Patent Publication Number: US-2005115807-A1

Title: Vibratory conveyor apparatus

Description:
This application is based on U.S. Provisional Patent Application No. 60/503,657, which was filed on Sep. 17, 2003. 
    
    
     BACKGROUND OF THE INVENTION  
      The present invention relates generally to a vibratory conveyor apparatus which includes a conveyor trough that is movably supported relative to a base. More specifically, the invention relates to such an apparatus which comprises an electromagnetic drive for reciprocating the conveyor trough relative to the base.  
      Vibratory conveyors are widely used for a variety of material conveying applications. Such devices typically include a conveyor trough which is reciprocated by an associated vibratory drive to thereby induce motion in the material carried in the trough. Heretofore, vibratory drives have been either mechanical or electromagnetic in nature. Mechanical vibratory drives typically include a number of eccentrically mounted weights which when rotated induce vibratory motion in the conveyor trough. Electromagnetic vibratory drives usually comprise a magnet and coil assembly which when activated induces a vibratory motion in the conveyor trough.  
     SUMMARY OF THE INVENTION  
      In accordance with the present invention, a vibratory conveyor apparatus is provided which comprises a base, a conveyor trough which is movably supported by the base, and an electromagnetic drive which includes at least one coil that is connected to the base and an armature that extends axially through the coil and is connected to the conveyor trough. Activation of the coil moves the armature axially in at least a first direction relative to the coil. Thus, the electromagnetic drive is operable to reciprocate the conveyor trough relative to the base.  
      In one embodiment of the invention, the conveyor apparatus also includes a mechanism for biasing the armature in at least a second direction which is opposite to the first direction. The biasing mechanism can be, for example, a spring member which is positioned against the armature. In addition, the force of the spring member against the armature is preferably adjustable.  
      In another embodiment of the invention, the electromagnetic drive comprises a least a second coil which when activated moves the armature in at least a second direction which is opposite to the first direction.  
      In yet another embodiment of the invention, activation of the coil alternately moves the armature axially in a first direction relative to the coil and in a second direction which is opposite to the first direction.  
      Thus, in contrast to prior art vibratory conveyor devices, the conveyor apparatus of the present invention is configured such that the armature of the electromagnetic drive is directly connected to the conveyor trough. The resulting construction of the conveyor apparatus is simple and economic to fabricate, can be readily configured into several embodiments, and can be used for a variety of material-handling applications.  
      Other features and advantages of the present invention will be made apparent from the following detailed description, with reference to the accompanying drawings.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a longitudinal cross sectional view of the vibratory conveyor apparatus of the present invention, with certain components shown schematically; and  
       FIG. 2  is an end elevation view of the vibratory conveyor apparatus illustrated in  FIG. 1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to  FIGS. 1 and 2 , the vibratory conveyor apparatus of the present invention, which is indicated generally by reference number  10 , includes a base  12 , a conveyor trough  14  which is movably supported on the base, and an electromagnetic drive  16  for reciprocating the conveyor trough relative to the base. The base  12  can comprise any suitable support for the conveyor trough  14 , such as an elongated member which comprises a channel-shaped cross section. In addition, the base  12  may be located in any desired position relative to the conveyor trough  14 , such as above or, as shown in the Figures, below the conveyor trough.  
      The conveyor trough  14  can comprise any configuration which may be desired or required for a particular conveying application. In the illustrated embodiment of the invention, for example, the conveyor trough  14  comprises an elongated, generally flat conveying surface  18 , two side walls  20  which extend generally upwardly from opposite sides of the conveying surface, an inlet end  22  which is located at one end of the conveying surface and a discharge end  24  which is located at a distal end of the conveying surface. Material to be conveyed by the conveyor apparatus  10  is deposited on the conveying surface  18  proximate the inlet end  22  and is transported longitudinally along the conveying surface to the discharge end  24 .  
      The conveyor trough  14  is movably supported on the base  12  by a number of upstanding support members  26 , four of which are employed in the embodiment of the invention illustrated in the drawings. Each support member  26  includes an elongated bracket  28  which comprises a first or upper end  30  that is ideally located proximate the conveyor trough  14  and a second or lower end  32  that is rigidly secured to the base, such as by a number of bolts  34 . Each support member  26  also includes a suspension link  36  which is connected between the bracket  28  and the conveyor trough  14 . For example, each suspension link  36  may comprise a first or upper end  38  that is pivotally connected to the first end  30  of the bracket  28  and a second or lower end  40  that is pivotally connected via a suitable pivot bar  42  to a corresponding trough bracket  44  which in turn is attached such as by welding to the bottom of the conveying surface  18 . Thus, the support members  26  provide vertical support for the conveying trough  14  while permitting the conveying trough to reciprocate longitudinally relative to the base  12 .  
      In accordance with the embodiment of the invention which is illustrated in the drawings, the electromagnetic drive  16  includes a number of electromagnetic coils  46  and an elongated armature  48  which extends axially through the coils. The coils  46  can comprise any conventional electromagnetic coil which is suitable for use in a linear electromagnetic drive. In addition, each coil  46  is preferably secured to the base  12  by suitable means, such as a corresponding radial clamp  50  which in turn is attached to the base by any known device.  
