Buoyancy compensator
I United States Patent 1191 1111 3,877,098  
 Braly ]*Apr. 15, 1975 [54] BUOYANCY COMPENSATOR FOREIGN PATENTS OR APPLICATIONS 1 lnvemorl Edmund Brflly, BayShOre 1,293,158 4/1962 France 9/316 Blvd, Paclfica, Cahf- 94402 883,100 7/1953 Germany 9/313 Notice: The portion of the term of this patent subsequent to July 24, 1990, m Exam&#34; er Trygve Bhx has been disclaimed&#39; Asszstant ExammerPaul E. Sauberer Attorney, Agent, or FirmFlehr, Hohbach, Test, Flledr y 2, 1973 Albritton &amp; Herbert 21 Appl. No.: 354,312  
 [57] ABSTRACT 52 us. (:1. 9/313 A buoyancy Pillow a free diver is attached to 51 Int. Cl. B63c 11/18 ventral Side of divefs trunk by Shoulder Waist and [58] 1 16111 of Search 9/313 316 311, 329 crotch Straps the Pillow including a bladder with a center of buoyancy located in its lower one-half por- [56] References Cited tion when inflated by the diver exhaling into a hose equipped with a mouthpiece having valve structure, UNITED STATES PATENTS and an over-pressure relief valve is provided. 3,727,250 4/1973 Koehn et al. 9/313 3,747,139 7/1973 Braly 9/313 3 Claims, 14 Drawmg Flgures PATENTEDAPR 1 51975 saw 3 0f 4 PATENTED a m A 3,877. 098  
 BUOYANCY COMPENSATOR BACKGROUND OF THE INVENTION This invention pertains to buoyancy compensation for free divers and specifically relates to a buoyancy pillow worn by the diver on the front of his trunk and inflatable and deflatable by him for adjusting his buoyancy in the water.  
  Buoyancy compensators in the art have been derived from the inflatable life vest and for that reason have a number of shortcomings. More specifically, the life vest type compensators invariably have an air compartment which encircles the neck of the wearer providing buoyancy behind the head and neck. While buoyancy in this region may be highly desirable in a life vest, when such a vest is worn in an inflated condition by a diver, it has the undesirable effect of tending to urge the head towards an upright attitude which makes swimming movements on the water surface inefficient and Iaborious to the free diver with his equipment.  
  Another deficiency of prior buoyancy compensators is that the inflation hoses which were provided so that the diver could orally inflate the vest were connected to the vest in an awkward position behind the divers head to obviate trapped air in the vest. In this location the inflation hoses would frequently interfere with the divers air breathing equipment. A further shortcoming was that inflating the vest underwater necessitated blowing a quantity of water from the mouthpiece through a relatively long hose to the vest inlet behind the divers neck. In the operation, the diver exerted himself unnecessarily and following use of such vest during a day&#39;s dives, the inflating operation would entrap a significant volume of water in the vest. Portions of this water were admitted each time the diver orally inflated the vest with the result of reducing the buoyancy capacity of the vest and diminishing its capacity for aiding the diver to regulate his buoyancy. Moreover. the prior art buoyancy compensators had a high center of buoyancy located near the divers chest. This tended to rotate the diver towards an undesired vertical attitude when surface swimming and placed the buoyant force upon the chest making chest expansion for breathing difficult.  
 SUMMARY OF THE INVENTION AND OBJECTS In summary, the present invention in a buoyancy pillow comprises an inflatable air bladder having strap members for attachment to the ventral side of divers torso for location from about the shoulders to above the crotch. An air inflation hose having a mouthpiece assembly arranged to communicate with the bladder at an uppermost portion thereof, the mouthpiece being equipped with valve means and a pressure-relief valve is provided. The bladder is shaped so as to locate the center of buoyancy in the lower half thereof.  
  An object of the invention is to provide an improved apparatus through the use of which a free diver may compensate his buoyancy in the water so as easily to maintain his torso in any selected attitude but most easily in a generally horizontal attitude while surface swimming.  
  Another object of the invention is to provide a buoyancy pillow arranged for oral inflation and which will entrain an insignificant volume of water after numerous submersed inflation-deflation cycles.  
  Further objects and features of the invention will appear from the following description taken in connection with the accompanying drawings.  
 BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a view of a free diver swimming in a body of water and having mounted on the anterior of his torso the buoyancy pillow of the present invention;  
 FIG. 2 is an enlarged perspective view taken from the front side of the buoyancy pillow shown in FIG. 1;  
  of the buoyancy pillow of FIG. 7;  
  FIGS. 9 and 10 are detailed views, in plan and vertical section respectively, of a pressure relief valve included in the embodiment of FIG. 7;  
  FIG. 1 1 is an enlarged sectional view of a mouthpiece and valve assembly useful with the buoyancy pillow of FIG. 7;  
  FIG. 12 is another view of the mouthpiece and valve assembly of FIG. 11; and  
  FIGS. 13 and 14 are detailed views of the connectors for the strap members for the buoyancy pillow.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 2 and 3, the buoyancy pillow 10 includes an inflatable bag or bladder 26 formed from front 27, back 28 and medial panels 29. The panels 27-29 preferably consist of rubberized fabric cemented or vulcanized together on overlapped portions 31 to define airproof and water-proof seams. The front 27 and back 28 panels may be identical in outline and the media] or side panels29 may be shaped to give the bag a desired tapered form when viewed from the side, (FIGS. 1 and 5) the bag being wider at the bottom portion than at the top; as shown best in FIGS. 2 and 6. The front and back panels have an outline which is generally ovoid or parabolic in the upper two-thirds to three-quarters of the panels. From the lower one-third to one-quarter of the panels 27 and 28 the outline generally resembles an ellipse cut at the long axis. It should be recognized that the configuration of the pillow may be varied somewhat from that illustrated herein, but is very advantageous that the pillow be shaped and sized to provide, when fully inflated, a buoyancy of 40 to 45 pounds in the water with the center of buoyancy located in the lower one-half and preferably close to the lower one-third region of the bladder. The amount of inflated buoyancy for the bladder is selected in relation to the weight of the divers air tank equipment 12-14 which, when the diver swims on the surface, places downward forces on the divers torso tending to make breathing laborious. An air pillow having buoyancy in the 40 to 45 pounds range is used with air tank equipment weighing about 37 pounds. Thus, depending upon the buoyancy of the divers body and the attached SCUBA equipment, there will be available for surface swimming from 3 to 8 pounds of positive buoyancy by reason of the buoyancy pillow.  
  As expressed above, the upper portion of the bladder 26 is ovoid in outline so that the top portion of the bag has an apex or high point 34, at which location a pillow inflation hose 36 is secured in communication with the bladder 26, FIGS. 2 and 6. More particularly, a coupling 39 is arranged at the apex 34 of the bag 26 (FIG. 2) and the inflation hose 36 is secured to the coupling 39 so as to establish an air-tight and water-tight connection between the hose 36 and the bag 26. A hose clamp 40 (FIG. is satisfactory to maintain the hose in operative association with the coupling 39.  
  The breather hose terminates in a generally L-shaped mouthpiece assembly 38 (FIG. 4) which will be described in detail below. The breather hose 36 may be of rubberized corrugated construction and may have a nominal inside diameter on the order of 0.75 inches. Because the highest point 34 of the bladder will reside near the divers chin, the hose 36 may be made quite short, as compared to the prior art, on the order of from 4 to 6 inches long.  
  To ensure that the buoyancy pillow is maintained at the desired position against the ventral side of the divers torso or trunk, an assembly of body-encircling straps is provided. This includes a waist strap 41 and left 42 and right 43 shoulder straps which join the waist strap 41 in a sleeve 44 (FIG. 3) slidable with respect to the waist strap 41. A crotch strap 46 unites at its upper end with the sleeve 44 and at its lower end is equipped with a snap clip 48 cooperable with a ring 47 secured to the bladder by the tang strip 49. The crotch strap functions to prevent the air pillow from shifting upwardly on the divers trunk. So as to provide clearance for the divers weight belt 19, the tang strip 49 carrying the ring 47 for connection to the slip 48 is mounted on the back panel 28 of the bladder a distance above the bottom of the bag, as clearly shown in FIG. 3. The strip 49 may be mounted at the panel 28 by cementing the strip 49 to the back panel 28.  
  Considering the waist belt 41, a ring 51 and snap clip 52 assembly is provided for linking the bladder with the waist strap or belt 41 to the divers trunk. The upper ends of the shoulder straps 42 and 43 are each secured to the upper portion of the back panel 28. The right hand portion of the waist belt 41 is attached to the rear panel 28 of the bag. Buckles 56 for adjusting the length of each of the straps are also provided. Thus, the buoyancy pillow 10 may be accommodated to divers of varying physical sizes by selective adjustment of the straps so that the air pillow may be held in the desired and preferred location on the divers trunk to extend on the chest to just above a line drawn through the nipples and downwardly to about a lateral line drawn through the hip joints.  
