Seat belt retractor

A seat belt retractor is comprised of a minimum number of component parts which may be interchangeably and optionally assembled upon a standard frame to provide a desired combination of mechanisms which control rotation of the belt reel. The optional control mechanisms include spring windup, belt sensitive lockup, vehicle sensitive lockup, and a comfort device for relieving tension on the belt. A pair of support members abut against the side walls of the frame to carry the control mechanisms and have integral bushings which journal the reel shaft. Covers are provided to enclose the operating mechanisms and have plug-in projections which extend through aligned apertures of the support members and frame side walls to attach the support members and associated control mechanism interchangeably on either of the frame side walls. The frame has first and second opposed facing pairs of mounting apertures to selectively mount the lock bar for engagement with oncoming sprocket teeth regardless of the selected direction of belt unwinding reel rotation. One of the support members carries the inertia weight and has first and second pairs of oppositely arranged apertured mounting bosses for selective alternate mounting of a lock bar energizing pawl to orient the pawl for engagement with oncoming gear teeth carried by the sprocket regardless of the direction of belt unwinding reel rotation.

The invention relates to a seat belt retractor and more particularly 
provides a modular retractor construction by which a minimum number of 
component parts comprise modules which may be interchangeably and 
optionally assembled upon a standard frame in multiple variations to 
provide a combination of desired features such as spring windup, belt 
sensitive lockup, vehicle sensitive lockup and comfort enhancing tension 
relief for compliance with diverse government regulations and customer 
expectations in worldwide markets and to provide a retractor arrangement 
and package size to fit various vehicle models and styles. 
BACKGROUND OF THE INVENTION 
As the motor vehicle industry becomes more competitive and international in 
scope, it is necessary for motor vehicle manufacturers to expand the 
manufacturing and distribution of motor vehicle products across national 
boundaries. this has given rise to the design of so-called world cars in 
which a particular motor vehicle model is designed to be simultaneously 
assembled and distributed in worldwide markets while the vehicle 
components may be manufactured in only one or two countries. 
A serious constraint on this worldwide manufacturing and marketing strategy 
resides in the fact that governments in various nations have different 
regulations governing the motor vehicles to be made or sold in that 
country. This is particularly the case with regard to safety equipment 
such as seat belt systems. As a result it is common for a manufacturer of 
a so-called world car to manufacture or purchase more than one type of 
seat belt retractor for use in a particular model of vehicle body. 
Seat belt retractors commonly include a frame having a base wall for 
attachment to a motor vehicle structure such as a pillar. The frame also 
has side walls with aligned apertures to receive a shaft which rotatably 
mounts a belt reel. A spiral spring acts between the housing and the reel 
shaft to bias the reel in the direction to wind up the restraint belt. A 
lock bar extends between the housing side walls and is movable into 
engagement with a pair of sprockets carried by the belt reel to lock the 
reel against belt unwinding rotation. 
A sensing mechanism is conventionally provided to lock up the reel by 
moving the lock bar into engagement with the reel sprockets. The sensing 
mechanism may be responsive to vehicle deceleration or to the rate of belt 
unwinding from the reel. The vehicle sensitive locking mechanism includes 
a ball or pendulum which moves relative to the lock bar upon occurrence of 
a vehicle deceleration condition to move the lock bar to the locked 
condition. 
The belt sensitive locking mechanism includes a weight which is carried by 
the reel and lags behind rotation of the reel in response to a certain 
condition of belt unwinding to initiate movement of the lock bar to the 
locked position. The vehicle sensitive locking feature is preferred in the 
United States and Canada but the belt sensitive locking feature is 
permissible. However, in Europe, governmental regulations require the use 
of both a vehicle sensitive locking mechanism and a belt sensitive locking 
mechanism. Accordingly, it is necessary to design, tool, and inventory 
more than one retractor even though the vehicle in which the retractor is 
used is intended for worldwide manufacture and distribution. 
Another feature available in seat belt retractors is a tension relief 
mechanism, also known as comfort mechanism, which includes a pawl and 
ratchet arrangement to lock the reel against rotation in the belt windup 
direction so that the belt is held at a slackened tension-free length 
about the occupant. This feature has gained wide acceptance in the United 
States and Canada. 
Another factor contributing to the proliferation of seat belt retractor 
designs is that it is sometimes desirable to have the belt exit from the 
back side of the reel adjacent the frame base wall and then in other 
vehicle installation it is desirable to have the belt exit off the front 
side of the reel away from the base wall. For example, in those vehicles 
where the belt is to be hidden behind a plastic trim panel attached to the 
pillar, the belt exits off the back side of the reel so that the belt lies 
close along the pillar. 
Heretofore it has been necessary to design and tool a particular seat belt 
retractor arrangement for each new motor vehicle, taking into account the 
direction of belt exit from the retractor, as well as the governmental 
requirements and customer preferences for each part of the world where 
such vehicles will be sold. 
It would be desirable to provide a universally adaptable retractor which 
could be assembled from off-the-shelf standard components to meet the 
particular requirements of each new vehicle offering. Such a retractor 
would compress the time required for product introduction, deproliferate 
the parts inventory, and substantially reduce tooling costs for new 
vehicle models. 
