Abstract:
The safety belt release mechanism includes a sensor component and a belt release component. The sensor component is installed at a low point within the vehicle. The sensor component contains a water-soluble material that retains a spring in its compressed state so long as the water-soluble material is dry. If the vehicle is immersed in water, the water-soluble material dissolves, releasing the spring. The spring drives a pin into the end of a pressurized gas (e.g., CO 2 ) cartridge, releasing the gas therein. The gas passes through a tube to the belt release component installed upon a belt latch mechanism to drive a pin from an engaged position in the latch to release the latch. While one such assembly is disclosed herein, it is most preferred that one such assembly be installed along each safety belt assembly of the vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/397,274, filed Jun. 10, 2010. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to seat belt systems, and particularly to a safety belt release mechanism that is activated by immersion in water to release the occupants of a motor vehicle from their seats in the event the vehicle is submerged in a body of water. 
     2. Description of the Related Art 
     A number of tragic accidents have occurred over the years when motor vehicles have ended up at least partially submerged in a body of water. Such a situation may be due to the failure of a parking brake, a collision, or loss of control of the vehicle, among various potential causes. In many instances the vehicle is relatively undamaged and the occupants may be physically capable of escape, but their seat belt systems may be locked or there may be too much pressure on the belt to allow the occupant(s) to unlatch the latch(es). 
     Thus, a safety belt release mechanism solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The safety belt release mechanism includes a sensor component and a belt release component. The sensor component is installed at some low point within the vehicle structure, and includes a water-soluble substance (e.g., bicarbonate of soda, etc.) that retains a spring in compression when the substance is dry. When the water-soluble material dissolves, the spring is released and drives a pin into a gas cartridge (e.g., carbon dioxide, CO 2 ) to release the pressurized gas within the cartridge. 
     The gas is transmitted under pressure through a flexible tube or line to the belt release component, which is secured to a belt latch assembly installed along the belt. The belt latch assembly to which the belt release component is installed is a separate latch assembly from the conventional manually operated latch, and is preferably located at some point adjacent one of the belt anchors in the vehicle. 
     If the vehicle becomes immersed in water, water enters the sensor unit to dissolve the water-soluble material therein so that the spring drives a pin into the penetrable seal of a pressurized gas cartridge (e.g., CO 2 , etc.). The gas from the cartridge travels through a flexible line or tube to the belt release component and drives a pin from the latch assembly to release the belt portions. 
     Any number of such installations may be provided in a motor vehicle. At least one such installation is provided in the driver&#39;s seat belt to allow the driver (if capable) to assist any other occupants of the vehicle after release of the driver&#39;s belt. Most preferably, however, a separate sensor and belt release system is installed in each safety belt of the vehicle. A plurality of sensor units may be installed with each actuator, the sensors being disposed in different locations in the vehicle to assure belt release regardless of the orientation of the vehicle when it comes to rest in a body of water. 
     These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an environmental, perspective view of a safety belt release mechanism according to the present invention. 
         FIG. 2  is an elevation view in section of the mechanism of  FIG. 1  in its armed state, illustrating various details thereof. 
         FIG. 3  is an elevation view in section of the mechanism of  FIGS. 1 and 2  in its activated configuration, illustrating the operation thereof. 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The safety belt release mechanism  10  is designed for installation in the seat belt assembly of a motor vehicle. The mechanism  10  is automatically activated to separate two belt portions from one another in the event the device is immersed in water in order to free the occupant restrained by the belt assembly, as when the motor vehicle plunges into a body of water in the event of an accident. 
       FIG. 1  of the drawings provides an environmental perspective view of the automated safety belt release mechanism  10  in an exemplary installation in a motor vehicle. The mechanism  10  is shown activated due to its immersion in water W in  FIG. 1 . The primary components of the system or mechanism  10  comprise a completely automated, water-activated sensor component  12  that is installed at some low point in the vehicle, and an actuator component  14  that is installed on the first latch component  16  of the belt assembly to communicate pneumatically with the sensor component  12 . The first latch component  16  is, in turn, attached to a relatively short first or anchor belt portion  18 , which extends from a safety belt anchor bracket  20  attached (e.g., bolted, etc.) to the seat support or other structure S of the vehicle. Alternatively, the first latch component  16  and its actuator component  14  may be constructed as an integral part of the safety belt anchor bracket  20 , and the short first or anchor belt portion may be eliminated, if desired. 
