Winding prevention belt retractor for passive shoulder belt system

An inertia locking seat belt retractor for winding a shoulder belt having one end mounted on the vehicle door to move the belt between stowed and restraining positions upon movement of the door. The retractor has a winding prevention mechanism including a pawl and ratchet for selectively blocking belt winding rotation of the belt reel to hold the belt extended at a set length to establish a slackened comfort condition relative the occupant. A manually actuatable control device has a normal condition blocking control of the pawl by a control disc frictionally clutched to the reel and is manually actuatable to release the pawl for control by the disc. The control disc actuates the pawl to provide the set length, defines a range of unwinding wherein the pawl is temporarily deactuated to permit subsequent rewinding to return the belt to the set length, and disengages the pawl upon still further unwinding rotation so that the pawl is deactuated upon belt unwinding during opening of the door. The manually actuatable control device may be operated to temporarily deactuate the pawl to allow belt unwinding. The pawl blocks return of the manually actuatable control device to the normal pawl blocking condition until belt unwinding causes the control disc to deactuate the pawl.

The invention relates to a seat belt retractor and more particularly to a 
seat belt retractor having a manually actuated winding prevention 
mechanism for a door actuated passive belt system. 
BACKGROUND OF THE INVENTION 
It is well known to provide a motor vehicle occupant restraint system 
having a shoulder belt which extends over the shoulder and across the 
chest of the seated occupant. An inertia responsive seat belt retractor is 
conventionally associated with one end of the shoulder belt and has a 
windup spring which rotates a reel to wind or retract the belt to a taut 
condition across the chest of the occupant. The inertia retractor permits 
belt unwinding rotation of the reel to extend the belt as the occupant 
leans forwardly to reach the vehicle operating controls and locks the belt 
against extension in response to an acceleration stimulus experienced by 
the vehicle body. 
It is also known to provide a retractor having a winding prevention 
mechanism which enhances occupant comfort locking the reel against belt 
winding rotation by the windup spring to hold the belt at a set length 
establishing a slackened condition about the occupant. U.S. Pat. No. 
4,023,746, issued to Joseph J. Magyar on May 17, 1977, provides an inertia 
locking retractor having a winding prevention mechanism which is 
selectively actuated and deactuated in response to a predetermined 
sequence of reel rotation induced by movement of the restrained occupant. 
U.S. Pat. No. 3,700,184, issued to R. E. Francis on Oct. 24, 1972 and U.S. 
Pat. No. 3,682,412, issued to G. G. Kuszynski on Aug. 8, 1972 provide 
inertia locking retractors having winding prevention mechanisms which are 
manually actuated and deactuated without regard to the condition or 
sequence of belt winding retraction or unwinding extension. 
U.S. Pat. No. 3,973,786, issued to L. W. Rogers, Jr. on Aug. 10, 1976, 
discloses a winding prevention mechanism of the Magyar type which is 
interconnected with the door for deactuation whenever the door is in the 
open position to insure belt winding rotation. 
It is also known to provide a passive belt system having one end of the 
belt mounted on the door, another end of the belt mounted on the vehicle 
body inboard the seat, and a retractor associated with one of the belt 
ends for winding the belt to a taut position about the occupant upon 
closing movement of the door and unwinding the belt to a stowed position 
forwardly of the seat upon opening movement of the door. 
It would be desirable to employ a winding prevention retractor in a door 
responsive passive seat belt system to enhance occupant comfort. However, 
it has been found that the Magyar type winding prevention mechanism which 
is controlled in response to the predetermined sequence of belt winding 
and unwinding could be subject to unintended actuation of the winding 
prevention mechanism upon inadvertent random oscillatory movement of the 
door in the open position so that the belt would not be wound to the 
restraining position about the occupant upon closure of the door. The 
Francis or Kuszynski type retractor could be used in a door responsive 
passive belt system but it would be necessary for the occupant to manually 
set the winding prevention mechanism subsequent to movement of the belt to 
the restraining position by closure of the door and to also manually 
release the winding prevention mechanism. If the occupant did not manually 
release the winding prevention mechanism before opening the door or before 
a subsequent closure of the door, the retractor would reestablish the 
previously set belt length irrespective of a different occupant entering 
the seat or the seat position being adjusted. Accordingly, an excessive 
amount of slack could result. The Rogers type retractor having the winding 
prevention mechanism interconnected with the door could be used in a door 
responsive passive belt system but a remote interconnect would be required 
in those instances where it is desired to mount the retractor inboard the 
occupant seating position. Furthermore, the use of a Rogers type door 
interconnect would render the winding prevention mechanism immediately 
operative in response to belt unwinding subsequent to closure of the door, 
even in those instances where the occupant may not have assumed his final 
adjusted position in the seat prior to closing movement of the door or 
where the occupant may not require or desire the use of this comfort 
enhancing feature. 