SUMMARY OF THE INVENTION 
According to the invention a retractor frame includes spaced apart side 
walls having aligned apertures receiving a reel shaft to rotatably mount 
the toothed sprockets of a belt reel. The side walls have a first pair of 
aligned apertures to pivotally mount a lock bar for movement into 
engagement with oncoming sprocket teeth when the reel is mounted for belt 
unwinding rotation in one direction and also has a second pair of aligned 
apertures for mounting the lock bar when the reel is optionally mounted 
for belt unwinding rotation in the opposite direction of rotation. Support 
members of injection molded plastic and generally planar configuration 
overlie the frame side walls on the opposite side thereof from the reel 
and have integral bushings which project axially into the apertures 
receiving the reel shaft to mount the shaft for low friction rotation. One 
of the support members carries a cup member supporting the inertia weight 
and pivotally mounts a pawl movable by the inertia weight into engagement 
with oncoming gear teeth carried by the sprocket so that the gear teeth 
further move the pawl into engagement with the lock bar to engage the lock 
bar with the oncoming sprocket teeth. First and second pairs of oppositely 
arranged apertured mounting bosses are provided for alternate mounting of 
the pawl for engagement with the oncoming gear teeth regardless of the 
selected belt unwinding direction of rotation of the reel and gear teeth 
carried thereby. The second support member carries a pawl engageable with 
a spiral cam keyed to the reel shaft for rotation therewith and cooperates 
to provide a comfort device which selectively locks the reel against 
rotation in the belt winding direction to thereby hold the belt extended 
at a certain slackened length to enhance occupant comfort. Each of the 
support members and each of the frame side walls have a plurality of 
similarly configured and aligned apertures therethrough. A first cover is 
provided for enclosing a windup spring acting between the cover and one 
end of the reel shaft and a second cover is provided for mounting on the 
second support member and enclosing the comfort device or a belt sensor 
optionally mounted on the other end of the reel shaft. Each of the covers 
has a plurality of plug-in securing elements which are matingly configured 
and aligned with the apertures of the first and second side walls and the 
support members to enable interchangeable and optional utilization of said 
support members and the mechanisms carried thereby on either of the first 
and second side walls of the retractor frame. A molded plastic cover for 
the retractor has first and second belt slots therethrough to accommodate 
belt exit from the retractor regardless of the direction of belt unwinding 
reel rotation. Furthermore, the second cover enclosing the comfort device 
has entry passages on both sides thereof to accommodate optional entry of 
a plunger operated release cable for releasing the comfort device. 
One object, feature and advantage of the invention resides in the provision 
of a plurality of aligned apertures on both side walls of a retractor 
frame and upon a control mechanism support member adapted to abut the 
frame side wall and in the further provision of a cover for enclosing the 
control mechanism and having plug-in securing elements matingly configured 
and aligned with the apertures in the side walls of the frame and the 
support member to enable optional mounting of the support member on either 
of the side walls of the frame. 
Another object, feature and advantage of the invention resides in the 
provision of a support member mounted on one of the side walls of the 
frame for mounting an inertia weight and having first and second apertured 
mounting bosses to enable alternate mounting of a pawl for pivotal 
movement into engagement with oncoming gear teeth carried by the belt reel 
in either of the selected clockwise or counterclockwise direction of belt 
unwinding rotation.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 is a schematic depiction of the seat belt retractor of this 
invention. A frame 10 receives a reel 12 which may be mounted for 
clockwise or counterclockwise rotation as will be discussed further 
hereinafter with reference to FIGS. 2 and 3. The spring 14 may be mounted 
on either side of the frame to bias the reel in the belt windup direction. 
Various mechanisms for controlling the rotation of the reel 12 relative to 
the frame 10 include a spring 14, vehicle sensor 16, belt sensor 18 and 
comfort device 20. 
The vehicle sensor 16 is provided for locking up the reel 12 in response to 
a sensed condition of vehicle deceleration. The vehicle sensor 16 may be 
mounted on either side of the frame 10. The belt sensor 18 may be employed 
to lock up the reel 12 in response to a sensed condition of rapid 
unwinding of belt from the reel. 
The belt sensor 18 is mounted on the opposite side of the frame 10 from the 
vehicle sensor 16 and spring 14 but can also be used without the vehicle 
sensor 16. The comfort device 20 is provided to lock the reel against belt 
windup rotation so that the belt is held at a slackened tension free 
length about the occupant. Either the comfort device 20 or the belt sensor 
18 may be employed on a particular retractor. 
THE FRAME 
Referring to FIGS. 2 and 4, it is seen that the retractor frame 10 includes 
a base wall 24 and laterally spaced apart side walls 26 and 28. The base 
wall 24 has a T-shaped projection 30 which is adapted to fit into a 
receptacle in the pillar of a motor vehicle body, not shown. The base wall 
24 also has an apertured boss 32 for receiving a bolt to attach the base 
wall 24 to the vehicle pillar. The side walls 26 and 28 have aligned 
apertures 36 and 38 for receiving and rotatably mounting reel shaft 40. 
