Abstract:
A magnetic hinge that connects and secures adjacent components while allowing for rotational movement of the components with respect to each other. The magnetic hinge may be incorporated into a magnetic stand magnifier or a variety of other structures. The magnetic hinge of this invention consists of an arm and a shaft with a magnet therebetween.

Description:
FIELD OF THE INVENTION 
     This invention relates to a magnetic hinge that connects and secures adjacent components while allowing for rotational movement of the components with respect to each other and a magnetic stand magnifier that provides a magnifying lens with the ability to pivot and rotate about a fixed base. 
     BACKGROUND OF THE INVENTION 
     Conventional mechanical hinges are among the oldest products of human technology. Hinged connections are useful in numerous applications requiring interconnection between components while permitting relative rotation at the point of connection. It is desirable that the components be capable of positive connection and disconnection as desired without the insertion or removal of special connecting parts or the use of special tools. Although there have been previous attempts to develop reliable magnetic hinges, the present invention provides a novel magnetic hinge that is both sturdy and useful. 
     An example of the usefulness of a magnetic hinge of this invention is illustrated by its use as part of a magnetic stand magnifier. Magnification reduces eyestrain and fatigue, which allows one to work longer with less visual effort. Since the magnification of an object is often secondary to another task, such as manipulating small objects, it is desirable to have a magnifier whose operation requires minimal activity. There are various types of magnifiers available, including hand-held magnifiers and stand magnifiers. 
     An advantage of stand, or mounted, magnifiers is that they allow both of a user&#39;s hands to be free. Whether taking measurements, cross stitching, or holding a newspaper, hands-free viewing is easier. In many situations, when a person needs a magnifier, the operation or work being performed is highly delicate and requires both hands of the user. When using a hand-held magnifier, the work can only be performed with the opposite hand. Thus, a stand magnifier is more convenient, and even required, in many instances. Furthermore, it is difficult to find the ideal position for the magnifier, eyes, viewed object, and light source when one hand is required to hold the magnifier. 
     Previous stand magnifiers have generally been limited in their use due to single-use type of stands. This severely limits the user and requires that the user keep multiple magnifiers for different purposes. Most stand magnifiers have the lens arranged parallel to the object to be viewed. Thus, in order to use the stand magnifier, the user has to lean over the magnifier to look vertically downward. The alternative is to tilt the viewed object and/or the stand magnifier to an angle where viewing is comfortable. This typically results in the user having to hold the magnifier to prevent it from slipping, essentially converting the magnifier into a hand-held magnifier. 
     SUMMARY OF THE INVENTION 
     The magnetic hinge of this invention connects and secures adjacent components while allowing for rotational movement of the components with respect to each other. The magnetic hinge may be incorporated into a magnetic stand magnifier, or a variety of other structures. An embodiment of the magnetic hinge of this invention consists of an arm and a shaft with a magnet therebetween. The flat mating surfaces of the arm and the shaft are in contact with each other and have corresponding flat-bottomed holes. The magnet is received in both of these holes and is attracted to both flat surfaces such that the magnet pulls the surfaces together and creates friction between the surfaces, while serving as an axle or hinge pin about which the arm and the shaft pivot. 
     The magnetic stand magnifier of this invention provides a magnifying lens with the ability to pivot and rotate about a fixed base. An embodiment of the magnetic stand magnifier of this invention includes a base, a magnetic hinge, and a magnifying lens. The base has one or more magnets on its bottom surface by which it may be attached to any ferromagnetic surface. The shaft of the magnetic hinge is inserted into a hole in the base and may be moved rotationally and longitudinally along the center axis of the base. A magnifying lens is coupled to the arm of the magnetic hinge. The friction between the arm and the shaft of the magnetic hinge is modest enough to allow the arm to pivot about the axis of the magnet, but strong enough to require positive action in order to move the arm, allowing the lens to remain at whatever inclination at which it is set. The magnetic stand magnifier can be used for numerous purposes including reading, craftwork, material inspection, and the assembly of small parts. A suitably sized version excels at facilitating reading a metal rule. Both the magnetic hinge and magnetic stand magnifier may be easily disassembled and conveniently placed in a small carrying case. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an embodiment of the magnetic hinge of this invention as part of an embodiment of the magnetic stand magnifier of this invention. 
