Abstract:
The present invention relates to a mechanical vibrating drive system for supplying a consistent, elliptical driving force to a conveyor trough. In a preferred embodiment of the invention, the vibrating conveyor has three parallel shafts, the intermediate shaft being located at the center of gravity for the vibrating conveyor, and the shafts are driven such that the outer shafts rotate in one direction while the intermediate shaft rotates in the opposite direction from the outer shafts. Each of the shafts bears essentially equal weight. The net result is a force output from the drive module that produces a uniform elliptical vibratory motion throughout the length of the conveyor trough. By reversing the motor, a symmetric elliptical motion for moving product in the opposite direction is generated without any further adjustments to the weights or shafts.

Description:
This application claims a benefit of Provisional No. 60/131,131, filed Apr. 27, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention is related to a mechanical vibrating drive system for a vibratory conveyor apparatus and, more particularly, to a vibratory conveyor apparatus utilizing a set of eccentric rotating weights to impart a resultant vibratory drive force to the conveyor apparatus. 
     There are various vibrating drive systems for controlling the direction and/or speed of product being carried by a vibratory conveyor. The vibrating conveyor apparatus typically includes a trough mounted for vibratory motion, such as provided by a plurality of springs. In general, product is moved along the conveyor trough by a force applied to the trough. The product can be moved along a linear path or along an elliptical path, the path being determined by the force applied to the conveyor trough. 
     One type of vibrating drive system is a mechanical system utilizing fixed eccentric rotating weights and a phase angle adjustment means. A system of this type is described in detail in U.S. Pat. No. 5,064,053, assigned to the same assignee as the present invention. In the system of the &#39;053 patent, a single rotating shaft bearing an eccentric weight is in a parallel relationship with and positioned between paired additional rotating shafts bearing eccentric weights. The centered single shaft rotates in one direction while the paired shafts rotate in the opposite direction but at the same number of revolutions per minute. When the shafts rotate, the weights impart a force to the conveyor trough which, in turn, causes the product to move along the conveyor. Because the force to move the product is supplied by the eccentric weights, the force generated in insensitive to the product load on the conveyor. Thus, there is a consistent force generated by the drive system regardless of the type or quantity of product that is conveyed. The user can reverse the direction in which the material is being conveyed, but to ensure that product moves along the desired path requires physically changing the positioning of one or more of the eccentric weights and its associated shaft by repositioning the phase angle adjustment means. This change-over requires considerable down time, which is highly undesirable when time is a critical factor in the application. 
     A second type of vibrating drive system is a mechanical system that uses a reversible motor and dynamic balancers to produce the driving forces. A system of this type is described in U.S. Pat. No. 5,713,457, assigned to General Kinematics Corporation. In the system of the &#39;457 patent, a reversible motor with a rotary output shaft and eccentric weight is mounted near the center of gravity on a conveyor apparatus, and a dynamic balancer is positioned at each end of the conveyor trough. The dynamic balancers are spring and weight systems designed to move the product in an elliptical path as it travels along the conveyor trough. For optimum performance, the dynamic balancers (or absorbers) must be selected such that their natural frequency is just greater than the operational frequency of the system as determined by the frequency of the motor. Maintaining a consistent driving force can be difficult with this type of system because the dynamic balancers are very highly tuned, so small changes in product load may affect the performance of the equipment. In particular, the user must be cautious of producing overstrokes that can permanently damage the conveying equipment. As with the eccentric weight systems, the user can reverse the direction of product flow in the system of the &#39;457 patent by reversing the motor. However, because the dynamic balancers are set only for one speed, to make any changes in the system other than reversing the direction of product flow requires that the system be completely modified, which can result in considerable down time. 
     Eccentric weight systems that include electronic drive capabilities, such as described in U.S. Pat. No. 5,615,763, assigned to the same assignee as the present invention, allow for a rapid change of direction of the product flow. However, such systems are expensive relative to the cost of mechanical systems. 
