Abstract:
A latching inertial reel temporarily holds an inertial reel in a locked position during a lateral acceleration and resetably holds the reel in a latched position as a result of a vertical acceleration. The reel is latched when a latching sensor experiences a vertical acceleration above a threshold. A latch holds the reel in the latched position after the acceleration reduces to prevent subsequent injury from secondary impacts of a vehicle occupant with objects or surfaces in the vehicle. The latch may later be reset to release the reel. A vehicle seat may further include a seat inertial reel to provide support to the seat during a crash. The seat inertial reel may be attached to a floor mounting point, or to an elevated mounting point.

Description:
[0001]     The present application claims the benefit of U.S. Provisional Application Ser. No. 60/675,794, filed Apr. 27, 2005, which application is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to restraint systems and in particular to a latching restraint system which latches during a crash, and remains latched until a release is actuated.  
         [0003]     Generally, automotive and FM shoulder strap type Inertial Reels (IRs) are of the lock/unlock type. That is, the IR will lock to protect the occupant at the onset of either vehicle motion or shoulder strap acceleration above a first higher preset acceleration level, and automatically unlock when the acceleration level drops below a second lower preset acceleration level. The acceleration levels are usually set at very low thresholds. The low thresholds insure consistent IR locking in crash situations. After the acceleration level event passes, the IR automatically unlocks to allow normal operation of the restraint system with flexibility for the occupant to move within the constraints of the maximum extension bounds of the restraint system.  
         [0004]     Unfortunately, a problem may occur with lock/unlock type restraint systems in certain crash or other scenarios. The onset of multiple discreet lock (or crash) events and the ability to unlock between events could allow the occupant to move away from a protected position where his shoulders are held tightly to the seat back. A typical event is an extended crash scenario where second and third impacts occur following the initial impact, for example, a military vehicle involved in a bomb blast from underneath. The initial concussion causes the restraint to lock. The trajectory of the vehicle will allow the restraint system to unlock as the vehicle ascends and then returns to earth. While the restraint system is unlocked, the occupant may become displaced from the protected position. When the vehicle impacts the ground, the occupant is free to impact the vehicle interior. The risk of injury is significantly higher in such situations. Similar scenarios may be predicted for multiple independent crash events with civilian vehicles, particularly after an airbag deflates.  
         [0005]     Additionally, vehicle seats often have occupant restraint systems mounted to the seat. As a result, the seats must bear crash loads through the structure of the seat. The resulting forces on the seat structures, and the forces at the seat to vehicle mounting points, are often significant, and substantial displacement of the vehicle occupants may result.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     The present invention addresses the above and other needs by providing a latching inertial reel which holds a belt reel in a locked position until a release is actuated. The belt reel is locked when a crash sensor experiences an acceleration over a threshold. A latch holds the belt reel in the locked position after the acceleration reduces to prevent subsequent injury from secondary impacts of a vehicle occupant with objects or surfaces in the vehicle. The latch may later be released to free the occupant. A vehicle seat may further include a seat inertial reel to provide support to the seat during a crash. The seat inertial reel may be attached to a floor mounting point, or to an elevated mounting point.  
         [0007]     In accordance with one aspect of the invention, there is provided a locking inertial reel having a reel portion, a locking tooth mechanism connected to the reel portion, a locking portion, and a latching portion. The locking portion comprises a horizontally sensing crash sensor and a locking mechanism for locking the reel portion. The locking mechanism includes a locking lever having a pivot end and an engaging end for engaging the locking tooth mechanism to lock the reel portion. The locking lever is moveable to engage the locking tooth mechanism in response to the crash sensor. The latching portion includes a vertically sensing latching sensor and a latching mechanism. The latching mechanism is responsive to the latching sensor and cooperates with the locking lever to engage the locking tooth mechanism.  
