Abstract:
The present invention discloses an adjustable forehead support for a nasal or full-face mask wherein the forehead support may be adjusted for the different shapes and sizes of a facial profile. The forehead support utilizes a dual-arm system that adjusts the position of the forehead support vis-á-vis the mask and/or airflow tube. The angle of the mask to the face may be adjusted with the present invention.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention generally relates to an improved comfort device to be used with a nasal mask. In particular, the device is useful in combination with masks which are used for the treatment of respiratory conditions and assisted respiration. The invention assists in fitting the mask to the face as well.  
           [0003]    2. General Background  
           [0004]    Nasal masks are commonly used in the treatment of respiratory conditions and sleep disorders by delivering a flow of breathable gas to a patient to either assist the patient in respiration or to provide a therapeutic form of gas to the patient to treat sleep disorders such as obstructive sleep apnea. These nasal masks typically receive a gas through a supply line which delivers gas into a chamber formed by walls of the mask. The mask is generally a semi-rigid mask which has a face portion which covers at least the wearer&#39;s nostrils. Additionally, the mask may be a full face mask. The mask is normally secured to the wearer&#39;s head by straps. The straps are adjusted to pull the mask against the face with sufficient force to achieve a gas tight seal between the mask and the wearer&#39;s face. Gas is thus delivered to the mask and the wearer&#39;s nasal passages and/or mouth.  
           [0005]    One of the problems that arises with the use of the mask is that in order for the straps to be tight, the mask is compressed against the wearer&#39;s face and may push unduly hard on the wearer&#39;s nose. Additionally, the mask may move around on the wearer&#39;s face. Thus, there has been provided a forehead support, which provides a support mechanism between the mask and the forehead. This forehead support prevents both the mask from pushing too strongly against the wearer&#39;s nose and/or facial region as well as minimize movement of the mask with the addition of a contact point between the mask and the wearer&#39;s head as well as minimize uncomfortable pressure points of the mask. Additionally, the forehead support may prevent the airflow tube from contacting the wearer&#39;s forehead or face.  
           [0006]    [0006]FIG. 1 shows a general perspective view of a related art forehead support  10 . The forehead rest or support  10  is attached to an airflow tube  12  extending from the mask  14 . The mask  14  and forehead support  10  are shown with headgear  16  which secures the mask  14  to the head of a patient. As can be seen in FIG. 1, the headgear  16  loops through the forehead support  10  at loops  18  and  20 . This pulls the forehead support  10  against the forehead, thus creating a snugly fitted mask  14  and also provides a stabilizing member for the mask  14 .  
           [0007]    [0007]FIG. 2 discloses the construction of the related art forehead support  10 . The forehead support  10  has pads  24  and  26 , a back side of which can be seen in greater detail in FIG. 10. These pads  24  and  26  are the actual contact points of the forehead support  10  to the forehead. The support pads  24  and  26  are mounted to the bridge  32 . Arms  34  and  36  are secured to bridge  32  by an adjustable locking mechanism which is better illustrated in the figures below. The bridge  32  provides three purposes to the forehead support  10 . First, it acts as a securing means for pads  24  and  26 . Second, it has loops  18  and  20  which receive the optional headgear  16  shown in FIG. 1. Finally, it receives arms  34  and  36 , which may be adjusted, as described below. The bridge  32  and arms  34  and  36  operate in a cantilever fashion and are made of a polymeric material, which may be easily molded. Additionally, arms  34  and  36  join together to create an annular space  38  to receive airflow tube  12  which is connected to a flow generator to generate breathable air or some type of therapeutic gas. Arms  34  and  36  create an operational hinge. The tube  12  is an axis of this hinge.  