THE REEL 
As best seen in FIGS. 2, 4 and 5, belt reel 12 includes a spool 44 
comprised of a C-shaped metal stamping. A pair of sprockets 46 and 48 are 
attached to the end of the spool 44 by a plurality of stakes 50 which 
extend through aligned slots 52 in the sprockets. The sprockets 46 and 48 
have a plurality of circumferentially spaced sprocket teeth 54 which face 
in the belt unwinding direction of reel rotation. A gear 56 of molded 
plastic has a plurality of projections 55 which extend into mating holes 
57 in the sprocket 48 so that the gear 56 rotates in unison with the reel. 
The sprocket 46 has similarly arranged mating holes 53 which permit 
mounting of gear 56 on sprocket 46 as well as sprocket 48. Gear 56 has 
gear teeth 59 which face in the belt unwinding direction. 
Restraint belt 58 has an end loop 60 which enters the spool 44 and 
encircles the reel shaft 40. The sprockets 46 and 48 have central 
apertures 62 and 64 which receive the reel shaft 40. Gear 56 has a similar 
central aperture 65. The aperture 62 is configured to nonrotatably receive 
a necked down flattened end 66 of the reel shaft 40 so that the reel shaft 
40 rotates in unison with the reel assembly 42. 
Referring to FIGS. 2 and 3 it will be understood that the reel 12 may be 
mounted on the frame 10 as shown in FIG. 2 so that the belt 58 exits the 
retractor off the front side of the reel 12 away from the base wall 24. On 
the other hand, as seen in FIG. 3, the belt reel may be mounted for 
rotation in the opposite direction so that the belt 58 will exit off the 
back side of the reel 12 adjacent to the base wall 24. The arrangement of 
FIG. 3 is desirable in vehicle body arrangements where the belt 58 is to 
be hidden behind a plastic trim panel attached to the body pillar. 
In FIG. 2, the sprocket rotates in the counterclockwise direction and its 
teeth 54 face in the counterclockwise direction. On the other hand, in 
FIG. 3 unwinding the belt 58 from the reel assembly 12 rotates the reel 
assembly in the clockwise direction so that the sprocket teeth 54 face in 
the clockwise direction. 
A lock bar 70 is pivotally mounted on the frame 10 for movement into 
locking engagement with the sprocket teeth 54 to lock the reel 12 against 
belt unwinding rotation so that the length of the belt is fixed and the 
seated occupant restrained thereby. As best seen in FIGS. 2, 3 and 4, the 
frame side walls 26 and 28 have two pairs of aligned lock bar mounting 
apertures which are situated on opposite sides of the reel shaft. The 
first pair of locking apertures includes an aperture 72 in the side wall 
26 and an aperture 74 in the side wall 28. A lug 76 of the lock bar 70 is 
inserted into the aperture 74. An entry slot 78 in the side wall 26 
communicates to the aperture 72 to enable a lug 80 at the other end of the 
lock bar to seat within the aperture 72. The apertures 72 and 74 are 
butterfly-shaped to permit the lock bar 70 to pivot from the disengaged 
position of FIG. 2 to a pivotally raised position in which locking teeth 
82 and 84 of the lock bar 70 engage with the oncoming sprocket teeth 54 of 
the reel 12 to lock the reel against further rotation in the belt 
unwinding direction. 
The second pair of apertures for mounting lock bar 70 include an aperture 
88 in the side wall 26 and aperture 90 in the side wall 28. An entry slot 
92 communicates with the aperture 90. As seen in FIG. 3, the lock bar lugs 
76 and 80 are mounted within the apertures 88 and 90. By the provision of 
first and second pairs of lock bar mounting apertures, it will be 
understood that a single frame 10 may be employed regardless of whether 
the reel 12 is to rotate in the clockwise or counterclockwise directions 
of rotation. 
THE VEHICLE SENSOR AND SPRING 
The vehicle sensor 16 is carried by a support 96 best shown in FIGS. 4 and 
5. The support 96 is an injection molded plastic unit which is generally 
planar in configuration and shaped to overlie either of the side walls 26 
and 28 of the retractor frame 10. Support 96 has an aperture 98 which 
aligns with the reel shaft aperture of the frame side wall and an integral 
bushing 100 which projects through the side wall aperture to provide a 
bushing which insures low friction rotation of the reel shaft 40 relative 
to the retractor frame. 
A cup member 102 is carried at the lower edge of the support 96 and defines 
an upwardly opening depression 104 in which an inertia weight 106 such as 
a stainless steel ball is mounted. The cup member 102 is a separately 
molded plastic element which has opposed facing recesses 103 and 105 which 
capture walls 107 and 108 defining a cutout aperture 101 in support 96 and 
walls 109 and 111 defining a similarly shaped cutout aperture 112 in frame 
side wall 28. Cup member 102 is assembled to the support 96 by seating 
apertures 113 and 115 of the cup member 102 onto mating projections, not 
shown, molded on the support 96. Alternatively, the cup member 102 may be 
molded integrally with the support 96. 
