Abstract:
Provided herein is an article which is by its nature readily clamped to the end portion of a metallic ware employed as a cable support rack, and driven into the ground. An insulative wedge according to the invention renders a linear metallic ware to not be in contact with the ground, and has the further advantage of comprising an end portion which penetrates earth readily but which is simultaneously deflected by subterranean conduits into which it may inadvertently come into contact with, thereby not interfering with the integrity of subterranean utilities, including wires, pipes, conduits, and the like.

Description:
TECHNICAL FIELD 
     This invention relates to an article useful for insulating metallic objects from ground contact. More specifically, it relates to an insulative wedge or shoe that is adapted to be attached to the end of a portion of a metallic frame or rail to enable the support of the metallic frame or rail in the earth in a state in which the frame or rail is electrically insulated from ground contact. 
     BACKGROUND 
     The development of pristine real estate and the maintenance of developed real estate often entails work by craftsman in several of the known trades, such as electricians, plumbers, linesmen, cable television installers, telephone installers, sewer lines, and natural gas lines, in addition to operators of heavy earthmoving equipment. It is commonplace for various conduits to be located in a subterranean environment, such as in the cases of buried pipes and wires. 
     A cable rack is a structural support framework which may exist in any configuration desired by the user. Cable racks are used to support cables and wires in a location which maintains their functionality while at the same time supporting them away from an area in which work, such as excavation, is carried out. To cite but one example, telecommunications companies drive steel bars directly into the ground in order to provide a vertical beam from which various wares, including cables may be hung. Such a practice is dangerous insomuch as the possibility exists that a steel bar so driven may on occasion strike an electrical supply line and pierce through its insulation, thus providing an effective electrical contact between the contents of a cable so breached and the steel bar. If a person is holding such a steel bar while it pierces such insulation, the person may become instantly in contact with an electrical potential of lethal electromotive force. 
     As a measure of safety, some telecommunications companies specify that a person who drives such bars into the ground must wear rubber gloves. 
     The prior art has addressed electrically insulating various metallic objects. For example, Re-reisve U.S. Pat. No. 26,779 discloses a street boundary post with a hollow space opening at least upwards, and having a holding arrangement for a rod-type snow sign. U.S. Pat. No. 5,022,618 provides a mailbox support apparatus comprising: a) a ground mount stake; b) a hollow post member of greater diameter than the ground mount stake, the hollow post member having a first open end and a second open end remote from and parallel to the first open end; c) spacer members detachably mountable upon the ground mount stake and sized to provide a pressure fit of the hollow post member upon the ground mount stake when the ground mount stake with the spacer members mounted thereon is longitudinally inserted into the first open end of the hollow post member; d) a mounting plate; e) a means for attaching the mounting plate to the second open end of the hollow post member; and f) a means for attaching the mounting plate to a bottom of a mailbox. U.S. Pat. No. 5,755,431 teaches a mounting fitting for securing a hollow post having an inner surface to a stake having a cross sectional configuration defining an outer surface, the mounting fitting comprising: a) a first member having an inner surface defining an aperture, in which the aperture includes a first leg and a second leg formed about a first axis and a third leg and a fourth leg formed about a second axis, and in which the first and second axes intersecting at a center, and in which the first, second, third, and fourth legs each including a terminal end remote from the center, the first member further including first sizing means for elastically deforming the inner surface and enlarging the aperture whereby the first member slidably accommodates stakes of varying sizes, the first sizing means including a slot formed in the inner surface; and b) a second member connected to the first member, the second member defining a peripheral surface adapted to be engageable with the hollow post to frictionally couple the hollow post to the mounting fitting. 
     However, of all the devices in the prior art, none is suitable for enabling the support of a metallic vertical beam portion of a cable rack or other framework in an insulated condition from the ground. Further, the prior art does not provide a means by which existing cable rack support framework may be rendered to have its end portion supported by the ground in an insulated condition. Further, the prior art does not provide a means by which an existing cable rack supporting framework may be conveniently pounded into the ground while being in an insulated condition with respect to the ground, which means is provided with a feature that greatly reduces or eliminates the propensity for breaching underground conduits, such as cables and pipes. However, by my invention, there is now available a device which provides the aforesaid means, as well as other advantages and features, which will become apparent to those skilled in the art after reading and understanding the contents of this specification. 
