Abstract:
A cartridge assembly for a laryngoscope includes a housing which supports an axially movable miniature lamp assembly in the instrument handle and includes at least one sealing member which provides a fluid tight seal for the electrical contacts of the lamp assembly and the power supply of the laryngoscope regardless of the axial position of the lamp assembly.

Description:
FIELD OF THE INVENTION 
     The invention generally relates to medical diagnostic devices and more particularly to a laryngoscope or similar device having internal electrical contacts which are effectively sealed from dirt, debris, fluid and the like without requiring a seal for the entire instrument. 
     BACKGROUND OF THE INVENTION 
     Laryngoscopes are commonly used medical diagnostic instruments used to observe the throat area of a patient generally including a handle and a laryngeal blade which is removably attachable to the handle. The handle typically retains a power supply, such as a set of dry cell batteries, which energize a miniature lamp retained in an upper end of the handle. Light from the miniature lamp is directed to the end of the attached laryngeal blade in order to provide illumination and allow examination of the larynx. The laryngeal blade is constructed so as to push on the tongue during examination. 
     Instruments having light sources mounted in the upper end of the handle do not energize the light source until the laryngeal blade is attached. Typically, connection of the blade to the instrument handle draws the electrical contacts of the lamp assembly to the corresponding contacts of the power source. 
     In prior art devices, as described, it is possible for debris and body fluids to enter the blade and ultimately the hollow handle and the lamp assembly, thereby fouling the electrical contacts to the point in which premature replacement is required. 
     Certain prior art devices, such as those described in U.S. Pat. Nos. 4,669,449 and 4,694,822, each issued to Bauman, describe laryngoscopes having handles which are completely submersible. These devices have elaborate sealing means which include a tubular elastomeric body which is fitted in an upper portion of the handle, the body having additional provision for a pair of electrical terminals extending through the elastomeric body. Though these devices are quite useful, it is not always necessary to make the entire instrument handle fluid tight. On the other hand, it is highly desirous for the reasons stated above to protect the internal electrical contacts interconnecting the lamp assembly and the power source. Moreover, it is equally desirous to be able to maintain an effective seal regardless of whether or not the blade is actually attached to the handle. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to overcome the above noted problems found in the prior art. 
     It is another primary object of the invention to provide an improved laryngoscope having internal electrical contacts that are effectively sealed from debris and/or fluids. 
     Therefore and according to a preferred aspect of the present invention, there is provided a laryngoscope comprising: 
     an instrument handle including a contained power supply; 
     a laryngeal blade releasably attachable to an upper end of said handle; 
     a lamp assembly including a miniature lamp biasedly attached to the upper end of said instrument handle such that attachment of said blade causes an electrical connection between said lamp assembly and said power supply to cause energization of said miniature lamp; and 
     a lamp cartridge including a housing for retaining said lamp assembly with respect to said instrument handle and sealing means for sealing electrical contacts of said lamp assembly and said power supply from fluid and debris. 
     Preferably, the lamp carrier member is attached to the cartridge housing to allow axial movement between respective nonengaged and engaged positions relative to the electrical contacts contained within the cartridge housing. The lamp carrier member is biased in the non-engaged position until the laryngeal blade has been positively attached to the instrument handle. Blade attachment then causes the lamp carrier member to be shifted axially to the engaged position in which the electrical contacts of the lamp assembly and the power supply are brought into contact with one another. 
     The lamp carrier member retains the sealing member, preferably a rubberized quad ring, diaphragm, or O-ring, which engages the interior wall of the cartridge housing and provides a seal regardless of the axial position of the lamp carrier member. 
     According to another preferred aspect of the present invention, there is disclosed a lamp cartridge assembly comprising: 
     a housing having an interior; 
     a lamp assembly retained by said housing having an electrical contact contained within said housing interior; and 
     sealing means for sealing the interior of the cartridge housing, including said electrical contact, from fluid and debris. 
     An advantage of the present invention is that an adequate fluid and dust tight seal is provided for the electrical contacts of the laryngoscope without requiring the entire handle to be sealed providing a cost effective and lightweight design. 
     Another advantage is that the seal is effective and reliable regardless of the axial position of the supported lamp carrier member. Furthermore, the components are each easily accessible for replacement as needed. 
     Another advantage of the present invention is that only external cleaning of the laryngoscope handle is required. That is, provision of a sealed cartridge assembly ensures that there is no need to concern oneself about the cleanliness of internalized areas. 
     Yet another advantage is that the described cartridge assembly can be cleaned as needed without the concerns of cleaning fluids entering the assembly and oxidizing or otherwise damaging the internal contacts so as to prevent proper function of the lamp assembly. 
