Abstract:
A door knob with a light-emitting location indicator comprises a knob designed for placement on a door, for being grasped by the hand of a user for opening the door. The knob comprises translucent material. One or more objects comprising light-emitting material that either phosphoresces or luminesces are mounted within the knob and are visible through a protective layer of translucent material. The light-emitting material is designed to emit light in a darkened space to thereby visually indicate the location of the knob in the darkened space.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a door knob that includes a light-emitting indication of its location, which is especially useful in a darkened location. 
   BACKGROUND OF THE INVENTION 
   Door knobs are placed on doors that open to allow humans to pass through a doorway, for example. Door knobs are also provided on doors for cabinets and drawers of a chest of drawers, for instance. In a darkened location, it would be desirable to provide light-emitting elements associated with a door knob to visually indicate the location of the door knob. It would be desirable to have the light-emitting elements function without an electrical power source, such as batteries. 
   The prior art generally addresses these concerns. For instance, U.S. Pat. No. 4,981,314 discloses a doorknob having various portions of an adornment on a door knob treated with a phosphorescent or luminescent material to produce a glowing effect at night or in the dark. 
   While the foregoing patent generally addresses the foregoing concerns, other concerns are not addressed. For instance, the light-emitting material, phosphorescent or luminescent, of the foregoing patent is exposed to the environment. Such light-emitting material is susceptible to degradation from external influences such as dirt, grime, or perspiration, for instance, from contact by a person&#39;s hand. Further, such light-emitting material is subject to wear and tear from abrasion with objects such as a person&#39;s hand or a key for a lock in, or near, the knob. Further, it may be desirable to protect one&#39;s hand from close contact with some light-emitting material, such as luminescent material energized from a radioactive salt, that could be harmful to a person. 
   Accordingly, it would be desirable to provide a door knob with a light-emitting location indicator that addresses the foregoing concerns. 
   SUMMARY OF THE INVENTION 
   In accordance with one form of the invention, a door knob with a light-emitting location indicator comprises a knob designed for placement on a door, for being grasped by the hand of a user for opening the door. The knob comprises translucent material. One or more objects comprising light-emitting material that either phosphoresces or luminesces are mounted within the knob and are visible through a protective layer of translucent material. The light-emitting material is designed to emit light in a darkened space to thereby visually indicate the location of the knob in the darkened space. 
   The objects of light-emitting material may comprise a base material that has been painted with paint containing light-emitting material, or it may fully comprise light-emitting material that may be solid or hollow, or some combination of these. As used in this specification and claims, “light-emitting material” embraces the foregoing alternative possibilities. 
   The light-emitting material in the foregoing door knob is both protected from the environment as well as serving to protect (or prevent) a person from contact with the light-emitting material. As such, the concerns mentioned above are addressed, such as protecting the light-emitting material from degradation due to contact with the environment, for instance. 
   Other features and objects of the invention will become apparent from the remainder of this specification. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is side view in perspective of a door knob in accordance with an embodiment of the invention. 
       FIG. 2  is a front view of the door knob of  FIG. 1 . 
       FIG. 3  is a fragmentary side view, partially in section, and partially in simplified form, of the left-side portion of the door knob of  FIG. 1 , showing an arrangement for mounting the knob on a door that closes a passage for human access. 
       FIG. 4  is a side view, partially in section and partially in simplified form, similar to  FIG. 3 , but showing an arrangement for mounting the knob to a door of a cabinet, for instance. 
       FIG. 5  shows a sectional fragment of translucent material of the door knob of  FIG. 1 , containing a object comprising light-emitting material. 
       FIG. 6  shows a star-shaped object comprising light-emitting material, showing various dimensions of the star shape. 
       FIG. 7  shows a fragment of the star shape of  FIG. 6  in enlarged form, showing an approximation of an angle of a point. 
       FIG. 8  shows a fragment of translucent material containing two objects each comprising light-emitting material. 
       FIG. 9  shows a fragment of translucent material containing two objects comprising light-emitting material having substantially the same shape. 
       FIG. 10  shows a fragment of translucent material containing an object comprising both light-emitting material and material that does not emit light. 
       FIG. 11  shows a front view of a door knob containing objects comprising entirely light-emitting material together with a separate object comprising material that does not emit light. 
       FIG. 12  shows a front view of a door knob and alternative locking mechanisms, mounted on a fragment of a door. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a door knob  10  having a translucent section  12  and a mounting section  14 . As shown in  FIGS. 1 and 2 , translucent section  12  contains one or more objects  16  comprising light-emitting material that either phosphoresce or luminesce, so as to visually indicate the location of the knob in a darkened space. The term “light-emitting material” is defined above, and includes, for instance, paint including light-emitting material that covers a base material which does not emit light. 
