Abstract:
A motor mounting configuration for a roll out table reduces bearing wear and allows the motor of the roll out table to be quickly removed and reinstalled. A method for retrofitting a roll out table with a motor mount configuration that allows the motor to be quickly removed and reinstalled includes the use of a hold down element. In addition, the retrofit roll out table includes a bearing configuration designed to better withstand the harsh operating environment of the roll out table. Further, the improved roll out table includes a coupling between the motor and the roller shaft that allows for adjustability.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority from U.S. Provisional Patent Application Serial No. 60/280,881 filed Apr. 2, 2001; the disclosures of which are incorporated herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Technical Field  
           [0003]    This invention generally relates to motor mounting configurations and methods for mounting motors at roll out tables. More particularly, the invention relates to a motor mounting configuration for a roll out table in a steel making facility that allows the motor to be quickly and easily installed and removed. The invention also relates to a method for retrofitting a roll out table with a new motor mounting configuration.  
           [0004]    2. Background Information  
           [0005]    Powered roll out tables such as the ones used to move steel in steel making facilities include rollers that carry and move the steel and motors that power the roller. The roll out tables are used in steel making facilities in relatively harsh environments such as where hot steel is cooled by water. In this situation, the hot steel member is being moved down the roll out table while cooling water is being poured over the hot steel. The elements of the roll out table are thus constantly exposed to water and heat that causes the parts to wear and rust relatively quickly. Specifically, the bearings that support the rollers of the roll out tables frequently fail causing undesirable down time. To replace the bearings, the maintenance workers must uncouple the motor and typically have the motor replaced or serviced while the motor is disconnected. In addition to the cost of maintaining or replacing the motor and maintaining or replacing the bearings, the disassembly process commonly takes up to three maintenance workers working for at least a few hours to change a motor. In a steel mill, the roll out tables may have hundreds of rollers with at least one of the hundreds of rollers needing maintenance each week. The owners of the roll out tables desire to decrease the frequency of the maintenance and desire to reduce the man hours required to change a roller and a motor.  
           [0006]    When roll out tables are assembled, the nuts and bolts used to mount the motors and used to hold the bearings in place are welded together so that maintenance workers must cut away the welds and cut the nuts from the bolts to disassemble the units. All of these connectors must be replaced and rewelded when the motor and bearings are reinstalled. The welding and cutting processes are not desirable because of the working environment and because of accessibility problems for the cutter and the welder. The art desires a mounting configuration that does not require the connectors to be welded and then cut apart.  
           [0007]    One attempted solution in the art has been to install grease pumps that constantly supply grease to the bearings. The supply of grease was believed to keep water and dirt out of the bearings and to increase bearing life in order to decrease maintenance. This solution has been unsatisfactory and may result in damaged seals. In addition, the cost of installing the grease pumps and grease lines is undesirable.  
         BRIEF SUMMARY OF THE INVENTION  
         [0008]    The invention generally provides an improved motor mounting configuration. The invention provides a motor mounting configuration for a roll out table that reduces bearing wear and allows the motor of the roll out table to be quickly removed and reinstalled. The invention also provides a method for retrofitting a roll out table with a motor mount configuration that allows the motor to be quickly removed and reinstalled. In addition, the retrofit roll out table includes a bearing configuration designed to better withstand the harsh operating environment of the roll out table. Further, the improved roll out table includes a coupling between the motor and the roller shaft that allows for adjustability.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a top plan view of a bank of roll out tables showing a piece of steel being moved by the rollers.  
         [0010]    [0010]FIG. 2 is a top plan view, with the middle portion broken away, of a single roll out table having two rollers and two motors.  
         [0011]    [0011]FIG. 3 is a side view of FIG. 2.  
         [0012]    [0012]FIG. 4 is an end view of FIG. 2.  
         [0013]    [0013]FIG. 5 is a view similar to FIG. 2 with the motors removed.  
         [0014]    [0014]FIG. 6 is a side view of FIG. 5.  
         [0015]    [0015]FIG. 7 is an end view of FIG. 5.  
