Abstract:
The present invention relates to a method and device for a self orienting floating apparatus which utilizes an external magnetic field to maintain a constant orientation, and specifically relates to a plain form hydrometer, a floating thermometer, and a thermohydrometer that continuously display a graduated scale in an operator pre-determined direction.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method and device for self orienting a floating apparatus which utilizes an external magnetic field to maintain a constant orientation, and specifically relates to a plain form hydrometer, a floating thermometer, and a thermohydrometer that continuously display a graduated scale in an operator predetermined direction. 
     2. Discussion of the Related Art 
     Various instruments have been used by both industry and the home owner to measure properties such as the density, (weight per unit volume) specific gravity (weight per unit volume compared with water), or temperature of various liquids. Examples are floating thermometers, used to measure temperature, hydrometers used to measure density, and thermohydrometers which are a combination of a floating thermometer and a constant mass, variable displacement type hydrometer (“plain form hydrometer”). Plain form hydrometers and thermohydrometers (“plain form instruments”) have been made of either glass or plastic. These instruments typically comprise a body having a lower ballast section having a weight secured within this section for weighting of the instrument, and a stem portion that is integrally formed with the ballast. The stem contains a rolled scale that is numbered to correspond to the liquid being tested, and provide for a direct read-out of the desired measurement. Different scales have been utilized for different applications. For example, in determining specific gravity, the following scales have been used: Baume, API (petroleum), Proof and Tralle (alcohol), Brix (sugar), salt, and percentage scales. Fahrenheit, Celsius, and Kelvin temperature scales have also been utilized. 
     These instruments are used by placing them in the liquid in which a desired measurement is to be obtained. In the case of a hydrometer, an appropriate density of the liquid can be read from the scale contained within the stem of the device, determined by the amount the hydrometer extends into the liquid. Likewise, the temperature can be read from the face of the scale contained within a thermohydrometer or floating thermometer. Such floating hydrometers have been described, for example, in U.S. Pat. No. 4,993,263. 
     When instruments are floating in a liquid, they have a tendency to spin in circles, causing the scale to face away from the user. The user invariably has to gently touch the instrument or stretch his/her neck in order to read the scale. 
     Magnetic fields have been utilized to control the position of floating objects. U.S. Pat. No. 4,400,978 to Guay, et al, discloses an electronic hydrometer having an electronic circuit capable of automatically controlling the position of a float by means of a variable current supply and providing an output signal indicative of the density of a liquid. A permanent magnet is mounted in proximity of a connecting shaft which is secured to a float which is disposed within a liquid receiving chamber. The magnet is utilized in conjunction with an electronic circuit to maintain a plate mounted on the shaft in a reference position relative to a beam of light, and not to orient the scale to a predetermined position. 
     U.S. Pat. No. 3,964,317 to Blanchard discloses a densimeter which utilizes a float to sense a density of a fluid. Through the use of (1) an electric current, (2) a cylindrical coil connected to the end of a shaft which is connected to a float, and (3) a permanent magnet, the float is maintained at a selected vertical reference position. In the invention of the &#39;317 patent, the magnet does not orient the scale to a predetermined rotational position. 
     U.S. Pat. No. 5,848,029 to Chang and U.S. Pat. No. 5,893,789 to Wu utilize magnetic forces to control the movement of a floating toy. These toys are not used to provide a readout, are not used for measuring, and do not need to be positioned in a fixed direction relative to the user. Magnetic forces are used to provide random movement to the toy. 
     What is needed is a method and device to be used on a floating apparatus that will allow a readout to orient in a position such that the readout is continuously facing a predetermined direction. 
