Field of the Invention
This invention relates to underwater breathing apparatus and more particularly it relates to underwater mouthpieces having members extending into the mouth for gripping between the teeth.
Background of the Invention
Underwater breathing apparatus with special mouthpiece structure is well known. For example, snorkels having mouthpieces retained in the mouth are described in U.S. Pat. No. 3,814,090--June 4, 1974--J. E. Hill.
These mouthpieces may be separately made of a flexible material such as rubber or plastic to snap on or fit over corresponding snorkel tube or other underwater breathing equipment as shown in U.S. Pat. No. 4,031,888--June 28, 1977 to W. D. Walters.
This patent and U.S. Pat. No. 3,929,548--Dec. 30, 1975 to R. B. Shamlian provide for retaining members on the mouthpiece that may be gripped in the teeth.
It is customary in such mouthpieces as the Shamlian and Hill embodiments to have a flange about a breathing tube over which the lips are placed to form a seal with the breathing tube. This flange is in the form of a generally flexible planar curved surface that abuts the teeth between the lips and outer teeth surfaces. Prior art flanges receive the teeth in an unnatural and uncomfortable position with the lower jaw protruded out of its relaxed normal resident position. Since the retainer members over long periods of time must be gripped firmly by the teeth to prevent dislodging in the event of striking an object or in any emergency condition, it is critical that the mouthpiece can be comfortably held. For example, in cold water the grip becomes even more difficult. Also in some extreme cases the jaw might be damaged because of a prolonged or excessively unnatural firm bite with jaw bones unseated.
It is therefore an objective of this invention to overcome such prior art deficiencies.
Disclosure of the Invention
Therefore in accordance with the present invention an underwater mouthpiece is provided with retainer members to be gripped by the teeth of a user with the jaws in a normal position. Thus the gripping position is one having the jaws in a comfortable and natural resident position with jaw bones seated. There is thus eliminated the requirement to unnaturally protrude the lower jaw.
This is achieved by special mouthpiece structure which offsets the flange against which the teeth abut to fit the lower and upper jaws in their natural position with a slight upper jaw overbite, so that the lower jaw need not be protruded to abut the flange. Thus an upper jaw flange portion is offset about 40 mm (1/4 inch) away from the mouth from the lower jaw flange portion to accommodate an average normal overbite.
Brief Description of the Drawings
In the drawing:
FIG. 1 is a profile side view sketch of the human oral arrangement of the upper and lower jaw bones and teeth shown with lower jaw bone protruded;
FIG. 2 is a top perspective view of the mouthpiece structure afforded by this invention;
FIG. 3 is a section view along lines 3--3 of the mouthpiece structure of FIG. 2; and
FIG. 4 is a profile side view sketch of the human teeth gripping a mouthpiece embodiment of the invention.
Description of the Preferred Embodiment
As may be seen in the sketch of FIG. 1, a lower jaw bone 15 (mandible) has a ball joint 16 (condyle) that fits into a socket 17 (glenoid fossa) of the upper jaw bone 18 (maxilla) and is held there in a way permitting limited movement (protrusion) of the lower jaw bone 15 out of the socket as held and controlled by muscular structure, not shown.
The normal position of this muscular structure and the lower jaw bone with the ball joint 16 seated into socket 17 (FIG. 4) gives a mating position of the molar teeth and allows a slight overbite of the front teeth normally in the order of about 40 mm (1/4 inch). In the position shown, the muscles holding the ball 16 in socket 17 are extended and tend to be uncomfortable and fatigued after a long period of time, which is quite an unnatural condition. Also cold water temperatures on the cheeks can affect the muscular reaction and comfort.
The jaws 15, 18 as shown in FIG. 1 are in the unnatural position necessary to abut the front of the teeth with the generally planar flange on the prior art mouthpieces, that is with the upper front teeth 20 and lower front teeth 21 aligned to abut a planar object. This is the position that need be taken to bite down on the retention members in the mouthpieces of the prior art. Furthermore, the molars do not mate in bite down position for a firm natural grip.
To correct this problem, the mouthpiece of this invention is constructed as shown in FIGS. 2 and 3 with offset upper 30 and lower 31 flange members that permit the grasping of the retention members 32, 33 between the molars in a normal mating bite position with the ball joint 16 of the lower jaw bone 15 seated into the socket 17, as shown in FIG. 4, and thus not introducing the discomfort and fatigue of abnormal positioning of the muscles and jaws when the lower jaw bone 15 is protruded. The ledge 34 lets the top teeth rest on the mouthpiece portion connecting the flange members 30, 31. Also the retainer lugs 33, etc. are gripped between the molars in natural mating position.
Thus, divers and underwater breathers can breathe in more comfort and with more safety with the novel structure of the offset upper and lower flange members provided by this invention.
Having thus advanced the state of the art, those novel features believed descriptive of the nature and spirit of the invention are defined with particularity in the appended claims.