         [0016]    [0016]FIG. 8 is a side view of a motor showing the intermediate portion of the motor coupling removed.  
         [0017]    [0017]FIG. 9 is an end view taken along line  9 - 9  of FIG. 8.  
         [0018]    [0018]FIG. 10 is a sectional view taken through the motor coupling when the intermediate portion of the motor coupling is installed.  
         [0019]    [0019]FIG. 11 is a view showing the motor being installed onto the roll out table.  
         [0020]    [0020]FIG. 12 is a view similar to FIG. 11 showing the motor in the installed position.  
         [0021]    [0021]FIG. 13 is an enlarged view of the encircled portion of FIG. 12.  
         [0022]    [0022]FIG. 14 is a top plan view of the motor coupling and the bearing assembly.  
         [0023]    [0023]FIG. 15 is a section view taken along line  15 - 15  of FIG. 14.  
         [0024]    [0024]FIG. 16 is an end view showing the first motor installed on the roll out table.  
         [0025]    [0025]FIG. 17 is an enlarged view of the encircled portion of FIG. 16.  
         [0026]    [0026]FIG. 18 is an enlarged view of the encircled portion of FIG. 16.  
         [0027]    [0027]FIG. 19 is a view similar to FIG. 16 showing an alternative embodiment of the invention wherein a yoke is used to hold the motors in place.  
         [0028]    [0028]FIG. 20 is a section view taken along line  20 - 20  of FIG. 19.  
         [0029]    [0029]FIG. 21 is a view similar to FIG. 19 showing a second alternative embodiment of the invention.  
         [0030]    [0030]FIG. 22 is a section view taken along line  22 - 22  of FIG. 21.  
         [0031]    [0031]FIG. 23 is a side view of the roll out table showing a shield installed over the motor coupling.  
         [0032]    [0032]FIG. 24 is a section view taken along line  24 - 24  of FIG. 23. 
     
    
       [0033]    Similar numbers refer to similar part throughout the specification.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0034]    [0034]FIG. 1 depicts a bank  2  of roll out tables  4  used to transport items such as steel  6  out of a furnace  8  so that the hot steel  6  may be cooled. In a hot mill process, water  10  is poured over the hot steel while the steel is being moved by the roll out tables  2 . In a cold mill process, the hot steel is air cooled while it is being rolled out by tables  2 .  
         [0035]    Each table  4  of bank  2  includes a base  12  that carries at least one roller  14  and at least one motor  16  that drives roller  14 . In the embodiment of the invention depicted in the drawings, each table  4  includes two spaced apart, substantially parallel rollers  14  and a motor  16  for each roller  14 . An air knife  18  may be disposed between rollers  14  to blow water away from rollers  14  and to remove debris from tables  4 .  
         [0036]    Each roller  14  is rotatably supported on base  12  by a pair of bearing assemblies  20 . Each bearing assembly  20  is supported from below by a seat  22  defined by a lower roller support  24  that extends up from the bottom plate  26  of base  12  at both ends of roller  14 . Seat  22  may be curved to match the outer curvature of bearing assembly  20 . In other embodiments, seat  22  is not curved and in further embodiments, the outer surface of bearing assemblies is not curved. An upper roller support  28  is bolted over bearing assemblies  20  to lock rollers  14  in place with respect to base  12 . Lower roller support  24  may include a shoulder  30  that abuts an inner shoulder  32  defined by bearing assembly  20 . Bearing assembly  20  also defines an outer shoulder  34  that abuts the outer edge of the lower roller support  24 . Upper roller support  28  fits between shoulders  32  and  34  to prevent bearing assembly  20  from moving toward or away from motor  16 .  
         [0037]    Each bearing assembly  20  includes a plurality of bearings  40  that ride between inner  42  and outer  44  bearing races. Inner bearing race  42  rides on the shaft  46  of roller  14  abutting a first shoulder  48  on shaft  46 . Inner bearing race  42  is held against shoulder  48  by a sleeve  50  that may be keyed to shaft  46 .  