     Use of the term “related art” is descriptive in nature only and references cited are not admitted to be “prior art” with respect to the present invention by their mention in this Background Section. All references cited are incorporated by reference as if fully set forth herein. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a device for self orienting a readout integral to a floating apparatus utilizing a magnet integral to a container. For purposes of this invention, integral means positioned within, affixed to a wall, affixed within, engraved or etched or printed on a wall or otherwise located within or on the apparatus. The container may be of any size or shape having sufficient volume to float. The magnet and/or the readout can be embedded in a cylinder, attached externally to a cylinder, integral with a cylinder, or placed within a cylinder, being supported by the apparatus or supported by an additional structure within the apparatus. 
     One structure which accomplishes this comprises attaching an orienting magnet to a pin, the pin having a first and a second end. The orienting magnet is attached to the first end (pinhead) of the pin. The second end of the pin is affixed to the apparatus by a first means to allow the orienting magnet to resistively rotate. A second means is provided to rotate the orienting magnet to a predetermined position such that when the orienting magnet is aligned with an external magnetic field, the readout of the apparatus orients itself in a direction pre-selected by a user, the pre-selected direction being independent of the external magnetic field. 
     The present invention also relates to a method for directionally orienting a readout of a floating apparatus which comprises the steps of: 
     a) integrating an orienting magnet to the floating apparatus, 
     b) orienting the magnet to a position relative to an external magnetic field, such that when the magnet aligns with the external magnetic field, a readout fixed to the floating apparatus orients itself to face a preselected direction. In one embodiment, the orienting magnet is integrated by resistively rotatably attaching. 
     The term “resistively rotatably attaching” means, for the purpose of this invention, the ability to rotate the orienting magnet only upon utilizing a force greater than the attractive forces between the orienting magnet and the apparatus, as explained in greater detail below. 
     A second embodiment comprises a device and method in which the orienting magnet is attached to the first end of the pin in a predetermined position. The second end of the pin is affixed to the apparatus so as to not allow the first permanent magnet to rotate, such that when the orienting magnet is aligned with an external magnetic field, the readout of the apparatus orients itself in a direction pre-selected by a user, the pre-selected direction being independent of the external magnetic field. 
     A third embodiment comprises embedding an orienting magnet within or on the apparatus such that when the orienting magnet is aligned with an external magnetic field, the readout of the apparatus orients itself in a direction pre-selected by a user, the pre-selected direction being independent of the external magnetic field. 
     Still another embodiment comprises either permanently or resistively rotatably affixing an orienting magnet to the readout and allowing the readout to float in a liquid contained within the apparatus such that when the orienting magnet is aligned with an external magnetic field, the readout of the apparatus orients itself in a direction pre-selected by a user, the pre-selected direction being independent of the external magnetic field. 
     In particular, an advantage of the present invention is to provide a device and method such that a plain form hydrometer, a floating thermometer, a thermohydrometer, or other floating instrument can be inexpensively and conveniently preset to face a predetermined direction. 
     Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the purpose of illustrating the invention, there is shown in the drawings forms which are presently preferred; it being understood, however, that the invention is not limited to the precise arrangement and instrumentalities shown. 
     FIG. 1 is a representative drawing of a plain form hydrometer with the directional device of the present invention. 
     FIG. 2 is a representative drawing of a side view of the magnet, nut, pin and tube assembly. 
     FIG. 3 is a representative drawing of a top view of the magnet, nut, pin and tube assembly. 
     FIG. 4 is a representative drawing of a thermohydrometer with the directional device of the present invention. 
     FIG. 5 is a representative drawing of a floating thermometer with the directional device of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings in detail, where, whenever possible, like numerals refer to like parts or elements, there is shown in FIG. 1 the present invention of the device for an orienting floating plain form hydrometer  100  which utilizes a magnetic field to maintain a constant orientation. 
     The preferred embodiment of the present invention, as shown in FIG.  1  through FIG. 3, comprises an orienting magnet  2  attached to the head  4  of a pin  6  which passes through a nut  8  into a tube  10  which is anchored in ballast  12 . The ballast  12  is contained within the body  14  of a cylinder  16  containing a readout  18 . 