  The mouthpiece assembly 38, best shown in FIG. 4, is constructed to include a valve mechanism which the diver may manipulate so that he may inflate the air bag 26 by expelling his breath through the mouthpiece such as for equalizing the diver-s buoyancy when submerged; and similarly for releasing air from the bag when ascendingfrom a sub-surface depth in the water. A provision is included in the mouthpiece for automatically releasing air from the bag so as to prevent the bag from rupture should the diver be inattentive or incapable of manipulating the valve during ascent. The arrangement of the mouthpiece 38 is such that the bag may be inflated and deflated a great number of times during a days diving without entraining any significant volume of water into the bag through the mouthpiece.  
  More particularly, the mouthpiece assembly 38 includes a generally L-shaped housing 57 connected at one end to the breather hose 36 and secured thereto by an encircling hose clamp 58. At the other end, the housing is fitted in an air-tight manner in a cup portion 59 of a mouth insert member 61 which the diver seals between his lips for blowing air into the mouthpiece assembly. The member 61 is arranged immediately adjacent to an axially shiftable valve disc 62 which the diver manipulates by depressing in a squeezing action a valve plunger rod 63 connected at one end to the valve disc. Inward movement of the rod 63 is resisted by the bias of a length of rubber tubing 64 which functions as a compression spring. In the closed condition shown in FIG. 4, the valve disc 62 seats against a spool 66 arranged inwardly of the mouth insert member 61, the innermost end 67 of the spool 66 serving as an axial guide for the valve rod 63. The spool end 67 is also provided with a plurality of air passageways 68 so that when the diver presses upon the rod 63 to move the valve disc from sealing engagement with the spool, he may expel air into the mouthpiece housing 57 through a passageway 70 and the air holes 68 and thence into the bag. A radially disposed array of ribs 69 are located on the inner face of the cup portion 59 to prevent the disc 62 in the forward or open condition from sealing the air inlet passageway 70. Thus, when the diver depresses the plunger rod 63 to place the disc 62 against the ribs 99, air will be expelled from the bag in response to ambient water pressure to the end that the buoyancy pillow may be deflated.  
  The pressure-relief valve function is provided in the mouthpiece assembly by the relationship of the area of the valve disc 62 exposed to the internal pressure of the bladder and the compression constant of the rubber spring 64. The area of the valve disc and spring constant are selected so that when the internal pressure of the air bag exceeds the ambient or outside water pressure on the opposite side of the valve disc by about onequarter atmosphere, the valve disc will shift from its seat on the spool to an open condition and automatically permit the expanded air to leave the bag through the mouthpiece 61.  
  It will be recognized that the valve disc operates in a chamber 72 of minimal volume being that the chamber of the cup portion is only slightly larger in diameter than the disc 62 and only as long as the stroke of the disc. This configuration, together with the small volume of the air inlet passageway, provides the advantageous feature that as the diver opens the valve and blows into the bag, a minimum volume of water will be carried into the bag. Thus, at the end of a days diving, the amount of water in the bag will be an insignificant amount, on the order of two cupfuls.  
  To maintain the mouthpiece assembly in a desired out-of-the-way position when not in use, a Velcro brand of fabric assembly 74 (comprising synthetic materials which adhere when pressed together, as is wellknown in the art and as shown and described in US. Pat. Nos. 2,717,437, 3,154,837, 3,154,837, 3,147,528, 3,076,244 and 3,009,235 is arranged on the pillow inflation hose 36 and the right shoulder strap 4350 that the diver may simply engage the breather hose with the shoulder strap and the Velcro assembly portions will lockingly engage and maintain the air hose upon the right shoulder strap in an unobstructing out-of-the-way position (FIGS. 2 and 3).  
 OPERATION The buoyancy pillow may be utilized by the diver when resting or moving on the water surface to equalize his buoyancy or to ascend in a controlled fashion from depth without having to exert himself unduly hard, e.g., to float to the surface without kicking and at a proper rate of ascent such as 60 feet per minute.  
