Patent Document

FIELD OF THE INVENTION 
     This invention relates generally to a protective cover for the probe of a medical instrument that is insertable into a body cavity. 
     BACKGROUND OF THE INVENTION 
     Many types of medical instruments, such as an infrared (IR) thermometer, contain a probe for insertion into a body cavity so that various body related measurement can be taken. In order to prevent cross contamination between patients or health care workers and patients, the probe is generally enclosed within a protective cover which can be disposed of in a sanitary manner after it has been used. Typically the covers are manufacted of plastic using different types of molding techniques many of which produce products that have surface imperfections or which can not be held to tight tolerances. Most protective covers are packaged and shipped with the covers being stacked one inside the other. Unstacking irregular formed covers and placing them upon the tip of an instrument can be extremely difficult. Defective covers tend to bind in the stack and as a consequence can be damaged and dropped during removal from the stack. Displacement or a misshapened cover from the instrument tip during an examination can also be unnerving to both the attending health care individuals and the patient. Lastly, an irregular formed covers can hang up on the instrument during removal thus requiring unwanted manual handling of a potentially contaminated product. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary object of this invention to improve disposable probe covers that are suitable for use in the protection of insertion tips of medical instruments. 
     Another object of the invention is to provide for easy removal of a protective probe cover from a supply stack of covers. 
     A further object of the invention is to more positively secure a protective probe cover to a medical instrument to insure that the cover does not become dislodged during a patient examination. 
     A still further object of the present invention is to allow for the free release of a used probe cover from a medical instrument. 
     Yet another object of the present invention is to minimize the amount of manual handling that is required when loading and unloading a protective probe cover from a medical instrument. 
     Still another object of the present invention is to minimize the risk of damaging a protective probe cover as the cover is being loaded upon a medical instrument. 
     These and other objects of the invention are attained by a removable protective cover for a medical instrument that contains a probe that is suitable for insertion into a body cavity. The cover contains a flexible tubular body that compliments the tip geometry and a radially disposed flange that surround the proximal end of the body. A series of snap on fasteners removably connect the cover to the instrument. A camming surface is located on the outer face of the flange which coacts with a cam follower that is movably mounted upon the instrument to flex the cover sufficiently to open the fastener and release the cover from the instrument. Alignment tabs are further provided on the flange that mate with openings in the instrument to properly register the cover with regard to the instrument. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of these and other objects of the invention, reference will be made to the following detailed description of the invention which is to be read in association with the accompanying drawings, wherein: 
         FIG. 1  is a partial view in perspective illustrating the probe end of a medical instrument showing a protective cover embodying the invention securely affixed to the instrument; 
         FIG. 2  is a perspective view similar to that illustrated in  FIG. 1 . showing the protective cover moved to a release position; 
         FIG. 3  is a further perspective view of the probe end of an IR thermometer with portion broken away to show the apparatus of the invention in greater detail; 
         FIG. 4  is a prospective view of the tip end of probe for use in a medical instrument embodying the present invention with the protective cover removed; 
         FIG. 5  is a prospective view similar to that illustrated in  FIG. 4  showing a protective cover mounted upon the probe tip in an unsecured condition; 
         FIG. 6  is a prospective view similar to that shown in  FIG. 5  with the cover secured to the tip of the instrument probe; 
         FIG. 7A  is a partial view in section showing the probe tip of a medical instrument with a protective cover secured to the instrument in a locked position; 
         FIG. 7B  is an enlarged partial view showing in greater detail one of the snap-on fasteners in a locked position as well as the cover ejector mechanism; 
         FIG. 8  is a view similar to  FIG. 7A  showing the ejector mechanism moved to a releasing position; 
         FIG. 9A  is a partial view similar to that shown in  FIG. 7A  showing a second embodiment of the invention with one of the fastener in a locked position; 
         FIG. 9B  is an enlarged view showing the snap-on fastener and the ejector mechanism shown in  FIG. 9A  in greater detail; and 
         FIG. 10  is an enlarged view illustrating a number of protective covers stacked one inside the other. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     Referring initially to  FIGS. 1-3 , the present invention involving a protective probe cover generally referenced  10  that will be described herein with regard to an infrared thermometer  11 . It should be clear to one skilled in the art, however, that the present invention can be used in conjunction with various other medical instruments having an extended probe for insertion into a body cavity. As pointed out above, disposable protective covers are placed over the probes to mitigate the danger of cross contamination occurring during and after an examination. The covers found in the prior art are typically made of plastic and are fabricated using various molding processes. Many of these molding methods, however, create imperfections in the final product and are unable to hold the product to close tolerances. Resulting in unwanted and potentially dangerous problems arising particularly during a medical procedure. 