     Yet another advantage is that provision of a seal as described prevents debris, body fluids, and/or cleaning fluids from penetrating the cartridge assembly and creating a potential area of bacterial growth. Consequently, there is no future risk of trapped fluid leakage from the cartridge, which previously could cause illness, contamination and undue stress of a patient. 
    
    
     These and other objects, features and advantages will become apparent upon reading the following Detailed Description which should be read in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of a laryngoscope; 
     FIG. 2 is a perspective view of a lamp cartridge assembly used in the laryngoscope of FIG,.  1  and made in accordance with a preferred aspect of the invention; 
     FIG. 3 is an exploded view of the lamp cartridge assembly of FIG. 2; 
     FIG. 4 is a sectioned view of the lamp cartridge assembly of FIGS. 2 and 3 with the lamp assembly disposed in an non electrically engaged position; and 
     FIG. 5 is the sectioned view of the lamp cartridge assembly of FIG. 4 with the lamp assembly in an electrically engaged position. 
    
    
     DETAILED DESCRIPTION 
     The following discussion relates to a preferred embodiment of a lamp cartridge assembly in accordance with the present invention. Throughout the course of this discussion certain terms including “top”, “upper”, “lower”, “front”, “back” and the like are used to provide a frame of reference with regard to the drawings. These terms, however, are not intended to be limiting of the claimed invention. 
     Turning to FIG. 1, there is shown a laryngoscope  10  which includes a hollow cylindrical instrument handle  12  having an interior sized for containing a pair of dry cell batteries (not shown). The batteries are typically stacked end to end and are used to power a lamp assembly  40 , identified in FIG. 4, retained by a lamp cartridge assembly  30  (partially shown in FIG. 1) which is fitted into an upper end  16  of the handle  12 . In brief, light emitted from the lamp assembly  40 , FIG. 4, is directed to a light pipe containing a bundle of optical fibers  23  disposed in a laryngeal blade  20  which is releasably connected to the upper end  16  of the instrument handle  12 . More particularly and according to this specific embodiment, the laryngeal blade  20  includes a slotted portion  22  at an attachment end  25  thereof which is fitted onto a lug  26  provided at the upper end  16  of the instrument handle  12 . Further details relating to the laryngeal blade  20  and attachment of the blade to the instrument handle  12  are as described, for example, in commonly assigned U.S. Ser. No. 09/257,762, filed Feb. 25, 1999, now U.S. Pat. No. 6,013,026, the entire contents of which are herein incorporated by reference. 
     Turning to FIG. 2, the lamp cartridge assembly  30  includes a cartridge housing  34  made from brass or other suitable material, the housing having a pair of opposing ends including an upper or top end  36  and a lower or bottom end  58 . Each of the upper and lower ends  36 ,  58  include respective openings  44 ,  46 , each shown in FIG. 3, defining a cartridge interior sized for receiving a number of components. These components will now be described in greater detail. 
     Referring to FIGS. 3-5, the lamp assembly  40  is slidingly fitted into the upper end  36  of the cartridge housing  34 , the assembly including a lamp carrier member  38  having a top opening  45 , FIG. 5, into which a miniature lamp  24  is threadingly fitted. An O-ring  28 , shown only in FIGS. 4 and 5, is provided to assist in sealing the electrical contacts  29  at the base  27  of the miniature lamp  24  between respective threaded portions  31 ,  33 . When engaged therewith, a portion of the miniature lamp  24  projects a predetermined distance from the upper end  56  of the lamp carrier member  38 . A plastic plunger or sleeve  47  engaged onto a set of external threads  54  at the upper end  56  of the lamp carrier member  38  protects the miniature lamp  24 , the plunger having a top opening  48 , permitting light to exit therefrom. 
     The bottom end  61  of the lamp carrier member  38  includes a cylindrical projecting portion  55  having a diameter which is smaller than the remainder of the carrier member, including a annular shoulder  59  abutting the upper end of the projecting portion. 
     An insulating body  66  made from plastic, phenolic, or other suitable material is press fitted and/or epoxied into the bottom end  58  of the cartridge housing  34 , the body having an upper end  67  which is sized to fit into a recess  68  defined in the projecting portion  55  of the lamp carrier member  38 . A lower end  72  of the insulating body  66  effectively fills the bottom end  58  of the cartridge housing  34  with the exception of a center through opening  75  containing a contact pin  70  biased into a first projecting position by an internal spring  74  supported between an upper shoulder  78  of the contact pin and a plug  80 , the upper end of which is tightly engaged into the center opening  75  of the insulating body  66  and having a head  84  which extends outwardly from the lower end  72  of the insulating body. 
     An axial portion of a biasing spring  42  is fitted about the exterior of the cylindrical projection  55  of the lamp carrier member  38  with the upper end of the spring bearing against the bottom surface  57  of the annular shoulder  59 . The lower end of the biasing spring  42  engages against a brass washer  50  disposed onto a shoulder intermediately disposed between the upper and lower ends  67 ,  72  of the insulating body  66 . 
