Automatic locking acceleration actuated vehicle safety belt retractor

Abstract

An automatic locking vehicle safety belt retractor includes a shaft on which is affixed a belt take up reel having similar first ratchet wheels at its opposite ends. A spring retracted transverse pawl member includes pawl teeth which are rockable with the pawl member into and out of braking engagement with the ratchet wheels and the pawl member is drive coupled to an internally toothed second ratchet wheel rockably mounted on the shaft. A fly wheel is freely rotatable on the shaft within the second ratchet reel and carries a spring retracted second pawl swingable into engagement with the second ratchet wheel and a cam wheel is rotatable with the shaft and engages a cam follower on the second pawl to advance the second pawl upon rotation of the cam wheel relative to the fly wheel. The numbers of teeth on the second ratchet wheel and on each of the first ratchet wheels are equal and the cam and ratchet wheels are so angularly related that when the retractor is braked, the pawls fully engage respective ratchet teeth.

I claim: 
     
       1. An automatic locking safety belt retractor comprising a shaft, a take-up reel mounted on and rotatable with said shaft and spring biased to in a belt rewind direction, a safety belt connected to and retractable by and withdrawable from said reel, a first ratchet wheel rotatable with said reel, a first pawl mounted for movement between positions engaging and disengaging said first ratchet wheel, a second ratchet wheel mounted on and rotatable relative to said shaft, a fly wheel rotatably mounted on said shaft, a second pawl mounted on said fly wheel and movable therewith and movable relative to said fly wheel between positions engaging and disengaging said second ratchet wheel, a cam member mounted on and rotatable with said shaft and engagable with said second pawl whereby rotation of said cam member a predetermined angle in advance of said fly wheel by the rotation of said shaft in response to a predetermined pull on said belt effects the actuation of said second pawl by said cam member into engagement with said second ratchet wheel to forwardly rock said second ratchet wheel, and actuating means drive coupling said second ratchet wheel and said first pawl whereby forward rocking of said second ratchet wheel advances said first pawl into engagement with said first ratchet wheel to lock said reel against belt withdrawal rotation, said first and second ratchet wheels having equal numbers of ratchet teeth. 
     
     
       2. The retractor of claim 1 wherein said first and second ratchet wheels and said cam member are so angularly related that said first and second pawls when actuated to their engaged positions engage the base portions of corresponding ratchet teeth of the respective first and second ratchet wheels. 
     
     
       3. The retractor of claim 1, including a first spring resilient biasing said first pawl toward its ratchet disengage position and a second spring resiliently biasing said second pawl toward its ratchet disengage position. 
     
     
       4. The retractor of claim 3 comprising a mounting bracket including a pair of transversely spaced side walls, said shaft extending between and projecting beyond and journalled to said side walls, a pair of said first ratchet wheels disposed at opposite ends of said reel proximate the confronting faces of said bracket side walls, a transverse cross bar extending between and rockably supported by said bracket side walls proximate said first ratchet wheels, and a pair of said first pawls located on said cross bar and rockable between positions engaging and disengaging respective first ratchet wheels. 
     
     
       5. The retractor of claim 4 wherein said fly wheel, second ratchet wheel, said second pawl and said cam member are located on said shaft along the outside face of one of said bracket side walls. 
     
     
       6. The retractor of claim 4, wherein said second ratchet wheel is internally toothed and is cap shaped and provided with an end wall journalled on said shaft, and fly wheel and second pawl being disposed within the space delineated by said second ratchet wheel. 
     
     
       7. The retractor of claim 4, wherein said second ratchet wheel end wall has a radially extending slot formed therein, and said actuating means comprises a lever engaging and rockable with said cross bar and provided with a follower element remote from said cross bar slideably engaging said slot. 
     