      The armature  48  can comprise any suitable device that is capable of producing a resultant force under the influence of the electric fields which are generated by the coils  46 . As shown in the drawings, for example, the armature  48  can comprise an elongated rod which has a circular cross section and a uniform diameter from end to end. In addition, the armature  48  can be made from any of a variety of suitable electrically-conductive materials, such as ferrous materials, aluminum, and the like. Thus, when the coils  46  are activated, the armature  48  will be forced to move axially relative to the coils.  
      In accordance with the present invention, this axial motion of the armature  48  is transferred to the conveyor trough  14  to thereby transport the materials on the conveying surface  18  from the inlet end  22  to the discharge end  24 . Accordingly, the conveying apparatus  10  also includes suitable means for transferring the motion of the armature  48  to the conveyor trough  14 . For example, when as shown in the drawings the armature  48  is located below the conveyor trough  14 , the conveying apparatus  10  may include a trough connector  52  which comprises an upper end that is attached such as by welding to the bottom of the conveying surface  18  and a lower end that may be either rigidly or pivotally connected to the armature  48 . Moreover, the electromagnetic drive  16  is ideally positioned with the armature  48  in alignment with the conveyor trough  14  so that the reciprocating motion of the armature may be transferred directly to the conveyor trough through the trough connector  52 .  
      The coils  46  can be activated in a variety of fashions to effect a desired reciprocating motion of the armature  48  and, thus, the conveyor trough  14 . In addition, the activation of the coils  46  is preferably controlled via suitable electronic control unit  54 . Furthermore, the conveyor apparatus  10  may include at least one operating switch  56  which is responsive to the position of the armature  48  to facilitate the activation of the coils  46  to effect the desired reciprocating motion of the armature. For example, the operating switch  56  may comprise a non-contact proximity switch which generates a signal when the armature  48  is at one end of its stroke. The operating switch  56  may alternatively comprise any of a variety of other switches, such as contact switches, optical switches, Hall-effect sensors, and the like.  
      In accordance with one embodiment of the invention, the coils  46  act in concert with each other and in opposition to a biasing mechanism  58 . In the embodiment of the invention shown in the drawings, the biasing mechanism  58  includes a spring member  60  which is supported on the end of a threaded rod  62  that is connected to the base  12  via a suitable bracket  64 . The biasing mechanism  58  is preferably designed so that the spring member  60  is positioned in axial alignment against an end of the armature  48 . In addition, the threaded rod  62  is secured to the bracket  64  with a number of counteracting nuts  66 . Thus, the pre-load force of the spring member  60  against the armature  48  can be selectively adjusted by changing the position of the threaded rod  62  relative to the bracket  64 . In this manner, the stroke of the armature  48  may also be adjusted. Although the spring member  60  is illustrated in the drawings as a compression coil spring, other types of spring members can be employed in the biasing mechanism  58 , including elastomeric spring elements. Additionally, the spring member  60  may be configured as a tension spring rather than a compression spring.  
      In the illustrated embodiment of the invention, the biasing mechanism  58  moves the armature  48  in the material-conveying direction, which is indicated by the arrow A in  FIG. 1 , while the coils  46  act together in opposition to the biasing mechanism to move the armature in the opposite, or return, direction. However, the conveyor apparatus  10  may be configured so that the coils  46  advance the armature  48  in the material-conveying direction, while the biasing mechanism  58  moves the armature in the return direction.  
      In an alternative embodiment of the invention, the coils  46  alone can be activated to reciprocate the armature  48 . In this embodiment, one of the coils  46  is oriented to move the armature  48  in the material-conveying direction and the other coil is oriented to move the armature in the return direction. The armature  48  can then be reciprocated by alternately activating the coils  46 . Alternatively, the conveyor apparatus  10  may employ one or more coils  46  which are capable of being reversibly activated. In this embodiment, the armature  48  may be reciprocated by merely reversing the polarity of the current which activates the coil  46 .  
      The conveyor apparatus  10  may also include a bumper  68  for the armature  48 . In the embodiment of the invention shown in  FIG. 1 , the bumper  68  is positioned at the end of the armature  48  opposite the biasing mechanism  58  and is connected to the base via a suitable bracket  70 . The bumper  68  may thus be used to limit the stroke of the armature  48  in the material-conveying direction.  
      The conveyor apparatus  10  functions generally in the nature of known mechanically-driven vibratory conveyor devices. As is well understood by persons skilled in the art, these devices create differing acceleration forces during the material-conveying and return strokes to thereby advance the material along the conveyor trough  14 . Generally, the conveyor trough  14  is accelerated more slowly in the material-conveying direction than in the return direction to incrementally and repeatedly advance the material along the conveying surface  18 . While the specific operational parameters of the conveyor apparatus  10  will depend upon the specific dimensions of the apparatus and the particular conveying requirements, it is presently contemplated that the electromagnetic drive  16  may be operated to stroke the conveyor trough  14  from between about 0.1 inch to about 0.4 inch.  
      It should be recognized that, while the present invention has been described in relation to the preferred embodiments thereof, those skilled in the art may develop a wide variation of structural and operational details without departing from the principles of the invention. Therefore, the appended claims are to be construed to cover all equivalents falling within the true scope and spirit of the invention.