Patent Publication Number: US-9408283-B2

Title: Electrical grounding arm

Description:
TECHNICAL FIELD 
     The present invention relates to an electrical grounding arm, and more specifically to an electrical grounding arm which is designed to connect the base frame, and a vibratory conveyor bed in such a manner so as to eliminate static electrical charge buildup in an appropriate manner. 
     BACKGROUND OF THE INVENTION 
     Vibratory conveyors have been used for decades in various industrial applications. As a general matter, vibratory conveyors include a base frame, and a vibratory conveyor bed which is mounted in spaced relation relative to the base frame, and which further reciprocates in a given pattern in order to move a product, or objects of interest along a given course of travel for further processing. 
     Depending upon the product being transported, and the environment in which the vibratory conveyor is used, static electricity may build up in either the base frame, or the vibratory conveyor, and which must be dissipated in order to avoid an accidental discharge of the static electricity. It is well known that these electrical discharges of static electricity may cause damage to the vibratory conveyor; electrical devices in the area of the vibratory conveyor, or potentially can ignite combustible materials in the region of the electrical discharge. 
     To electrically couple the movable vibratory conveyor bed with the underlying base frame so as to provide an electrical pathway for discharging a static electricity charge, various methodologies have been used in the past. For example, this electrical coupling has, heretofore, been achieved by a stainless steel braided cable which had crimped end connections which allowed the stainless steel cable or strap to be secured to the vibratory conveyor, and to the underlying base frame. In this regard this stainless steel braided cable typically was electrically connected by way of the fasteners which had been employed to secure a plurality of supporting, flexible leaf springs to the base frame, and conveyor bed. These flexible leaf springs supported the movement of the vibratory conveyor in spaced relation relative to the base frame. 
     While this solution worked with some degree of success, the attachment of the metal braided cable in this fashion created a continuous bending at a given location in the cable. This subsequent and repeated bending led to a failure of the cable near the crimped connection which had been formed. Therefore, periodic maintenance was required to replace these braided cables to prevent an accidental discharge of accumulated static electricity. 
     Other designs have been implemented to try and mitigate the failure which was attendant to the repeated movement of the cable by the reciprocal motion of the conveyor bed. One possible solution was to provide, a rolling-flex braided cable. However, the problem associated with using a rolling-flex cable to mitigate a bending failure was that such a rolling-flex cable required a rather large radius to achieve any measurable benefit. This large radius interfered with other assemblies mounted on the vibratory conveyor and therefore only provided minimal benefit. 
     In another attempt to try and solve the underlying problem discussed above, sheet metal straps were used, and which were fabricated in a manner so as to allow the stainless steel straps to be secured in the same manner as the earlier employed steel braided cable, to the leaf springs which support the vibratory conveyor bed. Again, this metal strap was still subjected to the same vibratory force experienced by the conveyor bed, and consequently a bending failure occurred in the stainless steel strap at the point where the metal strap was secured by fasteners to the conveyor bed. Further, a rolling configuration made from a strap of stainless steel was attempted. In this rolling-flex configuration the problems associated with the cable remained, that being, that the rather large radius required to achieve measurable benefit, and the subsequent interference with the adjacent spring assemblies used to support the conveyor bed achieved little or no measurable benefit. It was discovered that compromises made to the radiuses which were employed, resulted in premature failures that had only a slightly longer lifetime as compared to that experienced with the bending failure mode as seen with the earlier employed stainless steel braided cables. 
     In view of these problems, manufacturers of vibratory conveyors have continued to seek an effective means whereby a movable object, such as a vibratory conveyor, can be effectively, electrically coupled to an underlying base frame in a manner which provides effective dissipation of accumulated static electricity in a manner which avoids the shortcomings attendant with the prior art practices that were utilized heretofore. An electrical grounding arm is the subject matter of the present invention. 