     The hydrometer  100  of the preferred embodiment comprises a cylinder  16 , generally made of glass or plastic, that is wide on the lower end and narrower at the top. This wider lower end is called the body  14  and the narrower top end is called the stem  20 . Contained within the lowest end of the body  14  is the ballast  12  which makes the hydrometer sink in a particular liquid (not shown). By placing the ballast  12  in the lowest end of the body  14 , the center of gravity of the cylinder  16  is located in a manner so as to cause the cylinder  16  to float upright with the ballast  12  submerged when placed in a liquid (not shown). Generally, as is typically in the prior art, the ballast  12  comprises a material of sufficient density to locate the center of gravity of the cylinder  16  in a manner as described above. The ballast  12  may be, by way of example, lead, steel, grains of silica, or other heavy materials dense enough to displace the center of gravity of the cylinder  16  sufficiently downward so as to give the cylinder  16  stability when floating upright in a liquid. A preferred ballast is linotype, which is an alloy of antimony, lead and tin. 
     The ballast  12  is initially in a form that will allow insertion of the tube  10  into the ballast  12 . The ballast  12  is, for example, ball shaped, powder, or granular in form. The ballast  12  may be located in place, for example by melting the ballast into a solid mass, by utilizing melted and then cooled wax, by applying an adhesive, or any of the other methods known to those skilled in the art. An appropriate amount of ballast  12  is inserted into the body  14  and located in place so as to properly calibrate the hydrometer. 
     Contained within the stem  20  is a readout. The readout is, for example, a rolled scale  18  that is numbered to correspond to the liquid being tested. Such a scale may be, for example, a Baume scale, an API scale, a Proof and Tralle scale, a Brix scale, a salt scale, or a percentage scale. Fahrenheit, Celsius, and Kelvin temperature scales as well as any other scale utilized to measure a property of a liquid may also be used. Alternatively, the readout is an electronic readout. The scale  18  is made of, for example, paper, plastic, or metal and secured by, for example, an adhesive such as Permabond manufactured by Permabond Corp., Division of National Starch and Chemical or other appropriate adhesive, or mechanically fixed, such as by crimping a metal tie, or frictionally held in place. The scale may also be scribed, etched or painted onto the interior or exterior of the stem  20 . 
     A tube  10  is positioned vertically in the center of the ballast  12  such that the orienting magnet  2  is able to align itself with an external magnetic field (not shown). The tube  10  may be manufactured of, for example, glass, plastic, or metal such as, for example, stainless steel. The second end  11  of the tube  10  is anchored in the ballast  12  by, for example, placing the tube  10  in molten ballast  12  and allowing the ballast  12  to solidify around the tube  10 . By way of example, the second end  11  of the tube  10  is inserted in ballast  12  comprising a plurality of linotype balls. Linotype balls comprise a mixture of antimony, lead and tin. The body  14  is held upright by placement into sand of appropriate depth to support the body  14 . The sand is then heated by methods known to those skilled in the art to a temperature sufficient to melt the ballast  12 , but not the body  14 . Alternatively, the ballast  12  comprises a mixture of material as described above and wax. After insertion of the second end  11  of the tube  10  into the ballast  12  wax mixture, the mixture is heated and cooled by known methods sufficient for the wax to melt and re-solidify around the tube  10  and ballast  12  so as to create a single mass able to maintain the tube  10  in the desired position. 
     The tube  10  extends above the surface of the ballast  12  a sufficient distance to support a pin  6 . This distance is about 29 mm and the tube  10  diameter is about 3 mm i.d. However, it should be appreciated that the tube dimensions, as well as all other dimensions of the present invention are dependant upon the shape of the body  14  and may be varied as required for a particular situation. 