     Referring to FIG. 5, the respective outer dimensions of the lamp carrier member  38  and the inner diameter of the cartridge housing  34  permit axial movement of the lamp carrier member. The interior wall  64  of the cartridge housing  34  is narrowed immediately adjacent the upper end  36  in comparison with the remainder of the interior, the wall being outwardly stepped at an axial portion and forming a stop  86  when engaged by the annular shoulder  59  of the lamp carrier member  38 . A similar stop is provided in the opposing axial direction when the bottom of the cylindrical projecting portion  55  of the lamp carrier member  38  engages an abutment  88  of the insulating body  66 . 
     As most clearly illustrated in FIGS. 4 and 5, the lamp carrier member  38  includes a circumferential notch  62  into which a rubberized sealing ring  60  is positioned, the ring engaging the interior wall  64  of the cartridge housing  34  at the upper end  36  and preventing fluid or debris from entering the interior of the cartridge housing. According to this embodiment, the ring member  60  is defined by a quad (4 sided) configuration which remains in engagement with the interior wall  64  over the entire range of axial positions of the lamp carrier member  38 . 
     FIG. 4 shows the fully assembled cartridge assembly  30  prior to the attachment of the laryngeal blade  20 , FIG.  1 . Prior to blade attachment, the lamp carrier member  38  is fully acted upon by the biasing force supplied by the spring  42  which positions the electrical contacts  29  of the miniature lamp  24  away from the contact pin  70 . The sealing ring member  60  and the press fitted insulating body  66  protect the interior of the cartridge housing  34  and provide a substantial dust and fluid tight seal. As noted above, the annular shoulder  59  engages the stop  86 , defining a first or electrically unengaged position. 
     Referring now to FIGS. 1 and 5, and in operation, the laryngeal blade  20  is attached to the upper end  16  of the hollow instrument handle  12  by snapping the slotted portion  22  onto the lug  26  and rotating the section  22  such that the bottom edge  90  of the blade  20  is parallel to the handle neck surface  91 . Engagement of the blade  20  in this manner causes the attachment portion  25  to bear upon the projecting plastic plunger  47 , thereby axially shifting the lamp carrier member  38  against the biasing force supplied by the spring  42  to an electrically engaged position. In this “engaged” position, the electrical contacts  29  of the miniature lamp  24  are driven into intimate contact with the contact pin  70 . This engagement causes the contact pin  70  to shift axially against the biasing force of spring  74  and completing the electrical connection, the plug  80  being in engagement with the batteries (not shown) in the handle interior to cause energization of the miniature lamp  24 . 
     In the meantime, and regardless of the axial position of the lamp carrier member  38 , the rubberized sealing ring  60  prevents fluid or other debris from entering the interior of the cartridge housing  34 . According to the preferred embodiment, the sealing ring  60  is a quad ring having four (4) sides which maintain their position for wiping. The ring has a pair of opposing wiping surfaces as compared to a single wipe of an O-ring which is somewhat effective, but which makes this configuration more desirable. A diaphragm could also be substituted. 
     The entirety of the cartridge assembly  30  can be removed through the bottom of the handle  12 , as needed, for cleaning. 
     PARTS LIST FOR FIGS.  1 - 5   
       10  laryngoscope 
       12  hollow instrument handle 
       16  upper end 
       20  laryngeal blade 
       22  slotted portion 
       23  light pipe containing optical bundle 
       24  miniature lamp 
       25  attachment end 
       26  lug 
       27  lamp base 
       28  O ring 
       29  electrical contacts 
       30  lamp cartridge assembly 
       31  threaded portion 
       33  threaded portion 
       34  cartridge housing 
       36  upper end 
       38  lamp carrier member 
       40  lamp assembly 
       42  spring 
       44  opening 
       45  top opening 
       46  opening 
       47  plastic plunger 
       48  plunger opening 
       50  washer 
       54  external threads 
       55  cylindrical projecting portion 
       56  upper or top end 
       57  bottom surface 
       58  lower or bottom end 
       59  annular shoulder 
       60  sealing ring 
       61  bottom end 
       62  circumferential notch 
       63  center opening 
       64  interior wall 
       66  insulator body 
       67  upper end 
       68  recess 
       70  pin, contact 
       72  lower end (body) 
       74  spring 
       75  center opening 
       78  upper shoulder 
       80  plug 
       84  head 
       86  stop 
       88  abutment 
       90  bottom edge 
       91  handle neck surface 
     Though the above invention has been described in terms of a single embodiment, it be appreciated that variations and modifications are possible within the scope of the invention as claimed herein.