     SUMMARY OF THE INVENTION 
     A first aspect of the present invention relates to an electrical grounding arm which includes an elongated, electrically conductive main body having opposite first and second ends, and which are respectively electrically coupled to a first and second spaced object which cooperate, together, and wherein at least one of the first or second spaced objects moves relative to the other object, and wherein the main body of the electrical grounding arm has a predetermined geometry, and wherein the motion of one of the first of second objects imparts motion to the electrical grounding arm which is electrically coupled with each of the first and second spaced objects, and wherein the motion of the electrical grounding arm imparts stress to the main body thereof, and wherein the geometry of the main body of the electrical grounding arm dissipates the stress imparted to the main body so as to inhibit stress related damage from being imparted to the electrical grounding arm. 
     Still another aspect of the present invention relates to a grounding arm which includes an electrically conductive main body having opposite first and second ends, and which are respectively electrically coupled to a first and a second spaced object, and wherein at least one of the first or second, spaced objects, reciprocally moves relative to the other object, and wherein the main body has an intermediate portion which is located between the first and second ends, and which further has a peripheral edge, and wherein the main body of the electrical grounding arm has a width dimension which diminishes when measured from the opposite first and second ends, and in the direction of the intermediate portion of the main body. 
     These and other aspects of the present invention will be discussed in greater detail hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiment of the present invention is described below with reference to the following accompanying drawings. 
         FIG. 1  is a perspective, fragmentary, side elevation view of the electrical grounding arm of the present invention and which is shown in a typical operational environmental where it is installed on a vibratory conveyor of traditional design. 
         FIG. 2  is a first, side elevation view of the electrical grounding arm of the present invention. 
         FIG. 3  is a second, side elevation view taken from a position which is 90 degrees, offset, from that seen in  FIG. 2 . 
         FIG. 4  is a perspective, side elevation view of the electrical grounding arm. 
         FIG. 5  is a second, side elevation view of the electrical grounding arm of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts.” (Article I, Section 8). 
     Referring now to  FIG. 1  a vibratory conveyor  11  of traditional design is illustrated. The vibratory conveyor is positioned in spaced relation relative to an underlying supporting surface  12 . The vibratory conveyor includes an elongated base frame  13  which is mounted in spaced relation relative to the supporting surface  12 . The base frame  13  further mounts a drive assembly  14  of traditional design. The drive assembly, when energized, imparts energy or force into the base frame  13 , and which is subsequently transmitted to a reciprocally movable conveyor bed which is disposed in spaced relation relative thereto. The conveyor bed will be discussed in detail, below. 
     The vibratory conveyor  11 , as discussed, above, includes a reciprocally movable conveyor bed, which is generally indicated by the numeral  20 . The conveyor bed  20 , has a bottom surface  21 , and which is positioned in spaced relation relative to the base frame  13 . For purposes of the present application the base frame, and conveyor bed,  13  and  20 , respectively, constitute first and second, spaced objects which cooperate together, and wherein at least one of the first or second spaced objects moves, one relative to the other. As will be appreciated from the drawings, and which is well known in the art, the drive assembly  14  imparts energy or force into the base frame which is subsequently transmitted to the conveyor bed  20 , so as to facilitate a reciprocal motion of the conveyor bed  20  relative to the base frame  13 . This reciprocal motion is caused, at least in part, by the effect of a multiplicity of leaf spring assembles which are generally indicated by the numeral  22 , and which couple the conveyor bed  20  to the base frame  13 . The respective leaf spring assemblies will be discussed in the paragraphs below. As will be seen from a study of  FIG. 1 , the electrical grounding arm  10  as seen in  FIG. 1 , and following, provides an electrical pathway between the conveyor bed  20 , and the frame  13 , so as to allow an effective dissipation of any static electrical build-up which might occur between these two objects. As best seen in the drawings as provided, and which further is well known in the art, individual mounting fixtures  23  are respectfully attached to each of the base frame  13 , and conveyor bed  20 . The respective mounting fixtures  23 , have a base plate  24 , and which is affixed, as by welding or the like, to the respective base frame  13 , or conveyor bed  20 . The base plate  24 , therefore, provides an electrical connection to these respective assemblies. Still further, and mounted on the base plate  24 , and extending laterally outwardly relative thereto is a post  25  which is also formed of an electrically conductive material. The outwardly extending post has opposite sides  26 . Further, fastener apertures, which are generally indicated by the numeral  27 , pass or extend through the outwardly extending post  25 . This is seen in  FIG. 2 . 
