Abstract:
Disclosed within is a fist bracket comprising a base and a circumferential portion extending from the base in which the circumferential portion comprises an outer surface and an inner surface and the outer surface comprises a curved section and a planar section. Also disclosed within is a combination of a motor mount bracket and fist bracket comprising a fist bracket with a base and a circumferential portion extending from the base. The circumferential portion includes an outer surface and an inner surface and the outer surface comprises a curved section and a planar section. The combination further includes a bushing disposed within the circumferential portion of the fist bracket.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a divisional application of U.S. patent application Ser. No. 10/103,960, filed Mar. 22, 2002 now U.S. Pat. No. 6,827,223 and entitled “Vibratory Screening Machine With Single Motor Mounted to Produce Linear Motion”, which is hereby incorporated herein by reference. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not Applicable 

   BACKGROUND OF THE INVENTION 
   The present invention relates to an improved vibratory screening machine which will produce linear motion with only a single vibratory motor which is mounted thereon by unique mounting structure and to components of the unique motor mounting structure. 
   By way of background, in vibratory screening machines two vibratory motors are utilized in tandem to produce desired linear motion for effecting the vibratory screening operation. As is well known in the art, the two motors are rigidly secured to the resiliently mounted inner frame of the vibratory screening machine. These two motors are operated in opposite directions to thereby produce linear motion for conveying the material which is being screened. Insofar as known, a single motor mounted on a vibratory screening machine always produced orbital motion and was incapable of producing linear motion. 
   BRIEF SUMMARY OF THE INVENTION 
   It is accordingly one object of the present invention to provide an improved vibratory screening machine utilizing only a single vibratory motor which is capable of producing linear motion of the screen-carrying inner frame of the machine. 
   Another object of the present invention is to provide a combined fist bracket and motor mounting bracket structure for mounting a single vibratory motor to provide linear motion. 
   A further object of the present invention is to provide an improved fist bracket structure for use in a vibratory screening machine mounting a single motor to produce linear motion. 
   Still another object of the present invention is to provide an improved motor mount bracket for use in a vibratory screening machine mounting a single motor to produce linear motion. Other objects and attendant advantages of the present invention will be readily perceived hereafter. 
   The present invention relates to a vibratory screening machine comprising an outer frame, an inner frame resiliently mounted on said outer frame, a single vibratory motor having a center of rotation and first and second opposite ends, first and second motor mount structures mounting said first and second opposite ends, respectively, on said inner frame, first and second directionally stiff resilient bushings in said first and second motor mount structures, respectively, and said center of rotation of said vibratory motor being substantially aligned with the direction of said directional stiffness of said first and second resilient bushings. 
   The present invention also relates to a vibratory screening machine comprising an outer frame, an inner frame having first and second inner frame sides, resilient mounts mounting said inner frame on said outer frame, a single vibratory motor having first and second motor ends, and first and second motor mounting assemblies mounting each of said first and second motor ends, respectively, on said first and second inner frame sides, respectively, said first and second motor mounting assemblies including first and second fist brackets, respectively, bolted to said first and second inner frame sides, respectively, first and second directionally stiff resilient bushings mounted within said first and second fist brackets, respectively, said first and second directionally stiff resilient bushings being inclined with their stiffness attitudes oriented in the conveyance direction of said inner frame, first and second motor mount brackets mounted on said first and second directionally stiff resilient bushings, respectively, and said first and second motor mount brackets mounting said first and second motor ends, respectively. 
   The present invention also relates to a motor mount bracket and fist bracket combination comprising a fist bracket, a fist bracket base on said fist bracket, a housing on said fist bracket base, a housing wall on said housing, a thinner portion on said housing wall adjacent to a thicker portion of said housing wall, a bushing in said housing wall, a bushing housing on said bushing, a metal block having opposite ends extending outwardly from said housing, resilient members between said bushing housing and said metal block; and a motor mount bracket secured to said fist bracket, a motor mount bracket base on said motor mount bracket, inner and outer sides on said motor mount bracket base, and a pair of substantially parallel sides extending from said motor mount bracket base with each side bolted to one of said ends of said metal block. 
