Abstract:
A drive unit for imparting rotation to a drum assembly of a floor grinder. The drive unit includes a rotatable pulley positioned adjacent to and in contact with a rotatable drive surface of a driven pulley of the drum assembly and a drive surface of the drum assembly. The rotatable drive surface of the driven pulley is configured to impart rotation to the rotatable drive pulley during rotation of the rotatable drive surface, and the rotatable drive pulley is configured to impart rotation thereof to the drum assembly

Description:
FIELD 
       [0001]    This present disclosure relates to orbital surface treatment equipment. More particularly, the disclosure relates to a drive system for equipment for polishing, grinding, or otherwise treating stone and masonry flooring surfaces. 
       BACKGROUND 
       [0002]    Orbital floor grinders typically include an electric motor having an output shaft that extends through a drum assembly. The output shaft drives a belt that drives a plurality of treatment disks that contact the flooring surface. To improve handling of the machine and the treatment effects to the flooring, the orbital machine is typically configured to counter-rotate the drum housing relative to the direction of rotation of at least some of the treatment disks. 
         [0003]    The present disclosure relates to an improved configuration for rotating the drum assembly that avoids the need for a separate traveling belt for rotating the drum assembly. 
       SUMMARY 
       [0004]    The disclosure advantageously provides a floor grinder having a rotatable drum assembly. 
         [0005]    In one aspect, the grinder includes a drum assembly having a driven pulley having a rotatable drive surface; a drive surface operatively associated with the drum assembly; and a drive unit for imparting rotation to the drum assembly. 
         [0006]    The drive unit includes a rotatable pulley positioned adjacent to and in contact with the rotatable drive surface of the driven pulley of the drum assembly and the drive surface of the drum assembly. The rotatable drive surface of the driven pulley is configured to impart rotation to the rotatable drive pulley during rotation of the rotatable drive surface. The rotatable drive pulley is configured to impart rotation thereof to the drum assembly. 
         [0007]    In another embodiment, the grinder includes a motor having a rotatable output shaft and a drum assembly. The drum assembly includes a drive pulley connected to the output shaft of the motor, a driven pulley, and a traveling belt travelable around the output shaft and the driven pulley and configured to have a direction of travel imparted to it by the output shaft during operation of the motor to rotate the output shaft. The driven pulley has a shaft extending above an exterior portion of the drum assembly to provide a rotatable drive surface. 
         [0008]    The grinder further includes a motor mount connected to the motor; a bearing between the motor mount and the drum assembly to enable the drum assembly to rotate relative to the motor; a drive surface operatively associated with the drum assembly; and a drive unit for imparting rotation to the drum assembly. The drive unit includes a rotatable pulley positioned adjacent to and in contact with the rotatable drive surface of the driven pulley of the drum assembly and the drive surface of the drum assembly. The rotatable drive surface of the driven pulley is configured to impart rotation to the rotatable drive pulley during rotation of the rotatable drive surface, and the rotatable drive pulley is configured to impart rotation thereof to the drum assembly. 
         [0009]    During operation of the motor, the output shaft rotates to travel the traveling belt and impart rotation to the driven pulley and the drive surface. The drive surface imparts rotation to the drive pulley, which imparts rotation to the drum assembly. 
         [0010]    In yet another embodiment, the grinder includes a motor having a rotatable output shaft and a drum assembly. The drum assembly includes a drive pulley connected to the output shaft of the motor, at least two driven pulleys, and a traveling belt travelable around the output shaft and the two driven pulleys and configured to have a direction of travel imparted to it by the output shaft during operation of the motor to rotate the output shaft. The traveling belt is arranged to impart travel to one of the driven pulleys in a direction corresponding to the direction of travel imparted to the traveling belt and to impart travel to the other one of the driven pulleys in a direction of travel opposite to the direction of travel imparted to the traveling belt, one of the driven pulleys having a shaft extending above an exterior portion of the drum assembly to provide a rotatable drive surface. 
         [0011]    The grinder also includes a motor mount connected to the motor; a bearing between the motor mount and the drum assembly to enable the drum assembly to rotate relative to the motor; a drive surface operatively associated with the drum assembly; and a drive unit for imparting rotation to the drum assembly. The drive unit includes a rotatable pulley positioned adjacent to and in contact with the rotatable drive surface of the driven pulley of the drum assembly and the drive surface of the drum assembly. The rotatable drive surface of the driven pulley is configured to impart rotation to the rotatable drive pulley during rotation of the rotatable drive surface, and the rotatable drive pulley is configured to impart rotation thereof to the drum assembly. 
         [0012]    During operation of the motor, the output shaft rotates to travel the traveling belt and impart rotation to the two driven pulleys and the drive surface. The drive surface imparts rotation to the drive pulley, which imparts rotation to the drum assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Further advantages of the disclosure are apparent by reference to the detailed description in conjunction with the figures, wherein elements are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein: 
           [0014]      FIGS. 1 and 2  show a grinder according to the disclosure. 