         [0008]     In accordance with another aspect of the invention, there is provided a latching inertial reel. The latching inertial reel includes a reel portion and a locking portion. A locking tooth mechanism is connected to the reel portion and cooperates with a locking lever. The locking lever has a pivot end, and an engaging end which engages the locking tooth mechanism to lock the reel portion. The locking portion includes a locking mechanism including a ball residing in a ball seat having a sloped wall. The ball is displacable up the sloped wall by a horizontal acceleration, and the displacement of the ball up the sloped wall urges the locking lever to rotate about the pivot end to engage the engaging end with the locking tooth mechanism. The locking portion further includes a latching mechanism including the ball, the ball seat, a ball seat pivot, and a spring vertically supporting the ball seat. The locking lever pivot end is connected to the ball seat. Compressing the spring causes the ball seat to pivot about the ball seat pivot, the locking lever to pivot with the ball seat, and the locking lever to engage the locking tooth mechanism. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0009]     The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein:  
         [0010]      FIG. 1  is a side view of a seat and occupant.  
         [0011]      FIG. 2A  is a side view of a latching inertial reel according to the present invention.  
         [0012]      FIG. 2B  is an end view of the latching inertial reel according to the present invention.  
         [0013]      FIG. 3A  is a latching inertial reel according to the present invention in an unlocked position.  
         [0014]      FIG. 3B  is a latching inertial reel according to the present invention in a locked position.  
         [0015]      FIG. 3C  is a latching inertial reel according to the present invention in a latched position.  
         [0016]      FIG. 4A  is a prior art seat.  
         [0017]      FIG. 4B  shows the prior art seat bending during a crash.  
         [0018]      FIG. 5  shows a seat with an inertial reel connected to a seat back of the seat to limit seat bending during a crash. 
     
    
       [0019]     Corresponding reference characters indicate corresponding components throughout the several views of the drawings.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims.  
         [0021]     A side view of a seat comprising a seat back  10  and a seat bottom  12 , and an occupant  14 , is shown in  FIG. 1 . The occupant  14  is held in the seat by a lap belt  16   b , and a shoulder belt  16   a  (which may be one of two shoulder belts). The belts  16   a  and  16   b  are often connected to the seat, or other structure, using inertial reels. The inertial reels allow the belts  16   a  and  16   b  to be extended from or retracted into the inertial reel in the absence of accelerations, and prevent the extending of the belt  16   a  or  16   b  during accelerations, for example, during a crash. The inertial reel thus provides convenience and safety for the occupant. Unfortunately, known inertial reels unlock when accelerations subside, and may allow the occupant to be injured in the event of a second impact shortly following a first impact.  
         [0022]     A front view of a latching inertial reel  19  according to the present invention in shown in  FIG. 2A , and an end (or side) view of the latching inertial reel  19  is shown in  FIG. 2B . The latching inertial reel  19  comprises a reel portion  18 , a locking portion  20 , and a release button  22 . A belt  16  (which may be the lap belt  16   b  or the shoulder belt  16   a ) is wound inside the reel portion  18 , and in an unlocked position, the belt  16  freely extends from the reel portion  18  and retracts into the reel portion  18 . The locking portion  20  includes at least one inertial senor. When the inertial sensor experiences certain accelerations, the locking portion  20  locks the reel portion  18  preventing the extending and retracting of the belt  16   a  or  16   b.    
         [0023]     A detailed view of the locking portion  20  according to the present invention is shown in  FIG. 3A  in an unlocked and unlatched (or ready) position. A locking tooth mechanism  34  is attached to a reel in the reel portion  18  to control the extending and retracting of the belts  16   a  or  16   b . A locking lever  32  is disengaged from the locking tooth mechanism  34 , and the locking tooth mechanism  34  is free to rotate in the unlocked position, and as a result, the reel portion  18  is free to release or take-up the belt  16   a  or  16   b.    