The present invention features a new and improved winding prevention 
mechanism which is manually actuated subsequent to winding of the belt to 
the restraining position by closure of the door and is automatically 
released in response to reel rotation upon unwinding of the belt during 
opening movement of the door to assure winding of the belt and complete 
movement to a taut restraining position upon subsequent closure of the 
door. 
BRIEF SUMMARY OF THE INVENTION 
An inertia locking seat belt retractor for winding a shoulder belt having 
one end mounted on the vehicle door to move the belt between stowed and 
restraining positions upon movement of the door. The retractor has a 
winding prevention mechanism including a pawl and ratchet for selectively 
blocking belt winding rotation of the belt reel to hold the belt extended 
at a set length to establish a slackened comfort condition relative the 
occupant. A manually actuatable control means has a normal condition 
blocking control of the pawl by a control disc frictionally clutched to 
the reel and is manually actuatable to release the pawl for control by the 
disc. The control disc actuates the pawl to provide the set length, 
defines a range of unwinding wherein the pawl is temporarily deactuated to 
permit subsequent rewinding to return the belt to the set length, and 
disengages the pawl upon still further unwinding rotation so that the pawl 
is deactuated upon belt unwinding during opening of the door. The manually 
actuatable control means may be operated to temporarily deactuate the pawl 
to allow belt unwinding. The pawl blocks return of the manual control 
means to the normal pawl blocking condition until belt unwinding causes 
the control disc to deactuate the pawl. 
One object, feature and advantage of the invention resides in the provision 
of a winding prevention mechanism for a seat belt retractor which is 
actuated by manual deliberate effort of the seat occupant independently of 
reel rotation or door movement and which is automatically deactuated by 
predetermined belt unwinding. 
Another object, feature and advantage of the invention resides in the 
provision of a manually actuated winding prevention mechanism for an 
inertia locking retractor in a door connected passive shoulder belt system 
which is automatically released in response to belt unwinding reel 
rotation during opening movement of the door to assure winding of the belt 
to a taut restraining position upon subsequent closure of the door. 
A further object, feature and advantage of the invention resides in the 
provision of a manually actuated winding prevention mechanism for an 
inertia locking retractor in a door connected passive shoulder belt system 
having a frictionally driven control disc which is conditioned to measure 
unwinding rotation from the maximum obtained condition of belt windup and 
provide controlled actuation and deactuation relative thereto.

Referring to FIG. 1, a vehicle body, generally indicated by numeral 10, has 
a front passenger seat 12 including a seat back 14 and an adjacent door 
16. The vehicle body 10 also has a driver seat and adjacent driver door, 
not shown. 
A passive occupant restraint belt system associated with the seat 12 
includes a retractor assembly generally indicated at 18 and mounted on the 
drive line tunnel 20 as will be more fully described hereinafter. The 
retractor assembly 18 has a spring wound reel and associated inertia 
locking mechanism which anchor the inboard end of a shoulder belt 22. The 
outboard end of the shoulder belt 22 is attached to the window frame 24 of 
door 16 by an anchor plate 26. Accordingly, when the door 16 is in the 
open position of FIG. 1, the shoulder belt 22 is unwound from the 
retractor assembly 18 and disposed somewhat forwardly of the seat back 14 
to permit occupant ingress and egress. Upon closure of the door 16, the 
retractor assembly 18 winds the shoulder belt 22 to a taut restraining 
position across the chest of the seated occupant for restraint of the 
upper torso. The lower torso is restrained by a knee cushion 27 mounted 
beneath the instrument panel. 
An active lap belt system is also provided and includes a buckle 28 
attached to the retractor assembly 18 as will be described hereinafter. A 
lap belt 32 is mounted on the vehicle body floor outboard the seat 12 by a 
retractor and has a latch plate 30. The lap belt 32 is unwound from the 
retractor by the occupant to engage the latch plate 30 in the buckle 28 
for restraint of the lower torso. 