     SUMMARY OF THE INVENTION 
     The present invention provides an insulative wedge article for attachment to the ends of linear metallic wares. An article according to the invention comprises: a base portion and a clamping portion. The base portion exists substantially in the shape of a rectangular solid, and has a length dimension, a width dimension, a thickness dimension, a top surface, a bottom surface, a first end portion, and a second end portion. According to a preferred form of the invention, the top surface and the bottom surface taper towards one another in an intersecting orientation directed towards the first end portion. The second end portion of the base portion comprises a planar ledge of substantially rectangular dimensions having longest and shortest sides, wherein the length dimension of the planar ledge extends in the same direction as the length dimension of the base portion, and wherein the width dimension of the planar ledge extends in the same direction as the width dimension of the base portion. The planar ledge portion has a thickness dimension which is less than the thickness dimension of the base portion. The planar ledge comprises at least one locator block disposed thereon, and the ledge spans the entire width dimension of the base portion, and spans at least 25% of the length dimension of the wedge. The second end portion further comprises a plurality of fastener bosses disposed about the outer perimeter of the planar ledge along each of its longest sides, and the base portion further including a locator well in its top surface portion. The clamping portion exists substantially in the shape of a rectangular solid, and has a length dimension, a width dimension, a thickness dimension, a top surface, a bottom surface, a first end portion, and a second end portion. The bottom surface portion of the clamping portion includes at least one depression that is adapted to receive the at least one locator block. The first end portion of the clamping portion includes a tongue portion which protrudes lengthwise from its first end portion. The tongue portion further comprises a hook means which is adapted to connectively engage the locator well on the base portion. The clamping portion further comprises a plurality of fastener bosses disposed about the outer perimeter of each of its longest sides. The tongue portion is engaged in the locator well to provide an insulative wedge according to the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an assembled insulative wedge according to the invention; 
     FIG. 2 is a perspective view of the base portion of an insulative wedge according to the invention; 
     FIG. 3 a  is an overhead view of the base portion of an insulative wedge according to the invention; 
     FIG. 3 b  is a side elevational view of the base portion of an insulative wedge according to the invention; 
     FIG. 4 is perspective view of the clamping portion of an insulative wedge according to the invention; 
     FIG. 5 is an overhead view of the bottom of a clamping portion of an insulative wedge according to the invention; 
     FIG. 6 is a side elevational view of the clamping portion of an insulative wedge according to the invention; 
     FIG. 7 a  shows an overhead view of a length section of a prior art linear metallic ware which is suitable to be supported in an insulative wedge according to the invention; 
     FIG. 7 b  shows an end view of a length section of a prior art linear metallic ware which is suitable to be supported in an insulative wedge according to the invention; 
     FIG. 8 shows a length section of a prior art linear metallic ware which is supported in an insulative wedge according to the invention 
     FIG. 9 is a perspective view of an assembled insulative wedge according to an alternate form of the invention; 
     FIG. 10 is a perspective view of an assembled insulative wedge according to an alternate form of the invention; and 
     FIG. 11 is a perspective view.of an assembled insulative wedge according to the invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, and initially to FIG. 1, there is shown a perspective view of an insulative wedge  10  according to the invention. In this figure, the insulative wedge is seen to comprise a base portion  14 , and a clamping portion  12 . The clamping portion has a plurality of holes  73  through its surface. The insulative wedge  10  has a width dimension denoted by W. The thickness of the planar ledge portion  26 , as later described, is also shown as T 2 . 