     Thus, there is a paramount need for an inexpensive mechanical vibrating drive system that will allow the user to easily and frequently change the direction of flow of the conveyed product without incurring the down time of the system heretofore necessary with prior art mechanical vibrating drive systems. In addition, there is a need for an inexpensive eccentric weight drive system that will allow the user to convey product along a reversible, symmetric, elliptical path as it travels along the conveyor trough. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a mechanical vibrating drive system for supplying a consistent, elliptical driving force to a conveyor trough. The mechanism for supplying the force to vibrate the trough includes three parallel shafts with fixed eccentric weights, the weights being selected and positioned on the shafts such that the sum of the forces generated by the outermost weights is unequal to the force generated by the intermediate weight. The shafts are interconnected with a serpentine gear belt that drives the two outermost shafts in a counter rotation direction relative to the intermediate shaft. A standard reversing type motor is used to drive the shafts in either a forward or a reverse direction. 
     In a preferred embodiment of the invention, the three parallel shafts carry weights of essentially equal masses, and the intermediate shaft is located at the center of gravity for the vibrating conveyor. The net result is a force output from the drive module that produces a uniform elliptical vibratory motion throughout the length of the conveyor trough. By reversing the motor, a symmetric elliptical motion for moving product in the opposite direction is generated without any further adjustments to the weights or shafts. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic of an embodiment of the present invention showing a side view of a mechanical vibratory conveyor apparatus having eccentric weights mounted on rotating shafts to impart a vibratory motion to the conveying trough; 
     FIG. 1A is a schematic showing a side view of a spring member; 
     FIG. 2 is bottom view of the vibratory apparatus of the present invention showing the respective location of the eccentric weights and shaft driving elements; 
     FIG. 2A is a schematic showing the central shaft being driven by a single motor and in turn driving the two outboard shafts in an opposite rotational direction; 
     FIG. 3 is a sectional view of the apparatus illustrated in FIG. 1 along lines  3 — 3 ; 
     FIG. 4 is a depiction of the magnitude and direction of the forces produced by the eccentric weights of the apparatus illustrated in FIG. 1 when the weights are sized and oriented as described in Table 1; and 
     FIG. 5 is a depiction of the magnitude and direction of the forces produced by the eccentric weights of the apparatus illustrated in FIG. 1 when the weights are sized and oriented as described in Table 6. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The conveyor system depicted in the various Figures is a three shaft eccentric weight system driven by a single motor and is selected solely for the purposes of illustrating the invention. Other and different eccentric weight conveyor systems may utilize the inventive features described herein as well. Further, a plurality of systems can be utilized in a series along a single long conveyor. It is understood that the systems would need to be synchronized by a control system such as described in U.S. Pat. {application Ser. No. 08/985,140}, which is incorporated herein by reference, to operate cooperatively in this arrangement. 
     Reference is first made to FIGS. 1 through 3 in which the three shaft eccentric weight conveyor system constructed in accordance with the present invention is generally noted by the character numeral  10 . A vibratory trough or conveyor pan  12  is mounted to a frame  24  by square structural tubing  25 . The pan  12  is isolated from a stationary base  14  by a plurality of isolating springs  16 , which comprise a portion of the frame  24 , as shown in FIG.  1 A. As shown in FIG. 1, three shafts  18 ,  20  and  22 , are mounted for rotational movement within the frame  24 , preferably secured to the undercarriage of conveyor pan  12 . Alternatively, the shafts  18 ,  20 ,  22  can be mounted for rotational movement within a second frame (not shown), secured above the carriage of the pan  12 . In a preferred embodiment, the three shafts  18 ,  20  and  22 , are mounted within the frame  24  secured to the undercarriage of conveyor pan  12 , and the intermediate shaft  20  is positioned at the center of gravity for the vibrating conveyor  10 . 
     As shown in FIGS. 2 and 2A, a single motor  36  is used to drive all three shafts  18 ,  20 ,  22 . A belt  34  connects a pulley  37  on the motor  36  with a pulley  32  which is connected to shaft  20 . The other end of shaft  20  has a central sheave  21  that drives a double sided gear belt  40 , which simultaneously drives pulley  38 , connected to shaft  18 , and pulley  42  connected to shaft  22 . An idler  41  provides the proper tension to the gear belt  40 . As indicated by the directional arrows, shown in FIG. 2A, as the shafts  18  and  22  are driven in a first direction, shaft  20  is driven in the opposite rotational direction. Thus, the single motor  36  drives all three shafts  18 ,  20 ,  22 , with intermediate shaft  20  moving in the opposite rotational direction as the outermost shafts  18 ,  22 . 