         [0038]    Outer bearing race  44  is sandwiched between inner  52  and outer  54  housing members of bearing assembly  20 . Bolts  56  hold members  52  and  54  together. Bearing assembly  20  further includes seals  58  or bearing isolators that prevent water from entering assembly  20  and prevent grease from exiting assembly  20 . One type of seal or bearing isolator  58  that may be used in the invention is a bearing isolator sold under the name ProTech™ sold by J M Clipper of Nacogdoches, Tex.  
         [0039]    Slingers  60  are disposed axially outside seals  58  to help sling water and debris away from bearing assembly  20  when rollers  14  are rotating and water is being dumped over table  4 .  
         [0040]    Each motor  16  is connected to roller  14  by a coupling  70  that provides a range of adjustability so that motor  16  does not have to be perfectly mounted with respect to roller  14 . Coupling  70  includes an inner member  72  connected to shaft  46 , an outer member  74  connected to motor  16 , and an intermediate member  76  disposed between inner member  72  and outer member  74 . This type of coupling  70  may be obtained from Dodge Manufacturing Corporation of Indiana or Reliance Electric Industrial Company of Cleveland, Ohio. Other couplings  70  may also be used without departing from the concepts of the present invention. Coupling  70  shown in the drawings has the advantage that it can withstand the harsh operating environment where tables  4  are located while allowing the position of motor  16  to be slightly adjustable with respect to roller  14 . Coupling  70  also permits motor  70  to be slid into position as described below. In the past, the shaft of motor  16  included a flange that was bolted directly to a flange connected to shaft  46 . The bolts between motor  16  and shaft  14  were typically welded together so that the connector could not be adjusted and a disassembly was difficult.  
         [0041]    Each motor  16  includes a motor base  80  configured to be received on a portion of base  12  of table  4 . Each motor base  80  defines at least two openings  82  (FIGS. 8 and 13) configured to be slid over retaining studs  84  projecting up from base  12 . Studs  84  are positioned so that motor  16  will be aligned with roller  14  and spaced from roller  14  so that coupling  70  will properly fit between roller  14  and motor  16  when studs  84  are received in openings  82 . In the embodiment of the invention depicted in the drawings, two studs  84  are used to position motor  16 . In other embodiments, different stud configurations and numbers may be used without departing from the concepts of the present invention. The tolerance between the outer diameter of stud  84  and the inner diameter of opening  82  is designed to allow coupling  70  to properly function. In the embodiment depicted in the drawings, studs  84  are located at the back corners of motor  16  farthest from rollers  14  and farthest from coupling  70 . Each stud  84  projects upwardly from a mounting pad  86  connected to base  12 . Each pad  86  includes a stop  88  on the end of pad  86  facing roller  14 . Stop  88  is configured to abut with the front end of base  80  of motor  16  and properly position openings  82  with respect to studs  84 . Each pad  86  further includes an edge stop  90  configured to abut the edge of base  80  to longitudinally position base  80  of motor  16 .  
         [0042]    Base  12  includes a rib  92  extending longitudinally between motor  16 . Base  12  further defines three strap openings  94  configured to receive a hold down device in the form of a strap  96  that holds motors  16  in place. Each opening  94  is defined by a tab  98  or rod  98  connected to base  12  or integrally formed therewith.  
         [0043]    The length of each strap  96  is adjustable so that strap  96  may be tightened around motors  16 . In one embodiment, strap  96  includes a ratchet  100  configured to adjust the length of strap  96 . Strap  96  may also include hooks  102  configured to connect with tabs  98 . The members of strap  96  are preferably inextensible materials and fabricated from materials designed to withstand the harsh operating environment of table  4 . In the embodiment of the invention depicted in the drawings, one strap  96  retains two motors  16  by being connected to tab  98  on the left motor  16  as shown in FIG. 2, under middle tab  98 , over the right motor  16 , and connected back to the right tab  98 .  