     As seen in the drawings, the vibratory conveyor  11  utilizes individual leaf springs  30  of traditional design, and which moveably support the conveyor bed  20  in spaced relation to the base frame  13 . The respective leaf springs are well known, and have a main body  31  with opposite first and second ends  32  and  33  respectively. As seen in  FIG. 1 , the respective leaf springs  31  extend upwardly from the base frame  13  to support the conveyor bed  20  in spaced relation relative thereto. As seen in  FIG. 2 , fastener apertures  34  are formed in the opposite first and second ends  32  and  33  respectively. Further threaded fasteners  35  are provided, and which pass through the coaxially aligned apertures  27  and  34 , respectively, so as to secure the first and second ends  32  and  33 , of the main body  31 , to the respective opposite sides  26 , of the outwardly extending post  25 . A clamping plate  36 , of traditional design, is provided, and which is operable to sandwich the respective first and second ends  32  and  33  of the individual leaf springs between the clamping plate  36 , and the opposite sides  26  of the outwardly extending post  25 . This fastening technique is well known in the art. 
     The electrical grounding arm  10  as seen in  FIG. 1 , and following, includes an elongated main body which is generally indicated by the numeral  40 . The elongated main body is electrically conductive, and further has a first end  41 , and an opposite second end  42 . The main body has a length dimension, as measured between the opposite first and second ends  41  and  42 , and which is greater than a length dimension of the respective individual leaf springs  30 , as previously described. Still further, the main body  40  has a width dimension which is variable, but which is typically not greater than the width dimension of the multiplicity of leaf springs  30  as earlier described. The main body  40  further has an intermediate portion  43 , and which is located between the first and second ends  41  and  42 . As seen in the drawings, the main body  40  has a width dimension which, on the one hand, diminishes when measured in a direction extending from the first and second ends respectively  41  and  42 , and toward the intermediate portion  43 ; or, on the other hand, increases when measured from the intermediate portion  43 , and in the direction of the first and second ends  41  and  42 , respectively. As illustrated in the drawings, the main body  40  has spaced, generally longitudinally extending peripheral edges  44 , and which extend between the opposite first and second ends  41  and  42 . Still further, the main body  40  has an exterior facing surface  45 . As will be recognized from the drawings, the electrical grounding arm  10  has an exterior facing surface  45  which has a unique geometry such that no portion of the exterior facing surface of the electrical grounding arm has a region upon which a source of a fluid may pool, or collect, so as to create an unsanitary condition as may be the case when a vibratory conveyor of the current design  11  is employed in food processing applications. As can be seen by reference to  FIGS. 2 and 4 , the main body  40  has a geometry which includes a curvature in the main body  40 , and which extends longitudinally relative thereto, and between the first and second ends  41  and  42  respectively. As illustrated in the drawings ( FIG. 5 ), the longitudinally extending peripheral edges  44  include a first peripheral edge  46 , which is substantially straight along a preponderance of its length; and a second peripheral edge  47 , and which is spaced therefrom, and which has a predetermined curvature as seen in  FIGS. 2 and 5 . The geometry of the main body  40  provides other benefits as will be discussed in greater detail, below. 