         [0024]     A detailed view of the locking portion  20  according to the present invention is shown in  FIG. 3B  in a locked and unlatched position. The locking portion  20  includes a locking mechanism comprising a crash sensor and the locking lever  32 . The crash sensor (or sensing circuit) comprises a sensor ball  30  residing on a ball (or sensor) seat  36  for sensing a normal onset event (i.e., a vehicle crash). The seat  36  includes a sloped wall  36   a  sloping upward away from a ball resting point. The locking lever  32  has a lever pivot end  32   a  and a lever engaging end  32   b . The lever engaging end  32   b  is configured to engage the locking tooth mechanism  34  in a crash event to lock the reel portion  18 .  
         [0025]     Comparing  FIG. 3B  to  FIG. 3A , the sensor ball  30  reacts to an acceleration (e.g., a vehicle movement or crash event) by climbing the sloped wall  36   a  and urging the locking lever  32  to pivot about the lever pivot end  32   a  from the unlocked position (in  FIG. 3A ) into the locked position in contact with the locking tooth mechanism  34  (in  FIG. 3B .) The sensor ball  30 , sloped wall  36   a , locking lever  32  and locking tooth mechanism  34  thus provide the locking mechanism. Specifically, the sloped wall  36   a  of the ball seat  36  resides 360 degrees around the ball  30 . The slope of the sloped wall  36   a  is designed to couple a horizontal acceleration of a vehicle into a diagonal (both horizontal and vertical) motion of the ball  30  up the sloped wall  36   a , which motion of the ball  30  causes the locking lever  32  to pivot about lever pivot end  32   a  and to engage the toothed mechanism  34  and thereby lock the reel portion  18 . More specifically, the cooperation of the locking lever  32  with the locking tooth mechanism  34  acts to lock the reel portion  18  from further payout. Such known operation concept is embodied in, for example, Modular M-2K Belt Retractor Assembly ball and lever arm system for locking seat belt reels made by Key Safety Systems, Inc. in Detroit, Mich., and others. The sensing circuits are typically set at a very low acceleration level to keep the occupant  14  close to a seat (see  FIG. 1 ) during the onset of a potential crash, and to help the occupant  14  remain in position to keep control of a vehicle during bumps or maneuvers.  
         [0026]     The locking mechanism of the locking portion  20  may include elements based on known operational concepts for locking an inertial reel  18  during an onset event, and the locking mechanism described in  FIG. 3B  is an example of a preferred locking mechanism. However, a locking portion  20  including any locking mechanism is intended to come within the scope of the present invention.  
         [0027]     In the case of known restraint systems, the occupant  14  is held from further movement during the onset event (i.e., while the crash sensor senses a horizontal acceleration). As soon as the acceleration subsides to a level less than a pre-calibrated acceleration level, a known inertial reel unlocks, and allows free movement of the occupant  14 . The acceleration level for an onset event is preferably set to between approximately 0.3 Gs to approximately 6 Gs, and more preferably set between approximately 0.4 Gs to approximately 0.7 Gs, and most preferably set to approximately 0.7 Gs for an on the road vehicle and most preferably set to approximately 5.5 Gs for aircraft.  
         [0028]     In addition to providing locking during an onset event, the locking portion  20  of the present invention further includes a latching mechanism providing a capability to latch the inertial reel  19  as shown in  FIG. 3C . The latching mechanism includes the locking lever  32  and a latching sensor comprising the ball  30 , the ball seat  36 , and a calibration spring  40 . The latching sensor responds to an acceleration level established by the spring  40  residing under the ball  30  and the ball seat  36 . The latching sensor (and thus the latching mechanism) preferably responds to a positive (or upward) vertical acceleration between approximately 1 G and approximately 15 Gs. In this instance, the acceleration sensed is primarily a vertical acceleration, not a lateral (or horizontal) acceleration, although there may be some mechanical coupling between elements resulting in a lateral acceleration affecting the latching sensor. When a high vertical acceleration is experienced, the ball  30  and ball seat  36  are forced downward compressing the spring  40 . If the vertical acceleration (or the vertical component of any acceleration) sufficiently compresses the spring  40 , the ball seat  36  (still holding the ball  30 ) pivots down in a counter-clockwise rotation about a ball seat pivot  38 , and a stop  31  slides against a cooperating surface  36   a  on the ball seat  36  to hold the ball seat  36  in the counter-clockwise rotated position. The lever  32  rotates counterclockwise with the ball seat  36  around the pivot  38 , wherein the lever  32  engages the locking tooth mechanism  34 , thereby locking the inertial reel  10 , and also latching the inertial reel  19  which will remain locked until reset. The inertial reel  19  may be manually unlatched after a latching event by pressing a simple unlatch device  42  to release the stop  31  and reset the locking portion to the ready position. The Latching mechanism will remain latched until the device  42  is pressed. The unlatch device  42  may be a simple membrane covering an end of the stop  31 .  