A pawl 110 is pivotally mounted upon the cup member 102 and rests upon the 
inertia weight 106. The pawl 110 has a pawl tooth 114 which is poised 
beneath the gear 56 carried by the reel 12. 
The pivotal mounting of the pawl 110 upon the cup member 102 is provided by 
a pivot pin 118 which projects from one side of the pawl 110 and a similar 
pivot pin 120 which projects from the other side of the pawl 110. The 
pivot pins are pivotally received within a first pair of apertured 
mounting bosses 122 and 124 of the cup member 102. A similar pair of 
apertured mounting bosses 126 and 128 are provided on the other side of 
the cup member 102 for pivotally mounting the pawl 110 in those retractors 
where the reel 12 is to rotate in the opposite direction of rotation from 
that shown in the retractor arrangement depicted in FIGS. 4, 5 and 6. 
Referring again to FIG. 6, it will be understood when the motor vehicle 
experiences a rapid deceleration condition, the momentum of the inertia 
weight 106 will cause the inertia weight 106 to roll up the depression 104 
and thereby pivotally raise the pawl 110 so that its pawl tooth 114 
engages an oncoming tooth 59 of the gear 56. An initial unwinding rotation 
of the reel as the belt 58 restrains the occupant will rotate the gear 
tooth 59 into further engagement with the pawl tooth 114 so that the pawl 
110 is further pivoted and a pad 116 of the pawl 110 will engage with an 
operating tab 136 of the lock bar 70 to pivot the lock bar 70 into locking 
engagement with the sprocket teeth 54 and accordingly lock the reel 
against any further rotation in the belt unwinding direction. The 
operating tab 136 normally rests upon a stop 138 of the cup member 102 to 
poise the lock bar at the precise position of FIG. 6 in readiness for 
actuation by the pawl 110. As best seen in FIG. 4, a spring 133 underlies 
the lug 76 of lock bar 70 and has a leg 135 bearing on an abutment 137 of 
support 96 and a leg 139 bearing upon the operating tab 136. The spring 
133 holds the lock bar 70 poised at its position of FIGS. 5 and 6 engaging 
the stop 138. 
Referring again to FIGS. 4 and 5, it is seen that the support 96 is mounted 
upon the frame side wall 28 by plug-in elements 140 provided on the spring 
cover 142. The spring cover 142 is a molded plastic shaped member which is 
adapted to enclose a spiral spring 14. The spring 14 includes an inner tab 
146 which seats within a slot 148 in the end of the reel shaft 40. Spring 
14 also has an outer tab 152 which seats within a retainer slot 154 in the 
cover 142. The plug-in elements 140 extend through aligned and mating 
apertures 158 in the support 96 and apertures 160 in the frame side wall 
28. The plug-in elements 140 and apertures 158 and 160 are preferably 
provided in a circular pattern symmetrical about the reel shaft 40. The 
plug-in elements 140 are heat staked to provide a permanent connection 
between the spring cover 142 and the frame side wall 28 which captures the 
support 96 therebetween. 
As seen in FIG. 4, the frame side wall 26 has a plurality of aperatures 162 
which have the same shape and spacing and location as the apertures 160 of 
the frame side wall 28. Accordingly, it will be understood that the 
support 96 and spring cover 142 may be optionally installed onto the frame 
side wall 26 in those retractor constructions where such a configuration 
is required or desired. A snap-on molded plastic cover 166 is provided to 
enclose the cup member 102. 
THE COMFORT DEVICE 
The comfort device 20 is best shown in FIGS. 4, 7 and 8. The comfort device 
20 is carried by a support 170 which is an injection molded plastic unit 
similar to the support 96. The support 170 has a central aperture 172 for 
receiving the reel shaft 40 and includes an integral bushing 174 which 
extends into the aperture 36 of the frame side wall 26 to assure low 
friction rotation of the reel shaft 40. Support 170 also has opposed 
facing recesses 175 and 177 which capture walls 179 and 181 defining a 
cutout aperture 180 in frame side wall 26. Furthermore, the support 170 
has a plurality of apertures 176 which mate and align with the apertures 
162 provided in the frame side wall 26 as well as the apertures 160 of the 
frame side wall 28. 
The comfort device 20 includes a spiral cam 182 of molded plastic. The 
spiral cam 182 fits upon the flattened end 66 of the reel shaft 40 and is 
retained by a retainer ring 183 so that the spiral cam 182 rotates in 
unison with the shaft and reel 12. In general, the spiral cam 182 includes 
a plurality of spiral tracks 184 which contain various ramps and cams 
leading to a plurality of ratchet teeth 186 shown in FIG. 7. A follower 
pawl 188 rides within one of the plurality of spiral tracks 184. The 
follower pawl 188 includes a bent wire 190 mounted upon a molded plastic 
base 192 having a central aperture 194 which fits over a pivot pin 196 
integrally molded with the support 170. A coil spring 200 encircles the 
pivot pin 196 and has its end retained in a retention slot 202 on the end 
of the pivot pin 196. The other end of the spring is seated in a retention 
hole 204 of the base 192. The spring 200 functions to urge rotary movement 
of the follower pawl 188 radially inward to the phantom line indicated 
position of FIG. 7 and to also urge tilting movement about fulcrum 206 
provided on the base 192. 