     Testing has shown that probe covers that are fabricated by the injection molding process can be held to tight tolerances while still having a desired amount of flexibility that help overcome many fabrication problems. Accordingly, any references made herein involving a protective probe cover embodying the present invention will be specifically directed to a plastic cover that has been injection molded. 
       FIGS. 1-3  illustrate the top section of a hand held IR thermometer. The instrument includes a lower body section  12  and an upper head section  13  that contains an insertion probe  10 . That protrudes outwardly some distance from the head of the instrument. As best illustrated in  FIG. 3 , the proximal end section  15  of the probe is cylindrical in form and is secured by any suitable means to the head. The distal end  16  of the probe projects outwardly from the head and is conical shaped so as to taper downwardly from the cylindrical body of the probe towards the distal end tip  17 . An IR sensor  18  is mounted in the tip of the probe. Although not shown, the sensor is connected by electrical leads to a processor that is located within the body of the instrument which provides an accurate temperature read out to the user. 
     The probe cover  10  is shown in  FIGS. 1 and 3  mounted upon the extended end of the probe  10  in a locked position wherein the cover is securely fastened to the probe. The inner wall surface  32  of the cover complement the conical wall surface of probe. As will be explained in further detail below, the cover is releasably secured to the probe by a series of snap-on fasteners  50 . A best illustrated in  FIG. 3 , an ejector mechanism, generally referenced  25  is slidably mounted inside the instrument head upon the cylindrical section of the probe. The ejector mechanism is equipped with a circular ring  24  that surrounds the cylindrical section of the probe to provide a close running fit there between so that the ejector can be moved axially along the centerline  29  of the probe between a first cover locking position and a second cover releasing position. 
     The ring of the ejector contains a raised finger engagable control button  26  that passes upwardly through an opening  27  contained in the head of the instrument. When the control button is situated at the back of the opening as shown in  FIG. 1 , the ejector mechanism is in the first probe locking position. Manual movement of the control button to the front of the opening as illustrated in  FIG. 2  places the ejector mechanism a second probe releasing position. 
     Turning now to  FIGS. 4-6  there is illustrated the front circular shoulder mount  30  of the probe assembly which is retained within the front wall  31  of the instrument head to support the distal end  16  of the probe in assembly.  FIG. 4  shows probe without a cover. Two opposed arcute shaped slots  33 - 33  are located in the probe mount  30  that are centered upon the longitudinal axis  29  of the probe. A pair of arcute shaped fingers  35 - 35  that are intragally joined to the ejector ring  24  and are slidably contained within the slots  33 - 33 . The fingers are arranged to be extended and retracted as the ejector moves between the first and second positions. A series of circumferentially spaced segmented detent beads  38 - 38  are mounted upon the probe and, as will be explained in greater detail below, each bead section is the male part of a two part snap on fitting for releasably securing the probe cover  10  to the instrument. Preferably three equally spaced fittings are employed to secure the cover to the instruments, however, more or less fittings may be employed depending upon the particular application. 
       FIG. 5  illustrates a protective cover  10  mounted in a locked position upon the probe. At this time, the flange  40  of the cover has engaged the fingers  35 - 35  of the ejector mechanism and has moved the ejector back to the cover locking position due to the rearward movement of the cover over the probe. Full reward movement is attained when the snap-on fasteners engage the bead segments on the probe. 