Referring again to FIG. 1, it will be understood that the retractor 
assembly 18 includes a second reel associated with the shoulder belt for 
the vehicle driver seat and mounts a buckle for the driver's active lap 
belt. 
Referring to FIGS. 2 and 3, it is seen that the retractor assembly 18 
includes a stamped sheet metal housing 36 including laterally spaced 
sidewalls 38 and 40 having integral spaced apart stirrups 42 and 44 which 
straddle the drive line tunnel 20. A bolt 46 extends through a bolt hole 
in the stirrup 42 and threadedly engages a weld nut 48 located inside the 
drive line tunnel 20. A pair of buckle anchorages 52 and 54 are 
respectively struck from the sidewalls 38 and 40 of the housing 36. As 
seen in FIG. 2, the anchorage 52 has an elongated aperture 56 which 
receives a short length of belt 58 which mounts the buckle for the driver 
lap belt. A similar aperture is provided in anchorage 54 to receive a 
short length of belt 59 which mounts the buckle for the driver lap belt. 
The retractor housing 36 also has spaced apart forward and rearward walls 
60 and 62. As best seen in FIG. 4, the walls 60 and 62 have apertures 64 
and 66 which receive the ends of a reel shaft 68 which mounts a shoulder 
belt reel, generally indicated at 70. Like apertures are provided for 
rotatably mounting a reel for winding the shoulder belt for the driver 
seat. A bracket 72 is welded to the rearward wall 62 and is attached to 
the tunnel 20 by bolts 71 and 73. The housing 36 also has brackets 75 
which facilitate attachment of a decorative plastic housing, not shown, to 
enhance the appearance of the retractor assembly 18. 
As best seen in FIGS. 3 and 4, the belt reel 70 rotatably mounted by the 
reel shaft 68 includes an elongated drum 78 having ratchet plates 74 and 
76 attached to the ends thereof and keyed to the reel shaft 68 for 
rotation therewith. The ratchet plates 74 and 76 have teeth 80 that face 
in a clockwise belt unwinding direction of reel rotation as viewed in FIG. 
3. The ends of the reel shaft 68 are rotatably supported within the 
apertures 64 and 66 of the housing walls 60 and 62 by bushing portions 84 
and 86 of a pendulum support member, generally indicated at 90. The FIG. 4 
right-hand end of reel shaft extends outwardly through the housing wall 62 
and has a slot 92 which receives the inner end 94 of a windup spring 96. 
The outer end of spring 96 is suitably fixed to a plastic spring housing 
98 mounted on the housing wall 62. The spring 96 urges rotation of the 
belt reel 70 in the belt winding direction to store the belt 22. The 
left-hand end of reel shaft 68 extends outwardly through the adjacent 
housing wall 60 and is received by a winding prevention mechanism 
generally designated by 100. A top wall 97 of housing 36 has an escutcheon 
99 seated in a slot to guide the belt 22 onto the reel 70. 
The pendulum support member 90 is of injection molded plastic and includes 
depending legs 102 and 104 which extend downwardly from their respective 
bushing portions 84 and 86 encircling the ends of reel shaft 68. The lower 
ends of legs 102 and 104 are connected by an integral base 106 which is 
oriented in a horizontal plane. Base 106 has an aperture 108 which 
receives a stem 114 of a pendulum 112 which mushrooms outwardly above the 
base 106 into a control portion 116. A weight 118 is supported on the 
lower end of the stem 114. The control portion 116 is engaged by an 
adjustment clip 122 attached to a lock bar 124 which is pivotally 
supported on the pendulum support member 90 for movement into locking 
engagement with the ratchet teeth 80 of the ratchet plates 74 and 76. For 
a complete description of a preferred arrangement of the pendulum support 
member 90 and lock bar 124, reference may be had to U.S. patent 
application Ser. No. 809,193 by James C. Degras et al, filed June 23, 
1977, and assigned to the assignee of this invention. 
In operation the pendulum 112 swings from its vertically depending 
orientation of FIG. 3 to an inclined position in response to abrupt 
vehicle acceleration or deceleration in any horizontal direction. Swinging 
movement of the pendulum 112 causes the pendulum control portion 116 to 
pivot the lock bar 124 upwardly so that locking portions on the lock bar 
124 engage the ratchet teeth 80 of ratchet plates 74 and 76 to lock the 
reel 70 against belt unwinding rotation. When the vehicle acceleration or 
deceleration terminates, the pendulum 112 returns to its vertical position 
and allows the lock bar 124 to pivot downwardly out of engagement with the 
reel ratchet teeth 80 so that belt unwinding is again permitted. Since the 
lock bar 124 is the only restraint against unwinding reel rotation, the 
belt 22 can normally by unwound by the occupant leaning forward in the 
seat, by pulling on the belt, by moving the door 16 to the open position 
or by adjusting the seat forward. 