   The present invention also relates to a fist bracket comprising a base, a housing on said base, a housing wall on said housing, and a thinner portion on said housing wall located between two thicker portions of said housing wall. 
   The present invention also relates to a motor mount bracket comprising a base, an inner and outer side on said base, a pair of substantially parallel sides extending from said base, said inner side of said base being located within said sides, and a plurality of ribs on said inner side. 
   The various aspects of the present invention will be more fully understood when the following portions of the specification are read in conjunction with the accompanying drawings wherein: 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       FIG. 1  is a side elevational view of the vibratory screening machine mounting the unique motor mounting structure of the present invention which will cause a single vibratory motor to produce linear motion; 
       FIG. 2  is an end elevational view taken substantially in the direction of arrows  2 - 2  of  FIG. 1 ; 
       FIG. 2   a  is a fragmentary cross sectional schematic view of the structure for resiliently mounting the inner frame of the vibratory screening machine on the outer frame; 
       FIG. 3  is an enlarged fragmentary partially broken away side elevational view of the unique motor mount structure of the present invention mounting the vibratory motor onto the inner frame of the vibratory screening machine; 
       FIG. 4  is a fragmentary enlarged side elevational view of the improved motor mount structure; 
       FIG. 5  is an end elevational view of the improved motor mount structure taken substantially in the direction of arrows  5 - 5  of  FIG. 4 ; 
       FIG. 6  is a perspective view of the fist bracket showing the open side thereof; 
       FIG. 7  is a perspective view of the fist bracket showing the thinned circumferential side; 
       FIG. 8  is a side elevational view of the fist bracket; 
       FIG. 9  is a perspective view of the motor mount bracket; 
       FIG. 10  is a side elevational view of the motor mount bracket; 
       FIG. 11  is a view of the motor mount bracket taken substantially in the direction of  11 - 11  of  FIG. 10 ; 
       FIG. 12  is an end elevational view showing the resilient bushing construction which fits into the fist bracket and also showing schematically the alignment of the center of the vibratory motor with the center of the bushing and with the centers of aligned resilient members of the bushing; and 
       FIG. 13  is a side elevational view of the resilient bushing of  FIG. 12 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The improved vibratory screening machine  10  of the present invention includes an outer stationary frame  11  mounting an inner movable frame  12  by means of a plurality of resilient mounts  13  extending between a plurality of sites between the inner and outer frames, as is well known in the art. Relative to each resilient mount  13  ( FIG. 2A ), two bolts  14  extend through bores, not numbered, in side plate  15  of the outer frame and thread into a metal plate  17  which is bonded to one side of the resilient cylindrical member  16 , and two bolts  19  extend through bores in an associated side plate  20  of movable frame  12  and are received in threaded bores of plate  21  bonded to resilient cylindrical member  16 . The foregoing structure is conventional in the art. As can be seen from  FIG. 2 , the resilient mounts  13  are positioned between opposite sides of the movable frame  12  and the fixed frame  11 . Also,  FIG. 1  shows four resilient mounts  13  on one side of the vibratory screening machine, and there are four resilient mounts on the opposite side. As is well known in the art, the inner movable frame has a bed  18  on which vibratory screens are removably mounted. 
   In accordance with the present invention, a single motor  22  is mounted on rails  23  of inner frame  12  by unique mounting structure to provide the desired linear vibratory motion thereto. In the foregoing respect, a fist bracket  24  ( FIGS. 3 ,  6 ,  7 ,  8 ) includes a base  25  having spaced bores  27  therein which receive bolts  29  which secure each fist bracket  24  to a rail  23  of inner frame  12 . Except for the cutaway portion  59  of fist bracket housing  36 , the fist bracket is a prior art product, but insofar as known was never previously used as part of a structure for mounting a vibratory motor of a vibratory screening machine. 
