Abstract:
A swimming pool rescue apparatus includes a safety pool bottom substrate, having a periphery made of a buoyant material and at least one non-peripheral portion is buoyant. The buoyant material is urged into a fixed position at a bottom of the pool by a retaining member. A lifting mechanism raises and lowers the safety pool bottom substrate. The lifting mechanism communicates with a detection signal device detecting the presence of a person under water in the pool for a predetermined period of time. The electronic signal device has a trigger engaging the lifting mechanism to release the buoyant material from a fixed position at the bottom of the pool to a further position at an upper area above the water level of the pool.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to swimming pool rescue devices.  
         BACKGROUND OF THE INVENTION  
         [0002]    Safety swimming pool nets have been represented in the prior art as discussed in the background to this invention. Both hydraulic and mechanical means have been described for raising a net at the bottom of a pool during a potential drowning emergency.  
           [0003]    In these cases, the power requirements for performing this task are high since time is of the essence in raising a swimmer in distress to safety. The mechanisms must raise the weight of the potential victim as well as the weight of the net structure and net through resisting water in a short time.  
           [0004]    To increase reliability, it is desirable to have redundant power sources and/or an uninterruptable power supply (UPS) to power such a safety system during a power outage. With high power/energy requirements, this is an expensive proposition.  
           [0005]    One prior art system uses a submerged inflatable bladder and a storage tank filled with compressed air to quickly inflate the bladder thereby lifting the submerged safety net during an emergency. While fast acting in an emergency, the reliability of rubber-like inflatable bladders over long dormant periods is questionable. The difficulty in deflating such a bladder after use makes it unlikely that safety checks by deployment at scheduled intervals would be actually performed. Also, the requirement of a large diameter hose and an enormous air valve orifice to facilitate rapid inflation have adverse aesthetic and cost consequences.  
         OBJECTS AND SUMMARY OF THE INVENTION  
         [0006]    It is therefore an object of the present invention to provide a reliable device for bringing non-swimmer quickly to the surface of a swimming pool.  
           [0007]    In keeping with these objects and others which may become apparent, this invention uses a permanently buoyant safety net structure to avoid many of the shortcomings of the prior art. The only negative aspect of such an approach is the reduction of usable pool depth by three to five inches (76 to 127 mm); this seem to be a small price to pay for the benefits to be described. Mechanisms are used to force the net structure to a ready position at the bottom of the pool and keep it in a ready position for deployment in case of emergency. The buoyant force of the net structure must accommodate lifting a potential victim or victims as well as the net structure itself in a timely manner while encountering water resistance. Thus the potential energy of a submerged buoyant net structure is substantial. This must be provided by the submerging mechanisms after a deployment during a system test or actual emergency. However, this energy can be supplied at a slow rate (i.e.—low power) since this is not an emergency situation.  
           [0008]    The latter means that system cost can be reduced as compared to prior art systems since lower power mechanisms with low power wiring or piping requirements are used. Another factor is that there is no reason for a redundant or UPS power supply for this substantial energy requirement since it is not needed during an emergency situation. The very low energy required to trigger deployment of the buoyant submerged safety net can easily be supplied by a small UPS or alternate redundant power supply. This increases system emergency reliability by facilitating the incorporation of such redundant features since the cost for a triggering UPS is low due to its modest energy storage and power requirements.  
           [0009]    Finally, the system is fail-safe in the sense that a faulty trigger failing in the false-trigger mode would cause the net to rise in the vicinity of the failed mechanism. This also provides visual cues to a potential problem that can be repaired. The reliability design of actual components must be concerned with jamming of the deployment trigger mechanism and subsystem which is primarily a materials problem to be avoided through accelerated life testing and scheduled routine testing of the entire system by the pool owner. Thus from a system reliability design point of view, the actual design is biased toward false triggering since this is the fail-safe situation.  
