Note: Descriptions are shown in the official language in which they were submitted.
1045606
This invention relates to a seat belt retractor and
more particularly to an inertia retractor in which the seat
belt will automatically be locked against extension when the
vehicle is impacted to cause the occupant to move relative
to the vehicle with an acceleration above a predetermined
acceleration.
More specifically, when an accident occurs, the oc-
cupant's inertia may cause him to move relative to the vehicle
at a rate beyond which is deemed safe, and his seat belt re-
tractor automatically locks against further extension of theseat belt as would allow him to move to the maximum extent
of the seat belt. Locking retractors of the inertia kind have
been proposed in the past but have not been used as standard
equipment in automobiles and have had various shortcomings.
For example, some inertia retractors will only operate in a
given plane, usually because they have a gravity operated
- device th~rein, and ar~ not ~eliable when the vehicle is on
an incline or the retractor is mounted at an unusual angle
to the horizontal in the vehicle. Still other retractors have
been found to be not sufficiently sensitive for use in auto-
mobiles as they will not lock unless a relatively high accel-
; eration is applied and the seat belt is extended consider2bly.
Preferably, for automobiles the inertia retractor should be
sensitive to a one-half G acceleration with a belt extension
of one inch a ffer the belt has been extended three-fourths
; of its total length about the occupant.
On the other hand, other inertia retractors will lock
while the occupant is pulling the belt from the retractor reel
to secure it about himsel~ when pulling rapidly with over a
one-half G acceleration. Such locking may be annoying and a
source of consternation as to a proper method of withdrawal
of the belt for strapping about oneself.
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Other retractors are too complex in operation and
are constructed of many and expensive parts making them too
costly to be commercially feasible. Finally, with increas-
ingly strict government regulations to be met, the inertia
retractor must be very reliable and operate without fail for
large numbers of operations even when subjected to very ad-
verse conditions of snow, water, dust, heat or cold.
Often inertia retractors of the prior art were
equipped with a manual operator which had to be manipulated
to release the locked condition to allow the seat belt to
rewind on the retractor reel. Such manual operators restrict
the retractors from being placed to the side and rearwardly
of the seated occupant or from being totally inaccessible to
the seated occupant. The occupant must be able to get him-
self out a~fter a crash. While release cables or lever systems
could be designed to allow placement of the retractor at
various locations, these add to the cost, require space, and
may malfunction. Therefore, it is preferred that the re-
; tractor be operated with simple manipulations of the seat
belt itself between its various locked and released condi-
tions, particularly ~o release the belt for retraction onto
the retractor reel.
According to the present~inyention thexe is pro~ide a
seat belt retractor which has a support means with reel me~ns
rotatably mounted on the support to rotate about a longi-
tudinal axis and means for mounting a belt on the reel means
~or unwinding therefrom to be positioned about an occupant.
Biasing means bias the reel means to rewind the belt on the
reel means, and a pair of ratchet wheels is mounted on
opposite siaes of the reel means and is turnable therewith.
Pawl means, which include a pair of pawls pivotally moulted
on the support for movement into engagement with the ratchet
jab/' ~ - 2 -
., ,
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wheels, is provided to block unwinding of the belt from the
reel means. Inertia operable means pivot the pawls into
blocking engagement with the ratchet wheels at time of an
accident. Tension relieving means is operable by manipul-
ation of the belt and include a member coupled to the reel
means and a detent means engageable with the member to hold
the xeel means against turning in the retracting direction
and relieving the extended belt from the tension of the
biasing means. Means which include a cam means is operable
upon a subsequent protraction of the belt for disabling the
detent means and allowing the reel means to rewind the
protracted belt.
The retractor of the present invention, in one
embodiment thereof, may be rendered tensionless in the sense
that the force of the retracting reel spring pulling the seat
belt taut about the occupant will not be felt by the occùpant
! when the seat belt is WQrn. Also, the retractor of the
present invention may be constructed to allow the passenger
freedom of movements, when such movements slowly extend the
seat belt from the retractor, e~g., when leaning toward a
cigarette lighter. Preferably, the inertia seat belt re-
tractor will operate to satisfy these varying and seemingly
conflicting requirements and will not lock should the
occupant give a
jab/ - 2a -
z~
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sharp pull on the belt when extending the belt about himself
while loc~ing upon a sharp pull due to inertia of the wearer's
body at the time of an accident. Thus, a seat belt retractor
of this kind is carefully programmed and timed to operate in
various manners dependent upon the position of the belt and
the rate and direction of belt travel.
Accordingly, a general object of the present inven-
tion is to provide a new and improved inertia seat belt re-
tractor of the foregoing kind.