     FIG. 2 shows a perspective view of the base portion  14  of an insulative wedge according to the invention. In this figure is seen the top surface  43  and bottom surface  45  of the base portion, which taper towards one another in an intersecting orientation directed towards the first end portion  16 , at which is effectively disposed a curved tip. The base portion is preferably made from an insulative material, such as polyethylene or polypropylene, and is preferably made by an injection molding process. Thus, there are strength ribs  18  disposed along the length of the top surface portion, between which are depressions  20 . At the second end portion  75 , there is a planar ledge  26  having substantially rectangular dimensions, with longest sides and shortest sides. The length dimension of the planar ledge portion  26  extends in the same direction as the length dimension of the base portion  14  itself, and the width dimension of the planar ledge portion  26  extends in the same direction as the width dimension of the base portion  14  itself. Disposed about the outer periphery of the planar ledge portion along the longest sides of the substantially rectangular planar ledge is a plurality of fastener bosses  22 . In addition, in a preferred form of the invention, there is at least one locator block  24  disposed on the planar ledge portion. There is a locator well  30  disposed in the top surface portion  43  of the base portion  14 , which is a depression that is adapted to receive a complementary mating hook means which is an element of the clamping means  12 , as later set forth. According to a preferred form of the invention, the thickness T 2  (FIG. 1) of the planar ledge portion  26  is less than the thickness dimension of the base portion  14  as most clearly represented by T 1  in FIG. 3 b . According to a preferred form of the invention, the planar ledge portion  26  is of uniform thickness along its length. It is preferred that the length dimension of the planar ledge portion is at least 25% of the value of the overall value of the length dimension of the base portion taken as a whole, including the length of the planar ledge portion. 
     FIG. 3 a  shows a top view of the base portion  14  of FIG. 2, including a representation of the overall value of the length dimension L. In this figure are shown the first end portion having curved tip  16 , the strength ribs  18  and depressions  20  therebetween. The engaging well  30  is shown as a depression in the top surface  43  of the base portion  14 . At the second end portion  75  of the base portion  14  is shown the planar ledge portion  26 , having locator blocks  24  disposed thereon. According to a preferred form of the invention, the locator blocks have holes  73  disposed through their bodies, which holes extend through the thickness dimension T 2  of the planar ledge portion  26 , as shown in FIG.  1 . While depicted in the form of rectangular solids which protrude upwards from the surface of the planar ledge portion, the locator blocks  24  may be of any geometric form such as cylindrical solid, pyramidal solid, star-shaped solid, triangular solid, etc., provided the clamping portion  12  is provided with a complementary depression that is adapted to receive the locator blocs when the clamping portion  12  is in its normal position, as described elsewhere herein. In one preferred form of the invention, there are channels disposed in the planar ledge portion  26 , which channels extend in the same direction as the length dimension of the base portion viewed as a whole. Preferably, the channels are linear, continuous, and are uniform in their depth, which may be any depth desired. The fastener bosses  22  are also shown in their preferable locations disposed about the outer periphery of the planar ledge portion along its longest sides. 
     FIG. 3 b  shows a side perspective view of the base portion  14  of an insulative wedge  10  according to the invention. For the sake of clarity, depicted in this figure are the locator blocks  24 , the bottom surface portion  45 , top surface portion  43 , and first end portion having a rounded tip at  16 , and thickness T 1  is also shown. The top surface  43  may lie in a single plane, or may be a plurality of planes, such as when it is angled at a point P along its length, wherein the angle is any value between 160 and 180 degrees and point P may be located anywhere along the length of the top surface  43 . The present invention includes the presence of a plurality of points such as point P along the length of the top surface  43 . Likewise, the bottom surface  45  may lie in a single plane, or may be a plurality of planes, such as when it is angled at a point Q along its length, wherein the angle is any value between 160 and 180 degrees, and point Q may be located anywhere along the length of the bottom surface  45 . The present invention includes the presence of a plurality of points such as point Q along the length of the top surface  45 . 