   A bushing  30  ( FIGS. 12 and 13 ) is mounted within fist bracket  24 , and it includes an outer substantially cylindrical metal housing  31  having keyways  32  therein, and a key  33  ( FIG. 12 ) extends into the lowermost keyway  32  of the bushing housing  36  and the keyway  34  ( FIG. 6 ) in fist bracket housing  36  to orient the bushing housing  31  within the fist bracket housing  36 . Two bolts  35  extend through openings  37  in upper portion  39  of fist bracket housing  36  and are threadably received in threaded bores  38  of the fist bracket housing. When the bushing  30  is properly positioned within fist bracket housing  36  and the bolts  35  are tightened, the bushing will be securely clamped in position. 
   Bushing  30  includes an elongated metal block  40  of substantially square cross section within opening  41  of bushing housing  31 . It is held in position by two compressed resilient members  42  and two compressed resilient members  42 ′, as shown in  FIG. 12 . Resilient members  42  and  42 ′ are identical and of uniform cross section throughout their lengths and they extend the entire length of bushing housing  31 . The ends  43  of metal block  40  extend outwardly beyond the bushing housing  30  ( FIG. 13 ). Tapped bores  44  extend into opposite sides of metal block  40 . Bushing  30  is a commercially obtainable device. Bushing  30  is directionally stiff in the direction of arrow  46  which is the direction of the desired conveyance of the material on the screen of machine  10 , and when vibratory motor  22  is in operation, this feature produces linear motion. In the present instance the arrow  46  extends at an angle of  45  to the screen bed of the machine  10 . However, this angle may vary with different machines. 
   After the bushing  30  has been clamped in position within fist bracket  24 , a motor mount bracket  45  ( FIGS. 9-11 ) is bolted to block  40 . In this respect, the motor mount bracket  45  includes a base  47  and two substantially parallel spaced sides  49  extending from base  47 . Each side  49  has four bores  50  therein. Bolts  51  ( FIG. 4 ) extend through bores  50  in the sides  49  of the motor mount bracket  45  and are threadably received in tapped bores  44  of metal block  40  of bushing  30  to thereby mount the motor mount bracket  45  on the fist bracket  24 . A motor mount bracket  45  is mounted on each fist bracket  24 . The opposite ends  52  of motor  22  are bolted to the spaced motor mount brackets  45  mounted on rails  23 . In this respect, each end of motor  22  has two base portions  53 . Bolts  54  extend through base portions  53  and through bores  55  in the base  47  of each motor mount bracket  45  to thereby securely fasten the ends of motor  22  to spaced motor mount brackets  45 . Bosses  56  surround bores  55  on the inner side of base  47  to provide good support for bolts  54 . Bosses  56  are of the same height as adjacent portions of ribs  61  and  62 . 
   In accordance with the present invention, the foregoing mounting of the single vibratory motor produces linear motion. In this respect, the center of rotation C ( FIGS. 3 and 12 ) of the vibratory motor  22  is aligned with the center X of bushing  30  and with the centers of the two directionally stiff resilient members  42 ′. Thus, when the unbalance of the vibratory motor  22  is in line with the line passing through the center of rotation C of motor  22  and the center X of bushing  30  and the centers of resilient members  42 ′, the conveyance direction  46  ( FIG. 12 ) will be realized to produce the desired linear motion. Preferably, the centers C and X and those of resilient members  42 ′ and the direction of conveyance  46  will pass through the center of gravity of the movable frame  12 , but it need not be so. If it does not pass through, there will be a change in the conveyance angle. The main consideration is that when the unbalance of the rotating rotor of the motor is in line with the center of rotation C and the center X, linear motion will be produced because resilient members  42 ′ of bushing  30  will be directionally stiff in the direction  46 . When the unbalance of the rotating rotor of the vibratory motor is not in line with centers C and X, the resilient members  42  and  42 ′ will be distorted in torsion to thereby cause the thrusts of the vibratory motor to be attenuated in directions transverse to the line between centers C and X, thereby effectively eliminating orbital motion. It will be appreciated that there may be mounting structures where the directional stiffness of the resilient members may not be aligned with the center of the bushing. Therefore, the critical aspect of the mounting structure for obtaining linear motion is that the center of rotation C of the rotor of the vibratory motor should be aligned with the direction of the directional stiffness of the resilient members of the bushing, which is represented by arrow  46  which has been designated above as the direction of conveyance. In other words, the direction of the directional stiffness should pass through the center of rotation C of the rotor of the vibratory motor  22  whether or not it passes through the physical center X of the bushing. 