Referring to FIGS. 4 and 5, it is seen that the winding prevention 
mechanism 100 includes a housing cover 128 that is fixedly mounted on the 
adjacent housing wall 60. A ratchet plate 130 is suitably fixed to the 
reel shaft 68 for rotation with the reel 70 in both the belt winding and 
unwinding directions of rotation. The ratchet plate 130 has ratchet teeth 
132 which face in the clockwise belt winding direction of reel rotation, 
as viewed in FIG. 5, oppositely of the direction of the ratchet teeth 80 
on the ratchet plates 74 and 76. 
Referring to FIG. 5, a winding prevention pawl 136 is provided for 
engagement with the ratchet teeth 132 to block belt winding rotation of 
the reel 70 by the windup spring 96. The pawl 136 is pivoted to the 
housing wall 60 by a pivot shaft 138. A torsion spring 140 encircles the 
pivot shaft 138 and acts between the housing wall 60 and the pawl 136 to 
urge a pawl tooth 142 in the direction toward engagement with the ratchet 
teeth 132. A control disc 150 for controlling the pawl has a central 
aperture 152 which rotatably receives a reduced diameter end portion 154 
of the reel shaft 68. A peripheral annular rib 156 of the control disc 150 
is held in frictional driving engagement with the face of ratchet plate 
130 by a suitable compression spring 160 which acts between the housing 
cover 128 and an annular rib 162 on the control disc 150. 
FIG. 12 shows the configuration of the control disc 150 when viewed in an 
axial direction. The outer peripheral edge 164 of control disc 150 has a 
control surface 166 which extends over about 220.degree. of the 
circumference of the disc. One end of the control surface 166 has a cam 
surface 168 which rises radially of the control surface radius designated 
"R" in FIG. 12. The other end 170 of the control surface 166 is rounded as 
seen in FIG. 12, and cooperates with the radially raised cam surface 168 
to define a notch 172 which extends circumferentially over approximately 
140.degree. of the peripheral edge 164 of the disc 150. As seen in FIG. 5, 
the control surface 166 of the control disc 150 is located radially 
outwardly of the ratchet teeth 132 and support the pawl tooth 142 in a 
disengaged position relative the ratchet teeth 132. The notch 172 is 
located radially inward of the ratchet teeth 132 to expose several of the 
ratchet teeth 132 for engagement by the pawl tooth 142. The cam surface 
168 is located further radially outward from the control surface 166 to 
move the pawl tooth 142 to a furthest disengaged position. The control 
disc 150 also has a lateral projection 174 which extends laterally from 
the face of control disc 150 adjacent the cam surface 168 for limiting 
rotation of the control disc to one revolution as will be discussed 
hereinafter. 
The winding prevention mechanism 100 also includes an actuating member 180 
having a central aperture 182 which is rotatably journalled on a 
cylindrical abutment 184 of the cover. Referring to FIG. 5, it is seen 
that the housing cover 128 has a pair of stops 186 and 187 which are 
engageable by a handle portion 190 of the actuating member 180 to limit 
the rotation of the actuating member 180. A spring 192 acts between the 
handle portion 190 and the housing wall 60 to normally establish the 
actuating member 180 in the position of FIG. 5 wherein the pawl tooth 142 
is seated in a notch 196 of a tab 198 of actuating member 180 to support 
the pawl tooth 142 against movement toward the ratchet teeth 132. The 
actuating member 180 also has a notch 200 adjacent the tab 198 and carried 
into alignment with the pawl tooth 142 upon counterclockwise rotation of 
the actuating member 180 to the position of FIG. 8 to allow radial inward 
movement of the pawl tooth 142 toward engagement with the ratchet teeth 
132. The actuating member 180 also has a cam portion 188 which is carried 
into engagement with the pawl tooth 142 upon further counterclockwise 
rotation of the actuating member 180 to lift the pawl tooth 142 radially 
outward to the position of FIG. 11 wherein the pawl tooth 142 is 
disengaged from the ratchet teeth 132 to permit belt winding reel 
rotation. The actuating member has a lateral flange 202 which extends into 
lateral interference with the lateral projection 174 of control disc to 
limit rotation of the control disc. 