     Referring again to FIGS. 1,  2  and  3 , an eccentrically mounted weights  18   a ,  22   a  are positioned intermediate the ends thereof and rigidly fixed to the shafts  18 ,  22 , respectively. The intermediate shaft  20  bears eccentrically mounted weights  20   a ,  20   b , which are positioned intermediate the ends thereof and rigidly fixed to the shaft  20 , with sufficient separation between the weights  20   a ,  20   b  that the weights  20   a ,  20   b  does not interfere with the rotation of the weights  18   a ,  22   a . The single weight  18 —double weight  20   a ,  20   b —single weight  22   a  configuration shown in the Figures is for illustrative purposes only. Alternatively, each shaft  18 , 20 , 22  could bear only a single weight  18   a ,  20   a ,  22   a , respectively (not shown), or a plurality of weights can be fixed to one or more of the shafts  18 ,  20 ,  22  (also not shown), provided the weights are sized and positioned on the shaft such that the weights do not interfere with each other as they rotate, and the combined mass and resultant driving force meet the criteria set forth below. 
     As described in greater detail in U.S. Pat. No. 5,064,053, which is incorporated herein by reference, as the weights  18   a ,  20   a ,  20   b ,  22   a  rotate about their respective shafts  18 ,  20 ,  22 , each weight contributes a driving force component, which is a function of the magnitude and the direction of that weight, to the net driving force directed toward the conveyor pan  12 . The net driving force, then, is the summation of the individual force components, and can be reduced to a resultant magnitude component and a resultant direction component. This net driving force is transferred to the pan  12  which, in turn, transfers the force to the product on the pan  12  causing the product to move. When the weights  18   a ,  20   a ,  20   b ,  22   a  are balanced and oriented on the shafts  18 ,  20 ,  22  such that the resultant direction component of the net driving force varies linearly as the weights rotate, a linear driving force is directed at the pan  12 . If the resultant direction component varies non-linearly as the weights rotate, an elliptical driving force is directed at the pan  12 . 
     Tables are used herein to show the effect of varying weight masses, and/or the angular orientation of the weights, on the resultant direction and the resultant driving force as the weights  18   a ,  20   a ,  20   b ,  22   a  rotate 360° about the shafts  18 ,  20 ,  22 . Each table provides the conditions (the masses of the weights and the initial angular orientation), the angular orientation of the weights at various times, t x , and the resultant direction and resultant driving force at the various times t x . The table heading “#REV” indicates that the conditions are essentially identical at time t 0  as for the related table number (Table #), but that the motor has been reversed, with no other changes to the weights  18   a ,  20   a ,  20   b ,  22   a  or shafts  18 ,  20 ,  22 . 
     Linear Motion of the Vibratory Trough 
     As taught in the prior art, the resultant direction component varies linearly as the weights rotate if the weights  18   a ,  20   a ,  20   b ,  22   a  are sized such that the combined mass of the outermost weights  18   a ,  22   a  is essentially equal to the total mass borne by the intermediate shaft  20  (mass of intermediate weight  20   a  plus mass of intermediate weight  20   b ), and if the angular orientation for the weights  18   a ,  20   a ,  20   b ,  22   a  is selected such that the two outermost weights  18   a ,  22   a  have essentially the same orientation relative to each other. For example, as shown in Table 1 and as depicted schematically in FIGS. 4A-H, if the masses of the outermost weights  18   a ,  22   a  are each 25 lbs, the combined mass of the intermediate weights  20   a ,  20   b  is 50 lbs, and the angular orientation of each of the weights  18   a ,  20   a ,  20   b ,  22   a  at time zero, t 0 , is essentially 45°, the resultant driving force produced by the weights  18   a ,  20   a ,  20   b ,  22   a  varies from 0 lbs (at times t π/2  and t 3π/2 ) to 100 lbs (at times t 0  and t π ), and the resultant direction component is directed either at 45° or 225° from a horizontal plane “x” through the shafts  18 ,  20 ,  22  (as shown in FIG.  1 ), i.e. the direction varies linearly, when the motor is set to operate in a first, or forward, direction. As shown in Tables 2, 3 and 4, by changing the angular orientation of the weights  18   a ,  20   a ,  20   b ,  22   a  at t 0 , the resultant direction changes, but still varies linearly. 
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 25 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b = 50 lbs, t 0   
               