  When the diver uses the air pillow on the surface, such as when swimming between the shore and an offshore diving buoy, the diver orally inflates the air bag, first removingthe mouthpiece assembly from its secured position on the right shoulder strap and then expelling his breath into the bag through the mouth insert member 61 upon depressing the valve rod 63. The bag or bladder 26 may be&#39;fully inflated to provide the diver and his associated equipment with positive buoyancy. In this condition, the diver may swim in the water with his body draped over the buoyancy pillow, the head and legs drooping downwardly so that the diver may watch and observe the bottom while breathing through his breather hose 14, from the air tank and regulator 13 or from a snorkel (not shown).  
  As shown in FIG. 1, the downward arrow 76 represents the summation of the vertical downward or displacement forces of the diver and his equipment. The arrow 77 in FIG. 1 represents the summation of buoyancy forces including the buoyancy derived from the inflated buoyancy pillow, which itself is on the order of 40 to 45 pounds buoyancy. The horizontal displacement of the arrows 76 and 77 indicates a rotational moment acting upon the diver tending to rotate his body towards a horizontal attitude. This permits the diver through movement of his head to shift easily from a prone to an upright position in the water without having to work against a buoyancy pocket, such as was provided by the prior art neck-encircling life vest.  
  When the diver reaches the location for diving, such as defined by off-shore diving buoys, he may deflate the pillow by opening the valve by pressing on the plunger element 63 and air is expelled from the bag in response to the exterior water pressure acting on the bag. The diver descends towards the bottom with the air pillow in the deflated condition.  
  An ascent to the surface from a sub-surface position is made by the diver through use of the buoyancy pillow. In this situation, the diver first takes a breath from his tank of compressed air through the regulator mouthpiece therefor and expels that breath through the pillow inflator hose 36 into the bag. The first breath of air into the buoyancy pillow will not give the diver added buoyancy because he was simply transferring air from his lungs into the buoyancy pillow. To gain positive buoyancy, the diver takes a secnd breath from his air tank whereupon he achieves positive buoyancy from the air in his lungs added to that in the buoyancy pillow and he then begins to ascend. The positive buoyancy produced through use of the pillow permits the diver to ascend in a floating movement, without the exertion of swimming or foot-kicking, and at the desired upward rate of 60 feet per minute. During ascent, as air in the pillow expands, the diver should release air from the buoyancy pillow by depressing the valve plunger. Should the diver during ascent neglect to release air SECOND PREFERRED EMBODIMENT In FIGS. 7 and 8 of the drawings there is shown a second preferred embodiment of the present invention. The buoyancy pillow 80 includes an inflatable bag or bladder 81 formed from front 82, back 83, and media] or side panels 84. The panels 82-84 may consist of rubberized fabric, cemented or vulcanized together on overlapping portions 86 to define air-proof and waterproof seams. The front 82 and back 83 panels may be identical in outline and the medial or side panel 84 may be shaped to give the bag a desired tapered form when viewed from the side (FIG. 7), the bag having a large inflated depth or thickness at the bottom portion greater than that at the top. The front and back panels have an outline which is generally rectilinear having rounded portions at the upper and lower corners. Along the top margin a recess 87 is provided to afford clearance for the drivers chin and neck on either side of the recess there being provided a shoulder protrusion 88.  
  It will be recognized that the configuration of the pillow 80 may be varied somewhat from that illustrated herein, but it is advantageous that the pillow be shaped and sized to provide when fullyinflated a buoyancy of 40 to 45 pounds in the water with the center of buoyancy located in the lower one-half and preferably close to the lower one-third region of the bladder.  
  One of the shoulder protrusions 88 (the left hand protrusion as illustrated in FIG. 7) serves as a location for a pillow inflation hose 89 in the front panel 82. More particularly, a coupling 91 is mounted in the front panel 82 at an uppermost portion of the bladder 81 and the inflation hose 89 is secured to the coupling 91 in an air-tight and water-tight connection.  
  The inflation or breather hose 89 terminates in a generally L-shaped mouthpiece 92 (FIG. 11) and includes a valve mechanism which the diver maymanipulate so that he may inflate the air bag 81 by expelling his breath through the mouthpiece such as for equalizing the divers buoyancy when submerged; and similarily for releasing air from the bag when ascending from a sub-surface depth in the water. The mouthpiece 92 includes a housing 93 united by a hose clamp 94 to the breather hose 89. At the other end of the L-shaped housing there is provided a mouth insert member 96 which the diver seals between his lips while blowing air into the mouthpiece assembly. The valve member includes a piston actuator 97 biased by a spring 98 arranged within the housing. A valve disc 99 at the inner end of the piston 97 engages a valve seat 101 within the housing. Thus for inflating the air-bag the diver depresses the button head of the piston 97 and breathes through the mouth portion 96. Conversely, when the diver wishes to expel air from out of the bladder he simply depresses the piston 97 and air will be emitted through the mouthpiece portion 96 in response to external pressure on the bladder.  