     Permanently attached to a first, open end  9  of the tube  10  is a nut  8  made of steel, cobalt or other ferromagnetic material. The nut  8  is affixed by an adhesive bonding with an adhesive such as, for example, Permabond, or other appropriate adhesive, or mechanically fixed, such as, for example, by threading or by swaging. For purposes of this embodiment, swaging involves inserting a tool into the first end  9  of the tube  10  in such a manner as to expand the outside diameter of the first end  9  of the tube  10  against the inner walls of the nut opening (not shown) to provide the mechanical attachment of the nut  8  to the tube  10 . The nut  8  is attached horizontally, so that the nut opening (not shown) aligns with the first, open end  9 , allowing access to the interior of the tube  10 . 
     The head of the pin  4  is larger in diameter than the nut opening (not shown), so that when the second end of the pin  5  is inserted into the first end  9  of the tube  10 , the pin  6  is prevented from falling through the nut  8 . Additionally, the pinhead  4  separates the orienting magnet  2  from the nut  8  allowing it to resistively rotate. This separation is the thickness of the pinhead  4 , usually about 0.5 mm. The magnetic attraction between the orienting magnet  2  and the nut  8  resists any tendency for the orienting magnet  2  to rotate freely, thus keeping the orienting magnet  2  pointing in a preset direction relative to the scale  18  (FIG.  1 ). 
     As shown in FIGS. 2 and 3, the pin  6  has at its first end a pinhead  4 . The pin  6  is manufactured of any material, and is typically steel or plastic. The pinhead  4  is about 4 mm in diameter, and the pin  6  is about 2 mm in diameter and about 20 mm in length. Permanently attached to the pinhead  4  is an orienting magnet  2 . The orienting magnet  2  may be attached using an adhesive such as, for example, Permabond, or other appropriate adhesive, or it may be attached by an electro-mechanical means, such as, for example, by spot welding. The orienting magnet  2  is attached in a horizontal plane to the pinhead  4 , perpendicular to the pin  6  axis, such that the North Pole  32  and the South Pole  34  of the orienting magnet  2  are 180 degrees opposed. The orienting magnet  2  is about 3 mm by about 10 mm. 
     In a preferred embodiment the orienting magnet  2  resistively rotates using a combination of a ferromagnetic nut  8  having a central opening, the tube  10  having the first open end  9  opposed to the second end  11 , and the pin  6  having a head  4  on a first end, the head  4  larger in diameter than the tube central opening. The pinhead  4  is opposed to the pin second end  5 , wherein the orienting magnet  2  is affixed to the pinhead  4 ; the tube second end  11  is affixed to the apparatus; the tube  10  extends upward; and the nut  8  is affixed to the tube first open end  9  and aligned to allow passage of the pin second end  11  until the pinhead  4  rests on the nut  8 , so that a space remains between the orienting magnet  2  and the nut  8 . 
     In use, the operator determines in what direction the readout  18  (in the preferred embodiment, a gravity scale), should orient. Utilizing the magnetic attraction between a handheld direction setting magnet  200 , and the orienting magnet  2 , the operator rotates the orienting magnet  2  to a position such that when the orienting magnet  2  aligns itself with an external magnetic field (not shown), the gravity scale  18  orients in the desired direction. 
     The magnetic attraction between the orienting magnet  2  and the handheld direction setting magnet  200  is stronger than the magnetic attraction between the orienting magnet  2  and the ferromagnetic nut  8 , thus allowing movement of the hand held direction setting magnet to rotate the orienting magnet  2 . 
     The magnetic attraction between the orienting magnet  2  and the nut  8  is greater than the frictional and surface tension forces between the outside walls of the cylinder  16  and the liquid (not shown) in which the cylinder  16  floats. Therefore, as the orienting magnet  2  aligns itself with the external magnetic force, it will remain in the same relative position to the nut  8  and the entire cylinder  16  will rotate within the liquid (not shown) so that the scale  18  will orient to the predetermined position. 
     In this way, once the orienting magnet  2  is properly set, the gravity scale  18  will continuously face the desired direction, rather than rotating as the cylinder  16  spins within the liquid as it would without the present invention. 