Reference may be had to U.S. Pat. No. 4,002,311 issued Jan. 11, 1977 to 
Robert C. Fisher for a complete explanation of the structure and function 
of the spiral cam 182 and follower pawl 188. In general, a slight 
extension of the belt 58 from the retractor subsequent to having buckled 
the belt about a seated occupant causes the follower pawl 188 to engage 
one of the ratchet teeth 186 so that the follower pawl 188 blocks the 
spiral cam 182 and the reel 12 rotating in unison therewith against 
subsequent rotation in the belt rewinding direction. Accordingly, belt 58 
is held extended at a slackened tension free length about the seat 
occupant. Then if the occupant intentionally unwinds additional belt from 
the reel 12 the ramps and cams of the spiral cam 182 function to disengage 
the follower pawl 188 from the ratchet teeth 186 to enable subsequent 
rewinding of the belt upon the reel. 
The retractor also includes an auxiliary release for the comfort device 
according to the teachings of U.S. Pat. No. 3,973,786 issued to Lloyd W. 
Rogers, Jr. on Aug. 10, 1976. This release mechanism includes a release 
cam 210 which has a central aperture 212 by which the release cam 210 is 
pivotally mounted upon pivot pin 196 integral with the support 170. The 
release cam has a ramp surface 215 which underlies the base 192 of the 
follower pawl 188 oppositely from the fulcrum 206. Accordingly, upon 
pivotal movement of the release cam 210 from its solid line position of 
FIG. 7 to the phantom line position, the ramp surface 215 tilts the cam 
follower pawl 188 against the bias of spring 200 from the solid line 
indicated position of FIG. 5 to the phantom line position so that the 
follower pawl will be disengaged from any of the ratchet teeth 186 engaged 
thereby. The release cam 210 is operated by a cable 214 having an enlarged 
end 216 which is snap retained in an apertured tab 218 of the release cam 
210. 
The cable 214 is enclosed in a sheath 220 which leads to a plunger assembly 
shown in FIG. 8. The plunger assembly includes a housing 224 which is 
mounted on door pillar 222 by a plastic nut 226. A coil compression spring 
228 is captured within the housing 224 and biases a plunger 230 outwardly 
into the path of the vehicle door. When the door is opened, the coil 
compression spring 228 extends the plunger 230 to the extended position of 
FIG. 8 so that the cable 214 attached to the plunger is pulled to effect 
rotation of the release cam 210 from the solid line indicated position of 
FIG. 7 to the phantom line indicated position. 
As best seen in FIGS. 4 and 5, the comfort device 20 is enclosed by a 
molded plastic cover 236. The cover has a plurality of plug-in elements 
238 which project therefrom and are shaped and configured to extend 
through the aligned apertures 176 of the support 170 and apertures 162 of 
the frame side wall 26. Plug-in elements 238 are heat staked to provide a 
permanent retention of the cover 236 to the frame side wall 26 and capture 
the support 170 at its position abutting with the frame side wall 26. As 
best seen in FIG. 7 the cover 236 has bosses 244 and 246 located on 
opposite sides thereof so that the cable 214 and the sheath 220 thereof 
can enter the cover 236 from either direction. Accordingly the comfort 
device 20 can be modified to enable either clockwise or counterclockwise 
belt unwinding rotation by merely providing a different spiral cam member 
182 and release cam 210. 
THE BELT SENSOR 
Referring to FIGS. 4, 9 and 10, it is seen that the belt sensor 18 of the 
retractor may be employed in place of the comfort device 20. The belt 
sensor 18 includes an annular clutch 250 having a plurality of teeth 252 
formed on the inner surface thereof. A molded plastic extension 254 fits 
over the flattened end 66 of the reel shaft 40 and is retained thereon by 
the retainer ring 183. The extension 254 rotates in unison with the reel 
shaft 40 but permits the clutch 250 to rotate independently or remain at 
rest during rotation of the shaft. Extension 254 has an integrally molded 
pin 256 which pivotally mounts a flyweight 260. A coil tension spring 262 
seats on a pin 264 of the extension 254 and is connected to the flyweight 
260 so that the flyweight 260 is normally retained in a position of FIG. 
10 during belt winding and unwinding. A retainer 268 fits over the shaft 
40 and the pins 256 and 264 as well as an additional pin 270. Heat staking 
of the pins provides a permanent attachment so that the flyweight 260 is 
retained upon pivot pin 256. 
As best seen by referring to FIG. 9, the support 170 is interposed between 
the frame side wall 26 and the cover 236 so that its integral bushing 174 
assures low friction rotation of the reel shaft 40. The plug-in elements 
238 of the cover 236 retain both cover 236 and the support 170 in place. 