           [0008]    [0008]FIG. 3 is an exploded view of FIG. 2 and shows the forehead support  10  in greater detail. Bridge engaging pins  56 ,  58 ,  60  and  62  are shown in FIG. 3. As will be more apparent in the figures below, these engaging pins provide for the adjustability of the forehead support  10 . Bridge  32  includes slots  76 ,  78 ,  82 ,  84 ,  86 ,  88  and  90  (see FIG. 9) and a mirror set of slots on the upper portion of bridge  32  (not visible in FIG. 9) for selectively receiving pins  56 ,  58 ,  60  and  62 . These slots open to the forehead side of the bridge. Additionally, there is a space or recess at arms  34  and  36  shown on arm  34  as  64 . The purpose of this space  64  is so that the user may compress arm  34  and thus press pins  56  and  58  together by pressing on surfaces  66  and  68 . The purpose of the compression is to decrease the distance between pins  56  and  58  such that they may be selectively inserted and locked into the desired pair of slots on bridge  32 . The length of the pins  56  and  58  is such that even when the pins are pressed together, they do not clear the slots in the bridge sufficiently to allow the arms to be dissasembled from the bridge without further action.  
           [0009]    [0009]FIG. 4 is a side view of the mask  14  and forehead support  10 . The mask is shown as  14  with a dotted line showing the nose of a wearer  70  and the dotted line showing the forehead  72  of the wearer. Pad  26  is shown compressed by the forehead of the individual wearing the mask.  
           [0010]    [0010]FIG. 5 is a top view of the forehead support  10  taken along lines  5  of FIG. 4. Also, the mask  14  is not shown in FIG. 5. This figure illustrates the forehead support  10  in a position wherein the forehead support is in the closest position to the tube  12  (shown as merely a space in FIGS.  5 - 6 ). The bridge  32  is shown essentially in contact with tube  12 . The pins  56 ,  58 ,  60  and  62  are shown in their furthest position from the center of the bridge  32 , engaging slot pairs  88  and  90 . This position may be utilized by someone with a large, protruding or bulbous forehead, or a high nasal bridge, or someone who prefers the airflow tube to be snug against their forehead. FIG. 6 shows the same forehead support in the next position, wherein the bridge  32  is moved away from tube  12  such that there is a gap  74  between bridge  32  and tube  12 . Here, pins  56 ,  58 ,  60  and  62  engage slot pairs  76  and  86 . As is visible from the figure, the forehead support  10  is now moved away from tube  12 , and is positioned differently than in FIG. 5. This may be configured to fit someone with a less protruding forehead, or someone who wants the flexible tube further from their head than is possible in FIG. 5. FIGS. 7 and 8 show the third and fourth position for the forehead support.  
           [0011]    The related art arm  34  is shown in greater detail in FIGS.  11 - 13 . As can be seen in the top view of the arm  34  shown in FIG. 11, the arm  34  includes a semicircular portion  100 , on an interior of which the annular space  38  is situated. An extending portion  102  extends from the semicircular portion  100 . Surfaces  66  and  68 , space  64  and engaging pins  56  and  58  are positioned on the extending portion  102 . Each surface  66  and  68  includes a generally oval depression  106  and  108 , respectively, positioned near the pins  56  and  58 . These oval depressions  106  and  108  can be felt by the wearer of the mask and assist the wearer in properly positioning his or her fingers near the pins  56  and  58  when it is desired to adjust the forehead support. This is especially important when the mask and forehead support are positioned on the wearer&#39;s head because at such time, the wearer cannot easily see where to place his or her fingers to adjust the forehead support. The oval depressions not only assist the wearer in properly positioning his or her fingers for adjusting the support, by virtue of the fingers engaging the depressions, the depressions also help maintain the fingers in the appropriate position.  
           [0012]    [0012]FIG. 12 is a side view of the arm shown in FIG. 11. As can be seen there, the semicircular portion  100  only extends upward to half of the height of the arm  34 . Because of this, the arm  34  is reversible, i.e., it can be flipped over, and then can be used as arm  36 . Thus, only one arm design need be molded and this can be used as both arm  34  and arm  36 , depending on its orientation. Extending portion  102  includes two horizontal flanges  110  and  112  connected by an intermediate web  114 . The two horizontal flanges are thicker in the horizontal direction and thinner in the vertical direction than web  114 . The space  64  is positioned on web  114 . The force required to press the pins  56  and  58  together is a function of the amount of material of the extending portion  102  on either side of the space  64  in the vertical direction, the length space  64  extends along portion  102  (i.e., the length of each cantilever arm on either side of space  64 ) and the type of material from which the arm  34  is constructed. These arms have been constructed of a polycarbonate, specifically, Makrolon 2458 manufactured by Bayer.  