   In addition to the foregoing geometry which produces the desired linear motion, each fist bracket  24  and motor mount bracket  45  is configured so as to cause center of rotation C of motor  22  to be as close as possible to the center x of bushing  30 . The minimizing of this distance tends to decrease a pendulum effect created by the vibration of the motor relative to the center X of bushing  30  to thereby cause a greater amount of its thrust to be directed in the desired direction of conveyance of the material being screened, which gives rise to greater G forces applied to the inner frame than if the center of motor  22  was further away from the center X of bushing  30 . In this respect, as can be seen from  FIGS. 6 ,  7  and  8 , each fist bracket housing  36  has a circumferential portion  57  which is cut away at  59  to provide a thinner wall between two spaced portions  60  and  60 ′ of the fist housing wall  36  which are thicker. In addition, the base  47  of motor mount bracket  45  has a plurality of ribs  61 ,  62  and  63  which lend strength to base  47  while permitting the base to be relatively thin and relatively light weight to lessen the forces due to the pendulum effect. In the foregoing respect, ribs  61  extend crosswise of base  47  at bores  55 . A rib  62  extends lengthwise between bores  55  which are located in bosses  56  which are of the same height as the adjoining portions of ribs  61  and  62 . Ribs  63  extend crosswise of base  47  outwardly from rib  62 . Rib  62  is cut away at  64  ( FIG. 10 ), and the cutaway  64  extends between points  65 . Thus, when the motor mount brackets  45  are mounted on fist brackets  24 , the cutaway portions  59  of fist brackets  24  will lie within the cutaway portions  64  of ribs  62  of motor mount brackets  45  to thereby minimize the distance between center C and center X. Thus, because of the thinness of the bases  47  of motor mount brackets  45  and the cutaway portions  59  of the fist brackets  24  and the cutaway portions  64  of ribs  62 , the center C of motor  22  will lie closer to the center X of bushing  30  than if there were no cutaway portions  59  and no cutaway portions  64 . Thus, positioning the base portions  53  of motor  22  closer to center X of bushing  30  by virtue of the cutaway portions  59  and  64 , will reduce the pendulum affect which vibratory motor  22  will otherwise produce, and as noted above, the reduction of the pendulum effect will cause a greater thrust of motor  22  to be transmitted to inner frame  12  which in turn results in higher G forces than if the motor  22  was further away. The pendulum effect is produced when the unbalance of the vibratory motor is not being exerted in line with centers C and X and acts through a lever arm extending between center X and the distance to the unbalance. Therefore, the shorter the lever arm, the less will be the pendulum effect. 
   In addition to the foregoing, the motor mount brackets  45  are preferably fabricated of cast aluminum to thereby cause them to weigh less than if they were made out of conventional cast iron or steel. The above described rib structure of motor mount brackets  45 , when in cast aluminum, increases their strength so that they can withstand the loads to which they are subjected. Additionally, considering that the weight of motor mount brackets  45 , when in aluminum, is less than their weight in either steel or cast iron, this also reduces the pendulum affect. Preferably the fist brackets are fabricated of cast iron. 
   In the above portions of the specification reference was made to the unbalance of a vibratory motor. This is usually achieved by mounting an eccentric weight on the rotor, but it can be achieved in other ways. 
   While preferred embodiments of the present invention have been disclosed, it will be appreciated that it is not limited thereto but may be otherwise embodied within the scope of the following claims.