               
                   
                 position 45°; mass of weight 22a = 25 lbs, 
               
               
                   
                 t 0  position 45° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Orientation of: 
               
               
                 18a, 22a 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 20a, 20b 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 Resultant 
                 45° 
                 45° 
                 — 
                 225° 
                 225° 
                 225° 
                 — 
                 45° 
               
               
                 Direction 
               
               
                 Net Driving 
                 100 #   
                 71 #   
                  0 #   
                  71 #   
                 100 #   
                  71 #   
                  0 #   
                 71 #   
               
               
                 Force 
               
               
                   
               
             
          
         
       
     
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 a   
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 25 lbs, t 0  position 0°; 
               
               
                   
                 combined mass of weights 20a, 20b = 50 lbs, 
               
               
                   
                 t 0  position 0°; mass of weight 22a = 25 lbs, 
               
               
                   
                 to position 0° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Orientation of: 
               
               
                 18a, 22a 
                  0° 
                  45° 
                  90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
               
               
                 20a, 20b 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                  90° 
                  45° 
               
               
                 Res. Direction 
                  0° 
                  0° 
                 — 
                 180° 
                 180° 
                 180° 
                 — 
                  0° 
               
               
                 Net Dr. Force 
                 100 #   
                  71 #   
                  0 #   
                  71 #   
                 100 #   
                 71 #   
                  0 #   
                  71 #   
               
               
                   
               
               
                   a Because the resultant direction has no vertical component, there is no force directed at the conveyor pan 12 to cause the product to move, so the product remains essentially stationary.  
               
             
          
         
       
     
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 a   
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 25 lbs, t 0  position 0°; 
               
               
                   
                 combined mass of weights 20a, 20b = 50 lbs, 
               
               
                   
                 t 0  position 0°; mass of weight 22a = 25 lbs, 
               
               
                   
                 to position 0° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Orientation of: 
               
               
                 18a, 22a 
                  0° 
                  45° 
                  90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
               
               
                 20a, 20b 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                  90° 
                  45° 
               
               
                 Res. Direction 
                  0° 
                  0° 
                 — 
                 180° 
                 180° 
                 180° 
                 — 
                  0° 
               
               
                 Net Dr. Force 
                 100 #   
                  71 #   
                  0 #   
                  71 #   
                 100 #   
                 71 #   
                  0 #   
                  71 #   
               
               
                   
               
               
                   a Because the resultant direction has no vertical component, there is no force directed at the conveyor pan 12 to cause the product to move, so the product remains essentially stationary.  
               
             
          
         
       
     
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 a   
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 25 lbs, t 0  position 0°; 
               
               
                   
                 combined mass of weights 20a, 20b = 50 lbs, 
               
               
                   
                 t 0  position 0°; mass of weight 22a = 25 lbs, 
               
               
                   
                 to position 0° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Orientation of: 
               
               
                 18a, 22a 
                  0° 
                  45° 
                  90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
               
               
                 20a, 20b 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                  90° 
                  45° 
               
               
                 Res. Direction 
                  0° 
                  0° 
                 — 
                 180° 
                 180° 
                 180° 
                 — 
                  0° 
               
               
                 Net Dr. Force 
                 100 #   
                  71 #   
                  0 #   
                  71 #   
                 100 #   
                 71 #   
                  0 #   
                  71 #   
               
               
                   
               
               
                   a Because the resultant direction has no vertical component, there is no force directed at the conveyor pan 12 to cause the product to move, so the product remains essentially stationary.  
               
             
          
         
       
     
     As further taught in the prior art, when product is conveyed using a linear force, operating the motor in a second or reverse direction does not, in and of itself, change the resultant force direction. For example, as shown in Table 1Rev, if the motor is reversed using the conditions of Table 1, the resultant direction remains the same as when the motor operated in the forward direction (see Table 1). To reverse the flow of the product, the weights  18   a ,  20   a ,  20   b ,  22   a , must be repositioned, a time-consuming operation. For example, to reverse the flow of product from Table 1, the weights need to be effectively shifted by 90° (from an angle of +45° relative to the conveyor to an angle of −45° relative to the conveyor), as shown in Table 1Rev-Mod. 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Rev 
               
             
          
           
               
                 Conditions: 
                 mass of weight 18a = 25 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b = 50 lbs, 
               
               
                   
                 t 0  position 45°; mass of weight 22a = 25 lbs, 
               
               
                   
                 t 0  position 45° 
               
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Orientation of: 
               
               
                 18a, 22a 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 20a, 20b 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 Res. Direction 
                 45° 
                 45° 
                 — 
                 225° 
                 225° 
                 225° 
                 — 
                 45° 
               
