FIG. 2  and includes a plurality of conventional yokes or hangers  12  that suspend an electrified track  14  from a support beam  16 . Typically the support beam  16  may employ a cable tray  18  to hold the various electrical cables (not shown) that are used in connection with the rail assembly  10   a . The cable tray  18  also supports T-couplings (not shown) where various electrical connections are made between the rail assembly  10   a  components and the electrical cables running along the support beam  16 . 
         [0017]    The rail assembly  10   a  may also include a trolley assembly  20  in addition to an idler assembly  22 . Optionally, a plurality of idler assemblies  22  may be employed, which may depend in part on the overall length of the rail assembly  10   a  and a load which it is expected to carry. A controller  24  is mounted on the track  14  in a manner that does not interfere with movement of the trolley assembly  20  and the idler assembly  22 . The controller  24 , in one embodiment, may be a well known integrated distributed controller that assists in controlling motion of the trolley assembly  20  and the idler assembly  22 . However, the system  10  is not limited to use only with integrated distributed controllers but rather may incorporate any other suitable form of controller capable of controlling the application of electrical power to the track  14 . 
         [0018]    The rail assembly  10   a  also include a first switch or sensor  26  and a second switch or sensor  28 . The first sensor  26  may also be viewed as a “clear” sensor because it senses the arrival of one of the trolley assemblies  20  as the trolley assembly moves along the track  14  of each rail assembly  10 . Clear sensor  26  indicates to the prior rail assembly (i.e., the rail system “upstream” of rail system  10   a ) that rail system  10   a  is clear to receive a trolley assembly  20 . The second sensor  28  may be viewed as a “stop” sensor because it senses the trolley assembly  20  and turns power off to rail assembly  10  to stop the trolley assembly  20 . Sensors  26  and  28  may be conventional proximity sensors or any other suitable form of sensor or switch. 
         [0019]    Referring further to  FIG. 2 , each rail assembly  10   a - 10   c  may also include a load bar  30  that supports a carrier  32  therefrom. The carrier  32  may be specifically adapted to hold one or more of a particular type of part. The load bar  30  may include conventional rubber bumpers  34  at opposing longitudinal ends thereof to cushion and protect the load bar. 
         [0020]    An important advantage of the system  10  is that the rail assemblies  10   a - 10   c  are modular in construction. By “modular” it is meant that each includes its own controller  24  and its own sensor  26  and  28 , in addition to all T-connectors that enable it to be quickly and efficiently coupled to the electrical cabling extending along the support beam  16 . By providing each track  14  with its own controller  24 , rather than including a separate controller on each trolley assembly  20 , a significant cost savings is realized without compromising the overall utility of the system  10 . The rail assemblies  10   a - 10   c  may be provided in any suitable length that will be dictated at least in part by the needs of the specific application. However, it is anticipated that the rail assemblies  10   a - 10   c , in many applications, will each have an overall length between about four to six meters. 
         [0021]    With brief reference to  FIG. 3  a simplified cross-sectional view of the trolley assembly  20  is shown. The trolley assembly  20  may be viewed as a “drive” trolley because it provides the motive force to propel the load bar  30  and the carrier  32  along the tracks  14  of the track assemblies  10   a - 10   c . The trolley assembly  20  may include a frame portion  36  that supports a gear motor  38  thereon. The gear motor  38  is powered by a suitable power signal applied along electrified buss bars that extend along the track  14  of each rail assembly  10   a - 10   c . An exemplary power signal may be a 480 VAC power signal, although signals of other magnitudes may also be used. The frame portion  36  also includes a brush plate  40  and a sensor flag  42 . The sensor flag  42  is used to trip the sensors  26  and  28  as the trolley assembly  20  moves along the track  14 . The brush plate  40  engages a plurality of electrified buss bars  44   a - 44   c , as well as a ground buss bar  44   d , that extend along the track  14 . Upper and lower wheels  46  and  48  rotationally supported from the frame portion  36  enable smooth rolling motion of the trolley assembly  20  along the track. With brief reference to  FIG. 2 , idler assembly  22  is a conventional component that includes a plurality of wheels supported from a frame portion  50  which enable rolling motion along the track  14 . The load bar  30  is fixedly secured to the frame portions  36  and  50  so that the trolley assembly  20 , the idler assembly  22 , the load bar  30  and the carrier  32  form a single assembly that is propelled along the track  14  of each rail assembly  10   a - 10   c  by the gear motor  38 . 