           [0015]      FIGS. 3 and 4  are partially exploded views of the grinder of  FIGS. 1 and 2 . 
           [0016]      FIG. 5  is a lower perspective view of a drum assembly of the grinder of  FIGS. 1 and 2 . 
           [0017]      FIG. 6  is an exploded view of the drum assembly of  FIG. 5 . 
           [0018]      FIG. 7  is a partially exploded view of the drum assembly of  FIG. 5 . 
           [0019]      FIGS. 8 and 9  show a drum drive assembly of the grinder of  FIGS. 1 and 2 . 
           [0020]      FIGS. 10 and 11  are partially exploded views of the drum drive assembly of  FIGS. 8 and 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    With reference to the drawings, the disclosure relates to a grinder  10  having a motor  12  mounted by a motor mount  12   a  onto a drum assembly  14 , with one or more drive units  16  located on the exterior of the drum assembly  14  for rotation of the drum assembly  14 . A bearing assembly  18  interfaces between the motor mount  12   a  and the drum assembly  14  to enable the drum assembly  14  to rotate relative to the motor  12 . The grinder  10  may be integrated with a frame or the like having handles and controls for facilitating operation of the grinder  10 . 
         [0022]    The motor  12  is typically an electric motor. The motor  12  may have various motor power ratings, typically ranging between about 5 and 25 horsepower. The motor  12  is fixedly mounted to the motor mount  12   a,  and the motor mount  12   a  is rotatably mounted to the drum assembly  14  by the bearing  18 . The motor  12  includes an output shaft  12   b  that is preferably driven at a variable rotary speed of from about 350 to about 1,400 revolutions per minute. 
         [0023]    The drum assembly  14  includes a top plate  20  and circumferential sidewall  20   a,  a drive pulley  22 , a drive belt  24 , a plurality of idler pulleys  26   a - 26   c,  a plurality of driven pulleys  28   a - 28   d,  a bottom plate  30 , and plurality of driven disks  32   a - 32   d.  A belt tensioner  34  is mounted to the underside of the top plate  20  to desirably adjust the tension of the drive belt  24 . 
         [0024]    The motor  12  is mounted to the exterior of the top plate  20  by the motor mount  12   a.  The output shaft  12   b  of the motor  12  extends into the drum assembly  14  via an aperture  36  centrally located on the top plate  20 . The drive pulley  22  operatively engages the output shaft  12   b  of the motor  12  so as to rotate corresponding to the rotation of the output shaft  12   b.  The drive belt  24  travels around the idler pulleys  26   a - 26   c  and the driven pulleys  28   a - 28   d  and transfers rotation of the drive pulley to the driven pulleys  28   a - 28   d.  Together, the idler pulleys  26   a - 26   c  and the belt tensioner  34  serve to provide desired tension of the drive belt  24  and contact of the drive belt  24  with the driven pulleys  28   a - 28   d.  The drive belt  24  is the only traveling belt utilized on the grinder  10 . 
         [0025]    With reference to  FIG. 5 , it will be observed that the drive belt  24  is arranged to contact the driven pulleys  28   a  and  28   d  such that the driven pulleys  28   a  and  28   c  each rotate in the same direction and opposite to the direction of travel of the drive belt  24 , and the driven pulleys  28   b  and  28   d  each rotate in the same direction and in the same direction of travel of the drive belt  24 . Thus, if the drive belt  24  travels counter-clockwise, the driven pulleys  28   a  and  28   c  each rotate clockwise and the driven pulleys  28   b  and  28   d  each rotate counter-clockwise. 
         [0026]    The driven pulleys  28   a - 28   d  each include a downwardly extending shaft  38  that extends from the bottom of each of the driven pulleys  28   a - 28   d  and passes through a corresponding aperture  40  of the bottom plate  30 . The driven disks  34   a - 34   d  directly connect to the shafts  38  of the driven pulleys  28   a - 28   d  adjacent the exterior surface of the bottom plate  30 , and rotate with the driven pulleys  28   a - 28   d.  Various work pieces, such as grinding disks and the like, may be connected to the driven disks  34   a - 34   d  for treating a flooring surface. Two of the driven pulleys, such as the driven pulleys  28   a  and  28   c  located opposite of one another, include upwardly extending shafts  42  that extend upwardly from the driven pulleys and extend through apertures  44  of the top plate. 
         [0027]    With additional reference to  FIGS. 8-11 , the drive units  16  connect to and are driven by the upwardly extending shafts  42  of the driven pulleys  28   a  and  28   c.  In this regard, a gear pulley  46  is located on the shafts  46  to provide a rotary drive surface. Alternatively, the shaft  42  itself could provide the drive surface, or the shaft could be coated with rubber or the like to provide a drive surface. As described herein, the gear pulley  46  provides the drive surface. Each drive unit  16  includes an anchor plate  50  that mounts to the top plate  20  of the drum assembly  14 . The anchor plate  50  is connected by a spring loaded yoke system  52  to a pulley mount  54 . The drive units  16  are mounted onto the drum assembly  14  to drive the drum assembly in a direction opposite that of the rotation of the driven disks  32   a - 32   d.    