               
                 Net Dr. Force 
                 100 #   
                 71 #   
                  0 #   
                  71 #   
                 100 #   
                  71 #   
                  0 #   
                 71 #   
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Rev 
               
             
          
           
               
                 Conditions: 
                 mass of weight 18a = 25 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b = 50 lbs, 
               
               
                   
                 t 0  position 45°; mass of weight 22a = 25 lbs, 
               
               
                   
                 t 0  position 45° 
               
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 Orientation of: 
               
               
                 18a, 22a 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 20a, 20b 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 Res. Direction 
                 45° 
                 45° 
                 — 
                 225° 
                 225° 
                 225° 
                 — 
                 45° 
               
               
                 Net Dr. Force 
                 100 #   
                 71 #   
                  0 #   
                  71 #   
                 100 #   
                  71 #   
                  0 #   
                 71 #   
               
               
                   
               
             
          
         
       
     
     Elliptical Motion of the Vibratory Trough 
     If the resultant direction component varies in a non-linear pattern as the weights  18   a ,  20   a ,  20   b ,  22   a  rotate about their respective shafts  18 ,  20 ,  22 , an elliptical driving force is directed at the pan  12 . That is, with the motor operating in the forward direction, the pan  12  is continually moved in a first direction, e.g., counter-clockwise, along a path that resembles an ellipse. As shown herein, the elliptical path is generated by sizing and positioning the weights  18   a ,  20   a ,  20   b ,  22   a  so that the resultant driving force cannot be essentially equal to zero at any point during a complete rotation. This can be accomplished by selecting the weights  18   a ,  20   a ,  20   b ,  22   a  so that the combined mass of the outermost weights  18   a ,  22   a  does not equal the combined mass of the intermediate weights  20   a ,  20   b , or by positioning the weights  18   a ,  22   a  on the outermost shafts  18 ,  22  such that the weights  18   a ,  22   a  have different angular orientations at t 0  relative to each other, or by a combination thereof, provided the combination prevents the resultant driving force from being essentially equal to zero at any point during a complete rotation. 
     For example, the weights  18   a ,  20   a ,  20   b ,  22   a  can be selected such that the combined mass of the outermost weights  18   a ,  22   a  does not equal the combined mass of the intermediate weights  20   a ,  20   b . In this situation, because the outermost weights  18   a ,  22   a  rotate in one direction while the intermediate weights  20   a ,  20   b  are rotating in the opposite direction at the same rate, a net positive force will always be exerted in some direction. As shown in Table 5, if the masses of the weights  18   a ,  20   a ,  20   b ,  22   a  are each 33 lbs, and the angular orientation of the weights  18   a ,  20   a ,  20   b ,  22   a  at time zero, t 0 , is essentially 45°, the resultant direction varies non-linearly as the resultant force produced by the weights varies from 33 lbs (at times t π/2  and t 3π/2 ) to 99 lbs (at times t 0  and t π ). Table 6, which is shown schematically in FIGS. 5A-H, is the same as Table 5 except the angular orientation of the weights  18   a ,  20   a ,  20   b ,  22   a  at t 0  is essentially 0°. As shown in Table 7, the masses of the weights  18   a ,  20   a ,  20   b ,  22   a , can vary relative to each other and the pan  12  can move with an elliptical motion. 
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 5 
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 33 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b = 33 lbs, 
               
               
                   
                 t 0  position 45°; mass of weight 22a = 33 lbs, 
               
               
                   
                 t 0  position 45° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a, 22a 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 20a, 20b 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 Res. Direction 
                 45° 
                   63.4° 
                 135° 
                   206.6° 
                 225° 
                   243.4° 
                 315° 
                   26.6° 
               
               
                 Net Dr. Force 
                 99 #   
                 74 #   
                  33 #   
                  74 #   
                  99 #   
                  74 #   
                  33 #   
                 74 #   
               
               
                   
               
             
          
         
       
     
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 6 
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 33 lbs, t 0  position 0°; combined mass of weights 
               
               
                   
                 20a, 20b = 33 lbs, t 0  position 0°; mass of weight 22a = 33 lbs, 
               
               
                   
                 t 0  position 0° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a, 22a 
                 0° 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
               
               
                 20a, 20b 
                 0° 
                 315°  
                 270°  
                 225° 
                 180° 
                 135° 
                  90° 
                  45° 
               
