Patent Application
20060101552
Supplied air helmets are regularly worn in environments where the surrounding ambient air contains contaminants. These helmets have a fluid impermeable visor that is pulled down in front of the wearer's face. The visor has a window through which the wearer can see the surrounding environment. A face seal is attached to the visor to provide a breathing zone or interior gas space that is separate from the ambient, exterior gas space. The interior gas space is located in front of the wearer's face and is defined, for the most part, by the face seal that is attached to the visor, the visor body, and the wearer's face. U.S. Pat. Nos. 6,250,299, 6,016,805, 6,014,971, 4,462,399, and 4,280,491 disclose examples of supplied air helmets that use face seals.
To furnish the wearer with a safe supply of air for breathing, clean air is forced into the interior gas space from a supply tank or from a powered air system that drives the ambient air through a filter. The wearer breathes this clean air and exhales it back into the breathing zone. This exhaled air, along with excess clean air that is forced into the breathing zone exits the interior gas space through openings in the face seal. The positive pressure that generally occurs within the interior gas space precludes contaminants from entering the interior gas space through the openings. Welders often wear supplied air helmets as protection from breathing contaminants that are generated during welding procedures. Examples of welding helmets are shown in the following patent documents: U.S. Pat. Nos. 6,557,174, 6,591,424, 6,185,739, 5,533,206, 5,191,468, 5,140,707, 4,875,235, 4,853,973, 4,774,723, 4,011,594 and Des. 398,421; and WO 00/59421 and WO 99/26502.
Known face seals typically have been secured to the helmet by fasteners such as pegs, clips, adhesive tape, and hook and loop type devices. The use of such fasteners has required additional equipment that must be provided on the supplied air helmet or the face seal frame. In addition, when the face seal is secured to the supplied air helmet through use of pegs, these pegs must be disengaged from the face seal during its installation and replacement. Because a crown support member (for supporting the helmet on the wearer's head) typically also has been secured to the helmet through the same pegs, it has been a cumbersome process to replace the face seal. The use of adhesive tape and hook and loop type fasteners can be onerous as well, and they have provided locations for dirt and contaminants to accumulate, which accumulation can cause the fastener to cease functioning. Hook and loop type fasteners also tend to “peel-off” the helmet after repeated use in response to repeated tugging on the hook and loop material. Heat, for example, in a welding environment, also can cause the adhesive to soften, which softening may cause delamination of the fastener. Examples of supplied air helmets that use various methods for securing a face seal to a helmet are shown in U.S. Pat. Nos. 6,250,299 B1 and 6,014,971 to Danisch et al. (adhesive or mechanical attachment), U.S. Pat. No. 6,016,805 to Burns et al. (pegs or protrusions that mate with holes or use an adhesive), U.S. Pat. No. 5,054,479 to Yelland et al. (adhesive), and U.S. Pat. No. 4,280,491 to Berg et al. (adhesive).
The present invention involves a new manner of securing a face seal to a supplied air helmet. In brief summary, the present invention provides a supplied air helmet that comprises a visor and a face seal where the face seal includes a frame member and a sealing member and where the frame member is secured to the visor by frictional engagement.
The present invention differs from known supplied air helmets in that the face seal is secured to the supplied air helmet using frictional engagement rather than fasteners such as pegs, clips, and hook and loop materials. Because the present invention uses this new method of engagement, the use of separate fastening elements is avoided. Thus, less parts are needed to manufacture the final product, which can save on manufacturing costs. Further, installation and removal of the face seal may be achieved in less onerous manner. There also is less opportunity for failure over time, and the surface area onto which contaminants and dirt may accumulate is substantially less.
These and other advantages of the invention are more fully shown and described in the drawings and detailed description of this invention, where like reference numerals are used to represent similar parts. It is to be understood, however, that the drawings and description are for illustration purposes only and should not be read in a manner that would unduly limit the scope of this invention.
In this document, the terms set forth below will have the meanings as defined:
“breathing zone” means an interior gas space or a portion of the interior gas space where oxygen is inhaled by a wearer of a supplied air helmet;
“clean air” means air that has been filtered or that has otherwise been made safe to breathe;
“elastic” means the ability of a strained material (e.g., the sealing member or the yarns that comprise the sealing member) to substantially recover its original size and shape immediately after being stressed to about twice its original length.
“exterior gas space” means the ambient atmospheric gas space that surrounds the exterior of a supplied air helmet when worn on a person;
“face” means the area on the front of a person's head, defined mainly by the cheeks and temporal area (or side portions of the facial regions), chin, forehead, and facial area located therebetween;
“face seal” means a structure that contacts a person's face and/or neck and/or other portions of the head to help separate an interior gas space of a supplied air helmet from an exterior gas space;
“filtered air” means air that has been passed through a filter material to reduce the amount of any contaminants that may have been present in the air before it was filtered;
“frame member” means a structural part(s) that plays a role in supporting a sealing member;
“frictionally” means essentially through use of friction;
“frictional engagement” means that the engagement occurs as a result of friction between the two parts intending to be joined without need for additional fastening from elements such as pins, pegs, clips, and/or hook and loop materials;
“helmet” means a device that is worn on a person's head for safety and/or protection purposes;
“interior gas space” means the space that exists between a visor, a face seal, and a person's face when a supplied air helmet is being worn;
“sealing member” means a structure or combination of parts that may be solid and/or porous and that conformably contacts at least a portion of a person's face to assist in defining a separation between an interior gas space and an exterior gas space;
“supplied air helmet” means a helmet that receives a supply of clean air for a wearer of the device to breathe;
“visor” means a structure that is located in front of a person's face when worn and that has a window to allow the person to see through it; and
“welding helmet” means a helmet that has a darkened or darkening window.