Operation 
The manner in which the control disc 150 and the actuating member 180 
cooperate to control the engaged and disengaged positions of the pawl 
tooth 142 with ratchet teeth 132 will now be described by first referring 
to FIGS. 1 and 6 in which the door 16 is open and the belt is fully 
unwound from the reel 70. As seen in FIG. 6, the previous unwinding 
rottion of the reel as the door 16 is opened carries the control disc to 
its limit of rotation in the unwinding direction wherein the control disc 
lateral projection 174 engages the lateral flange 202 of the actuating 
member 180. The effort of spring 192 exceeds the friction force on the 
control disc 150 to assure that the control disc does not rotate the 
actuating member 180. 
As the occupant enters the seat 12 and closes the door 16, the belt 22 is 
wound on the reel 70 by the windup spring 96. The initial rotation of the 
reel 70 in the winding direction causes the control disc 150 to rotate 
from its FIG. 6 unwinding limit of rotation to the FIG. 5 winding limit of 
rotation wherein the control disc lateral projection 174 engages the 
lateral flange 202 of the actuating member 180. The frictional drive 
provided by spring 160 allows control disc 150 to idle at the position of 
FIG. 5 during continued belt winding rotation of the reel 70 as the door 
16 is latched and the occupant settles against the seat back 14 of the 
seat 12. A subsequent unwinding of the belt 22 by forward leaning movement 
of the occupant will initiate rotation of the control disc 150 with the 
reel 70 in the unwinding direction, but the control disc 150 will rewind 
with the reel 70 upon subsequent belt windup and will idle at the winding 
limit of rotation if the occupant leans further rearwardly or adjusts the 
seat rearwardly so that the control disc 150 is conditioned to initiate 
its subsequent unwinding rotation from the maximum obtained condition of 
belt windup. 
During such winding and unwinding of the belt, the pawl tooth 142 is poised 
in its FIGS. 5 and 6 position of disengagement from the ratchet teeth 132 
by capture in the notch 196 of the actuating member tab 198. If and when 
the occupant desires to relieve the tautness on the belt 22 to enhance his 
comfort, the actuating member 180 is rotated in the counterclockwise 
direction by manual actuation of the handle portion 190. Such actuation, 
as seen in FIG. 7, rotates the actuating member tab 198 out of engagement 
with the pawl tooth 142 allowing the pawl spring 140 to pivot the pawl 136 
and carry the pawl tooth 142 into engagement with the aligned ratchet 
tooth 132. If the pawl tooth 142 comes to rest on the inclined portion of 
the ratchet tooth 132, as seen in FIG. 7, the windup spring 96 is allowed 
to rotate reel 70 somewhat in the winding direction or the occupant may 
unwind the belt further so that the pawl tooth 142 engages the vertical 
face of one of the ratchet teeth 132, as seen in FIG. 8. As seen in FIG. 
8, the pawl tooth 142 engages the actuating member lateral flange 202 to 
block spring 192 from returning the actuating member 180 to the normal 
position engaging stop 186. Thus, the engagement of pawl tooth 142 with 
ratchet teeth 132 locks the reel 70 against rotation in the belt winding 
direction by the windup spring 96. 
FIG. 8 shows the pawl tooth 142 engaged with the first available ratchet 
tooth 132 exposed by notch 172 of control disc 150 and notch 200 of 
actuating member 180. Unwinding rotation of the reel 70 upon forward 
leaning movement of the occupant or by the occupant pulling the belt 
causes the pawl tooth 142 to ratchet over the ratchet teeth 132 exposed by 
the control disc notch 172 as the ratchet plate 130 and control disc 150 
rotate in the counterclockwise belt unwinding direction. FIG. 9 shows the 
pawl tooth 142 engaged with the last available ratchet tooth 132 prior to 
engagement of the pawl tooth 142 by the rounded end 170 of the control 
surface 166. Thus, the circumferential extent of notch 172 defines a range 
of one-way reel rotation to introduce additional increments of slack into 
the belt. 
A further unwinding rotation of the reel 70 causes the rounded end 170 to 
lift the pawl tooth 142 radially outward to the position of FIG. 10 
wherein the pawl tooth 142 is disengaged from the ratchet teeth 132 but 
remains in blocking engagement with the lateral flange 202 of the 
actuating member 180. When the unwinding effort is relieved from the belt 
22, as for example when the occupant leans back against the seat back 14, 
the windup spring 96 rotates the reel 70 in the clockwise direction to 
rewind the belt 22 and return the control disc 150 and ratchet plate 130 
to the position of FIG. 9 wherein the rounded end 170 lowers the pawl 
tooth 142 into engagement with the last available ratchet teeth exposed by 
control disc notch 172. 