     The first latch component  16  has a receptacle or slot  22  therein to accept the tongue or tab configuration of the second latch component  24 . The second latch component  24  extends from the second safety belt component  26  and serves to connect the first and second belt components  18  and  26  directly to one another during normal operation. 
       FIGS. 2 and 3  provide elevation views in section of the mechanism or system  10  in its normal, non-activated (connected) state and its activated (belt separation) state, respectively. The sensor unit or component  12  comprises a sensor body  28  having opposite first and second ends  30  and  32  and a wall  34  extending between the two ends  30 ,  32 . The first and second ends  30 ,  32  and the wall  34  of the sensor body  28  define an interior chamber  36 . At least one water passage  38  (and preferably a plurality of such passages) extends through the wall  34  to allow water to flow into the interior chamber  36  when the sensor unit  12  is submerged. 
     A pressurized gas cartridge  40  (e.g., a CO 2  cartridge) extends from the first end  30  of the sensor body  28 . The neck of the cartridge  40  extends into the interior chamber  36 , and defines a mouth closed by a penetrable seal. A water-soluble material  42  (e.g., bicarbonate of soda, etc.) is placed within the interior chamber  36 , adjacent the first end  30  of the sensor body  28 . A cartridge-penetrating pin  44  is installed within the interior chamber  36 , and is oriented toward the penetrable seal of the pressurized gas cartridge  40 . A compression spring  46  is installed within the interior chamber  36  adjacent the second end  32  of the sensor body  28 , and is biased against the wider head  44   a  of the pin  44  to urge the pin toward the gas cartridge  40 . However, the pin  44  is restricted from penetrating the end of the cartridge  40  by the water-soluble material  42 , which is located within the interior chamber  36  between the pin  44  and the first end  30  of the sensor body  28 . Thus, the pressurized gas cartridge  40  cannot be punctured to allow the gas to escape to the belt release actuator component  14  through the interconnecting flexible pneumatic tube or line  48  unless and until the water-soluble material is dissolved and/or washed from the interior chamber  36  of the sensor body  28 . 
     Although it is not anticipated that the automatic safety belt release mechanism  10  would be reused in a motor vehicle, the mechanism  10  may be configured to allow it to be reworked for reuse, if so desired. It will be seen that the second end  32  of the sensor unit  12  may comprise a separable cap (e.g., a threaded cap) that may be removed and replaced. Also, the pressurized gas cartridge  40  may be removed from the opposite first end  30  of the sensor unit  12 . Accordingly, the depleted cartridge  40  may be replaced with a fresh, fully charged cartridge, and the cap at the second end  32  of the sensor unit  12  may be removed to access the interior chamber  36  of the sensor unit  12 . The spring  46  and the pin  44  are removed, and a fresh charge of water-soluble material is placed within the first end  30  of the sensor unit  12 . The pin  44  and the spring  46  are then replaced in proper order, and the cap at the second end  32  is replaced to ready the sensor unit  12  for reuse. 
     The actuator unit  14  that extends from the first latch component  16  includes a latch attachment end  50 , an opposite spring housing end  52 , and a wall  54  extending therebetween. The latch attachment end  50  of the actuator  14  may comprise a portion of the surface of the first latch component  16 , if so desired. The latch attachment end  50 , spring housing end  52 , and wall  54  define an interior chamber  56  within the actuator unit  14 . The latch attachment end  50 , i.e., the mating surface of the first latch component  16 , has a latch pin passage  58  formed therethrough that continues concentrically through the opposite side of the first latch component  16 . The opposite spring housing end  52  of the actuator unit  14  also has a corresponding latch pin passage  60  formed therethrough, the latch pin passages  58  and  60  being concentric with one another. 