In describing preferred embodiments of the invention, specific terminology is used for the sake of clarity. The invention, however, is not intended to be limited to the specific terms so selected, and it is to be understood that each term so selected includes all technical equivalents that operate similarly.
In the practice of the present invention, a new face seal is provided that can be frictionally secured to a visor of a supplied air helmet at multiple locations. The frictional securement enables less parts be used in the manufacture of the supplied air helmet and, as opposed to a commonly-used hook and loop fastening means, can provide a cleaner, more durable, and simpler form of engagement.
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In operation, air is supplied to the interior gas space under pressure from a powered air supply source. Examples of these types of devices are shown in U.S. Pat. Nos. 6,279,572B1, 6,250,299B1, 6,014,971, 5,125,402, 4,965,887, 4,462,399, and 4,280,491. The air may be channeled into the interior gas space via an air duct that is in fluid communication with the powered air supply source (not shown). When using a powered air supply source, the ambient air is powered or forced through an air filter before being directed into the interior gas space. Examples of blowers that may be used in connection with a supplied air system for directing clean air into the interior gas space are shown in U.S. Pat. Nos. 6,575,165B1 and D449,099S. A flow sensor may be used on the supplied air helmet to provide an indication of when air flow into the breathing zone falls below a safe level—see U.S. Pat. No. 6,615,828 B1 to Petherbridge. In addition, a non-volatile memory device may be attached to the filter element to keep a record of the filter element's usage—see U.S. Pat. No. 6,186,140 B1 to Hogue.
The sealing member can take the form of a knitted fabric that comprises, for example, a blend of acrylic and cotton. The fabric may be elastomeric or may include elastomeric yam to improve stretchability. The fabric also can be fashioned to be inherently flame retardant, which may be important for welding and grinding applications. The fabric can be essentially any color and can be made from materials such as polyester, modified acrylic, or a mixture or blend of these polymeric materials. With respect to its thickness, the fabric may have a thickness of a single fifties count yam, although other thicknesses may be suitably used. What is important is that the face seal is comfortable to wear and that it allows exhausted air to be rapidly purged from the interior gas space. A knitted fabric that contains elastic yam and has a fold where the periphery of the seal member makes predominant contact with the wearer's face has been found to be particularly comfortable. The knitted fabric may be secured to a frame member made of, for example, a 1 mm thick polypropylene plastic. The frame member desirably has a matted surface on at least one side to avoid reflection that could interfere with the user's vision. In general, the plastic frame may be about 0.4 mm to 3 mm thick and can be structured such that it is not overly flimsy and such that it retains its intended shape when not being subjected to manual forces or pressure.
An example of a face seal that has a porous knitted sealing member is described in more detail in U.S. patent application Ser. No. __/______, entitled Supplied Air Helmet Having Knitted Face Seal, filed on Nov. 12, 2004 under attorney docket number 60019US002. The face seal may have a differentiated permeability design to improve airflow through the breathing zone—see U.S. patent application Ser. No. __/______, entitled Supplied Air Helmet Having A Face Seal With Differentiated Permeability, filed on Nov. 12, 2004 under attorney docket number 60020US002. Another example of a face seal is shown in U.S. Pat. No. 6,016,805 to Burns et al.
In addition to the supplied air systems mentioned above, the present invention also could be used in conjunction with a compressed air system such as a self-contained breathing apparatus (SCBA) that has a tank of air or oxygen, typically under pressure, for supplying clean air to a person. Examples of SCBA systems are shown in the following U.S. Pat. Nos.: 6,478,025, 4,886,056, 4,586,500, and 4,437,460. For purposes of construing this invention, a SCBA system is considered to be a supplied air system. Further, the inventive supplied air systems may be used not only in conjunction with welding helmets or welding environments but may also be used, for example, in helmets fashioned for surgical environments and clean air rooms—see, for example, U.S. Pat. Nos. 4,901,716, 4,055,173, 4,019,508, and 3,955,570.
This invention may take on various modifications and alterations without departing from the spirit and scope thereof. Accordingly, it is to be understood that this invention is not to be limited to the above-described, but it is to be controlled by the limitations set forth in the following claims and any equivalents thereof.
It is also to be understood that this invention may be suitably practiced in the absence of any element not specifically disclosed herein.
All patents and patent applications cited above, including those in the Background section, are incorporated by reference into this document in total.
