Abstract:
A disposable face shield having an improved attachment mechanism for securing a band to attach the shield to a user&#39;s face is disclosed. The disposable face shield includes a flexible transparent member having at least one slit therethrough. The slit edges have points that grab the elastic holding strap at a selected location to make a selected adjustment of the face shield to the user&#39;s head. A flexible forehead support member is provided on the upper portion of the transparent member to nestle against a user&#39;s forehead.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates generally to face shields. More particularly, this invention relates to a disposable face shield having an improved adjustable attachment for a band securing the shield to the user&#39;s head. 
       BACKGROUND OF THE INVENTION 
       [0002]    It has long been advantageous for individuals working with liquids to wear a protective face shield to prevent those liquids from spattering on the face. For example, face protection in medical procedures to prevent the splattering of blood on the face is recommended. It is also advantageous in medical procedures to use disposable surgical equipment where possible to substantially reduce the risk of infection and the cost of sterilizing the surgical equipment. Additionally, cleaning face shields of deposited chemicals, such as blood, paint, adhesives, dyes, solvents, resins, etc., is time consuming and often ineffective. Thus, disposable face shields have seen a wide application in various industries, e.g. medicine, dentistry, painting, manufacturing, and the like. 
         [0003]    Because of the wide application and use of disposable face shields, the mounting bands or straps which secure the shield to the face must be adjustable to accommodate a variety of different sized faces and heads. Some prior art face shields utilize a fastener or integral member to attach the band or strap to the shield. A prior art face shield as disclosed in U.S. Pat. No. 5,983,390 to Desy makes use of slits with smooth edges, formed in the flexible transparent face shield material itself. A strap having a width greater than the width of the slits is looped through the slits. The straps are threaded in a particular direction through the slits. Pulling on the ends of the strap, so threaded, decreases the amount of strap positioned to hold the shield to a user&#39;s head, thus making a secure fit. 
         [0004]    However, such slits, and therefore disposable face shields having those slits, can be improved upon as will be disclosed in the present application. 
       SUMMARY OF THE INVENTION 
       [0005]    A face shield has a flexible transparent portion with a flexible forehead support member, and is held on a user&#39;s head by an elastic strap. The elastic strap has pores, and is threaded through at least one slit in the flexible transparent portion. The edges of the slits have points that enter the pores of the strap, and keep the elastic strap at a desired position in the slits, so that the face shield has a desired tightness and remains in position on the wearer. 
         [0006]    Another version of the face shield has a strap without pores. The pointed teeth or edges of the slit press into the surfaces of the strap, since they cannot enter pores. 
         [0007]    In another version, face shields having slits are available without a strap attached. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  illustrates an embodiment of a disposable face shield of the present invention being worn by a user. 
           [0009]      FIG. 2A  is a top view of the embodiment of  FIG. 1 , removed from the user. 
           [0010]      FIG. 2B  is a schematic top view of the embodiment of  FIG. 1  while being tightened on a user. 
           [0011]      FIG. 3  is a view taken on view lines  3 - 3  in  FIG. 2B , with the strap shifted and drawn as a phantom schematic, for descriptive clarity. 
           [0012]      FIGS. 4A ,  4 B,  4 C are sequential schematic cross-sectional views of the slit area in the embodiment of  FIG. 3 , rotated for clarity. 
           [0013]      FIGS. 5A ,  5 B,  5 C are illustrations of other embodiments. 
           [0014]      FIG. 6  is similar to  FIG. 4B , but illustrates another embodiment of a disposable face shield. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    With respect to  FIG. 1 , the head  5  of a wearer  6  has a disposable face shield  10  secured by a strap  12 . The face shield  10  has a transparent member  14  and a flexible support member  16  made of foam and having relief cuts  18 . The foam support member may be of many materials and configurations, as is already known in the art. The transparent member  14  may be a variety of flexible materials known in the art, such as for example, polyethylene terephthalate (PET), with a thickness range of 0.20 to 0.24 mm. 