     The main body  40  of the electrical grounding arm  10  includes a pair of laterally extending arms that are generally indicated by the numeral  50 , and which are individually mounted to, or made integral with, the first and second ends  41  and  42 , thereof. The pair of laterally extending arms  50  include a first arm  51 , which extends laterally outwardly from the first end  41 ; and a second arm  52  which extends laterally outwardly relative to the second end  42  of the main body  40 . Each of the first and second arms  51  and  52  are formed of a first portion  53  which is made integral with, and extends outwardly relative to the opposite first and second ends  41  and  42  respectively. Still further the respective first and second arms  51  and  52  has a second portion  54 , and which is made integral with the first portion  53 , and which is positioned substantially perpendicular relative thereto. The second portion  54  has a given angular geometry relative to the first portion, and it further has a pair of fastening apertures  55  which are formed therethrough. Still further, a predetermined gap  56  is defined between the second portion  54 , and the respective first and second ends  41  and  42  respectively. As will be appreciated from the drawings, the second portion  54  is sandwiched, or otherwise clamped between the respective ends  32  and  33  of one of the leaf springs  30  as illustrated in the drawings, and one of the opposite sides  26 , of the outwardly extending post  25 , and which are made integral with a mounting fixture  23 . The fastening apertures  55  are formed in a fashion so that they individually coaxially align with, and can receive therethrough the individual fasteners  34  which extend through the outwardly extending post  25 . Again, the leaf springs, and the second portion  55  are held in place by the clamping plate  36 . As will be recognized in this arrangement, the elongated main body  40  of the grounding arm  10  is clamped into a secure, electrically conductive relationship relative to the outwardly extending post  25  thereby securably electrically coupling the main body  40  in an orientation so as to effectively conduct electrical current between the vibratory conveyor bed  20 , and the underlying and spaced base frame  13 . 
     As seen in the drawings, the present electrical grounding arm  10  has a unique geometry which provides an effective means for the electrical grounding arm  10  to dissipate stress which is imparted to the main body  40  by the reciprocal motion of the conveyor bed  20 . The motion of the conveyor bed  20 , of course, causes a corresponding motion to the individual leaf springs  30 , and which support the conveyor bed  20  in spaced relation relative to the base frame  13 . In view of the nature of the movement of the respect leaf springs  30  as illustrated, the bending stress imparted by the movement to the main body  40  is dissipated by the geometry of the main body  40  so as to inhibit any stress related damage from being imparted to the electrical grounding arm  10 . In this regard, the unique geometry features of the main body  40  include that it is curved. This is seen in  FIG. 2 . Still further, the unique width dimensions of the main body, that is, that the width of the main body  40  diminishes when measured from the opposite first and second ends  41  and  42  towards the intermediate portion  43  ( FIG. 5 ) is effective, to so some degree, to dissipate the stress imparted to the main body  40  by the reciprocal motion of the conveyor bed  20 . Still further and as illustrated, ( FIG. 1 ), it will be seen that the peripheral edges,  60 , of the first and second ends of the respective leaf springs  32  and  33  are generally perpendicular relative to the longitudinal axis of the respective springs. However, as will be recognized, ( FIG. 3 ), the first portion  53  of the respective pair of laterally extending arms  50  is oriented in an angularly outwardly extending orientation relative to ends of the respective leaf springs  30 . Additionally, the second portion  54  is oriented in substantially parallel, juxtaposed relation relative to the first and second ends  32  and  33  of the respective leaf springs  30 . It has been discovered that the geometry, as illustrated, and described herein, is effective in dissipating the bending stress imparted by the reciprocal motion of the conveyor bed  20  to the main body  40  thereby enhancing the longevity of the grounding arm&#39;s operational lifetime, and preventing the grounding arm from breaking electrical contact between the conveyor bed  20  and the base frame  13 . 
     OPERATION 
     The operation of the described embodiment of the present invention is believed to be readily apparent, and is briefly summarized at this point. 