         [0044]    The installation of motor  16  and coupling  70  is depicted in FIGS.  5 - 18 . In FIG. 5, rollers  14  are installed with bearing assemblies  20 . Bearing assemblies  20  may have already been taken apart and cleaned or replaced. Coupling member  72  has been attached to shaft  46  and rollers  14  are ready to receive motors  16 . Intermediate coupling element  76  is placed into coupling element  74  as depicted in FIGS.  8 - 10 . Motor  16  may then be lifted with a crane by a single user and brought into alignment with roller  14  as depicted in FIG. 11. The front of motor  16  is tilted down so that intermediate coupling element  76  may be pivoted into coupling element  72 . Once coupling elements  76  and  72  are aligned, the user moves motor  16  toward coupling element  72  as indicated by the arrow shown in FIG. 11. The front edge of base  80  will eventually slide along pads  86  until it contacts stops  88 . As base  80  slides along pads  86 , the upper surface of studs  84  will contact the lower surface of base  80  until they align with openings  82 . Base  80  will then drop down over studs  84  and motor  16  is properly positioned with respect to roller  14 . This position is depicted in FIGS. 12 and 14. Once the user has installed one motor  16 , the user positions strap  96  over the first motor  16  and through opening  94  defined by tab  98  between the motor mounts as depicted in FIG. 16. The free end of strap  96  is then moved out of the way so that the second motor  16  may be mounted. The second motor is mounted in the same fashion and strap  96  is wrapped over the second motor and tightened with ratchet  100  so that motors  16  cannot move upwardly away from base  12 . The combination of strap  96  and studs  84  prevent motor  16  from moving out of position during operation of roll out table  4 . The overall mounting process can be performed by a single user operating a small crane and can be performed in a few minutes. Motor  16  may be dismounted by reversing the process.  
         [0045]    An existing roll out table may be retrofit for motor installation in this manner by disassembling the elements from the table and installing studs  84  at appropriate locations. Base  80  of motor  16  must be provided with openings  82  to snugly fit over studs  84  to properly position motor  16  with respect to rollers  14 . Coupling  70  is installed and bearing assemblies  20  are built for rollers  14 . The retrofit allows motor  16  to be quickly and easily removed and replaced. The retrofit also increases the life of the bearings because of the new configuration for bearing assemblies  20 . With the retrofit configuration, the grease pumps can be eliminated and the long man hours required to remove and install motors can be eliminated. Significant benefit to this configuration is that the connections between the motor and the base and the motor and the roller do not have to be welded and cut apart as in the past.  
         [0046]    In FIGS. 23 and 24, a shield  110  is positioned over coupling  70  to guard coupling  70  against the water being poured on table  4 . Shield  110  may extend out from upper roller supports  28  and may be supported in a space location from couplings  70 . Such shields have not been used in the past. Shield  110  will prevent a majority of water and debris from entering coupling  70  and will prevent water and debris from engaging one side of bearing assembly  20 .  
         [0047]    A first alternative embodiment of the invention is depicted in FIGS. 19 and 20. In this embodiment, strap  96  is not used and a hold down device in the form of a yoke  120  is positioned above each motor  16  to hold motors  16  in place. Yoke  120  is clamped down onto motors  16  by a threaded rod  122  that threadedly engages a block  124 . Block  124  is connected to base  12  by appropriate connectors such as cables  126 . Yoke  120  is thus pushed down against motor  16  when threaded rod  122  is rotated with respect to block  124 . Such rotation creates tension in cables  126  and pushes the foot  128  of threaded rod  122  down against yoke  120 .  
         [0048]    A second alternative embodiment of the invention is depicted in FIGS. 21 and 22 wherein the hold down device is in the form of a yoke  120  that is clamped down onto motors  16  by a rod  140  that is pivoted at one end by a first pivot  142  and is threadably connected by a turn buckle  144  at its other end. FIG. 22 shows the locked position of yoke  120 . Motor  16  may be clamped more securely by tightening turn buckle  144 . Yoke  120  may be removed by loosening turn buckle  144  and pivoting rod  140  upwardly away from motors  16 .  
         [0049]    In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.  
         [0050]    Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.