Upon unwinding rotation of the reel 70 and control disc 150 beyond the 
position of FIG. 10, the cam surface 168 of the control disc 150 moves 
pawl tooth 142 further radially outward to the position of FIG. 6 in which 
the pawl tooth 142 is disengaged from the lateral flange 202 of the 
actuating member 180 permitting spring 192 to rotate the actuating member 
180 in the clockwise direction to again capture the pawl tooth 142 in the 
notch 196 of the control disc tab 198. Accordingly, unwinding rotation of 
the reel through about 360.degree. of rotation to the unwinding limit of 
control disc rotation cancels the winding prevention mechanism. Thus, 
whenever the vehicle door 16 is moved to the open position and the belt 22 
is unwound substantially from the reel 70, winding prevention mechanism is 
cancelled by the control disc rotation so that windup of the belt 22 by 
the reel windup spring 96 is assured during a subsequent closing movement 
of the door. Furthermore, the occupant may cancel the winding prevention 
mechanism whenever desired by simply unmwinding the belt 22 sufficiently 
to carry the cam surface 168 into engagement with the pawl tooth 142. 
Referring to FIG. 11, the pawl 136 may be manually deactuated by rotating 
the actuating member 180 in the counterclockwise direction to the position 
of FIG. 11 wherein the cam portion 188 engages and lifts the pawl tooth 
142 radially outwardly from engagement with the ratchet teeth 132. This 
manual release mode of operation shown in FIG. 11 may be advantageously 
employed under several operating circumstances. For example, the occupant 
may wish to reduce the amount of slack in the belt from the condition 
corresponding to the FIG. 9 engagement with the last available ratchet 
tooth 132 by momentarily disengaging the pawl tooth 142 from the ratchet 
teeth 132 and reengaging the pawl tooth 142 in the position of FIG. 8. 
Furthermore, the occupant may wish to adjust the seat 12 in the rearward 
direction and reset the control disc 150 relative the reel 70 to obtain a 
new starting point of maximum obtained belt windup. Furthermore, it may be 
desirable to manually release the winding prevention mechanism if 
inadvertently actuated when the door 16 is in the open position and a 
further unwinding rotation sufficient to disengage the pawl 136 by the cam 
surface 168 of the control disc 150 cannot be achieved. 
An important feature of this invention is that the winding rotation of the 
reel during closure of door and any further winding movement as the 
occupant leans back against the seat and/or adjusts the seat rearwardly 
will establish the control disc 150 at a winding limit of rotation 
corresponding to the maximum obtained condition of belt windup. During 
subsequent belt unwinding, the control disc 150 rotates with the reel to 
measure the extent of belt winding from the maximum obtained condition of 
belt windup. Thus, if the occupant actuates the handle portion 190 
subsequent to an unwinding of the belt corresponding to movement of the 
control disc 150 to the position of FIG. 10, the control surface 166 
supports the pawl tooth 142 against engagement with a pawl tooth 132 which 
would result in an introduction of an excessive amount of belt slack when 
the occupant returns rearwardly to the normal position against the 
backrest. 
The configuration of the control disc 150 may be modified to obtain a 
desired control of the pawl. For example, it may be desired to change the 
circumferential extent of the notch 172 in order to obtain a desired range 
of permissible one-way reel rotation to introduce additional increments of 
slack from the first obtained set length. Furthermore, it may be desirable 
to modify the circumferential extent of the control surface 166 in order 
to obtain the desired range of permissible further belt unwinding beyond 
the one-way ratchet range when the pawl 136 is temporarily deactuated but 
continues to block return of the actuating member 180 to its normal 
position blocking the pawl from control by the control disc 150. It may 
also be desired to vary the location of the cam surface 168 relative the 
notch 172 and/or lateral projection 174 in order to modify the point of 
unwinding at which the pawl is lifted to its furthest outward condition 
and disengaged from the actuating member lateral flange 202 to permit the 
spring 192 to return the actuating member 180 to its position blocking the 
pawl 142. 
Thus, the invention provides a new and improved winding prevention 
mechanism for a door actuated passive seat belt system.