           [0010]    The safety net of this invention floats about three inches (76 mm) above the surface of the water when floating. In this position, it serves as a protective covering over the entire pool during periods when the pool is not in use or is unattended. By positioning submerging mechanisms where needed along the periphery of the pool, any shape pool can be accommodated even with multiple levels. With the safety net in the floating position, sections can be removed from the attachment to the submerging mechanisms and folded back to permit cleaning, maintenance and repairs of the pool bottom. For security, a wrench with a matching female configuration to special screw heads should be used to prevent unauthorized detachment of the safety net. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The present invention can best be understood in conjunction with the accompanying drawings, in which:  
         [0012]    [0012]FIG. 1 is a top perspective view of a pool with another embodiment for a safety net of this invention;  
         [0013]    [0013]FIG. 2 is a top detail view of a detail of a woven net material of this invention;  
         [0014]    [0014]FIG. 3 is a side elevational view in crossection of a pool with the safety net of this invention;  
         [0015]    [0015]FIG. 4 is a top plan view of a hydraulic submerging mechanism of this invention;  
         [0016]    [0016]FIG. 5 is a side elevational view of a hydraulic submerging mechanism;  
         [0017]    [0017]FIG. 6 is a block diagram of a hydraulic system embodiment of this invention;  
         [0018]    [0018]FIG. 7 is a front view of an alternate embodiment for an electromechanical submerging mechanism; and  
         [0019]    [0019]FIG. 8 is a block diagram of the electromechanical system embodiment thereof. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]    [0020]FIG. 1 shows pool  1  with submerged buoyant safety bottom  4  held down by hydraulic submerging mechanisms  5 . Water level is shown at  3 . A rigid non-buoyant material is depicted for safety bottom  4 , peripheral floats  10  are illustrated. Additional floatation is provided as a thick ring of floatation material at the site of each of the circular drains  6  which are distributed over the surface.  
         [0021]    The material of bottom  4  is preferably a fiber reinforced light weight plastic sheet. Each of the drain rings  6  is sealed with wire or plastic mesh with openings of the order of ½″ (12.7 mm) or less precluding entanglement of fingers or toes.  
         [0022]    The distribution of edge  10  and central  6  floatation insures that the weight distribution of a disabled person on a floating safety bottom  4  would not cause any part of the person&#39;s body to sink below the surface of the water.  
         [0023]    The buoyant material is a rigid closed cell foam as used in marine floatation safety devices; it must also have a skin that is resistant to chlorine as is often used in pools. Material with a specific gravity of 0.25 provides the minimal required peripheral floatation  10  in a mere 3″ diameter (76 mm) tubular form (although this would not be the ideal crossection shape) if the area density of the bottom  4  sheeting is of the order 0.2 pounds per square foot (977 gm/square meter).  
         [0024]    [0024]FIG. 2 shows a detail of an alternative more flexible woven material  7  with a floatation device  8  attached below for a safety pool bottom; it is a true net. Flat fiber reinforced plastic straps or even buoyant tubular members can be woven. A 25% open weave wherein the warp and weft strands are bonded at each intersection is strongly suggested. The open weave permits easy drainage; the openings should be kept to ½″ squares (12.7 mm) or smaller to prevent entanglement of fingers or toes. The bonding prevents shifting of the strands.  
         [0025]    [0025]FIG. 3 shows a crossection of a pool  1  with different depths. Submerging mechanisms  5  are positioned at inflection points in the bottom contour. Also, their length is related to the local depth. The material of the safety pool bottom  4  must have a flexible seam at the inflection point if it is of a rigid material.  
         [0026]    [0026]FIGS. 4 and 5 depict a hydraulic submerging mechanism  5 . It is a hydraulic cylinder  16  of the order of 2.5″ (63.5 mm) bore operated by pressurized pool water. Side baffles  17  are stationary members which blend into the pool sides. Pushing member  18  is attached to the cylinder  16  piston rod and forces down the edge of safety pool bottom  4  and its peripheral floatation  10  which is attached to mounting flange  19 . Cylinder  16  is attached to pool bottom by flange  23 . Ring  24  attached to pushing member  18  rides along the outside surface of cylinder  16  to counteract twisting moments; it guides member  18  in straight line motion in both up and down excursions.  
         [0027]    The pressurized water enters the top of cylinder  16  at conduit  21  while dump valve  20  is opened by the triggering system to depressurize cylinder  16  permitting water above the internal piston to be dumped into the pool quickly thereby permitting the buoyant pool bottom structure  4  to rise.  