In the event that a rapid vehicle deceleration results in a forward 
movement of the occupant relative to the seat, the rapid rate of unwinding 
of the belt 58 from the retractor will cause the flyweight 260 to pivot 
about pin 256 so that a tooth 274 of the flyweight 260 will engage with 
one of the plurality of teeth 252 on the clutch 250. Resulting rotary 
movement of the clutch 250 in the belt unwinding direction of rotation 
causes a ramp face 276 on a depending arm 278 molded integrally with the 
clutch to engage with the lock bar 70 and thereby lift the lock bar into 
locking engagement with one of the oncoming sprocket teeth 54. 
FIG. 11 is a view similar to FIG. 10 but showing the belt sensor mechanism 
applied to a seat belt retractor in which the reel is rotating in the 
opposite direction because the belt exits off the back side of the reel 12 
adjacent to the frame base wall 24. 
THE COVER 
A cover 280 is provided for enclosing the retractor. The cover 280 is of 
injection molded plastic and is snap retained upon the frame 10. As best 
seen in FIG. 4 the frame side wall 26 has a pair of projections 282 which 
extend into mating receptacles 284 provided in the cover 280. Likewise the 
frame side wall 28 has a pair of projections 286 which extend into 
receptacles 288 provided in the cover 280. At the upper wall of the cover 
280, a pair of upturned tabs 292 snap into a pair of apertures 294 in the 
frame base wall 24 as best shown in FIGS. 5 and 6. Similar downturned 
projections 296 at the lower wall of the cover 280 snap fit into apertures 
298 provided in the frame base wall 24 of the frame. 
As best seen in FIGS. 2, 3 and 4, the cover 280 has a belt exit slot 300 
through which the belt exits in those retractor arrangements where the 
belt exits the reel on the front side away from the base wall 24. The 
cover 280 also has a belt exit slot 302 for exit of the belt 58 in those 
retractor arrangements such as shown in FIG. 3 where the belt exits the 
reel at the back side thereof adjacent to the base wall 24. 
OPTIONAL AND INTERCHANGEABLE ASSEMBLY ARRANGEMENTS 
FIGS. 13 through 22 show various ways in which the modules may be 
interchangeably and optionally assembled upon the standard retractor frame 
to provide various combinations of desired features, arrangements and 
package sizes. 
FIG. 13 shows the retractor arrangement of FIGS. 5, 6 and 7 where the 
spring and vehicle sensor are mounted on the right hand side of the frame 
via a support 96. The comfort device is mounted on the left hand side of 
the retractor via a support 170. FIG. 14 shows a retractor which also has 
the spring, vehicle sensor, and comfort features of the retractor of FIG. 
13 except that the retractor is assembled with the spring and vehicle 
sensor and their support 96 mounted on the left hand side of the frame 10 
while the comfort device is mounted on the right hand side of the frame 10 
by its support 170. This interchangeable mounting of the supports 96 and 
170 and their respective covers 142 and 236 on either of the frame side 
walls 28 and 26 is enabled by the mating and alignment of the side wall 
apertures 160 and 162 with the support apertures 158 and 176 and the 
plug-in securing elements 140 and 238 of the covers 142 and 236. 
Furthermore, the dimension of the cutout aperture 112 in frame side wall 
28 defined by walls 109 and 111 is the same as the cutout aperture 180 in 
frame side wall 26 defined by 179 and 181 to further accommodate the 
mounting of either support on either side wall. 
Referring to FIG. 15, the retractor has a spring and vehicle sensor mounted 
on the right hand side of the frame by the support 96. The belt sensor is 
mounted on the left hand side of the frame by a support 170 or, 
optionally, by a support 96. FIG. 16 is oppositely arranged with the 
spring and vehicle sensor on the left hand side and the belt sensor 
arranged on the right hand side. 
FIGS. 17 and 18 show the right and left hand arrangements of a retractor 
with the spring and the vehicle sensor mounted by a support 96. Even 
though the opposite side of the retractor carries neither the belt sensor 
or comfort device, a support 96 or 170 is installed to provide a bearing 
for the reel shaft 40 and a cover 142 or 236 is installed to retain the 
support and to also cooperate with the support to close any openings in 
the frame. 
FIGS. 19 and 20 show yet another arrangement of the retractor in which the 
spring and vehicle sensor are employed but are mounted on opposite sides 
of the retractor frame. The vehicle sensor may be mounted on either the 
left hand side or right hand side of the frame via a support 96. The 
spring module is mounted on either the right hand or left hand side of the 
retractor by either a support 96 or a support 170 and the spring cover 
142. 
FIGS. 21 and 22 show yet another possible retractor arrangement where the 
spring is mounted on either the right or left hand side of the retractor 
and the belt sensor module is mounted on the opposite side of the 
retractor frame. Again, the spring module can be mounted by either a 
support 96 or support 170 in conjunction with a spring cover 142 while the 
belt sensor is mounted by its support 170. 
In addition to the various optional and interchangeable assembly 
arrangements shown in FIGS. 13-22, it will be understood that each of the 
arrangements disclosed therein may have the belt exiting the retractor 
from either the front side of the reel as shown in FIG. 2 or the back side 
of the reel as shown in FIG. 3. This optional choice of belt exit from the 
reel is enabled by the lock bar 70 being optionally mounted as shown in 
FIGS. 2 or 3 for locking engagement with sprocket teeth oncoming from 
either the clockwise or counterclockwise belt unwinding direction. 