  An automatic pressure relief valve 106 is included in the buoyancy compensator and may be arranged in the 7 rear panel 83 (FIG. 8). The pressure relief valve 106 includes an outer housing 107, and internal diaphragm 108 biased by a spring 109. The relief valve 106 is fitted over an opening 111 in the bag wall and the spring 109 is calibrated to release the diaphragm 108 when a predetermined pressure differential between the bags internal pressure and the ambient pressure is exceeded. Thus when the internal pressure of a bag has risen to an excessive amount the diaphragm 108 will cause the spring 109 to compress and air will move from the bag through the opening 111 and thence out through the openings within the housing 107 until the pressures are equalized.  
  An assembly of body encircling straps is provided to insure that the buoyancy pillow is maintained at the desired position against the ventral side of the divers torso or trunk. The strap assembly includes a waist strap 116 and left 117 and right 118 shoulder straps which cross intermediate their ends, all the straps an choring to an attachment strip 119 at the lower portion of the posterior side of the bladder, (FIG. 8). A crotch strap 121 is united to the waist strap 116 by a loop 122 at one end and a snap fastener 123 at the other. The snap fastener 123 cooperates with a Dee ring 124, well known in the art. The upper ends of the shoulder straps 117 and 118 connect to the bag or bladder at the shoulder protrusion poritons 88, (as shown in FIG. 8). Adjustmentmeans are provided on the straps in the form of double loop rings 126 (FIG. 13) so that the straps may be lengthened or shortened appropriately to accommodate the various physical dimensions of divers.  
  A pocket 102 provided with a flap 103 is arranged on the front panel 82 for holding various of a divers small accessory equipment.  
  The operation of the buoyancy pillow 80 is substantially the same as that of the buoyancy pillow l previously described.  
  In view of the above description and drawings, it will be apparent that there has been disclosed herein a buoyancy pillow which permits a free diver to move easily along the surface of the water and to ascend from depth at a controlled rate. Should the diver neglect to properly expel expanding air from the air pillow during ascent to the water surface, the release valve is automatically activated to release air from the bag. While the specific embodiments of the invention are set forth above, the scope thereof is defined by the following claims,  
 I claim:  
  1. An improved buoyancy pillow for a free diver and of the type characterized as including an inflatable bladder adapted to be secured exclusively against the ventral side of the torso of the divers body and sized to be positioned entirely within the zone between the shoulders and crotch, comprising front and rear panels for said inflatable bladder formed from rubberized fabric material, means interconnecting said panels in an airand watertight manner, the upper portion of said front and rear panels being joined together along a contour which is centrally, inwardly recessed defining a clearance space for the divers neck and chin and establishing spaced apart shoulder protrusions adapted to lay along the divers shoulders, a flexible inflation hose connected at one end to said front panel at one of said shoulder protrusions, the other end of said hose terminating in a mouthpiece assembly including manually actuable valve means serving to permit the entry and exhaust of air with respect to said bladder, pressure release valve means mounted in the sidewall of said bladder and being responsive to a positive pressure differential between the internal and external pressures on said bladder for automatically permitting air discharge from said bladder at a pre-established pressure differential, said means interconnecting said front and rear panels being formed so that in longitudinal cross section said bladder tapers from a narrow section at the top to a wide cross section at the bottom providing said bladder with a center of buoyancy located in the lower one-third portion, and strap assembly means secured to said bladder against the torso of the diver entirely within the above defined zone.  
  2. The improved buoyancy pillow of claim 1 wherein said strap assembly comprises an attachment base secured to the rear panel of said bladder in the lower onethird portion thereof, and includes a pair of crisscrossed shoulder straps connected at their upper ends to said rear panel at said shoulder protrusions and connected at their lower ends to said attachment base, a waist strap connected at its two ends to said attachment base, and a crotch strap connected at one end to said waist strap and connected at the other end to said attachment base at a mid-portion thereof.  
  3. The buoyancy pillow of claim 2 wherein said front panel of said bladder is equipped with means defining a pocket-like compartment for enclosure of divers accessories and the like.