         [0016]      FIGS. 2A and 2B  are top views of the face shield  10  while removed, and while being worn. For purposes of describing face shield  10 , directions, orientations, and centerlines will be used from the perspective of a wearer. There is an inner area  20 , an outer area  22 , a right side  24  a left side  26  a front  28  and a back  30 . An imaginary centerline  32  divides the transparent member  14  into a right half  34  and a left half  36 . A right slit  38  in the right half divides the right half in to a right forward member  40  and a right end  42 . A left slit  44  in the left half divides the left half into a left forward member  46  and a left end  48 . The right slit  38  is visible in  FIG. 1 , but the left slit  44  is hidden from view. Only one of the two slits is necessary to practice the invention, although having both slits is preferred. In an embodiment without the second slit, the strap  12  may be secured to the transparent member  14  in some other manner, that may or may not be adjustable. 
         [0017]    The strap has a right end  50 , an opposing left end  52 , an inner surface  54 , an outer surface  56 , and a width  58  ( FIG. 3 ). When installed in the transparent member  14 , the slits  38 ,  44  surround the strap proximal each opposing end,  50 ,  52 . The slits divide the strap, (for descriptive purposes) into a right pull  60 , a left pull  62 , and a wrap section  64  between the right pull and left pull. As illustrated, the left and right pulls have an optional folded over section (not numbered) making the strap  12  easier for a wearer  6  to grip. The strap  12  may be plain as illustrated, or have a different shape. 
         [0018]    The arrows in  FIG. 2B  indicate how a wearer  6  would use the right pull  60  and left pull  62  to comfortably tighten the face shield  10  once they have placed it around their head  5 . As they tighten or loosen the face shield  10 , the relative amount of strap  12  in the wrap section  64  and the right pull  60  and left pull  62  changes. This embodiment of the disposable face shield  10  has two slits  38 ,  44  rather than one. This is advantageous when tightening, because pulling equally with both hands to tighten the face shield  10  does not shift the transparent member  14  around the wearer&#39;s head  5 . If instead only one slit was in the transparent member  14  surrounding only one end of the strap  12 , and the other strap end was fixed (or not easily adjustable concurrent with the first strap end), then repositioning of transparent member  14  after tightening may be necessary. 
         [0019]    The slits  38  and  44  and their interactions with the strap  12  will be further described with reference to  FIGS. 3-5 , that detail the right slit  38 . This description applies equally to a second or any other slit, for example the left slit  44 . Slit  38  is made by cutting the transparent member  14  in a zigzag pattern to form forward teeth  66  on a forward edge  68  on the right forward member  40 , and rear teeth  70  on a rear edge  72  on the right end  42 . In this embodiment each of the teeth  66  and  70  has a point  73 , although in other embodiments the teeth may not be pointed. The zigzag cut is typically made by a die, and it may be the same die that cuts the transparent member  14  from a larger expanse of material. The illustrated embodiment is of a zigzag along a straight axis rather than a non-straight axis, although another embodiment may have an axis that is not straight. “Axis” is used herein to mean the general path of travel of a line bisecting the zigzag in its longitudinal direction. The material is cut rather than punched. The term “punched” is used herein to mean a process that results in material being removed and typically discarded. Since no material is removed from the transparent member  14 , edge  68  abuts edge  72 . The teeth  66 ,  70  have a width  74  and a pitch  76 . Because the illustrated teeth are a zigzag, the width  74  and pitch  76  are the same value, but that need not be the case. Other slits, for example  200  ( FIG. 5B ) may have teeth in which a pitch  78  is different than a width  80 . The slit  38  has a width  82  and relief holes  84  at either end. The relief holes  84  are punched out to prevent a crack propagating through the material, as is well known in the art. 
         [0020]    The illustrated strap  12  has a strap width  58  less than the slit width  82 , but greater than the tooth width  74 . As can be seen in the illustration and understood with further discussion, the strap  12  need not be as wide as slit  38 . However the invention may have a slit that is wider (not shown), because the distance (not numbered) along the zigzag path is greater than the straight line width  82  along the axis, and a wide strap can at least partly conform in the zigzag path. This allows a variety of straps to be used in combination with a variety of slits. In a preferred embodiment, the strap width  58  is approximately 20 mm, the tooth width  74  is approximately 4 mm, and the slit width is approximately 17 mm. 