       FIG. 6  illustrates a probe cover located upon the probe with the ejector mechanism in the cover releasing position. At this time the control button  25  ( FIG. 3 ) has been moved forward causing the ejector mechanism to unlock the fasteners thus releasing the cover. In addition the continued movement of the ejector toward the distal end of the probe frees the cover from the probe. 
       FIGS. 7A ,  7 B and  8  illustrate a first embodiment of the invention detailing apparatus for securing and releasing a probe cover from the instrument.  FIG. 7A  shows the above described ejector mechanism  25  moved back into the first cover locking position and a snap-on fasteners generally reference  50  in a cover securing condition. At this time the cover is snuggly contained upon the probe. The cover contains an IR transparent lens or window  19  mounted in the distal tip thereof which is now located in close proximity with the IR sensor  18  (see  FIG. 3 ). 
     With further reference to  FIG. 7B  the securing and releasing apparatus is shown in further detail in the locked position. Each snap-on fastener  50  includes two mating parts or sections. These include the previously noted bead segment  38  located upon the probe surface that mates with an arcuate shaped cove  42  that is contained in the inner wall  53  of the cover adjacent to the proximal end flange  40 . The cove preferable extends circularly about the axis of the cover and services each of the detent beads. The cover wall section that encircles the cove provides a weaker section in the cover about which the cover can flex when an upward force is applied to the outer face  56  of the flange. A circular camming surface  58  is contained in the outer face of the flange that rung along the rim of the flange. The camming surface is angularly offset with regard to the axis of the cover. The distal end of the two fingers  35  of the ejector mechanism is provided with a arcute surface  60  that is arranged to ride in contact with camming surface  58  as the ejector mechanism moves between the first and second positions. Surface  60  thus serves as a cam follower in system. Although surface  60  is shown arcute in form, it can, in practice, be a flat surface that rides in sliding contact with camming surface  58  without departing from the teachings of the present invention. 
       FIG. 7B  shows the probe cover  10  in a locked position with the snap fitting closed thereby securing the cover to the probe. At this time the ejector mechanism is in the cover locking position. Moving the ejector button forward moves the cam follower against the camming surface of flange causing the lower portion of the cover to flex about the weakened wall section which surrounds the cove  42 . Sufficient flexure is provided to free the detent beads  38  from the cove  42 . Thus releasing the cover from the probe. As shown in  FIG. 8  further forward movement of the ejector moves the cover well clear of the probe surface so that it can fall easily from probe under the influences of gravity. 
     A series of semi circular tabs  65  are circumferentially space upon the outer face of the flange that arranged to mate with openings  66  in the raised shoulder  30  of the probe so that the snap-on fittings will mate properly at the time of closure. 
     Turning now to  FIGS. 9A and 9B , there is illustrated a second embodiment of the invention in which the probe cover is generally referenced  70 . In this embodiment, the probe cover is also equipped with a series of snap-on fittings  50  as described above. The cove that is formed in the inner wall of the cover body adjacent to the flange is also provided with a weakened section about which the flange can flex. A circular groove  63  is provided in the outer face of the flange which contain a camming surface  65  that is angularly offset with regard to the longitudinal axis of the probe. The end  67  of each ejector mechanism finger  35  is arcuate shaped and acts as a cam followers that ride in sliding contact with the camming surface  65 . Again, as the ejector is moved from the first cover locking position to the second release position, each snap on fitting  50  is opened and the cover is released from the probe. 
     As noted, it is the general practice to package and ship the covers in stacks. A number of probe covers  10 - 10  are illustrated in  FIG. 10  in a stacked configuration. When stacked one on top of the other the semi circular tabs on the upper cover are arrange to seat upon the flange of the underlying cover to prevent the outer wall surface of the lower cover from moving into binding contact with the inner surface of the upper cover. In addition, the inclined edge surfaces  58  on the outer face of cover flange  40  provide an easily accessible space between each of the cover which can be utilized to further facilitate removal of individual covers from the stack. 
     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof to adapt to particular situations without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims.

Technology Category: 3