     The external magnetic field may be the earth&#39;s gravitational field, an electromagnetic field, or any other operator applied magnetic field. 
     FIG. 4 shows a second embodiment of a device for a self orienting floating instrument according to the present invention. 
     As seen in the thermohydrometer of FIG. 4, in the present embodiment, a thermometer scale  50  is positioned above and adjacent to the ballast  12 . The barrel of the thermometer  52  has a first  53  and second  55  end, and is positioned vertically, such that the second end  55  terminates in a thermometer bulb  54  which extends beneath the ballast  12 . The tube  10  is attached to the firs end  53  and is secured by, for example, an adhesive such as Permabond or other appropriate adhesive, or mechanically fixed, such as by crimping a metal tie, or frictionally held in place, to the first end of the thermometer barrel  52 . In all other respects, the embodiment of FIG. 4 is the same as the preferred embodiment of FIG.  1  through FIG.  3 . For the sake of clarity, the individual parts not directly connected with the invention have been omitted from FIG.  4 . 
     The floating thermometer embodiment of FIG. 5 differs from that of FIG. 4 only in that the gravity scale  18  is not present, but rather the body  14  and stem  20  are equal in diameter, with the stem  20  culminating in a ring  60 . Otherwise, the arrangement of FIG. 5 is identical with that of FIG.  4 . For the sake of clarity, the individual parts not directly connected with the invention have been omitted from FIG.  5 . 
     Most laboratories have a designated area where solutions are tested. The present invention would allow a laboratory to preset their instruments such that the gravity scale  18  would be continuously facing the technician, thus saving time and making it convenient for the technician to read the instrument. Optionally, rather than having the orienting magnet  2  be operator controlled, the orienting magnet  2  may be factory present in a desired position. 
     In yet another embodiment of the present invention, the orienting magnet  2  is factory set to a fixed permanent positioned. The tube  10  and nut  8  are omitted and the second end  5  of the pin  6  is non-rotatably affixed, using methods such as, for example, those described above for affixing the tube second end  11  to the ballast  12  of FIG. 1 or to the superior end of the thermometer barrel  52  of FIGS. 4 and 5. 
     Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. For example, the present invention may be used in what is commonly called “syringe type hydrometers”. 
     In a syringe type hydrometer, the operator puts one end in a liquid and draws the liquid up in a glass or plastic cylinder using a rubber bulb. The instrument floats in the drawn solution to give a reading. The present invention can be utilized so that the floating instrument contained within the syringe type hydrometer continuously faces in a desired direction. 
     In yet another variation, the present invention may have the orienting magnet integral with the apparatus, such as, for example, embedded within the ballast, or attached to the apparatus, such as, for example, by using an adhesive to adhere the orienting magnet to the internal or external surfaces of the apparatus, or painting a magnetic material on a surface of the apparatus, and rotating the readout to a position such that the readout will orient itself to this preselected position upon alignment of the orienting magnet with an external magnetic field. This rotation of the readout may be accomplished, for example, by painting, etching, or scribing the readout to a rotating section of the cylinder, or by rotatably affixing a readout to the apparatus, either within or outside of the cylinder, such as, for example, by painting, etching, or scribing a readout on a sleeve fitting around or within the cylinder, or attaching a readout to a shaft affixed either within or without the cylinder. 
     In another variation, an orienting magnet may be either permanently or resistively rotatably attached (as previously described) to the readout. The cylinder is partially filled with a liquid having a density greater than the readout. The readout is placed within the cylinder so as to float in the liquid. When the orienting magnet orients itself to an external magnetic field, the floating readout will orient itself to the predetermined direction. 
     The present invention may also be used in a floating buoy so as to continually orient a sign affixed to the buoy in a preset direction. 
     Although the present invention has been described in connection with specific examples and embodiments, those skilled in the art will recognize that the present invention is capable of other variations and modifications within its scope. These examples and embodiments are intended as typical of, rather than in any way limiting on, the scope of the present invention as presented in the appended claims.