Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
1999-08-12
2001-05-15
Nguyen, John Q. (Department: 3653)
Winding, tensioning, or guiding
Reeling device
With spring motor
C242S384200, C242S384500, C280S806000, C280S807000
Reexamination Certificate
active
06230997
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an adjustment mechanism for a safety belt retractor locking sensor, adjustable height locking sensor and safety belt retractor including an adjustment mechanism for the locking sensor.
BACKGROUND OF THE INVENTION
One known locking sensor for a vehicle safety belt retractor comprises a mass arranged to tip over at a predetermined angle of inclination or level of acceleration. The mass is connected to a rod that engages a base of a lever. When the mass tips over, the rod pushes the lever so that the tip of the lever is moved into engagement with a toothed wheel on the retractor spool. Engagement of the lever tip with the wheel locks the lock cup to the wheel. The lock cup includes a cam surface. As the safety belt pays out further, the spool turns the toothed wheel and thus the lock cup. As the lock cup rotates, the cam surface on the lock cup engages a pivotally mounted locking tooth, pushing the tooth into engagement with a further locking wheel on the spool thus preventing further rotation of the spool. It is the locking tooth engaging the locking wheel that prevents payout of the safety belt.
In the arrangement described, the gap between the lever tip and the ratchet must be closely controlled. If the gap is too large, poor locking performance will result. If the gap is too small, the belt will lock prematurely, erroneously and too frequently. That, in turn, will result in faults due to excessive wear on the retractor components and customer returns.
The gap size is very small and the build up of apparently insignificant manufacturing tolerances can vary the gap and affect the performance of the device quite significantly.
It has been proposed to provide some adjustment means to enable fine tuning of the lever tip position relative to the ratchet. One such example comprises a separate mechanism mounted directly to the retractor frame. The housing and lever are assembled to this mechanism which pivots at one end and is secured at the other by a screw. To adjust the tip gap the screw is loosened, the mechanism rotated about its pivot until the desired gap is obtained and the screw is tightened to hold the mechanism in position to maintain the gap.
That arrangement is rather large and it is difficult to maintain a reliable, consistent gap size from one retractor to another. Each retractor has to be measured and set individually which is time consuming and not readily repeatable.
DISCUSSION OF THE PRIOR ART
Adjustable features in safety belt retractors have been disclosed for example in: FIGS. 5 and 6 of UK patent publication 2 328 184A; FIG. 9 of UK patent publication 1 068 344A; FIG. 9 of U.S. Pat. No. 4,765,559; and FIG. 3 of U.S. Pat. No. 4,645,138.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved adjustment mechanism.
According to a first aspect of the invention there is provided an adjustment mechanism for a safety belt retractor locking sensor, comprising a first part mountable to a mounting member such as a lock cup spade or a mechanism bush, a second part mountable to a housing of the sensor, one of the parts being rotatable and conversion means for converting rotational displacement of said one part into relative translational displacement, between the housing and the lock cup spade.
According to a second aspect of the invention there is provided a safety belt retractor locking sensor comprising a sensor member arranged on a housing so as to cause locking of the retractor when the sensor is subjected to appropriate force, the housing being mountable on a lock cup spade of a retractor, the sensor having an adjustment mechanism comprising a first part mountable to a lock cup spade of a retractor, a second part mounted to the housing, one of the parts being rotatable, the adjustment mechanism further comprising conversion means for converting rotational displacement of said one part into translational displacement between the housing and the lock cup spade.
According to a third aspect of the invention there is provided a safety belt retractor comprising a lock cup spade and a locking sensor, the sensor including a housing movably mounted to the lock cup spade, the sensor being arranged to lock the retractor when subjected to appropriate force, the sensor including an adjustment mechanism comprising a first part mounted to the lock cup spade of the retractor, a second part mounted to the housing of the sensor, one of the parts being rotatable, the adjustment mechanism further comprising conversion means for converting rotational displacement of said one part into relative translational displacement between the housing and the lock cup spade.
In that way, the adjustment mechanism can be used to fine tune the position of the lever tip of the locking sensor relative to the ratchet of the retractor so as to provide optimum performance of the locking sensor.
Preferably the first and second parts are rotatably mountable.
In a preferred embodiment the first and second parts are formed in one piece. Most preferably, the first and second parts are integrally molded.
The conversion means may be provided partly on the lock cup spade. In a preferred embodiment the conversion means comprises a toothed rack formed in the lock cup spade and the first part comprises a toothed wheel arranged to engage the teeth of the toothed rack, the second part being rotatably mounted within the housing, whereby rotation of the second part, rotates the first part so that the toothed wheel moves along the toothed rack so as to move the housing relative to the lock cup spade.
In another embodiment the conversion means comprises a cam member on the second part and a cam surface formed in the housing. In such a case, the first and second parts are integral and the cam member rotates about the axis of rotation of the first part, the cam member following the cam surface formed in the housing so as to move the housing relative to the lock cup spade. In a preferred embodiment of the camming arrangement the cam member of the second part comprises a substantially circular member arranged eccentrically of the axis of rotation of the first part. Most preferably the cam surface comprises a slot in the housing. In such a case, means may be provided on the second part to effect rotation of the first and second parts. The means to effect rotation may be a projecting knob arranged coaxially of the first part whereby rotation of the knob rotates the first part within its rotational mounting so as to rotate the cam member also. Alternatively, the means to effect rotation may be a slot formed in the second part and arranged on the axis of rotation of the first part to allow manipulation by means of a suitable tool, for example a screwdriver.
Preferably, the housing is slidably mounted on the lock cup spade. In a preferred embodiment a track is provided on either the lock cup spade or housing and a projection is provided on the other of the lock cup spade and housing, the projection projecting into the track, so as to effect the aforesaid sliding mounting of the housing on the lock cup spade. Most preferably two such tracks are provided and two corresponding projections are provided. The, or each, track preferably comprises a slot. The, or each, track may also include a stop to restrict the extent of sliding movement of the housing. In that way, adjustment of the sensor can be limited between end positions so that the sensor cannot be accidentally adjusted too close to the ratchet or too far away from the ratchet. The slots on the housing are shown in the vertical position but these are notched in on the assembly line and may be positioned at approximately +/−15° about the vertical direction. With the slots arranged at different angles, the position of the housing which the mass sits on can be chosen according to different installation angles for different vehicles. Thus one housing can be used for various installations.
Where the first part is rotatably mounted and the second part includes the cam member the lock cup
Breed Automotive Technology Inc.
Drayer Lonnie
Nguyen John Q.
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