A reel-type retractor for a safety belt incorporating an improved automatic locking device. The retractor is designed so that a driving member rotating in accordance with the reel, cooperates with a driven member to actuate a locking device, thus preventing further extension of the belt when the acceleration of the reel exceeds a preselected rate. I. Field of the Invention This invention relates to safety belt retractors, and more particularly to those retractors which are normally unlocked when the belt is extended and buckled about the user but automatically lock in response to the forces which develop during the moment of impact should a collision occur. II. Description of the Prior Art Emergency-locking seat belt retractors usually have a reel which is connected to the belt for retraction. In these retractors of the prior art, the reel is normally unlocked under ordinary driving conditions even though the belt is buckled about the user, thus paying out more belt or taking up the slack in accordance with the normal movements of the individual. A locking device is provided, responsive to the forces which develop at the moment of impact, thus preventing further extension of the belt and retaining the user in his or her seat. The state of the art in this type of retraction device is exemplified by reference to U.S. Pat. Nos. 3,341,250; 3,348,789; 3,412,952; 3,446,454; 3,450,368; 3,467,337; and 3,482,799. Many of these prior art devices are unduly complex, are not fail-safe in construction and are not positive acting, incorporating parts which may fail with wear or in the event that a lubricant should inadvertently reach their friction surfaces. SUMMARY OF THE INVENTION An automatic seat belt retracting device is disclosed having a locking member which is biased in a locking position, but is normally held in an unlocked position by a cam. This cam is biased to retain the locking member in its unlocked position under those conditions when the retracting reel is fully retracted or when the belt is extended at a substantially uniform rate or at a low rate of acceleration. When the reel is turned at a rapidly accelerated rate even for a matter of milliseconds, however, such as would occur when the user moves against the belt under crash conditions, a driven rotating member acting through the cam actuates the lock bar into locking engagment with the reel, thus preventing further extension of the belt. This is positive, fail-safe action and no friction surfaces are involved at this point of criticality. As an added feature to prevent the possible annoyance of the belt locking while being extended during the buckling operation, a slip clutch is included in the retractor connecting the belt wind-up reel and the locking device. This clutch retains the locking member in the unlocked position under all circumstances where the amount of belt withdrawn drawn is insufficient for buckling and also during periods of continuous extension of the belt as occurs during the process of "buckling up."
A reel type retractor for a safety belt having at least two locking pawls, staggered in relation to ratchet teeth incorporated into the reel and arranged for independent engagement therewith.
An emergency locking device equipped with a safety belt retractor wherein a reel (2) for winding a safety belt (1) thereon is rotatably mounted on a fixed reel support (4) with a shaft (3) fixed to the reel (2) being journaled on the support (4), and the reel (2) is biased to rotate in a belt rewinding direction by a return spring (5). In order to initiate the locking operation of the emergency locking device, there are provided a locking initiating member (21) fixedly mounted on the shaft (3) and an inertia plate (17) rotatably mounted on the shaft (3). The locking initiating member (21) is provided with a gear (21a) on its outer peripheral surface. A locking transmission pawl (19) is mounted rotatably about an axis (18) on the inertia plate (17). The locking transmission pawl (19) is provided with a gear (22) which is engaged with the gear (21a). The movement of the locking initiating member (21) is transmitted to the locking transmission pawl (19) by gears (21a, 22), the locking transmission pawl (19) is then engaged with one of a number of inner ratchet teeth (14) of a drum-shaped clutching wheel (12) whereby the rotation of the shaft (3) is transmitted to the clutching wheel (12), which moves a locking pawl (9) to engage a ratchet wheel (8) fixed to the reel (2), to prevent rotation of shaft (3) and thus the withdrawal of the safety belt (1).
An improved flywheel and clutch mechanism is adapted for use in a safety belt retractor which has a vehicle-sensitive mechanism and a pawl. The improvement includes: a polymeric flywheel, a clutch plate, a mechanical member, a biasing means and a retaining means. The flywheel has a recess in the interior thereof. An outer circumferential surface of the flywheel has ratchet teeth thereon. The pawl is located adjacent to the ratchet teeth and can engage a ratchet tooth when the pawl is actuated by the vehicle-sensitive mechanism. The clutch plate is disposed within the recess. The mechanical member is rigidly affixed to the center of the clutch plate and extends from the exterior side of the clutch plate. The biasing means is disposed in the recess of the flywheel adjacent to an interior surface of the clutch plate. The biasing means presses against the clutch plate in a direction urging the clutch plate away from the flywheel. The retaining means is disposed around the outer circumferential ridge of the flywheel. The flywheel and clutch mechanism includes three embodiments: a lower torque embodiment; an intermediate torque embodiment; and a higher torque embodiment.
A safety belt device having a frame and a shaft journaled for rotation in the frame. A spool is rotatably mounted on the shaft and a strap is secured to the shaft and adapted to be wound onto the spool. A rewind spring is operatively connected to both the frame and the shaft for rewinding the strap back onto the spool when it is extended out of the frame. A tooth gear is also mounted on the shaft and rotatable therewith. A lock bar is mounted on the frame and has a locking pawl adapted to engage the gear to lock the gear and thus the shaft from rotation. Inertia responsive means are provided responsive to sudden acceleration of the strap off of the spool to move the pawl into locking engagement. Strap state sensing means are also provided to sense the rolled-up condition of the strap on the spool and hold the pawl out of locking engagement with the gear until a predetermined amount of strap is unrolled off of the spool. Blocking means are also provided for holding the pawl out of engagement with the gear while the strap is being unwound from the spool and releasing the pawl for locking engagement with the gear when a predetermined amount of strap is wound back onto the spool by the rewind spring. In this manner, the strap can be freely pulled from the spool, and the lock bar, which is normally biased into locking engagement with the gear, is only released for such engagement means upon actuation of the inertia response means and after the blocking means is unblocked and the strap sensing means is disengaged. Accidental acceleration of the strap or belt by the user when extending the same from the reel cannot lock the reel prematurely.
A vehicle occupant restraint belt retractor including a metallic locking member gravity biased to an unlocked position out of engagement with annular ratchet configurations on metallic end plates of the retractor belt reel to allow unwinding belt rotation of the reel. An inertia member responsive to abrupt horizontal vehicle acceleration or deceleration moves the locking member to a locked position in engagement with radial locking surfaces of the ratchet configurations so as to prevent belt unwinding rotation of the reel. Plastic disks carried by the reel alongside the end plates include cushioning portions which prevent metal-to-metal engagement between the locking member and connecting surfaces of the ratchet configurations that extend generally circumferentially of the reel between the inner and outer ends of adjacent locking surfaces. The plastic cushioning portions thus mitigate rattling noise of the retractor when vertical acceleration pulses move the locking member to locked position, such as during use of the retractor on a vehicle negotiating a bumpy road.
