Winding – tensioning – or guiding – Reeling device – With spring motor
Patent
1997-02-13
1998-07-14
Darling, John P.
Winding, tensioning, or guiding
Reeling device
With spring motor
2423791, B60R 2228
Patent
active
057791775
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a belt retractor for a safety belt, comprising a housing which possesses two parallel limbs, in each of which an opening is formed, a belt drum, which is so mounted rotatably in the housing that sets of ratchet teeth provided at the drums's axial ends are arranged within the openings with an allround clearance from the same, and a load bearing pawl, which for a selective locking of the belt drum is able to be engaged with the ratchet teeth thereof, the belt drum being adapted to be shifted in a radial direction in relation to its axis by a load applied to it in the locked condition until the ratchet teeth thereof are supported in the openings of the limbs.
When the belt drum locks it is possible for the tension load applied via the belt drum to lead to a radial displacement of the belt drum, whose bearings are designed to yield. In the case of a high load, as for instance during emergency braking, the ratchet teeth on the belt drum come into contact with the edges of the openings in the housing limbs with the result that the belt drum will now bear radially against the housing. However, the pawl moved into engagement with the teeth of the belt drum bears the full locking load in the peripheral direction. Should this engagement be caused by a crash, such locking load will assume extremely high values.
One object of the invention is to reduce the maximum locking load which acts on the pawl of a belt retractor of the type initially mentioned.
In accordance with the invention there is a provision such that a set of teeth is formed at the edge of each opening, which corresponds to the sets of ratchet teeth but possesses at least one support portion which is adapted to be plastically deformed by the ratchet teeth when the belt drum is shifted under a high load in the radial direction. Owing to the invention it is only necessary for the pawl to bear a part of the locking load, since the housing makes a substantial contribution to withstanding the load in the peripheral direction.
In accordance with a preferred embodiment of the invention the support portion is a metal web, which fills a gap between two adjacent ones of the teeth. This design renders possible a particularly simple and low-cost structure of the support portion.
Further advantageous developments of the invention are recited in the dependent claims.
A preferred embodiment of the invention will now be described with reference to the accompanying drawings in detail.
FIG. 1 is a lateral elevation of a belt retractor in accordance with the invention in the resting state thereof.
FIG. 2 is a lateral elevation of the belt retractor according to FIG. 1 with a pawl engaged.
FIG. 3 shows the belt retractor of FIG. 1, the ratchet teeth bearing against the limbs.
FIG. 4 shows the belt retractor of FIG. 1 with a plastically deformed support portion.
In the FIGS. 1 through 4 the reader will see a lateral elevation of a belt retractor 10 in accordance with the invention for a safety belt. Same comprises a housing 12, which is U-shaped with two parallel limbs and an intermediate connecting transverse part. In the figures only the limb 14 of the housing and the sectioned middle part 16 thereof are seen. In each limb an opening 18 is formed.
In the housing a belt drum 20 is rotatably mounted which has an axis C and ratchet teeth 22 formed at its axial ends. These ratchet teeth 22 are so placed in the opening 18 that in the normal condition of the belt retractor, the ratchet teeth 22 have a clearance on all sides from the edge of the opening 18. Up to a certain load of the locked belt drum the bearing (not illustrated) of the belt drum will hold the same with the essentially stationary axis C in the housing.
A pawl 30 is arranged on the housing and may be pivoted out of the normal condition depicted in FIG. 1 into the locking condition illustrated in FIGS. 2 through 4, in which the belt drum 20 locks owing to engagement of the free end of the pawl 30 with the ratchet teeth 22 to prevent rotation in the draw off direction of the belt webbing (n
REFERENCES:
patent: 4497458 (1985-02-01), Gueguen et al.
patent: 4506844 (1985-03-01), Ernst
patent: 4844375 (1989-07-01), Ballet
patent: 5333906 (1994-08-01), Fujimura et al.
patent: 5558295 (1996-09-01), Bauer
Darling John P.
TRW Occupant Restraint Systems GmbH
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