     A latch pin  62  extends concentrically through the latch pin passages  58  and  60  of the actuator component or unit  14 . The latch pin  62  has a latch-securing end  64  extending from the latch attachment end  50  of the actuator  14  when the mechanism  10  is armed, and an opposite guide end  66  extending from the spring housing end  52  of the actuator. The latch pin  62  further has a generally medially located sealing disc  68  disposed concentrically therearound, the sealing disc  68  defining a pneumatic chamber  70  between the disc  68  and the latch attachment end  50  of the actuator  14 . A spring  72  is installed about the latch pin  62  between the spring housing end  52  of the actuator  14  and the sealing disc  68  of the latch pin  62 . The spring  72  urges the sealing disc  68 , and thus the latch pin  62 , toward the first latch component  16  to extend the latch-securing end  64  of the latch pin  62  outwardly from the actuator  14 . A stop  74  is disposed upon the latch pin  62  to limit the extension of the latch-securing end  64  of the latch pin  62 . 
     The mechanism or system  10  is normally configured, as shown in  FIG. 2 , with the latch-securing end  64  of the latch pin  62  extended through the latch pin passage  58  of the first latch component  16  and the corresponding concentric latch pin passage  76  of the second latch component  24  installed within the receptacle  22  of the first latch component  16 . The latch pin  62  in its extended state, as shown in  FIG. 2 , thus secures the two latch components  16  and  24  together to join the two belt portions  18  and  26 . 
     However, when the sensor unit or component  12  is immersed in water, as when the motor vehicle is at least partially submerged, water enters the interior chamber  36  of the sensor body  28  through the water inlet passages  38  to dissolve and/or wash out the water soluble material  42  therein. When this material  42  is removed from the internal volume between the first end  30  and the head  44   a  of the pin  44  within the sensor body  28 , the spring  46  extends to force the pin  44  into the penetrable seal in the end or mouth of the neck of the pressurized gas cartridge  40 , generally as shown in  FIG. 3 . This allows the pressurized CO 2  or other gas within the cartridge to escape through the flexible pneumatic line  48  that connects the sensor  12  to the actuator  14 . The gas cannot escape from the water inlet passages  38  through the wall  34  of the sensor body  28  because the head  44   a  of the pin  44  is pushed by the spring  46  to a position blocking the passages  38 , as shown in  FIG. 3 . 
     As the gas flows through the line or tube  48  into the pneumatic chamber  70  of the actuator unit  14 , the increasing pressure drives the sealing disc  68  toward the spring housing end  52  of the actuator  14 , compressing the spring  72  therein. Since the sealing disc  68  is an integral and fixed component of the latch pin  62 , the latch securing end  64  of the pin  62  travels with the disc  68 , retracting from its normally extended position through the latch pin passages  58  and  76 , respectively, of the first latch component  16  and second latch component  24 . This allows the second latch component  24  to release from its position in the receptacle  22  of the first latch component  16 , thus releasing the two belt portions  18  and  26  to allow an occupant restrained thereby to escape the vehicle. A supplemental spring may be placed at the bottom of the receptacle  22  of the first latch component  16  to eject the second latch component  24  therefrom, if desired, but the normal tension on the belt assembly as assisted by any retractors or tensioners in the system will normally provide sufficient tensile force on the belt system to separate the two belt components from one another when the latch pin  62  is withdrawn from the latch components  16  and  24 . 
     While only a single belt release mechanism  10  is illustrated and described herein, it should be noted that most preferably one such system or mechanism is installed at each safety or seat belt position within the vehicle. It should also be noted that while only a single actuator is shown and described for the mechanism  10 , additional actuators may be provided at various locations in order to assure belt release regardless of the orientation of the vehicle when it comes to rest in a body of water. For example, a second actuator (for each belt assembly) may be installed in or near the roof of the vehicle to actuate the belt release mechanism if the vehicle were to overturn in a relatively shallow body of water, e.g., submerging the inverted vehicle from roof to window line on the doors. A trapped occupant restrained by his or her belts in such a situation might drown if otherwise unable to escape by releasing his or her seatbelt assembly. Accordingly, such a system will provide a measure of safety not previously found in conventional motor vehicles. 
     It is to be understood that the present invention is not limited to the embodiment described above, but encompasses any and all embodiments within the scope of the following claims.