Abstract:
Provided herein are devices useful for guiding cables, wires, cords, and the like. A device according to the present invention is particularly useful for guiding a cable that is used in providing an external liquid-level gauge on an oil tank. A cable guide means according to the present invention provides gauging means for judging the liquid levels in tanks which are more reliable than provided by the prior art, and which are essentially maintenance-free over their lifetime.

Description:
TECHNICAL FIELD 
   This invention relates generally to tanks in which liquid substances are stored. More particularly, it relates to gauges which are affixed to an external surface of a storage tank, for indicating the level of a liquid substance inside the tank. 
   BACKGROUND 
   Above-ground tanks for storing liquids such as water and petroleum products have been in widespread use for over a century. In that time various devices have been contrived for enabling a workman associated with tank or tank farm maintenance to quickly judge the level of a liquid substance within a storage tank. One method for judging the level of a liquid in a tank includes a vertical tube mounted to an outside surface of a tank, with a weight suspended within the tube by a cable that is connected at its other end to a float contained within the tank through one or more pulleys. Prior art setups for this have been seen to be relatively complicated, as shown in U.S. Pat. Nos. 1,741,792 and 1,879,805. Such systems, with all their attendant components, make for an expensive way to do what should be a simple task. 
   Some workers, such as the inventors of U.S. Pat. D 334,718 have attempted to simplify external tank gauges. However, the design provided by these workers is not without inherent problems, as explained further in other parts of this specification. Thus, the present invention provides an inexpensive and reliable means for judging the liquid level in a tank by glancing at an external, mechanically-operated sight gauge. 
   SUMMARY OF THE INVENTION 
   The present invention provides devices useful for guiding cables, wires, and cords and the like. A device according to the invention comprises: a first frame member having a length dimension, a top portion, and a bottom portion; and a second frame member having a length dimension, a top portion, and a bottom portion. There is a first lower brace that is connectively attached to the bottom portion of the first frame member and the second frame member. There is an upper brace that is connectively attached to the top portion of the first frame member and the second frame member. There is further a first axle, having a length dimension, and the first axle is disposed between the first frame member and the second frame member such that the length dimension of the first axle is substantially perpendicular to the length dimension of the first and second frame members. The first axle further comprises a pulley rotably disposed on it. There is also a second axle, having a length dimension, and the second axle is disposed between the first frame member and the second frame member such that the length dimension of the second axle is substantially perpendicular to the length dimension of the first and second frame members. The second axle further comprises a second pulley rotably disposed on it as well. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the annexed drawings, 
       FIG. 1  shows a perspective view of a liquid storage tank having an external gauge according to the prior art; 
       FIG. 2  shows a perspective view of a cable guide means according to one form of the present invention; 
       FIG. 3  shows and overhead view of a cable guide means according to one form of the present invention; 
       FIG. 4  shows a perspective view of a liquid storage tank having an external gauge according to one form of the present invention; 
       FIG. 5  shows a perspective view of a liquid storage tank having an external gauge according to one form of the present invention with a cover and optional stabilizer; and 
       FIG. 6  shows and exploded view of a cable guide means according to one form of the present invention and a means by which it may be shielded from the environment. 
   

   DETAILED DESCRIPTION 
   Referring to the drawings and initially to  FIG. 1  there is shown a liquid storage tank according to the prior art. Although liquid storage tanks may take on any physical shape, it is common for such tanks to be configured as a cylinder. In this  FIG. 1 , the storage tank contains a liquid  1 , present at a height h. There is a gauge tube  33  that functions as a gauge that is mounted externally to the tank by means of conventional fastening means, such as brackets, screws, rivets or the like. The gauge tube  33  may comprise a hollow tube, made from a translucent material such as glass, methyl methacrylate, polycarbonate, polypropylene, etc., and preferably includes graduation marks on its surface. There is a weight  31  within the gauge tube  33 , which weight serves as an indicator and is attached to a first end of a cable  29 , wherein the second end of the cable is attached to a float  47  disposed within the tank through a hole  40 . In this prior art embodiment, the cable  29  is supported by means of a framework which comprises a rod  27  that is supported by two pairs of “feet”  86 , which may be comprised of shorter sections of the material from which rod  27  is fabricated, such as ¼″ diameter rod stock, and which feet are simply welded to the rod  27 . The rod  27  serves as a support from which pulleys  23  and  25  hang, thus enabling the cable  29  to pass from the weight  31 , over pulley  25 , through the underside of the “v” formed by each pair of legs, over pulley  23 , and down into the tank  21  through the hole  40 , where the second end of the cable  29  is attached to the float  47 . Thus, observing the position of the weight  31  in relation to a graduated scale on the gauge tube enables one to glance at the gauge tube and have a fairly accurate understanding of the liquid level in the tank, as the length of cable, vertical position of the gauge tube on the exterior of the tank, and location of graduations on the tube are all readily adjustable by one of ordinary skill, so as to render easy calibration of the gauge to correspond with the level of the liquid in the tank. 