         [0029]     The acceleration level classified as a crash, which would latch the inertial reel in the locked condition, can be set individually depending on the vehicle and engineering requirements. A typical crash may involve an acceleration event from a low of approximately 3 Gs to approximately 4 Gs to well over 10 Gs. The spring  40  may be selected to provide latching of the inertial reel at acceleration levels above non-crash events, such as experienced on a bumpy road or driving off road. Different requirements are stipulated for on-road vehicles as well as civilian and military aircraft. The inertial reel can be manually unlocked at a later time by the occupant or optionally by maintenance personnel after a vehicle inspection has verified the vehicle and restraint are in operational condition.  
         [0030]     While the latching sensor is described above as comprising the ball  30 , the ball seat  36 , and the spring  40 , the latching sensor may in general comprise a mass, a pivoting member, and a spring, wherein the mass and pivoting member rotate about a pivot to compress the spring when under vertical acceleration, and a locking lever connected to the pivoting member rotates with the pivoting member and latches the reel portion.  
         [0031]     While the locking and latching mechanisms described above are mechanical apparatus, a hybrid mechanical and electronic locking and/or latching mechanism is also contemplated. In the instance of such hybrid mechanism, the sensor may be replaced by a one or more axis accelerometer, and/or the lever  32  may be replaced by a servo mechanism.  
         [0032]     A prior art seat having a seat back  110  is shown in  FIG. 4A  in a rest position and the prior art seat is shown in  FIG. 4B  during a crash. As can be seen, the occupant  14  and the seat back  110  move significantly during the crash. The resulting occupant  14  contact with vehicle interiors is a major contributor to crash related injuries. Because of the need to minimize weight in vehicles, the use of heavy load bearing components is not desirable. The heavy load bearing components might be avoided by using multiple mounting points for the seat to distribute crash loads, but the issue then becomes the complication required to allow seat adjustability for vehicle operation or occupant comfort, and to allow for a folding seat for access to areas behind the seat.  
         [0033]     An inertial reel seat restraint according to the present invention is shown attached to the seat in  FIG. 5 , during a crash event. A flexible link to the seat is provided by a seat inertia reel  122  and a webbing strap (or belt)  120  attached from the vehicle structure at floor mounting point  116  or elevated mounting point  118  to the seat back  110 . The inertia reel  122  would allow full seat adjustability under normal conditions, wherein the inertial real  122  is unlocked. This allows the webbing strap  120  to extend and retract as required. A retractor spring would keep a slight tension on the webbing strap  120  to insure a close coupling between the seat  110  and the mounting points  116  or  118 . The inertia reel  122  would automatically lock in a crash and reduce or prevent the seat  110  from moving. The additional restraint in seat movement will also restrain seat occupant  14  displacement. Less occupant  14  displacement will reduce the opportunity for the occupant  14  contact with interior vehicle components. A suitable seat inertial reel  122  is the Modular M-2K Belt Retractor Assembly made by Key Safety Systems, Inc in Detroit, Mich., or may be a latching inertial reel as described above.  
         [0034]     While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.