Patent Publication Number: US-6700981-B1

Title: Dual input headphone apparatus

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to the field of audio headphones and more particularly to a dual input headphone apparatus. 
     BACKGROUND OF THE INVENTION 
     The prior art related to headphones includes the following US Patent. 
     U.S. Pat. No. 4,829,571 to Kakiuchi, et al. shows a stereo headphone set which is connected to an input plug and which includes a mutina switch located on an intermediate portion of the headphone cord to allow muting of the input signal. The muting switch disconnects the headphone set from an audio source and allows the user to listen to surrounding sounds. 
     Despite the various developments in the prior art, there remains a need for a dual input headphone apparatus which can enable a user to receive simultaneous audio signal inputs from two different audio sources. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a dual input headphone apparatus which enables a user to practice playing an electronic musical instrument while listening to musical accompaniment without disturbing others in the surrounding area. 
     Another object of the present invention is to provide a dual input headphone apparatus which facilitates a user learning to play an electronic musical instrument by enabling the user to listen to listen to his or her musical instrument while also listening to audio instruction. 
     Another object of the present invention is to provide a dual input headphone apparatus which enables a user to practice playing an electronic musical instrument while reducing associated tedium. 
     Another object of the present invention is to provide a dual input headphone apparatus which enables a user to practice playing an electronic musical instrument without disturbing others. 
     Another object of the present invention is to provide a dual input headphone apparatus which enables a user to practice playing an electronic musical instrument while listening to other musicians or vocalists. 
     Another object of the present invention is to provide a dual input headphone apparatus which does not interfere with a user playing an electronic musical instrument. 
     Yet another object of the present invention is to provide a dual input headphone apparatus which comprises a relatively small number of component parts which can be manufactured economically in volume resulting in a relatively low overall cost. 
     The foregoing and other objects and advantages of the invention will appear more clearly hereinafter. 
     In accordance with the present invention there is provided a dual input headphone apparatus which includes a headphone unit having left and right ear piece units and an input cord having two conductors. An end of the input cord projects into a housing. Within the housing, the input cord is connected to a pair of equipment cords each of which is connected to an input plug. Each of the equipment cords has two lines. The input plugs have input portions for receiving left hand and right hand audio signals. The lines carrying left hand audio signals from the input plugs are connected to the input cord conductor which leads to the left ear piece unit and the lines carrying right hand audio signals from the two plugs are connected to the input line conductor which leads to the right ear piece unit. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     Other important objects and advantages of the invention will be apparent from the following detailed description of the invention taken in connection with the accompanying drawings in which: 
     FIG. 1 is an overall perspective view of a dual input headphone apparatus, made according to the present invention; 
     FIG. 2 is a cross-sectional view taken along the line  2 — 2  of FIG. 1; 
     FIG. 3 is a schematic view of the dual input headphone apparatus, showing the apparatus in use connected to an electronic musical instrument amplifier and also to a stereo amplifier, and 
     FIG. 4 is a cross-sectional view, similar to FIG. 3, showing an alternative embodiment of the housing of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the drawings, in which like reference numbers designate like or corresponding parts throughout, there is shown in FIG. 1 a dual input headphone apparatus, generally designated by reference number  10 , made in accordance with the present invention, which includes a headphone unit  12 , having left and right ear piece units  14 , 16 , an input cord  18 , which has two lines  20 , 22  which carry left audio signals and right audio signals, respectively, and a pair of equipment cords  24 , 26 . Each of the equipment cords  24 , 26  has two lines  28 , 30  and  32 , 34  which carry left audio signals and right audio signals, respectively. The first end  36 , 38  of each of the equipment cords  24 , 26  is connected to an input plug  40 , 42 . As is best shown in FIG. 2, the second ends  44 , 46  of the equipment cords  24 , 26  are connected to the lines  20 , 22  of the input cord  18  in a manner which will be presently described. 
     The equipment cords  24 , 26  and the input cord  18  enter the housing  48  via apertures  50 , 52  which are formed in the upper end  54  and the lower end  56  of the housing  48 , respectively. The housing  48  is generally cylindrical and includes an outer shell  58  and an inner shell  60 . The outer shell  58  fits closely over the inner shell  60  and the inner and outer shells  58 , 60  may be joined by the application of a bead of adhesive  62  in the area indicated by the reference number  64 . The housing  48  is elongated in configuration and has a diameter which is only slightly greater than the diameter of the input cord  18  and the equipment cords  24 , 26  thereby resulting in a structure which does not add any appreciable bulk to the input cord  18  and the equipment cords  24 , 26  and does not interfere with the normal playing of a musical instrument. The housing  48  may be proportioned to provide space in the areas designated by the reference numerals  66 , 68  to accommodate a knot indicated schematically by the broken lines  70 , 72  being tied in the input cord  18  and in the equipment cords  24 , 26  for the purpose of preventing forces in the directions shown by the arrows  74 , 76  from pulling the input cord  18  and the equipment cords  24 , 26  out of the housing  48 . 
     As is shown in FIGS. 2 and 3, the equipment cord  24 , 26  lines  28 , 30  which carry left audio signals are connected to the input line  20  which carries left audio signals to the ear piece unit  16  and similarly, the equipment cord lines  32 , 34  which carry right audio signals are connected to the input line  22  which carries right audio signals to the ear piece unit  14 . The electrical connections connecting the lines  20 , 28 , 30  and  22 , 32 , 34  indicated by the reference numbers  78 , 80  may by accomplished by soldering, crimping or any other process which results in a reliable electrical connection. The electrical connections  82 , 84  are covered by insulating sleeves  85  or insulating tape. 
     The input plugs  40 ,  42  each have portions  86 , 88  which receive left audio signals and portions  90 , 92  which receive right audio signals. The lines  28 , 30  are connected to the portions  86 ,  88  and the lines  32 , 34  are connected to the portions  90 , 92 . 
     As is shown in FIG. 3, during use the user is able to receive audio signals from the musical instrument amplifier  94  as well as the stereo amplifier  96 . The user is thus able to hear his or her musical performance without disturbing others while simultaneously hearing music or instructional material from the stereo amplifier  96 . 
     FIG. 4 shows an alternate version of the housing  200  which includes a upper shell  202  and a lower shell  204  which are joined together by interlocking snap-fit portions  206 , 208 . The end  210  of the upper shell  202  has an aperture  212  for the introduction of the input cord  18  and the lower shell  204  has an aperture  214  for the introduction of the equipment cords  24 , 26 . 
     Adjacent to the apertures  212 , 214  there are integrally formed inwardly directed flexible collars  216 , 218  which are displaced, or deflected outwardly by the introduction of the input cord  18  and the equipment cords  24 , 26 . The collars  216 , 218  are proportioned to grip the input cord  18  and the equipment cords  24 , 26  tightly and resist the removal of the input cord  18  and the equipment cords  24 , 26  from the housing  200 . The housing  200  thus retains the input cord  18  and the equipment cords  24 , 26  and prevents stress from being applied to the electrical connections  78 , 80  during handling and use. 
     The foregoing specific embodiment of the present invention as set forth in the specification herein is for illustrative purposes only. Various deviations and modifications may be made within the spirit and scope of this invention without departing from the main theme thereof.