   Although useful, a system as shown in  FIG. 1  is not without its drawbacks. For example, the cable guide means which comprises the rod  27 , sets of feet  86 , and pulleys  23  and  25  tends to be moved as a whole by environmental forces, particularly wind gusts, and possibly torque exerted by the cable tension being out of perfect alignment, over time, which can cause this cable guide means to be sufficiently skewed as to render the weight  31  to be non-indicative of the level of the liquid within the tank by virtue of attendant fouling of the pulleys, flipping over of the cable guide means, or other reasons. 
     FIG. 2  shows a perspective view of a cable guide means according to one form of the present invention. There is a first frame member  3  having a length dimension indicated by L, a top portion T, and a bottom portion B. There is also a second frame member  5  having a corresponding length dimension, a top portion, and a bottom portion as well. The first and second frame members  3 ,  5  may be comprised of any material, including composites, polymers, wood, metals, alloys, etc. in a wide possible range of shapes and sizes; however, in a preferred embodiment the first and second frame members  3 ,  5  are preferably comprised of sheet metal, with stainless steel being especially preferred. In such an embodiment, the top portion T and bottom portion B of each frame member are edges; however, these could just as easily represent the top portion of a frame member which is comprised of, say, bar stock, rod stock, etc. There is a first lower brace  15  connectively attached to the bottom portion of said first frame member  3  and said second frame member  5 . The first lower brace  15  may be comprised from any material, as aforesaid. However, in one preferred embodiment the first lower brace  15  is comprised of sheet metal, with a stainless steel being especially preferred. In a preferred embodiment, the first lower brace  15  includes a hole  66  through its surface, which is instrumental in attaching a cable guide means  10  according to the invention to the top of a storage tank. This may be accomplished by a machine screw (not shown) or other conventional fastening means disposed through the hole  66  and threadingly engaged with the top of the tank. 
   In one optional embodiment, there is a second lower brace  17  connectively attached to the bottom portion of said first frame member  3  and said second frame member  5 . The second lower brace  17  may be comprised from any material, as aforesaid. However, in one preferred embodiment the second lower brace  17  is comprised of sheet metal, with a stainless steel being especially preferred. In a preferred embodiment, the first lower brace  17  includes a hole  68  through its surface, which is instrumental in attaching a cable guide means  10  according to the invention to the top of a storage tank. 
   One form of the invention also includes an upper brace  19  connectively attached to the top portion of the first frame member  3  and the second frame member  5 . The upper brace  19  may be comprised from any material, as aforesaid. However, in one preferred embodiment the upper brace  19  is comprised of sheet metal, with a stainless steel being especially preferred. In a preferred embodiment, the upper brace  19  comprises a top surface and includes a hole  67  through its surface, which is instrumental in attaching a cover over the cable guide means  10  ( FIG. 6 ) by means of a threaded stud, to protect the assembly from environmental conditions. 
   There is a first axle  7 , having a length dimension, wherein said first axle  7  is disposed between the first frame member  3  and the second frame member  5  such that the length dimension L of the first axle  7  is substantially perpendicular to the length dimension of the first frame member  3  and the second frame member  5 . The first axle  7  further comprises a first pulley  13  rotably disposed thereon, such that the first pulley  13  is free to rotate about the first axle  7 . 
   There is a second axle  9 , having a length dimension, wherein the second axle  9  is disposed between the first frame member  3  and the second frame member  5  such that the length dimension of the second axle  9  is substantially perpendicular to the length dimension L of the first frame member  3  and the second frame member  5 . The second axle  9  further comprises a second pulley  11  rotably disposed thereon such that the second pulley  11  is free to rotate freely about the second axle  9 . 
