Surgery – Respiratory method or device – Including body or head supported means covering user's scalp
Reexamination Certificate
1999-09-10
2001-10-16
Dawson, Glenn K. (Department: 3761)
Surgery
Respiratory method or device
Including body or head supported means covering user's scalp
C128S206210, C128S206280
Reexamination Certificate
active
06302103
ABSTRACT:
FIELD OF INVENTION
The present invention relates generally to respiratory protective devices and more particularly to a protective hood with an integrated, externally adjustable noseclip.
BACKGROUND OF THE INVENTION
Respiratory protective hoods are well known in the prior art They typically comprise an air-inpermeable enclosure sealed at the wearer's neck and fitted with a substantially transparent visor and breathing respirator.
Some respiratory protective hoods use a half-mask (aka “nose cup”) breathing interface. The half-mask seals around the wearer's nose and mouth area. However, a half-mask must be sized to accommodate the facial variations within a given population and a particular sized half-mask must be matched to the proper user. The inability of a hood with a half-mask to universally fit an adult population significantly complicates the logistics of protecting that same population. Another drawback of a hood with half-mask is the size and cost. These masks are difficult to store in a compact form. This hinders the portability and storage properties of the mask. Hoods with a half-mask utilize a significant amount of materials, thereby increasing their costs. Still another drawback to these designs is the pressure needed to keep the half-mask sealed to the face. Methods of applying pressure include placing tensioned straps around the head of the wearer. Properly adjusting these straps requires additional training and expends additional donning time in an emergency situation. Furthermore, the tension used to draw the mask to the face makes the design highly claustrophobic. The greater sealing area and the required tensioning system necessitate higher manufacturing costs, greater weight, greater bulk and more complexity in operation.
Many problems with the hood with half-mask are overcome by the use of a mouthpiece respirator. Mouthpiece respirators engaged by the wearer's mouth purify air drawn in through the oral pathway to the lungs by inhalation. The mouthpiece respirators also provide a pathway for exhalation. The mouthpiece respirator provides a number of distinct advantages over a hood with half-mask.
Mouthpiece respirators may be engaged and disengaged by the wearer while still wearing the protective hood. In addition, tension straps are not required when using the mouthpiece respirator as the support and seal to the air purifying means is provided by the wearer's mouth. This provides a marked level of control and comfort by the wearer. Conversely, the wearer of a hood with half-mask suffers from continual pressure as the mask is pulled up against the face by tension in the straps.
An advantage of using a mouthpiece over a hood with half-mask is that of size. Mouthpiece respirators engage the oral cavity of the user while a half-mask must cover a significant area of the face. Accordingly, mouthpiece respirators are smaller and more compact while a hood with half-mask is larger and more bulky. This size difference also contributes to a lower manufacturing cost, better portability and easier storage for the mouthpiece design.
Another advantage of the mouthpiece respirator over a hood with half-mask is that of simplicity and speed. A hood with half-mask must be securely sealed against the face with a sufficient amount of pressure. If the amount of force is too little, leakage may occur, thereby lowering or negating the protection factor of the device. If the amount of force is too high, then the mask becomes too uncomfortable to wear. Some hoods with a half-mask utilize manual straps to adjust the tension level while other designs automatically provide a predetermined level of tension. Requiring the wearer to adjust manual straps in order to properly fit the hood requires significant training and repeated practice in order to assure the wearer is able to don the hood properly in an emergency situation. However, regardless of proficiency and skill, each adjustment step requires time in which the user may be subject to hazardous or even deadly conditions.
Designs that utilize a predetermined amount of tension to secure the mask risk being either uncomfortably tight or so loose that an effective seal is not obtained. It is important to note that an uncomfortable mask will likely be worn less than a comfortable mask. Tight-fitting masks may cause tissue soreness, claustrophobia, headaches and other ailments. A user suffering from these discomforts will not only become distracted from the tasks at hand, but will be more likely to remove the mask before it is safe to do so. Therefore, the comfort provided by the mouthpiece respirator has a direct and beneficial effect on the overall safety of the wearer and the ability of the wearer to maintain that safety level for extended periods of time. Nevertheless, a number of problems remain with current mouthpiece technology.
A significant problem with current mouthpiece designs is achieving and maintaining nasal occlusion. Protective hoods that utilize mouthpiece respirators will not function properly unless the nose is occluded. The wearer must not breath through his nose. Nasal inhalation effectively bypasses the purification systems connected to the mouthpiece respirator, which greatly diminishes the protection factor of the protective hood. In addition, continued nasal inhalation produces a vacuum within the hood enclosure. This vacuum may lead to the introduction of outside, contaminated air into the enclosure.
Without nasal occlusion, nasal exhalation bypasses the mouthpiece respirator. This may lead to the accumulation of moisture and carbon dioxide-rich air within the ocular region of the hood. The cumulative effect of this process may fog the hood's visor and cause the hood to become uncomfortably hot.
In order to achieve nasal occlusion, prior art protective hoods generally utilize a noseclip comprising two opposing nostril pads biased towards each other. The wearer places the noseclip over his nose which is then pinched off. Additionally, outward extending fingers may extend from each nostril pad permitting the wearer to engage or disengage the noseclip from his nose.
When utilizing a noseclip with current protective hoods, the noseclip must be engaged before the protective hood is donned. Once the noseclip is in place, the wearer may then don the protective hood over his head. However, once the protective hood is placed over the wearer's head, the noseclip may no longer be adjusted, repositioned, or put back on if it falls off without removing the hood or otherwise breaking the substantially airtight seal. This is a potentially dangerous situation for the wearer. If the wearer wishes to fix the noseclip to properly occlude the nose, he must break the airtight seal of the protective hood thereby exposing himself to hazardous conditions.
U.S. Pat. No. 5,186,165 to Swann describes a deployable hood and mouthpiece which utilize a flexible, substantially transparent hood in place of a visor. As the Swann patent utilizes a mouthpiece respirator, the requisite noseclip is also described and illustrated. While the flexible, substantially transparent hood in the Swann patent might permit limited external articulation of the noseclip; it does not provide a universal fit to an adult population. The noseclip in the Swann patent is pivotally secured to the mouthpiece (column 8, line 22). Accordingly, no adjustment means are taught or provided by the Swann patent. The flexible properties of the substantially transparent material in the Swann patent that permit limited external actuation of the noseclip also distort outward vision. There are no external grasping means for articulating the Swann noseclip. This would make external actuation a difficult and blind operation with no clear or obvious means of control, particularly in an emergency situation. Furthermore, materials and sealing mechanisms of the Swann patent do not provide for a substantially airtight seal required for chemical, biological and nuclear agent protection (column 9, lines 4-5). Consequently, what is needed is a means to externall
Dawson Glenn K.
Hopen Anton J.
Smith & Hopen , P.A.
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