           [0013]    [0013]FIG. 13 shows a cross-section of the arm  34  along line  13 - 13  in FIG. 12. The comparative thicknesses of the flange  112  and the web  114  in the horizontal direction can best be seen here. The hatched portion of the arm  34  is the portion of the web  114  beyond the extended length of the space  64 .  
           [0014]    It has been found that while the related art forehead support performs correctly if operated according to the instructions, an improvement can be made to reduce the risk of breakage when the forehead support is operated in a manner contrary to instructions.  
           [0015]    Further, because depressions  106  and  108  are relatively narrow, an improvement can be made to allow the user to positively and firmly position his or her fingers to press the pins  56  and  58  together. Finally, because there is a relatively large amount of material contact between an interior of semicircular portion  100  and an exterior of airflow tube  12 , this can result in a relatively large amount of friction between the arm  34  and the tube  12 , thereby requiring additional force to pivot the arm  34  around the tube  12  for adjustment purposes.  
         SUMMARY OF THE INVENTION  
         [0016]    The present invention is directed to an improved version of the type of forehead support discussed above. In particular, the present invention utilizes improved arms extending from the mask or gas supply line for adjustably engaging the bridge for allowing positioning of the mask on the face. First, extending portions of the arms are redesigned to compress more easily than the extending portions of the related art arms discussed above while at the same time maintaining the strength necessary for adequately supporting the airflow tube. Thus, the engaging pins may more easily be compressed together to allow for adjustment of the arms with respect to the bridge.  
           [0017]    Furthermore, the extending portions of the arms are provided with locking portions that maintain alignment of the pins with respect to one another as they are being compressed to prevent lateral deflection of the pins, unintended stress loading on the arms and to allow easier engagement of the pins with the slots upon release of the extending portions.  
           [0018]    Finally, arc portions of the arms that come into contact with the airflow tube  12  are undercut and radiused to prevent sticking or binding of the arms as they are pivoted about the airflow tube during adjustment of the forehead support, as compared to the related arm embodiment. Thus, the arms more easily pivot about the airflow tube during adjustment of the forehead support.  
           [0019]    These improvements make it easier to adjust the forehead support, as well as make it easier to disassemble the arms from the bridge to allow thorough cleaning of the bridge and other support components. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is a perspective view of a related art forehead support attached to a mask, headgear and a gas supply tube;  
         [0021]    [0021]FIG. 2 is a perspective view of the forehead support of FIG. 1 removed from the mask and gas line;  
         [0022]    [0022]FIG. 3 is an exploded view of the forehead support of FIG. 1;  
         [0023]    [0023]FIG. 4 is a side view of the forehead support of FIG. 1 secured to a mask;  
         [0024]    [0024]FIG. 5 is a top view of the forehead support of FIG. 1 in a first position;  
         [0025]    [0025]FIG. 6 is a top view of the forehead support of FIG. 1 in a second position;  
         [0026]    [0026]FIG. 7 is a top view of the forehead support of FIG. 1 in a third position;  
         [0027]    [0027]FIG. 8 is a top view of the forehead support of FIG. 1 in a fourth position;  
         [0028]    [0028]FIG. 9 is a front view of a bridge of the support of FIG. 1;  
         [0029]    [0029]FIG. 10 is a single pad of the support of FIG. 1;  
         [0030]    [0030]FIG. 11 is a top view of a of an arm for use in the forehead support of FIG. 2;  
         [0031]    [0031]FIG. 12 is a side view of the arm of FIG. 11;  
         [0032]    [0032]FIG. 13 is a section view of the arm of FIG. 12 along section line  13 - 13 ;  
