Abstract:
A tank gauge for measuring the level of a liquid in a tank or other container is disclosed. The gauge comprises a float which floats on the surface of the liquid to be measured or monitored, mechanically linked to a direct drive system for indicating the level of the liquid with easily read numbered wheels. This direct drive system provides a one-to-one ratio of liquid level indication with the length of play of the chain.

Description:
RELATED U.S. PATENT APPLICATION DATA  
       [0001]     Applicant claims priority for this application to U.S. Provisional Application No. 60/725,973 filed on Oct. 12, 2005. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention described herein generally relates to improved mechanical tank gauges specifically designed for constant measuring or monitoring of the level of liquid in a tank or like container.  
       DESCRIPTION OF THE RELATED ART  
       [0003]     There are numerous types of devices used to measure or monitor the level of liquids in a tank or container. Closed containers preclude the use of visual measurement techniques and must rely on electronic or mechanical devices for measurement of liquid levels.  
         [0004]     Existing mechanical tank gauges use a string-like material or filament to connect a float to the gauge assembly. This string-like material or filament tends to fray, tangle, stretch, rot, and ultimately break, rendering the gauge useless. Further, existing mechanical gauges retract the string-like material or filament in a bobbin-like fashion whereby the string or filament is wound upon itself, increasing the diameter of the bobbin as more string is wound. This increasing diameter skews the accuracy of the measurement of the gauge. The disclosed gauge overcomes these problems by using a nickel plated brass beaded chain, also known as a ball chain, to attach the float to the gauge assembly and by providing a retraction mechanism whereby the diameter of the chain pulley, with the chain on it, remains the same when the chain is extended or retracted. The beaded chain allows the float to swivel without fraying, tangling, stretching, rotting, or breaking. Further, the disclosed tank gauge provides a direct drive grooved chain pulley which directly drives at least one numbered wheel, revealing the liquid level in the tank in a one-to-one ratio. Thus, the accuracy of the disclosed gauge remains true as the liquid level falls or rises.  
         [0005]     Existing gauges are not generally depth adjustable, requiring distributors to stock many different gauges for use in different depth tanks. The present invention is fully adjustable to all tank depths by using the chain which can be calibrated to a tank&#39;s specific depth by the installer. Moreover, to date, there is on the market no tank gauge other than the Red Fox™ that is designed specifically to measure inches to full. Heretofore, users have found it necessary to mark tanks with a message to indicate whether they were watching it for high tank or low tank status. With the disclosed invention, a tank can be measured to full or to empty, depending on the use of the Black Knight™ or Red Fox™ gauges.  
         [0006]     It should be noted that the disclosed tank gauge which indicates how many inches of liquid are left until the container is empty is known as the Black Knight™. The disclosed gauge which indicates how many inches remain before the container is full, is known as the Red FOX™. Both of these gauges have enjoyed considerable commercial success because of the advantages described, as well as the large numerical displays which are simple to read, the ease of attaching the disclosed gauge to a container or tank, the ease by which the gauge is calibrated to a specific tank, and its simple mechanical design with primarily non-corrosive materials.  
       SUMMARY OF THE INVENTION  
       [0007]     Generally, the Black Knight™ and Red Fox™ tank gauges are mechanical tank gauges designed for measuring the level of liquid in tanks and other containers. Incorporated into their design is a grooved chain pulley which directly drives at least one numbered wheel which indicates the liquid level in a one-to-one ratio. The grooved chain pulley is retracted by a spring which maintains tension on the ball chain connected to the weighted float which rides on top of the liquid in the storage tank.  
         [0008]     The disclosed tank gauge is easily calibrated to the specific depth of a tank in the following manner. Once the depth of the tank is determined (for example, 67 inches), the ball chain is pulled until the display reads 67 inches (the specific tank depth). The chain is marked and another 1½ feet of chain is extended. The chain at that point is secured with an eyelet. An eyelet is a standard device used on ball chains whereby the ball onto which the eyelet is snapped is precluded from passing through a hole sized to accommodate the ball without an eyelet attached. The chain is then cut below the point at which the eyelet is attached so that the eyelet remains at the bottom of the chain. The chain is then ready to use for the specified 67 inch tank. The float is inserted through the tank bung hole and lowered to float upon the liquid level. The gauge housing is then affixed to the tank using a pipe wrench on the housing nipple. The disclosed gauge is easily attached to conventional tanks with the use of Teflon® tape or pipe sealant to the nipple threads at the base of the housing.  