     FIG. 2 is an exploded view of the embodiments shown in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In an embodiment of this invention, a magnetic hinge is incorporated into a magnetic stand magnifier  10 , as shown in FIGS. 1 and 2. A base  12  has magnets  14  in its bottom. Magnets  14  are attracted to any close ferromagnetic material, such as a ferromagnetic rule  16  as shown in FIG. 1, so that base  12  will remain attached to a ferromagnetic surface against which it is placed. Although the embodiment shown in FIG. 2 has two magnets, a single magnet may be used. Base  12  has a through-hole  18  along its center axis, as shown in FIG.  2 . Through-hole  18  includes an annular depression  20  that holds an o-ring  22 . 
     A round shaft  24  of appropriate diameter is inserted into through-hole  18 . Shaft  24  is made of ferromagnetic material and has a friction fit with o-ring  22 . This allows shaft  24  to be moved longitudinally and rotationally about the axis, while also providing sufficient friction so that shaft  24  will remain in position when movement is stopped. The top of shaft  24  is machined to have a flat face  26  lying on or near the longitudinal axis of shaft  24  with a shallow flat-bottomed or “blind” round hole  28 . 
     An arm  30  interfaces with shaft  24 , as shown in FIGS. 1 and 2. In a preferred embodiment, arm  30  is made from the same material and has the same diameter as shaft  24 . Arm  30  has a flat face  32  with an integral, flat-bottomed or “blind” hole  34  at the end which interfaces with shaft  24 , as shown in FIG.  2 . In a preferred embodiment, hole  34  in arm  30  is generally deeper than hole  28  in shaft  24 , but equal depth holes are also usable. The opposite end of arm  30  has a second flat face  36  and a threaded hole  38  to receive a machine screw  40 . Flat face  36  is rotated 90 degrees from flat face  32 , as shown in FIG. 2. A magnifying lens  42  is coupled to this end of arm  30  by machine screw  40 . 
     As shown in FIG. 2, a cylindrical magnet  44  is placed in hole  34  of arm  30 . Magnet  44  is positioned within the corresponding holes  28  and  34  of shaft  24  and arm  30 , respectively, and effectively acts as a hinge pin or axle. Magnet  44  is attracted to both shaft  24  and arm  30  and pulls them together, causing contact between face  26  of shaft  24  and face  32  of arm  30 . Arm  30  can pivot about the axis of magnet  44 , but friction between flat faces  26  and  32  is sufficient for arm  30  and lens  42  to hold their positions when movement of arm  30  is stopped. 
     An acceptable level of friction is achieved by making the combined depth of holes  28  and  34  slightly greater than the thickness of magnet  44 , so that flat faces  26  and  32  surrounding magnet  44  remain in contact with each other. This combination of attractive force and friction of the adjoining faces is sufficient to hold lens  42  in a fixed position. The combined depth of holes  28  and  34  must not be too much greater than the thickness of magnet  44 ; otherwise, the gap between the exposed face of magnet  44  and the adjacent attractive material will increase, diminishing the attractive force beyond what is necessary to support lens  42 . 
     In another embodiment, magnet  44  is sunk flush to slightly below either arm  30  or shaft  24 . The attractive force tends to keep the other hinge component (the part into which the magnet is not sunk) centralized as it is pivoted. The asymmetric flat-bottomed holes  28  and  34  provide improved registration at the joint, and the deeper flat-bottomed hole could be in either arm  30  or shaft  24 . In a preferred embodiment, the deeper flat-bottomed hole  34  is in arm  30  to ensure that magnet  44  will remain in arm  30  when the arm is pulled away from shaft  24 . This allows arm  30  to then be coupled to any ferromagnetic surface. An example of when this would be desirable is in making a long reach magnifier using a ferromagnetic rule. 
     The magnetic stand magnifier  10  of this invention can be used in the same manner as any stand or base-mounted magnifier. However, the magnets in the base allow the device to be placed in a fixed position on any ferromagnetic surface, such as a ferromagnetic rule. The lens may be adjusted to clarify a desired graduation such that a very fine line can be accurately transferred to the workpiece below. This allows fine increments, such as {fraction (1/64)} or {fraction (1/10)} of an inch, to be transferred with ease. Additionally, the magnetic stand magnifier of this invention can be placed on other ferromagnetic surfaces and used for numerous other purposes including reading, craftwork, material inspection, and the assembly of small parts. 
     The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of the invention. For instance, magnets  14  and  44  can be magnets of various types, although powerful rare earth magnets work particularly well. The hinge can be used for devices other than magnifying lenses, such as lights, lamps, clips, or spring clamps. Different bases could be used such as, for instance, clamp-on bases, marble bases, or heavy duty plastic or metal bases.