         [0022]    Referring briefly to  FIG. 4 , a high level electrical schematic diagram is shown of rail assemblies  10   a - 10   c . A controller, for example a programmable logic controller  54  (hereinafter simply the “logic controller”  54 ), applies control signals to a control signal buss  56  that may in turn provide the signals to the controller  24  on each track  14  to assist the controller  24  in turning on and off power to its high power buss bars. An auxiliary control power signal (e.g., a 120 VAC signal) may be applied on a power buss  58  to power the controllers  24  mounted on each track  14 . A high voltage, three phase power signal may be applied on a power buss  60  that communicates with buss bars  44   a - 44   c  (i.e., a three phase electrical signal using three buss bars for the three phases and one buss bar ( 44   d ) for ground) on the track  14 . The first and second sensors  26  and  28  of each track  14  are also electrically coupled to the controller  24  of their associated track  14 . T-couplings  62  and other plug in cables (not shown) are used as needed to make the required connections between the electrical cables and the controller  24  of each track  14 . 
         [0023]    With reference to  FIG. 5 , a sequence of operation of the system  10  will now be provided. For the purpose of discussion, the components including the trolley assembly  20 , the idler assembly  22 , the load bar  30  and the carrier  32  will be referred to collectively as the “carrier assembly”  64 . In operation, the carrier assembly  64  may initially be present on track  14   a  of rail assembly  10   a . The controller  24  on rail assembly  10 c may supply a signal to the logic controller  54  ( FIG. 3 ) indicating that track  14   b  is clear to accept carrier assembly  64 . The controller  24  on track  14   c  knows this because a carrier assembly moving from track  14   b  to  14   c  actuated the track  14   c  clear sensor  26  (i.e., sensing the presence of a carrier assembly). The logic controller  54  then applies a control signal to the controller  24   a  of track  14   a  and the controller  24   b  of track  14   b  instructing both controllers  24   a , 24   b  to apply power to their high power buss bars (e.g., buss bars  44   a - 44   c ). This simultaneously causes the controllers  24   a  and  24   b  to turn on power to their respective high power buss bars  44   a - 44   c . When this occurs, power is applied through the high power buss bars  44   a - 44   c  to gear motor  38  causing gear motor  38  to begin propelling the carrier assembly  64  in the direction of arrow  66 . The flag  42  mounted on the trolley assembly  20  will pass stop sensor  28  on track  14   a  which informs the controller  24   a  that the carrier assembly  64  is moving off of the track  14   a . The carrier assembly  64  will continue to travel to track  14   b . When the carrier assembly  64  passes the clear sensor  26  on track  14   b , then this information is sent to logic controller  54  which tells the controller  24   a  to turn off power to the high power buss bars  44   a - 44   c  on track  14   a  if there is no carrier assembly present on the prior (i.e., upstream) track. However, power at this time remains turned on to the high power buss bars  44   a - 44   c  of track  14   b  by controller  24   b , which continues to power the gear motor  38  along the track  14   b . When the flag  42  trips the stop sensor  28  on track  14   b , the controller  24   b  turns off the high power signal to its high power buss bars  44   a - 44   c , and the carrier assembly  64  will quickly coast to a stop within a predetermined distance after power is removed from the gear motor  38 . 
         [0024]    Preferably, the flag  42  is selected to have a physical length such that the carrier assembly  64  will come to a complete stop within the length of the flag  42 . When the clear sensor  26  on track  14   b  is tripped by the flag  42 , the controller  24   b  on track  14   b  will send a signal to the logic controller  54  on the control buss  56  ( FIG. 4 ). This signal indicates to the logic controller  54  that the carrier assembly  64  is presently located on its track  14   b  and that track  14   a  is clear to accept a carrier assembly  64 . The above sequence of operation then will be repeated but for rail assemblies  10   c  and  10   b . Thus, the logic controller  54  will send a signal to the controller  24   c  of rail assembly  10   c  and to the controller  24   b  of rail assembly  10   b  that the carrier assembly  64  may be moved onto rail assembly  10   c . The controller  24   b  will then apply power to its high power buss bars  44   a - 44   c  on track  14   b  while controller  24   c  applies power to its high power buss bars  44   a - 44   c  on track  14   c . The gear motor  38  will then propel the carrier assembly  64  from track  14   b  to track  14   c.    
         [0025]    From the foregoing it will be appreciated that the system  10  provides a highly cost efficient alternative to traditional electrified monorail assemblies that require the use of a dedicated controller on each carrier assembly. The present system  10  and method, because of its significantly lower cost and ease of installation, is expected to find utility in many applications where a traditional electrified monorail assembly would have been too costly to implement. Furthermore, since the system  10  is modular in its construction, the rail assemblies can easily be made to specific lengths to suit the particular needs of each application. 
         [0026]    While various embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the present disclosure. The examples illustrate the various embodiments and are not intended to limit the present disclosure. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.