         [0009]     These and other advantages are shown in the claims below and form a part hereof. For a better understanding of this invention and its advantages, reference should be made to the figure which forms a further part hereof and to the accompanying descriptive matter in which there is described a preferred embodiment of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The invention will be described in detail hereunder with reference to the accompanying  FIG. 1  which shows a detailed exploded view of the disclosed tank gauge.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]     Referring now to  FIG. 1 , the disclosed gauge is comprised of the following components which act together to accurately indicate the liquid level in a tank. Main shaft  3 , when the gauge is fully assembled, is held in holes  40  in housing  1 . Attached to main shaft  3  by shaft spring screw  26  is spring  6 . Spring  6  is commonly known as a clock form spring made from flat steel. The interior end of spring  6  is attached to main shaft  3  by shaft spring screw  26 . The exterior end of spring  6  is attached by spring retaining screw  17  to chain pulley  4  and secured with spring retaining nut  18 . Attached to chain pulley  4  is one end of drive pin  9 , the other end of which is inserted into a receiving hole  41  in numbered wheel  10 , which in turn in interconnected to index gear  12  which meshes with the gear integral to numbered wheel and gear  11 , whereby for each  10  turns of numbered wheel  10 , numbered wheel with gear  11  moves one digit. Index gear  12  is rotatably held by index gear arm pin  14  which in turn is held by index gear arm  13 , which is secured to the main shaft  3  by index gear set screw  15 . Chain pulley  4 , numbered wheel  10 , and numbered wheel and gear  11  rotate on main shaft  3  and are held from sideways motion with e-clips  16 . Spring cover  7  covers spring  6  while it is engaged with chain pulley  4 . Chain  5 , preferably a nickel plated brass beaded chain, also known as a ball chain, is wound in individual grooves on the radial surface of chain pulley  4 . The proximal end of chain  5  is secured to chain pulley  4 . Chain  5  is then wound around chain pulley  4  in an inclined plane groove such that each encirclement of chain pulley  4  by chain  5  is with the same length. Chain  5 , before being attached at its distal end to float  24 , is passed through nipple  42  at the bottom of casing  1 . The distal end of chain  5  is adjustably attached to float  24  through a hole in weight  22  with an eyelet (not shown). Float  24  comprises two hollow parts made of plastic or other material which will not be degraded by the measured liquid or vapors therefrom. These two hollow parts are attached with threaded stud  23  which passes through weight  22  between the two hollow parts of float  24 . Chain roller  2  is in frictional contact with chain pulley  4  and helps guide chain  5  into the groove on the radial surface of chain pulley  4 . Tension retaining pin  8  is placed into hole  43  in main shaft  3  and prevents main shaft  3  from turning while tension from spring  6  is increased by the extension of chain  5 . It should be noted that the tension of spring  6  is designed to be just sufficient to keep slack out of chain  5  as the level of liquid in the tank is lowered or raised. All components on main shaft  3  are placed within housing  1  and main shaft  3  is held by holes  40  in housing  1  at each end of main shaft  3 . Covering the front of housing  1  is a front gasket  19 . Covering gasket  19  is face plate  20  and clear cover  21 . Cover screws  25  secure clear cover  21 , face plate  20 , and front gasket  19  to housing  1  for a completed unit. Gasket  19 , when secured by clear cover  21  and face plate  20  with cover screws  25  keeps all components within housing  1  safe from weather and a corrosive environment.  
         [0012]     When in use, the direct drive mechanism of the disclosed invention allows accurate monitoring of liquid levels in tanks or containers as the liquid level rises and falls. Depending on the arrangement of numbers on numbered wheel  10  and numbered wheel with gear  11 , the gauge can indicate the number of inches to full or the number of inches to empty. Further, chain  5  allows full 360° rotation of float  24  at the bottom of chain  5  without the risk of tangling, kinking, or otherwise binding as chain  5  is retracted into or extended out of the tank gauge assembly. Moreover, the nickel plated brass beaded chain is resistant to deterioration, degradation, or corrosion by most fluids sought to be monitored or ambient vapors.  
         [0013]     The advantages of the Black Knight™ and Red Fox™ tank gauges have been readily accepted by the market and have resulted from their dependable accuracy and simple mechanical design. No electronic devices are necessary.  
         [0014]     Even though the specific details of the structure and function of the disclosed invention is presented, it is for illustration only, recognizing that slight changes may be made in the shape, size and arrangement of the parts within the disclosed invention, thus the principles of the invention to the full extent described by the broad, general meaning of the terms used in the following claims are sought to be covered by these letters patent.  
         [0015]     While a specific embodiment of the invention has been shown and described in detail, it will be understood that the invention may be modified without departing from the spirit of the inventive principles set forth in the following claims.