Furthermore, the first and second pairs of mounting bosses on the cup 
member 102 are optionally used for pivotally mounting the pawl 110 for 
engagement with the teeth 59 of gear 56 oncoming from either direction. 
It will be understood that the various components shown in FIG. 4 are 
standardized for interchangeable and optional use in any of the retractor 
arrangements described herein. Nonetheless a few component parts of the 
retractor must be tooled to provide both right and left hand parts. These 
component parts include the gear 56, the lock bar 70, the spiral cam 182, 
the release cam 210, the clutch 250 and extension 254. 
Thus, the seat belt retractor of this invention provides a minimum number 
of component parts which may be interchangeably and optionally assembled 
upon a standard frame in multiple variations to provide a combination of 
desired features, such as spring windup, belt sensitive lockup, vehicle 
sensitive lockup and comfort enhancing tension relief. 
DESCRIPTION OF AN ALTERNATE EMBODIMENT 
FIGS. 23, 24, 25 and 26 disclose an alternate embodiment of the invention 
in which some of the various components described hereinbefore with 
respect to FIGS. 1 through 22 have alternate details of construction and 
assembly. In order to simplify the comparison and understanding of these 
differences, like reference numerals are employed for like construction 
features of the alternate embodiment and the following description will 
generally be directed to the differences and will employ additional 
reference numerals as appropriate to describe these differences. 
THE FRAME 
As best seen in FIG. 23, the side walls 26 and 28 of retractor frame 10 
respectively have a plurality of lightening apertures 320 and 322 which 
serve to lighten the retractor frame 10. In addition, the side walls 26 
and 28 respectively have tabs 324 and 326 projecting upwardly from the top 
thereof. Furthermore, the side walls 26 and 28 respectively have aligned 
apertures 328 and 330. Other features of the retractor frame 10 are 
essentially identical with the embodiment of FIGS. 1-22 and accordingly 
are identified by like numerals. 
THE REEL 
The sprockets 46 and 48 of the reel 12 respectively have a plurality of 
apertures 336 and 338 which lighten the weight of the reel. The end loop 
60 enters the spool 44 and a retaining pin 340 is inserted into the end 
loop 60 to effect the anchorage of the restraint belt 58 to the spool 44. 
Flanged bushings 339 and 341, best seen in FIGS. 23 and 26, are installed 
in the aligned apertures 36 and 38 of frame side walls 26 and 28 to 
journal the reel shaft 40 for rotation. 
THE VEHICLE SENSOR AND SPRING 
The vehicle sensor 16 is carried by the support 96 and includes a mushroom 
shaped inertia weight 342 which seats in cup member 102 and operates the 
pawl 110. The support 96 has a pair of apertures 158 which align with a 
pair of apertures 160 in the frame side wall 28. The support 96 is mounted 
on the frame side wall by a pair of plug-in elements 140 provided on the 
spring cover 142. The spring cover 142 also has an integral flange 344 
along the sides and top thereof which project over and surround the outer 
edge of the support 96 and the side wall 28. This flange 344 has a 
rectangular opening 346 which is installed over the tab 326 of the frame 
side wall 28 so that the support 96 is captured between the spring cover 
142 and the frame side wall 28. The plug-in elements 140 are heat staked 
to provide a permanent connection between the spring cover 142 and the 
frame side wall 28 with the support 96 captured therebetween. 
THE COMFORT DEVICE AND BELT SENSOR 
The comfort device is carried by support 170 which has integral bosses 350 
and 352 for receiving and mounting the sheath 220 of the cable 214. The 
end of the cable 214 carries a transverse pin 354 which slides into a 
cylindrical boss 356 of the release cam 210. The support 170 has a pair of 
apertures 176 which align with a pair of apertures 162 of the frame side 
wall 26. Cover 236 has a pair of plug-in elements 238 which extend through 
the aligned apertures 176 of the support 170 and 162 of the frame side 
wall 26. The plug-in elements 238 are heat staked to provide a permanent 
attachment of the cover 236 on the frame side wall 26 and thereby capture 
the support 170 in abutting relationship with the frame side wall 26. 
The cover 236 has a flange 358 which projects over and surrounds edges of 
the support 170 and the frame side wall 26 to thereby capture the support 
170 between the cover 236 and the frame side wall 26 as best seen in FIGS. 
24 and 26. The top wall of the flange 358 has a rectangular opening 360 
which fits over the tab 324 of side wall 26 to retain the cover 236 upon 
the side wall 28. 