         [0033]    [0033]FIG. 14 is a top view of an improved arm for use in the forehead support of FIG. 2;  
         [0034]    [0034]FIG. 15 is a side view of the arm of FIG. 14;  
         [0035]    [0035]FIG. 16 is a section view of the arm of FIG. 15 along section line  16 - 16 ;  
         [0036]    [0036]FIG. 17 is a perspective view of the arm of FIG. 11;  
         [0037]    [0037]FIG. 18 is a partial section view of the arm of FIG. 13 along section line  18 - 18 ;  
         [0038]    [0038]FIG. 19 is a partial section view of the arm of FIG. 15 along section line  19 - 19 ; and  
         [0039]    [0039]FIG. 20 is a partial section view of the arm of FIG. 15 along section line  19 - 19 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0040]    [0040]FIG. 14 shows a top view of an improved embodiment of an arm for use with the present invention. Arm  200  includes a semicircular portion  202  and an extending portion  204  attached thereto. Semicircular portion  202  includes two arc portions  230  and  232  and an inner bore  234 . The two arc portions  230  and  232  are both recessed or undercut near their ends, as shown by the phantom lines  236  and  238 . Thus, the inner bore  234  is not perfectly circular in shape near the ends of arc portions  230  and  232 . Ends  240  and  242  of the arc portions  230  and  232 , respectively, are well radiused to prevent binding of the arm on the airflow tube during pivoting.  
         [0041]    Extending portion  204  includes two flange portions  206  and  208  on which generally oval depressions  210  and  212  are respectively positioned. Bridge engagement pins  214  and  216  are positioned at far ends of flange portions  206  and  208 , respectively, and project, respectively, upwardly and downwardly from the arm  200 . A space  218  separates the flange portions  206  and  208  and in this embodiment, it can be seen that there is no vertical web between the respective flange portions and the space  218 . Also, it can be seen that the space  218  extends along a greater portion of arm  200  than does the embodiment shown in FIG. 12. Thus, the cantilever arm portions of the arm of FIG. 14 are longer than the cantilever arm portions of the arm of FIG. 2. Further, the cantilever arm portions of the arm of FIG. 14 are tapered along their length, such that the thickness of these portions is less near the pins than the semicircular portion  202 . Compare the thicker section of the arm of FIG. 15 shown in FIG. 19 with the thinner section of the arm taken nearer the pin  214  shown in FIG. 20.  
         [0042]    Even though the thickness of the cantilever arm portions of the arm of FIG. 15 have been reduced as compared to the arm of FIG. 2, the width of these portions has been increased with respect to the arm of FIG. 2. Compare the widths of the arm of FIG. 15 shown in FIGS. 19 and 20 with the width of the arm of FIG. 13 shown in FIG. 18. The increased width of the improved arm of FIG. 15 provides a stiffness in the lateral plane that is about 8 times greater than the stiffness of the arm of FIG. 2. This increased stiffness prevents most accidental lateral deflections of the pins and would likely require a determined intentional action to laterally deflect the cantilever arm portions and pins.  
         [0043]    A male locking portion  220  is positioned inboard of pin  214  and a female locking portion  222  is correspondingly positioned inboard of pin  216 . The male and female locking portions are configured so as to be able to fittingly mate with one another when the two flanges portions  206  and  208  are pressed together. As seen in FIG. 16, a section along line  16 - 16  in FIG. 15, the female locking portion can be configured as a chevron-shaped slot Correspondingly, the male locking portion  220  would be configured as a chevron-shaped projection to mate with the chevron-shaped slot of female locking portion  222 . The male and female locking portions can also have different shapes, as long as they will lockingly mate together when the two flange portions are pressed together. As with the arm  34  above, the arm  200  can be flipped over to provide the second arm of the forehead support and thus, only one mold is needed to cast both required arms.  