         [0028]    Cylinder  16  is open at the bottom to permit water in cylinder  16  below the piston to enter or leave in a relatively unimpeded manner so as not to restrict motion.  
         [0029]    [0029]FIG. 6 shows a system block diagram of the hydraulic and triggering system. A hard-wired electrical connection  37  to the supply mains is fed to a UPS  38  with internal storage battery. This, in turn, supplies power to a switching circuit  39  such as a relay which powers all dump valves  20  through conductor  41  (which is “daisy-chained”) on all cylinders  16  if a trigger signal  40  is received from the detection circuit (not shown). When such a signal is received, water from cylinders  16  quickly escapes through discharge tubes  42  back into the pool.  
         [0030]    Since there is now an unbalanced force, the safety pool bottom or net  4  rises quickly.  
         [0031]    The detection system also has a manual switch which simulates an emergency for testing purposes or can be used in actual emergencies. The detectors themselves consist of any number of prior art devices including infrared/acoustic systems, acoustic transmitters with hydrophones, visual detection systems and so forth. Some of these systems incorporate computers and sophisticated detection software with time delays. The detection system is not claimed by this invention.  
         [0032]    To redeploy the safety pool bottom or net  4  to the bottom of the pool after an emergency or test, a pump  30  is used to pressurize pool water  33  suctioned through inlet conduit  32  and discharged through pressurized conduit  34 . Each cylinder  16  receives pressurized water through check valve  35 . In this manner, the cylinder  16  will remain pressurized after pump  30  is stopped; indeed, conduit  34  can even be disconnected from each cylinder  16 .  
         [0033]    Actually, for small pools or above-ground pools with few cylinders  16 , the entire deployment subsystem can be portable and removable. Motor  31  can be just plugged into an outlet at  33  with manual switch  32  turned on after conduit  34  is connected via “pigtails” to each cylinder. Subsystem consisting of motor  31  and pump  30  can be mounted on a wheeled carriage. Conduit  32  is simply a hose with its end dipped into the pool. A ½ HP motor can power a jet pump which would redeploy a safety net  4  in less than 2 minutes for a small pool. Of course, it is more convenient to have a permanently installed deployment subsystem, especially for large pools.  
         [0034]    In an alternate embodiment, an electromechanical system is used for deployment (submerging) the safety pool bottom or net  4 .  
         [0035]    [0035]FIG. 7 shows the design of such an electromagnetic mechanism  49 . These are distributed around the periphery of the pool just as the hydraulic units  5  above. Each mechanism  49  has a small gear motor  53 , a drive belt pulley  51 , timing belt  54 , engagement nib  55  and bottom idler belt pulley  52 . A member  50  which attaches to pool safety bottom  4  is held down by engagement nib  55  but is able to ride up along belt  54  by guidance rails (not shown) if nib  55  is permitted to rise. Motor  53  uses a worm gear in the gear train such that it will not be backdriven by the buoyant force of member  50 .  
         [0036]    The key to the operation of this system is that drive pulley  51  is driven by motor  53  through an electrically disengageable clutch such as a solenoid-operated wrap-spring clutch of known construction. Preferably motor  53  is unidirectional, a fact that reduces its cost by permitting the use of simple AC induction motors.  
         [0037]    When an emergency is detected or a system test is performed, the clutch release mechanisms are energized (e.g. solenoids) which permit drive pulleys  51  to rotate freely (in a direction opposite to their motor driven direction). This releases tension on belt  54  allowing engagement nib  55  to rise under buoyant force from safety net  4  as transmitted by member  50 .  
         [0038]    A block diagram of this alternate embodiment is shown in FIG. 8. As in the previous embodiment, hard wired electrical supply at  37  supplies power to UPS  38  which powers the triggering mechanisms through switching circuit  39  upon signals from detectors or manual switch  40 . Line  62  is “daisy-chained” to each submerging mechanism triggering element such as a solenoid. For redeployment (submerging) plug  33  supplies AC mains power through manual switch  60  and conductors  61  to each motor  53  in each electromechanical submerging mechanism. Each submerging mechanism  49  has a switch which automatically turns motor  53  off when the bottom position is reached; alternatively, a stall detector can be used.  
         [0039]    It is further noted that other modifications may be made to the present invention without departing from the scope of the invention, as noted in the appended claims.