THE COVER 
The cover 280 for enclosing the retractor covers only the lower half of the 
retractor whereas the cover 280 shown hereinbefore with respect to the 
embodiment of FIGS. 1-22 covered the top half of the retractor as well. As 
best seen in FIG. 23, the cover 280 has a pair of downturned projections 
296 at its lower end thereof which snap-fit into apertures 298 in the 
frame base wall 24. Furthermore, as best seen in FIG. 23, the cover 280 
has a pair of ears 360 which have aligned apertures 362. A molded plastic 
retaining pin 364 is provided for retaining the cover 280 on the 
retractor. As best seen in FIGS. 23 and 24, the retaining pin 364 extends 
through aperture 366 of cover 236, the aperture 368 of the support 170, 
the aperture 328 of the frame side wall 26, the aligned apertures 362 of 
the ears 360, the aperture 330 of frame side wall 28, the aperture 370 of 
the support 96 and aperture 372 of the cover 142. These apertures 336, 
368, 328, 362, 330, 370 and 372 are all aligned with one another to permit 
the installation of the retaining pin 364 therethrough. A retainer 376 is 
pushed onto the end of the pin 364 to prevent its removal. 
OPTIONAL AND INTERCHANGEABLE ASSEMBLY ARRANGEMENTS 
The embodiment of FIGS. 23-26 may be interchangeably and optionally 
assembled upon a standard retractor frame to provide the same various 
combinations of desired features, arrangements and package sizes, as 
schematically represented in FIGS. 13 through 22. 
The covers 142 and 236 and the supports 96 and 170 are adapted for mounting 
upon either of the frame side walls 26 and 28 because the mounting 
features of the frame side walls, including the tabs 324 and 326, the 
apertures 160 and 162, and apertures 112 and 180 are matingly aligned with 
the various mounting elements of the supports and covers. For example, 
plug-in elements 140 and rectangular slot 346 of cover 142 are engageable 
with either the apertures 160 and tab 326 of side wall 28 or with the 
apertures 162 and tab 324 of side wall 26. Furthermore, as best seen in 
FIG. 23, the shape of the side walls 26 and 28 is symmetrical about the 
centerline of the side walls so that the flange 344 of cover 142 will fit 
over and surround the edges of either of the frame side walls 26 or 28. 
Furthermore, as best seen in FIG. 23, the cover 142 has an aperture 380 
and the support 96 has an aligned aperture 382 which are adapted to align 
with one another and with the aperture 328 of the frame side wall 26 in 
those retractor configurations where the support 96 and cover 142 are 
installed upon the frame side wall 26. Likewise, the support 170 has an 
aperture 386 and the cover 236 has an aperture 388 which aiign with one 
another and with the aperture 330 of the frame side wall 28 in those 
retractor configurations where the support 170 and cover 232 are to be 
mounted upon the frame side wall 28. Accordingly, whichever retractor 
configuration is used, aligned and mated apertures are provided to admit 
the plastic retaining pin 364 for retaining the cover 280 upon the 
retractor. 
Thus, upon consideration of the alternate embodiment of FIGS. 23-26, it 
will be understood that the optional and interchangeable assembly of the 
retractor is enabled by the cooperation of various mating and aligned 
mounting features and elements which interact between the frame side 
walls, the support members, the covers, and control mechanisms to enable 
optional and interchangeable utilization of the support members and 
control mechanisms on either of the side walls of the retractor frame. 
Furthermore, and more particularly, these cooperating mounting features 
and mounting elements can include various combinations of apertures 
cooperating with mounting elements, frame tabs cooperating with apertures, 
and also the configuration of the outline shapes of the frame side walls 
and supports to be captured by flanges provided on the covers. 
Thus, while the invention is described herein with respect to the disclosed 
embodiments of the invention, the invention is not limited to the 
particular cooperating mounting features and elements but rather only to 
thee extent set forth in the appended claims. 
DESCRIPTION OF ANOTHER ALTERNATE EMBODIMENT 
Referring to FIG. 27, there is shown another optional and interchangeable 
arrangement of the invention. In particular, the retractor has both a 
comfort device and a belt sensor as well as winding spring and vehicle 
sensor which are assembled in the arrangement shown in FIG. 28. The 
comfort mechanism and belt sensor may be mounted on either side wall of 
the retractor frame. The retractor of FIG. 27 is constructed of components 
which are generally the same as the components shown in FIG. 4. The frame 
10, the reel 12, support 96, cover 142 and spring 14 are identical with 
FIG. 4 and are designated by like numerals. 
The neck down flattened end 66 of the reel shaft 40 is extended in its 
length so that both the belt sensor 18 and the comfort device 20 can be 
fitted onto the end of the shaft. More particularly, the annular clutch 
250, extension 254 and retainer 268 are first installed upon the flattened 
end 66 of the shaft. Then the spiral cam 182 of the comfort device 20 is 
fitted onto the shaft. The support 170 is similar to that of FIGS. 1-22 
except that the pivot pin 196 thereof has an extended length to mount the 
follower pawl 188 in proper operating alignment with respect to the spiral 
cam 182. Furthermore, the release cam 20 has its ramp surface 215 extended 
sufficiently to properly align with the follower pawl 188. Furthermore, 
the cover 236 has an extended depth as necessary to cover the extended 
length of the reel shaft and the belt sensor 18 and comfort device 20. 
FIGS. 28 and 29 provide a schematic representation of the embodiment of 
FIG. 27 and in particular show that the belt, sensor and comfort device 
can be mounted on either side wall of the retractor frame to provide the 
desired retractor package.