         [0028]    The anchor plate  50  may be an L-shaped metal plate having an aperture  50   a  in for mounting of the anchor plate  50  to the top plate  20  as by use of a fastener. An upstanding portion of the anchor plate includes an aperture  50   b  for mounting of the yoke system  52  to the anchor plate  50 . 
         [0029]    The yoke system  52  includes a yoke end  56  having a pair of arms  56   a  and  56   b  with aligned apertures for mounting of the yoke end  56  onto the pulley mount  54 . To enable some controlled lateral relative movement, a threaded bolt  58  adjustably connects to the yoke end  56  and a compression spring  60  is located on the bolt  58  opposite the yoke end  56  to bear against the anchor plate  50 . A compression spring  62  interfaces between the yoke end  56  and the pulley mount  54  for enabling controlled vertical movement of the pulley mount  54  relative to the yoke system  52 . 
         [0030]    The pulley mount  54  includes a frame  64  having an aperture  66  configured to receive the gear pulley  46  and configured to permit rotation of the gear pulley  46  as driven by the driven pulley  28   a  or  28   c.  The frame  64  is also configured to rotatably mount, preferably utilizing bearings or the like, a gear pulley  68  adjacent to and in frictional contact with the gear pulley  46  for being driven by the gear pulley  46 . In this regard, the gear pulley  46  and the gear pulley  68  may include surfaces configured to encourage frictional interaction, such as including rubberized surfaces and/or cooperating ridges  46   a  and  68   a,  respectively. The ridges  46   a  and  68   a  are shown partly around the circumference, it being understood that they may preferably extend around the circumference. As will be understood, the gear pulley  46  rotating in a first direction, such as clockwise, will impart a rotation to the gear pulley  68  in a second, opposite direction, such as counter-clockwise. 
         [0031]    The anchor plate  50 , yoke system  52 , and the pulley mount  54  cooperate to rotatably position the gear pulley  68  in contact with a circumferential surface  70  of the motor mount  12   a.  The circumferential surface  70  is preferably coated with a rubber or like material to frictionally engage the gear pulley, yet enable some slippage if substantial counter-rotational forces are encountered. Alternatively, a replaceable fixed (non-traveling) belt or band or sleeve or the like may be located around the circumferential surface  70  to contact the gear pulley  68 . 
         [0032]    In operation of the grinder  10 , it will be understood that rotation of the output shaft  12   b  is transferred by the drive pulley  22  to cause the drive belt  24  to travel and transfer rotation to the driven pulleys  28   a - 28   d,  causing rotation of the driven disks  34   a - 34   d  in a first direction, such as clockwise. The clockwise rotation of the driven pulleys  28   a  and  28   c  provides clockwise rotation of the gear pulleys  46  mounted thereon, which transfers an opposite rotation of the gear pulleys  68 . Thus, for example, clockwise rotation of the driven pulleys  28   a  and  28   c  provides clockwise rotation to the gear pulleys  46 . The clockwise rotation of the gear pulleys  46  imparts opposite or counterclockwise rotation to the gear pulleys  68 . The gear pulleys  68  contact the circumferential surface  70  of the motor mount  12   b,  imparting an opposite, clockwise motion to the drum assembly  14 . 
         [0033]    Accordingly, in operation, rotation of the output shaft  12   a  of the motor  12  is transferred by the traveling drive belt  24 . The drive belt  24  transfers its rotation to the driven pulleys  28   a - 28   d  to cause the driven pulleys  28   a  and  28   c  to rotate opposite of the direction of travel of the belt  24 , and the cause the driven pulleys  28   b  and  28   d  to rotate in the same direction of travel as the drive belt  24 . The rotation of the driven pulleys  28   a  and  28   c  rotates the gear pulleys  46  mounted thereto. The gear pulleys  46  contact the gear pulleys  68  of the drive units  16  to cause the gear pulleys  68  to rotate opposite of the driven pulleys  28   a  and  28   c.  The gear pulleys  68  contact the circumferential surface  70  of the motor mount  12   a  to cause the drum assembly  14  to rotate opposite the direction of rotation of the gear pulleys  68  and in the same direction as the driven pulleys  28   a  and  28   c.  The driven pulleys  28   b  and  28   d  rotate opposite of the drum assembly  14  and the driven pulleys  28   a  and  28   c.    
         [0034]    The foregoing description of preferred embodiments for this disclosure have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the disclosure and its practical application, and to thereby enable one of ordinary skill in the art to utilize the disclosure in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the disclosure as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.