               
                 Res. Direction 
                 0° 
                   18.4° 
                 90° 
                   161.6° 
                 180° 
                   198.4° 
                 270° 
                   341.6° 
               
               
                 Net Dr. Force 
                 99 #   
                 74 #   
                 33 #   
                  74 #   
                  99 #   
                  74 #   
                  33 #   
                  74 #   
               
               
                   
               
             
          
         
       
     
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 6 
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 33 lbs, t 0  position 0°; combined mass of weights 
               
               
                   
                 20a, 20b = 33 lbs, t 0  position 0°; mass of weight 22a = 33 lbs, 
               
               
                   
                 t 0  position 0° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a, 22a 
                 0° 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
               
               
                 20a, 20b 
                 0° 
                 315°  
                 270°  
                 225° 
                 180° 
                 135° 
                  90° 
                  45° 
               
               
                 Res. Direction 
                 0° 
                   18.4° 
                 90° 
                   161.6° 
                 180° 
                   198.4° 
                 270° 
                   341.6° 
               
               
                 Net Dr. Force 
                 99 #   
                 74 #   
                 33 #   
                  74 #   
                  99 #   
                  74 #   
                  33 #   
                  74 #   
               
               
                   
               
             
          
         
       
     
     When the motor is reversed, the pan  12  is moved along an essentially identical elliptical path as when the motor operates in the forward direction, except that the product moves in the opposite direction. That is, if as the motor operates in the forward direction, the pan  12  moves counterclockwise about the elliptical path, then as the motor operates in the reverse direction, the pan  12  moves clockwise about the elliptical path. More importantly, by reversing the rotational direction of the motor, the product effectively moves in the opposite direction along the conveyor pan  12 . This symmetrical but reverse elliptical path is generated by simply reversing the motor, without any further adjustments to the weights  18   a ,  20   a ,  20   b ,  22   a  or shafts  18 ,  20 ,  22 . Tables 5Rev, 6Rev and 7Rev show the effect of reversing the motor on the resultant direction and the resultant force for Tables 5, 6 and 7, respectively. 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Rev 
               
             
          
           
               
                 Conditions: 
                 mass of weight 18a = 33 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b = 33 lbs, t 0  position 45°; 
               
               
                   
                 mass of weight 22a = 33 lbs, to position 45° 
               
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a, 22a 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 20a, 20b 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 Res. Direction 
                 45° 
                   26.6° 
                 315° 
                   243.4° 
                 225° 
                   206.6° 
                 135° 
                   26.6° 
               
               
                 Net Dr. Force 
                 99 #   
                 74 #   
                  33 #   
                  74 #   
                  99 #   
                  74 #   
                  33 #   
                 74 #   
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Rev 
               
             
          
           
               
                 Conditions: 
                 mass of weight 18a = 33 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b = 33 lbs, t 0  position 45°; 
               
               
                   
                 mass of weight 22a = 33 lbs, to position 45° 
               
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a, 22a 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 20a, 20b 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 Res. Direction 
                 45° 
                   26.6° 
                 315° 
                   243.4° 
                 225° 
                   206.6° 
                 135° 
                   26.6° 
               
               
                 Net Dr. Force 
                 99 #   
                 74 #   
                  33 #   
                  74 #   
                  99 #   
                  74 #   
                  33 #   
                 74 #   
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Rev 
               
             
          
           
               
                 Conditions: 
                 mass of weight 18a = 33 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b = 33 lbs, t 0  position 45°; 
               
               
                   
                 mass of weight 22a = 33 lbs, to position 45° 
               
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a, 22a 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 20a, 20b 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 Res. Direction 
                 45° 
                   26.6° 
                 315° 
                   243.4° 
                 225° 
                   206.6° 
                 135° 
                   26.6° 
               
               
                 Net Dr. Force 
                 99 #   
                 74 #   
                  33 #   
                  74 #   
                  99 #   
                  74 #   
                  33 #   
                 74 #   
               
               
                   
               
             
          
         
       
     