     Referring now to the drawings, it will be seen that the present invention includes, or is directed to, an electrical grounding arm  10  which has an elongated, electrically conductive main body  40 . The main body  40  has opposite first and second ends  41  and  42 , and which are respectively electrically coupled to a first and second spaced object, here indicated by the numerals  13  and  20 , respectively, and which movably cooperate, together. Still further, in the arrangement, as illustrated, the main body  40  of the electrical grounding arm  10 , has a predetermined geometry, and wherein the motion of one of the first or second objects  13  and  20 , respectively, imparts motion to the electrical grounding arm  10 . The motion of the electrical grounding arm  10  imparts stress to the main body  40  thereof. The geometry of the main body  40  of the electrical grounding arm  10  dissipates the stress imparted to the main body  40  so as to inhibit stress related damage from being imparted to the electrical grounding arm  10 . As earlier disclosed, past attempts to electrically couple two moving objects together has resulted in failure of the electrical coupling due to the bending forces imparted on the electrical pathway coupling the two objects together. 
     In the present invention, the main body  40  of the electrical grounding arm  10  has an exterior facing surface  45 . The geometry of the main body  40  of the electrical grounding arm  10  has no exterior facing surfaces  45  upon which a source of a fluid may pool or collect so as to create an unsanitary condition. This feature is particularly important when a vibratory conveyor  11 , such as illustrated in  FIG. 1  is employed in food processing applications. 
     As seen in the drawings, the main body  40  of the electrical grounding arm  10  has an intermediate portion  43 , and which is located between the first and second ends  41  and  42  thereof. Further, the main body  40  has opposite, longitudinally oriented peripheral edges  44 . The main body  40  has a width dimension which increases when measured in a direction extending from the intermediate portion  43  of the main body  40  and in the direction of the first and second ends  41  and  42  thereof. As seen in the drawings, at least one of the opposite, longitudinally oriented peripheral edges  44  of the main body  40 , has a predetermined curvature which is generally indicated by the numeral  47 . 
     The main body  40  of the electrical grounding arm  10  has a pair of laterally extending arms  50 , and which are individually mounted to the first and second ends  41  and  42  thereof. The respective laterally extending arms have a first portion  53  which is made integral with the main body  40 , and a second portion  54  which is made integral with the first portion  53 . The first and second portions  53  and  54  are oriented in a perpendicular relationship, one relative to the other. In the arrangement as seen in the drawings, the first object comprises a base frame  13  for a vibratory conveyor  11 , and the second object comprises a reciprocally movable conveyor bed  20 , and which is held in spaced relation relative to the base frame  13  by a multiplicity of leaf springs  30 , and which extend in a given direction outwardly from the base frame  30 , and which further support the conveyor bed  20  for movement relative to the base frame  13 . The respective leaf springs  30  are mounted to each of the base frame  13 , and conveyor bed  20  by electrically conductive mounting fixtures  23 . The second portion  54  of the laterally extending arms  50  are located between at least one of the leaf springs  30 , and one of the underlying mounting fixtures  23 , and which is located on, and electrically coupled to either the base frame  13 , or the conveyor bed  20 . In this arrangement, the electrical grounding arm  10  is electrically coupled, as by clamping, to the base frame  30 , and the conveyor bed  20 . The geometry of the electrical grounding arm  10  is such that the intermediate portion  43  of the main body  40  is located in predetermined spaced relation relative to the underlying leaf springs  30 . 
     Therefore, it will be seen that the present invention  10  provides a convenient means whereby spaced objects, here shown as a base frame  13 , and a conveyor bed  20 , and which is reciprocally movable relative thereto, may be electrically coupled together in a predetermined way so as to provide a dissipation of a static electrical charge in a manner not possible heretofore. The present invention is robust; resists bending and other stress related damage which might be imparted to same by the continued reciprocal movement of the conveyor bed; and further, has a geometry which is easy to clean and prevents the accumulation of liquids and other materials which might pool or collect on the exterior facing surface  45  so as to create an unsanitary and unsafe environment. 
     In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific feature shown and described since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalence.