Vibrating arrangement

A vibrating unit for machinery, comprising:

• a frame;
• a table supported on the frame through vibration-isolating cushions to permit vertical vibration of the table relative to the frame while substantially isolating the frame from the vibrations;
• first and second vibration generators rotatably mounted on said table in generally parallel but sidewardly spaced relationship for permitting imposition of a vertically oriented up-and-down vibration on the table;
• each said vibration generator including first and second coaxially aligned and rotatable shafts which each have distal first ends and mutually adjacent second ends, one of said second ends being hollow and rotatably receiving therein the other of said second ends, said first and second shafts each having a shaft pulley mounted on said distal first ends for rotation thereof and respectively mounting on said mutually adjacent second ends first and second radially eccentric weights for causing said vibration, the first and second radially eccentric weights of each said vibration generator being sized and radially and axially positioned on said mutually adjacent second ends so as to be effectively balanced and induce no rotational vibration when the weights are disposed in a first position wherein they are substantially radially opposed, said weights when relatively moved into a second position wherein they are both disposed in the same radial direction being such as to create an unbalanced vertical vibratory force when the respective vibration generator is rotated;
• first and second driving pulleys mounted on a main drive shaft rotatably supported on said frame;
• means for rotating said main drive shaft;
• first and second drive trains connected between said table and said frame for rotatably driving both of said first and second vibration generators at the same rotational speeds but in opposite rotational directions;
• said first drive train including first flexible drive belt means drivingly connected to and driven from said first driving pulley, said first drive belt means being drivingly engaged with the shaft pulley of the first shaft of each of said first and second vibration generators for effecting simultaneous and synchronous rotation of each of said first shafts in an opposite rotational direction relative to the other of said first shafts;
• said second drive train including second flexible drive belt means drivingly engaged with and driven from said second driving pulley, said second drive belt means being drivingly engaged with the end pulleys of the second shafts of said first and second vibration generators for causing simultaneous and synchronous rotation of each of said second shafts in an opposite rotational direction relative to the other of said second shafts;
• each of said first and second drive trains including a toothed driving belt engaged with the respective driving pulley and a toothed driven belt engaged with said shaft pulleys associated with the respective shafts, said driving and driven belts being engaged with end pulleys mounted on a rotatable intermediate shaft mounted on said frame, said driven belts extending between the end pulleys on said frame and the shaft pulleys on said table to isolate transmission of vibrations from the table to the frame;
• and
• position adjusting means cooperating with said driven belt of said second drive belt means for adjusting the position of said second drive belt means relative to said first drive belt means during the simultaneous rotations thereof to cause a corresponding angular adjustment in the positions of said second shafts relative to said first shafts to enable the eccentric weights on said second shafts to be angularly adjusted between said first and second positions relative to said first shafts;
• said position adjusting means including a first intermediate position-adjusting pulley engaged with a first intermediate belt reach of said driving belt of said second drive belt means, a driving device for shiftably moving said first intermediate position-adjusting pulley transversely relative to said first intermediate belt reach for changing the length of said first intermediate belt reach to change the position of the second drive belt means relative to said first drive belt means, at least one elongate guide member mounted to said frame and extending transverse to said first intermediate belt reach and a second intermediate belt reach of said driving belt of said second drive belt means, a second intermediate position-adjusting pulley engaged with said second intermediate belt reach, and first and second slide members slidingly engaged with said guide member and respectively having said first and second intermediate position-adjusting pulleys rotatably mounted thereon, said driving device operatively engaging said first and second slide members for shiftably moving said slide members transversely in the same direction along said guide member to move said intermediate position-adjusting pulleys for changing the lengths of said intermediate belt reaches and angularly adjusting said second shafts relative to said first shafts.