         [0044]    The lengths of the pins  214  and  216  are provided such that when the pins are pressed together to the extent allowed by the locking portions, the pins will clear the slots in the bridge, contrary to the pins of the related art arms.  
         [0045]    In a preferred embodiment, these improved arms are constructed of a polycarbonate, specifically, Makrolon 2858 manufactured by Bayer.  
         [0046]    There are several advantages to this improved arm embodiment. First, because the space  218  extends farther along the arm  200 , the lack of a web between the flanges  206  and  208  and the tapering of the cantilever arm portions, it is as easy or easier to press the pins  214  and  216  together when adjusting the forehead support, even with the increased lateral strength of the improved arms. This is especially important because during the adjustment while the mask is on the wearer&#39;s head, the wearer cannot easily see the forehead support as he or she is performing the adjustment. The increased lateral strength helps resist accidental lateral deflection of the cantilever arm portions and pins, as well as providing a stronger support to the airflow tube. The end result is that at the outer portion of the arm  200  near the pins, the extending portion  204  has a greater stiffness and resistance to bending in the lateral or horizontal direction (i.e., the pivoting direction) than it does in the vertical direction (the non-pivoting direction). This is contrary to the embodiment shown in FIGS.  11 - 13  where the stiffness and resistance to bending is greater in the vertical direction than in the horizontal direction.  
         [0047]    Of course, the taper, shape and/or the thickness of the cantilevered arm portions can be altered to vary the stiffness of the cantilevered arm portions in the horizontal or vertical directions, as circumstances warrant. Further, under certain circumstances, it is contemplated that the stiffness of the cantilevered arm portions in the vertical direction can be less, similar to, or even greater than the comparable stiffness of the cantilevered arm portions of the related art design in the vertical direction.  
         [0048]    The use of the wider flanges also allows the use of broader oval depressions  210  and  212 . These broader depressions better accommodate the wearer&#39;s fingers and thus, give the wearer a more positive and more comfortable grip on the arms during adjustment.  
         [0049]    The provision of the male and female locking portions assures that the two flange portions remained aligned with one another during the pressing together of the pins  214  and  216 . Thus, the pins are also maintained in alignment during compression, making it easier for both pins to align with their respective slots in the bridge during adjustment of the bridge. Without the locking mechanism, the pins can be twisted and splayed with respect to another during compression, making it more difficult to position the pins in the desired respective slots in the bridge during adjustment. Further, the locking portions also prevent the user from laterally deflecting the pins with respect to one another when disassembling the arm from the bridge. Since the pins are short enough to clear the slots in the bridge when pressed together, the arm need not be rotated or the pins laterally displaced from one another to allow the pins to clear the slots in the bridge. This reduces that the chance that a user can operate the arms contrary to instructions and thereby place undue stresses on the arms that could lead to premature failure of the arms.  
         [0050]    Finally, the provision of the undercut or recessed portions  236  and  238  on arc portions  230  and  232  reduces the amount of material of the arm that comes into contact with the airflow tube  12  (or other pivot point). This helps prevent sticking or binding of the arm as it is pivoted about the airflow tube during adjustment of the forehead support, as compared to the related arm embodiment. The radiused ends  240  and  242  are also less likely to catch and hang up on imperfections in the airflow tube during pivoting, as compared to the sharper ends of the related arm embodiment. Thus, the arm  200  more easily pivots about the airflow tube during adjustment of the forehead support.  
         [0051]    These improvements in arm  200  thus make it easier to adjust the forehead support, as well as make it easier to disassemble the arms from the bridge to allow thorough cleaning of the bridge and other support components. They also help prevent actions by the user contrary to instructions that could increase the risk of breakage of the forehead support.  
         [0052]    While several improvements have been discussed above, it is contemplated that an improved forehead support according to the present invention need not utilize all such improvements but can utilize one or more of such improvements in various combinations.  
         [0053]    It is to be understood that while the invention has been described above in conjunction with preferred specific embodiments, the description and examples are intended to illustrate and not limit the scope of the invention.