     In FIG. 4 is a perspective view of the clamping portion  12  of an insulative wedge  10  according to the present invention. The clamping portion  12  exists substantially in the form of a rectangular solid and has a length dimension (“L” in FIG.  6 ), a width dimension, a thickness dimension, a top surface ( 54  in FIG.  6 ), a bottom surface  36 , first end portion  69 , and a second end portion  47 . The bottom surface portion  36  includes at least one depression  34  that is shapely configured complimentary to, and as such is thus adapted to receive at least one of the locator blocks  24  from the base portion  14 . The first end portion  69  further includes a tongue portion  38  which protrudes lengthwise from the first end portion, and the tongue portion further comprises a hook means  40  which is configured to connectively engage the engaging well  30  on the base portion  14  when the clamping portion  12  is connectively affixed to the base portion  14  using fasteners, such as  101  from FIG.  1 . Although FIG. 1 only shows a single nut and bolt  101  in the bosses, the present invention intends for all bosses capable of receiving fastening means to be so fitted. While the clamping portion  12  and base portion  14  may be connected to one another using any conventional fastening means, the use of nuts and bolts is preferred. Also shown in FIG. 4 are fastener bosses  32  disposed about the outer perimeter of each of its longest sides. According to a preferred form of the invention, the fastener bosses  22  and  32  are cast-in features of each of the clamping portion  12  and base portion  14 , when these elements are, as in a preferred embodiment, single articles of manufacture made by a plastic injection molding process. 
     FIG. 5 is an overhead view of the underside of a clamping portion  12  of an insulative wedge  10  according to the invention showing the bottom surface  36  having depressions  34  in its surface. Also shown are fastener bosses  32  disposed about the outer perimeter of each of its longest sides. The tongue portion  38  and its hook means  40  is also shown. 
     FIG. 6 is a side perspective view of a clamping means  12  of the invention, having top surface  54 , bottom surface  36 , tongue portion  38  and hook portion  40 . Preferably, the tongue  38  and hook means  40  are cast-in features of each of the clamping portion  12  when these elements are, as in a preferred embodiment, single articles of manufacture made by a plastic injection molding process. 
     FIG. 7 a  shows a linear metallic ware according to the prior art, which is an extruded stock having a flat portion  42  and two side rails  44 , as more clearly shown in FIG. 7 b  which is a cross-sectional view of the metallic ware of FIG. 7 a . There are voids  103  disposed along the length of the extruded stock at regularly spaced intervals so as to render the stock to take on an appearance somewhat reminiscent of a ladder. Such stock is commonly used in creating cable racks by workmen. 
     FIG. 8 shows a linear metallic ware, such as that shown in FIGS. 7 a  and  7   b  clampedly disposed in the space defined as in-between the bottom surface portion of the clamping portion and the planar ledge of the base portion. This configuration is arrived at by placing the linear metallic ware into the base portion so that the rails  44  of the linear metallic ware reside in the channels  28  of the base portion  14 , with the voids  103  being disposed about the locator blocks  24 , for added stability. Next, the clamping portion  12  is placed into position over the linear metallic ware so that the hook means  40  engages in the engaging well  30 , so as to provide a configuration as shown in FIG. 1 with the linear metallic ware disposed in the location of the hole O. Then, fastening means are disposed commonly in each of the fastening bosses  32  and  22  and tightened to provide the rigid construct such as that in FIG.  8 . 
     The construct of FIG. 8 may be driven into the ground without worry that an underground cable or other conduit will be breached owing to the ability of the curved end  16  to be deflect itself away from an underground conduit. In addition, because an insulative wedge according to the invention is constructed from materials which are electrically insulating, there is no contact between the linear metallic ware selected and the ground. 
     FIGS. 9,  10 , and  11  depict alternate embodiments of the invention when the fasteners employed are dowel pins, rivets, and screws. 
     A device according to the present invention is suitable for attachment to the ends of a variety of linear metallic wares, including bars having a cross-section selected from the group consisting of: round, oval, square, rectangular, triangular, pentagonal and hexagonal. In addition, a device according to the invention is suitable for attachment to the end of angle iron, or L-shaped beams, and I-beams as well. 
     Consideration must be given to the fact that although this invention has been described and disclosed in relation to certain preferred embodiments, obvious equivalent modifications and alterations thereof will become apparent to one of ordinary skill in this art upon reading and understanding this specification and the claims appended hereto. Accordingly, the presently disclosed invention is intended to cover all such modifications and alterations, and is limited only by the scope of the claims which follow.