     Alternatively, if the weights  18   a ,  20   a ,  20   b ,  22   a  are selected such that the combined mass of the outermost weights  18   a ,  22   a  is essentially equal to the mass of the intermediate weight  20   a ,  20   b  the force direction can be varied non-linearly by positioning the weights on the outermost shafts  18 ,  22  such that the weights  18   a ,  22   a  have different angular orientations at t 0  relative to each other. For example, with the weight masses having a ratio of 1:2:1 (for the weights  18   a : 20   a : 22   a , respectively), allowing the outermost weights  18   a ,  22   a  to have different angular orientations at t 0  relative to each other prevents the weights  18   a ,  22   a  from generating an equal but opposite force relative to the intermediate weight  20   a ,  20   b  as is required for the resultant driving force to equal essentially zero. The effect of varying the t 0  angular orientations for the outermost weights  18   a ,  22   a  is shown by comparing the resultant direction and resultant driving force for Table 8 with Table 1. (Table 8 is the same as Table 1 except that the outermost weights  18   a ,  22   a  differ in angular orientation by 90° throughout the rotation.) Similar, but more subtle, results are observed when the outermost weights  18   a ,  22   a  differ in angular orientation by 45° throughout the rotation, as shown in Table 9. The effect of reversing the motor on the resultant direction and resultant force for Tables 8 and 9 is shown in Tables 8Rev and 9Rev, respectively. Again, as the motor operates in the forward direction, the pan  12  moves counterclockwise about the elliptical path, and as the motor operates in the reverse direction, the pan  12  moves clockwise about the elliptical path. This symmetrical but reverse elliptical path is generated by simply reversing the motor, without any further adjustments to the weights  18   a ,  20   a ,  20   b ,  22   a  or shafts  18 ,  20 ,  22 . 
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 8 
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 25 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b = 50 lbs, 
               
               
                   
                 t 0  position 45°; mass of weight 22a = 25 lbs, t 0  position 135° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 20a, 20b 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 22a 
                 135°  
                 180°  
                 225° 
                 270° 
                 315° 
                  0° 
                  45° 
                 90° 
               
               
                 Res. Direction 
                   63.4° 
                 45° 
                 270° 
                   251.6° 
                   243.4° 
                 225° 
                  90° 
                   71.6° 
               
               
                 Net Dr. Force 
                 79 #   
                 35 #   
                  35 #   
                  79 #   
                  79 #   
                  35 #   
                  35 #   
                 79 #   
               
               
                   
               
             
          
         
       
     
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 8 
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 25 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b = 50 lbs, 
               
               
                   
                 t 0  position 45°; mass of weight 22a = 25 lbs, t 0  position 135° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 20a, 20b 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 22a 
                 135°  
                 180°  
                 225° 
                 270° 
                 315° 
                  0° 
                  45° 
                 90° 
               
               
                 Res. Direction 
                   63.4° 
                 45° 
                 270° 
                   251.6° 
                   243.4° 
                 225° 
                  90° 
                   71.6° 
               
               
                 Net Dr. Force 
                 79 #   
                 35 #   
                  35 #   
                  79 #   
                  79 #   
                  35 #   
                  35 #   
                 79 #   
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 8 
               
             
             
               
                   
               
               
                 ev 
               
             
          
           
               
                 Conditions: 
                 mass of weight 18a = 25 lbs, t 0  position 45°; combined mass of weights 
               
               
                   
                 20a, 20b = 50 lbs, t 0  position 45°; mass of weight 22a = 25 lbs, 
               
               
                   
                 t 0  position 135° 
               
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 20a, 20b 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 22a 
                 135°  
                 90° 
                  45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180°  
               
               
                 Res. Direction 
                   63.4° 
                   71.6° 
                  90° 
                 225° 
                   243.4° 
                   251.6° 
                 270° 
                 45° 
               
               
                 Net Dr. Force 
                 79 #   
                 79 #   
                  35 #   
                  35 #   
                  79 #   
                  79 #   
                  35 #   
                 35 #   
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 8 
               
             
             
               
                   
               
               
                 ev 
               
             
          
           
               
                 Conditions: 
                 mass of weight 18a = 25 lbs, t 0  position 45°; combined mass of weights 
               
               
                   
                 20a, 20b = 50 lbs, t 0  position 45°; mass of weight 22a = 25 lbs, 
               
               
                   
                 t 0  position 135° 
               
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135° 
                 90° 
               
               
                 20a, 20b 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315° 
                  0° 
               
               
                 22a 
                 135°  
                 90° 
                  45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180°  
               
               
                 Res. Direction 
                   63.4° 
                   71.6° 
                  90° 
                 225° 
                   243.4° 
                   251.6° 
                 270° 
                 45° 
               