     
       8. An emergency locking type vehicle safety belt retractor, comprising a U-shaped frame 1; a shaft mounted intermediate the upright sides of the U-shaped frame, said shaft loosely carrying on one outside of the frame, a cap-shaped latch wheel with internal teeth, an inertia wheel fitted with a pawl, a cam wheel press fitted on the shaft, a spring washer fitted on the shaft, and a stop plate also fitted on the shaft; ratchet wheels provided to both insides of the U-shaped frame and having the same number of teeth as those of the latch wheel; a belt-winding reel press fitted on the shaft; a pawl plate mounted intermediate the upright sides of the frame and in the proximity of the ratchet wheels; and a pawl plate actuating plate transversely extending from an end part of pawl plate; wherein, when the vehicle is subjected to an abrupt impact or sudden change in the operating state, said inertia wheel operates to rotate with the cam wheel, but with a time lag when the belt is suddenly extracted, the pawl on the inertia wheel thus engaging with the latch wheel to rotate the latter, thereby engaging the pawl plate with the ratchet wheels through the pawl plate actuating plate and preventing further reeling out of the safety belt; and wherein the number of teeth of the ratchet wheels is equal to that of the latch wheel to make the pivot angle of the ratchet wheels and that of the latch wheel equal to each other to synchronize the movement of the ratchet wheels with that of the pawl plate by adequate selection of the angle of operation of the latch wheel and the fulcrum distance of the pawl plate and the pawl plate actuating plate. .Iadd. 9. An automatic locking safety belt retractor comprising a rotatable take-up reel spring biased in a belt rewind direction, a safety belt connected to and retractable by and withdrawable from said reel, a first ratchet wheel rotatable with said reel, a first pawl mounted for movement between positions engaging and disengaging said first ratchet wheel, a second ratchet wheel coaxial with and rotatable relative to said first ratchet wheel, a second pawl rotatable with said first ratchet wheel and movable between positions engaging and disengaging said second ratchet wheel and normally urged to said ratchet wheel disengage position, actuating means for urging said second pawl into engagement with said second ratchet wheel, and means drive coupling said second ratchet wheel and said first pawl whereby rocking of said second ratchet wheel advances said first pawl into engagement with said first ratchet wheel to lock said reel against belt withdrawal rotation, said retractor being characterized by said first and second ratchet wheels having equal numbers of ratchet teeth..Iaddend..Iadd. 10. The retractor of claim 9 wherein said actuating means includes means responsive to a predetermined rotational parameter of said reel for motivating said actuating means..Iaddend. .Iadd. 11. The retractor of claim 9 wherein said first and second ratchet wheels, said first and second pawls, said actuating means and said drive coupling means are so related that said first pawl when advanced to its ratchet wheel engage position engages the base portion of a tooth of the first ratchet wheel..Iaddend. .Iadd. 12. An automatic locking safety belt retractor comprising a shaft, a take-up reel mounted on and rotatable with said shaft and spring biased to rotate in a belt rewind direction, a safety belt connected to and retractable by and withdrawable from said reel, a first ratchet wheel rotatable with said reel, a first pawl mounted for movement between positions engaging and disengaging said first ratchet wheel, a second ratchet wheel mounted on and rotatable relative to said shaft, a support wheel mounted on said shaft, a second pawl mounted on said support wheel and means responsive and movable relative to said support wheel in response to a predetermined rotational parameter of said reel for moving said second pawl between positions engaging and disengaging said second ratchet wheel whereby a predetermined pull on said belt effects the actuation of said second pawl into engagement with said second ratchet wheel to forwardly rock said second ratchet wheel, and means drive coupling said second ratchet wheel and said first pawl whereby forward rocking of said second ratchet wheel advances said first pawl into engagement with said first ratchet wheel to lock said reel against belt withdrawal rotation, said first and second ratchet wheels having equal numbers of ratchet teeth..Iaddend. .Iadd. 13. The retractor of claim 12 wherein said first and second ratchet wheels, said first pawl, said second pawl moving means and said drive coupling means are so related that said first pawl when actuated to its engaged position engages the base portion of a tooth of the first ratchet wheel..Iaddend. .Iadd. 14. The retractor of claim 12 including a first spring resiliently biasing said first pawl toward its ratchet disengage position and a second spring resiliently biasing said second pawl toward its ratchet disengaging position..Iaddend..Iadd. 15. The retractor of claim 14 comprising a mounting bracket including a pair of transversely spaced side walls, said shaft extending between and projecting beyond and journalled to said side walls, a pair of said first ratchet wheels disposed at opposite ends of said reel proximate the confronting faces of said bracket side walls, a transverse cross bar extending between and rockably supported by said bracket side walls proximate said first ratchet wheels, and a pair of said first pawls located on said cross bar and rockable between positions engaging and disengaging respective first ratchet wheels..Iaddend..Iadd. 16. The retractor of claim 15 wherein said support wheel, second ratchet wheel, and said second pawl are located on said shaft along the outside face of one of said bracket side walls..Iaddend..Iadd. 17. The retractor of claim 15, wherein said second ratchet wheel is internally toothed and is cap shaped and provided with an end wall journalled on said shaft, and said support wheel and second pawl being disposed within the space delineated by said second ratchet wheel..Iaddend..Iadd. 18. The retractor of claim 15, wherein said second ratchet wheel end wall has a radially extending slot formed therein, and said actuating means comprises a lever engaging and rockable with said cross bar and provided with a follower element remote from said cross bar slideably engaging said slot..Iaddend.