   Thus, in one form of the invention, the first and second frame members  3 ,  5  are each comprised of sheet metal shaped in a substantially rectangular configuration, with each having one hole disposed through its surface at positions corresponding to locations  105 ,  107  ( FIG. 2 ) near each of their end portions, with the center of these holes being disposed preferably within about 1 to 3 inches from the end of the frame member. These holes serve as locations at which the axles  7 ,  9  are to be mounted or connectively attached at their ends to the first and second frame members respectively. In one embodiment, the holes through which the axles  7 ,  9  are mounted are round holes, and in another embodiment, they are oval shaped to enable adjustment of the position of an axle mounted within them. In one embodiment, the first lower brace  15  and second lower brace  17  are substantially square or rectangular pieces of sheet metal which are welded to the first and second frame members  3 ,  5  in one preferred embodiment their bottom edges. Similarly, the upper brace  19  is welded to each of the first and second frame members  3 ,  5  and in one preferred embodiment this is at their top edge. The first and second axles  7 ,  9  may be pieces of rod stock, or simply bolts, or any functional equivalent, which are then positioned in the holes in the first and second frame members at positions corresponding to locations  105  and  107 . The first frame member  3  and second frame member  5  each have corresponding holes through which, or to which, the axle means  7 ,  9  are commonly disposed Thus, in one embodiment, a bolt which serves as axle  9  is inserted into a hole at  107 , and then a pulley such as  11  is placed over the bolt/axle  9 . Subsequently, the bolt is placed through the corresponding hole in the first frame member  3  and finally capped with a nut on its end. The other axle  7  may be similarly comprised. Alternatively, the axles  7 ,  9  may be rod stock which is welded into position after fitment of each with a pulley at locations corresponding to  105  and  107  on each of the frame members. In one embodiment, the pulleys may be any pulley which is sized to fit over the axles such that the pulley is freely rotatable. 
     FIG. 3  shows and overhead view of a cable guide means  10  according to one form of the present invention. In this  FIG. 3  are shown the respective positions of the various elements of such combination, including the first and second frame members  3 ,  5 ; upper brace  19 ; first lower brace  15 ; second lower brace  17 ; first axle  7 ; second axle  9 ; first pulley  11 ; and second pulley  13 . An underside view of this same device appears identical to  FIG. 3 . Each of the upper brace  19 ; first lower brace  15 ; second lower brace  17  include holes ( 67 ,  66 ,  68  respectively) through them in this embodiment for reasons as explained elsewhere herein. 
     FIG. 4  shows a perspective view of a liquid storage tank  21  having an external gauge and utilizing a cable support means  10  according to one form of the present invention. In this  FIG. 4 , the device  10  from  FIG. 2  is seen mounted to the top of an oil storage tank. There is a graduated gauge tube  33  having a weight  31  disposed within it, which is suspended by cable  29  and counterbalanced by the float  47  within the tank. The cable  29  which is attached at one of its ends to the float  47  and which is attached at its other end to the weight  31 , passes from the float  47  through hole  40  in the top of the oil tank and over the first pulley. It then passes through a location that is between the first and second frame members  3 ,  5  of the cable guide means  10  and above the lower braces  15 ,  17  but below the upper brace  19  before passing over the second pulley on its way to the weight  31 . Since the lower braces  15 ,  17  of the cable guide means  10  each have a hole disposed through them, the present cable guide means  10  is readily attached to the top of the oil tank  21  by the use of fasteners, such as machine screws disposed through the holes  66 ,  68  on the lower braces and threaded into the top of the tank itself. This provides the ability to fix the cable guide means rigidly in place, thus precluding its becoming fouled by environmental conditions or torque forces exerted by the float&#39;s repeated up and down movement over time, which is a major advantage for oil tanks equipped with such a cable guide means  10 . Use of a cable guide means  10  according to the present invention in this regard renders sight gauges more reliable over time. 
     FIG. 5  shows a perspective view of a liquid storage tank using a cable guide means according to one form of the present invention as shown in  FIG. 4  and further comprising a cover  49  disposed over the cable guide means  10 , thus placing the cable guide means out of view. Such provision has a wide utility, from keeping insects from building nests in the cable guide means, to keeping rain and ice from forming on the pulleys and cable. In one embodiment, the cover  49  is held in place by a stabilizer  101 , which may be a strip of sheet metal that is screwed on one of its ends to the cover  49  and screwed on its other end to the top of the tank. In  FIG. 6  is shown a preferred method for affixing a cover  49  to a cable guide means  10  according to the invention, by providing a stud  71  to be disposed on the upper brace in an upward orientation. Then, by providing a hole in the cover  49 , the cover may be placed over the cable guide means  10  and secured in place with a wing nut  99 . 
   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. This includes subject matter defined by any combination of any one of the various claims appended hereto with any one or more of the remaining claims, including the incorporation of the features and/or limitations of any dependent claim, singly or in combination with features and/or limitations of any one or more of the other dependent claims, with features and/or limitations of any one or more of the independent claims, with the remaining dependent claims in their original text being read and applied to any independent claims so modified. This also includes combination of the features and/or limitations of one or more of the independent claims with features and/or limitations of another independent claims to arrive at a modified independent claim, with the remaining dependent claims in their original text being read and applied to any independent claim so modified.