               
                 Net Dr. Force 
                 79 #   
                 79 #   
                  35 #   
                  35 #   
                  79 #   
                  79 #   
                  35 #   
                 35 #   
               
               
                   
               
             
          
         
       
     
     The resultant force direction can also be varied non-linearly by positioning the weights on the outermost shafts  18 ,  22  such that the weights  18   a ,  22   a  have different angular orientations at t 0  relative to each other, and by selecting the weights  18   a ,  20   a ,  20   b ,  22   a  such that the combined mass of the outermost weights  18   a ,  22   a  does not equal the combined mass of the intermediate weights  20   a ,  20   b . For example, in Table 10 the shafts  18 ,  20   a ,  22  bear essentially the same masses, similar to Tables 5 and 6, but the outermost weights  18   a ,  22   a  differ in angular orientation by 90° throughout the rotation. As in the prior examples, by simply reversing the motor, without any further adjustments to the weights  18   a ,  20   a ,  20   b ,  22   a  or shafts  18 ,  20 ,  22 , the direction in which the product moves about the elliptical path can be changed from counterclockwise (Table 10) to clockwise (Table 10Rev). 
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 10 
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 33 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b =33 lbs, t 0  position 45°; 
               
               
                   
                 mass of weight 22a = 33 lbs, t 0  position 90° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315°  
                 0° 
               
               
                 20a, 20b 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135°  
                 90° 
               
               
                 22a 
                 135°  
                 180°  
                 225° 
                 270° 
                 315° 
                  0° 
                 45° 
                 90° 
               
               
                 Res. Direction 
                   71.6° 
                 90° 
                 225° 
                   243.4 
                   251.6° 
                 270° 
                 45° 
                   63.4° 
               
               
                 Net Dr. Force 
                 74 #   
                 33 #   
                  33 #   
                  74 #   
                  74 #   
                 33 #   
                 33 #   
                 74 #   
               
               
                   
               
             
          
         
       
     
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 10 
               
               
                   
               
               
                 Conditions: 
                 mass of weight 18a = 33 lbs, t 0  position 45°; 
               
               
                   
                 combined mass of weights 20a, 20b =33 lbs, t 0  position 45°; 
               
               
                   
                 mass of weight 22a = 33 lbs, t 0  position 90° 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Time 
                 t 0   
                 t π/4   
                 t π/2   
                 t 3π/4   
                 t π   
                 t 5π/4   
                 t 3π/2   
                 t 7π/4   
               
               
                   
               
               
                 Angular Orientation of: 
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 18a 
                 45° 
                 90° 
                 135° 
                 180° 
                 225° 
                 270° 
                 315°  
                 0° 
               
               
                 20a, 20b 
                 45° 
                  0° 
                 315° 
                 270° 
                 225° 
                 180° 
                 135°  
                 90° 
               
               
                 22a 
                 135°  
                 180°  
                 225° 
                 270° 
                 315° 
                  0° 
                 45° 
                 90° 
               
               
                 Res. Direction 
                   71.6° 
                 90° 
                 225° 
                   243.4 
                   251.6° 
                 270° 
                 45° 
                   63.4° 
               
               
                 Net Dr. Force 
                 74 #   
                 33 #   
                  33 #   
                  74 #   
                  74 #   
                 33 #   
                 33 #   
                 74 #   
               
               
                   
               
             
          
         
       
     
     In a preferred embodiment of the present invention, each shaft  18 ,  20 ,  22  bears one weight  18   a ,  20   a ,  22   a , and masses of the weights  18   a ,  20   a  and  22   a  are proportioned 31:38:31 (1:1.225:1). At a time zero, t 0 , all of the weights  18   a ,  20   a ,  22   a  have essentially the same angular orientation with respect to their associated shafts  18 ,  20 ,  22 . Upon starting the motor  36 , the shafts  18  and  22  are driven in a first direction, ie. counter-clockwise, and shaft  20  is driven in a second opposite rotational direction, i.e. clockwise, causing the weights  18   a ,  20   a ,  22   a  to change angular orientation. In the most preferred embodiment, the ellipse generated has a length that is approximately four times its width. 
     It is understood that, in light of a reading of the foregoing description and drawings, those with ordinary skill in the art will be able to make changes and modifications to the present invention without departing from the spirit or scope of the invention, as defined herein.