         [0021]    As schematically shown in  FIGS. 3 and 4A , strap  12  is a woven fabric having pores  88  in the form of spaces between threads  90  and transverse threads  92 . As the strap  12  is pulled ( FIG. 2B , and  FIG. 4A ) it stretches longitudinally. Gaps  88  form between transverse threads  92  while the forward teeth  66  and rear teeth  70  bend and allow the wrap section  64  to travel through the slit  38 , becoming the right pull  60 . As longitudinal tension applied by the wearer  6  is released ( FIG. 4B ), and the elastic tension in the wrap section  64  pulls back on the right end  50 , at least one rear tooth  70  enters a pore  88  and engages a transverse thread  92  to prevent further loosening. As seen in  FIG. 4C , the aft teeth  70  and the forward teeth  66  engage the strap  12 , allowing the elasticity of wrap portion  64  and resilience of flexible support member  16  to keep the transparent member  14  stably positioned on the wearer&#39;s head  5 . 
         [0022]    The figures describe the actions of the teeth of transparent member  14  in a simple schematic way, however one should realize that a series of opposing teeth in a flexible thin material may not consistently react and align in the same way each time they are moved. Factors such as sequence of pull, direction and magnitude of pull, strap fold-over, and other factors may make the teeth orient in varying positions. However in total, the teeth  66 ,  70  keep the strap  12  at a longitudinal position in the slit  38 , as well as allow the strap to be pulled to another selected longitudinal position, within the slit  38 . 
         [0023]    Although the direction of the strap  12  in the transparent member  14  is shown in a preferred way, with the pulls  60  and  62  outside ( 22 ) to the wrap portion  64  so that the wearer can easily feel and grab the pulls, that need not be the case. The present invention will also work if the strap is threaded in the opposite direction, with the wrap portion  64  outside the right end  42  and left end  48 . It will also perform sufficiently if the threading is done in one direction on the right side  24 , and the other direction on the left side  26 . The present invention, therefore, is robust and not dependent upon a consistent strap path. 
         [0024]      FIGS. 5A ,  5 B, and  5 C illustrate embodiments having different slits. Slit  100  is an embodiment having an aft edge  102  with two aft teeth  104  with points  73  and a forward edge  106  that does not have points  73 . Instead there is a straight portion  108  on the forward edge  106 , and a corresponding straight portion  110  on the aft edge  102 . Slit  200  is an embodiment in which the rear edge  202  has at least one tooth  266  with a point  73  and forward edge  206  has at least one tooth  270  with a point  73 . Slit  300  is an embodiment having truncated teeth  366  and  370  like the teeth  66 ,  70  in  FIG. 3 , except that sharp points  73  are cut off. This may be done, for example, at the same time as the punching of the relief holes  84 , or may be done at a different time in the manufacturing process. A reason for truncated teeth  366 ,  370  will become apparent with discussion of different strap materials, that follows. 
         [0025]      FIG. 6  illustrates a face shield  400  having teeth  66  and  70 , but rather than a strap having pores  88 , instead strap  402  may be made of a material without pores. The strap material may be, for example, foam or film having an inside surface  402  and an outside surface  404 . As seen in  FIG. 6 , the points  73  of teeth  66 ,  70  hold the strap  402  at a selected position by poking and depressing surfaces  404  and  406 . Pores  88  are not necessary. Because the teeth do not need to be sized to enter pores, they may instead be truncated teeth  366 ,  370  as in  FIG. 5C , or rounded, or any other shape. An optimum shape may be chosen based on the characteristics of the selected strap  402 , and the desired holding and release characteristics. The optimum shape may be determined experimentally, or by relationship to strap durometer, hardness, flexibility, or the like. 
         [0026]    While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details of the representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of applicant&#39;s general inventive concept.