   Translucent section  12  may comprise plastic or other material suitable for use as a door knob, and may be transparent. Section  14  is a section for mounting to a door.  FIG. 3  shows knob  10  mounted to a door  20  used to close a doorway for human access. Translucent section  12  is shown in simplified form with phantom lines. Mounting section  14 , which may be metal or plastic, for instance, is held to a shaft  22  by a screw  24  in conventional manner. Shaft  22  controls a door latch  25  in conventional manner.  FIG. 4  shows an alternative mounting section  14  connected to a door  26  of a cabinet by a screw  28 . As in  FIG. 3 , translucent section  12  is shown in simplified form with phantom lines. 
     FIG. 5  shows a feature of the invention of an object  30  comprising light-emitting material that is visible through a protective layer of translucent material  32  of translucent section  12  of knob  10  of  FIG. 1 . Preferably, object  30  is completely surrounded by translucent material  32 . More preferably, substantially the entire outer surface of object  30  is intimately surrounded by translucent material  32 , for optimum protection of the object. 
   Preferably, the shapes of the objects comprising light-emitting material are selected to provide a visual interest differing from that of a mere door knob. This can be done by shaping the light-emitting objects in the form of an adornment or scene differing from that of a door knob. 
   In providing visual interest, one or more of the shapes preferably have respective outlines that are non-circular. For instance, object  30  ( FIG. 5 ) shows a polygonal (star) shape. More preferably, one or more of the outlines may comprise a multi-pointed shape, such as a star shape  36  shown in  FIG. 6 . The reason is that a multi-pointed shape has a relatively strong attention-focusing power, so as to provide a more prominent visual indication of the location of the door knob in a darkened space. 
   Guidelines for making prominent points on a shape are described with reference to  FIGS. 6 and 7 . Preferably, each point  36   a  ( FIG. 7 ), for instance, approximates an angle  38  substantially less than 90 degrees, and preferably below about 65 degrees, with the length  42  of each point (e.g.,  36   a ) being at least about 15 percent of the maximum dimension  40  ( FIG. 6 ) of an outline of the shape, and more preferably at least about 25 percent of the maximum dimension  40 . 
   As shown in  FIG. 8 , visual interest can also be imparted to an object comprising light-emitting material by forming it with at least two portions that emit light in respectively different colors. For instance, a butterfly shape  44  in translucent material  46  of a door knob comprises blue portions  48  and  50 , pink portions  52 , orange portions  53 , and green portions  54 . All of these portions may emit light, or, for instance, orange portions  53  might not emit light. The combination of such multiple, light-emitting or non-light emitting colors gives a high degree of visual interest to butterfly shape  44 , and is pleasing to observe. Additional visual interest is provided by providing another object  51  comprising light-emitting material. 
   Another way of adding visual interest to objects comprising light-emitting material is to include at least two objects that emit light in respectively different colors, which may be respective, single colors. Thus,  FIG. 9  shows, in translucent material  55  of a door knob, a star shaped object  56  of material that emits light only in blue and a star-shaped object  58  of material that emits light only in pink. Objects  56  and  58  are separated from each other. 
   A still further way of adding visual interest to an object comprising light-emitting material is to include one or more non-light-emitting portions visible in daylight. For instance,  FIG. 10  shows, in translucent material  60  of a door knob, a flower-shaped object  62  with portions  64  that emit light in pink, whereas interior portions  66  of the object comprise non-light-emitting portions  66  that are brown. Flower-shaped object  62  will have a considerably different appearance in a darkened space than in daylight. This adds a changing perspective to the visual appearance of the object. Additionally, the inclusion in translucent material  60  of another object  61  comprising light-emitting material adds more visual interest. 
     FIG. 11  shows a door knob  64  including a translucent section  66  and a mounting section  14 . Contained within translucent section  66  are objects  68  with outlines of stars and an object  70  with an outline of a crescent moon. The portions of star-shaped objects  68  visible in  FIG. 11  are entirely light-emitting. In contrast, the visible portion of crescent moon-shaped object  70  is non-light emitting. This creates a type of changing perspective to the visual appearance of the objects that differs from that described in connection with  FIG. 10 . Of course, not all portions of objects  68  need to emit light, as is apparent from the above discussion of  FIG. 10 . 
     FIG. 12  shows a door knob  74  and optional locking mechanism  76  mounted on a door  78 . Knob  74  may contain an optional locking mechanism  80  having a keyhole  82  for receiving a key (not shown). Similarly, optional locking mechanism  76  includes a keyhole  84  for receiving a key (now shown). With both locking mechanisms, a person over time may repeatedly press a key towards one of the keyholes and might miss the keyhole. According to an aspect of the invention, objects  86 , within knob  74 , comprising light-emitting material are protected from damage due to a person missing the keyhole and accidentally pressing the key against the knob. 
   While the invention has been described with respect to specific embodiments by way of illustration, many modifications and changes will occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit and scope of the invention.