Other objects and advantages of the invention will ~e-
come apparent from the following detailed description taken
in connection with the accompanying drawings in which:
FIGURE 1 is a longitudinal sectional view taken through
a retractor embodying the features of the invention;
FIGURE 2 is an elevational view of the retractor shown
in FIGURE l;
FIGURB 3 is an exploded perspective view of-the re--
tractor illustra~ed in FIGURE 1;
FIGURE 4 is a partial sectional view taken substantially
along the line 4-4 of FIGURE l;
FIGURE 5 is a view taken substantially along the line
5-5 of FIGURE l;
FIGURE 6 is a view similar to FIGU~E 5 but with the
pawl engaged;
FIGURE 7 is an elevational view of an inertia wheel
used in the retractor of FIGURE l;
FIGURE 8 is a view which illustrates a pawl and inertia
wheel in a non-locking position;
FIGURE 9 is a view which illustrates the pawl and
inertia wheel in an operative position holding a seat ~elt
tensionless;
FIGURES 10 and 11 is a view which illustrate another
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embodiment o~ the invention with means to prevent reel locking
when the belt is fully retracted;
FIGURES 12, 13 and 19 is a view which illustrate an
inertia means used in the retractor shown in FIGURE 10;
FIGURES 14 and 15 are views which illustrate a hold-
out means used in the retractor of FIGURE 10;
~IGURE 16 is a view which illustrates another embodi-
m~nt of the hold-out means;
FIGURES 17 and 18 are views which illustrate a braking
disc; and
FIGURE 19 is an exploded view of the embodiment of
the invention illustrated in FIGURES 10 and 11.
~erein, the invention is embodied in a seat belt re-
tractor 11 having a support means 13 in the form of a U-shaped
casing or frame in which is rotatably mounted a reel means 15
. .
including a reel 16 on which i5 wound a se2t belt 17. The
seat belt 17 is wound on ~he rael 16 under the urging of a
biasing means 19 in the form of a spring to retract an extended
portion 21 of the seat belt extending outwardly from the reel
16. After the belt is extended about the occupant, the reel
16 will be automatically locked to stop further turning of
the reel 16 and further extension of the seat belt 17 when
the seat belt is accelerated outwardly from the reel means
~` above a p~edetermined acceleration, for example, one-half G,
an inertia means 23 operates a pawl means 25, comprising at
least one pawl 26, to shift from a release position to an
operative position in blocking or lockins engagement with a
: tooth or shoulder 29 on a ratchet means 31 ~.rhich includes at
least one ratchet wheel 32. Preferably two ratchet wheels 32
. 30 and a pair of cooperating pawls 26 are provided.
In the first described embodiment of the invention,
: the occupant may be relieved of thc tension and the pull of
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the belt about his body, i.e., the belt will be tensionless
and merely resting on his body, by following a programmed
seguence of events, namely allowing a slight retraction of
the belt, which occurs naturally when the occupant fastens
the belt or brings it into rastening position, and then exerting
a sharp snap or acceleration of the belt. This se~uence, as
will be explained in greater detail, causes the inertia means
23 to operate the pawls 26 to a position holding the reel 16
against retracting. This relieves the tension in the extended
belt portion as would retract the belt tautly against the oc-
cupant, making him uncomfortable. ~lthough the ~eat belt 17
is then tensionless, it remains operative to restrain the oc-
cupant. As will be explained in greater detail the occupant
may move slowly to cause the belt to be extended even when
the belt has been placed in this tensionless state.
On the other hand, should the belted occupant exper-
ience a sudden acceleration relative to the vehicle as under
a sudden impact during an accident, the occupant's body will
exert a sharpjerk on the belt in the unwind direction but any
substantial belt unwinding is prevented by pawls 26 abutting
tee~h 29 on the ratchet wheels 32 and holding the reel 16
against turning. When the seat belt is tensionless and the
occupant desires to remove the seat belt 17 and to cause it
to retract autom~tically, the occupant releases the belt
fastening means, a buckle, and exerts a slight pull on the
seat belt 17 causing the inertia means 23 to release the pawls
26 to shift to the non-blocking position. Then, upon release
of the belt by the occupant, the spring means 1~ turns the
reel 16 and rewinds the extended seat belt portion 21 into
the retractor 11. Thus, it will be seen that the belt may
be readily extended, held tensionless about the body, e~tended
with slow movements, loc~ed with fast movements, and readily
_5_
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released for rewinding.
If the seat belt is not placed in the tensionless
state but rather is tensioned about the occupant, a sudden
extension of the belt 17 beyond a predetermined rate also
causes the inertia means 23 to shift the pawls 26 to abut
teeth 29 on the ratchet wheels 32 and lock the reel against-
further extension. If the belt is in its tensioned state
about the occupant who then releases the belt for retraction,
the reel biasing means 19 is operative to rewind the belt to
its fully retracted condition without an additional operation
of the inertia means 23 as is necessary when the belt is in
the tensionless state.
In accordance with another important aspect of the
invention, the pawls 26 are structurally related to the iner-
tia means 23 and to the ratchet teeth 29 and timed to operate
~- with one another to assure that teeth engaging noses 35 of
the pawls 26 will b~ closed, that is, positioned inwardly of
and between adjacent teeth on each ratchet wheel 32 to abut
against ratchet teeth turning into the pawl noses 35 thereby
blocking further reel turning and belt extension. The rota-
-~ tional and spatial relationships, as will be explained in
detail, are such that the pawl noses 35 cannot strike the tops
of the ratchet teeth hut must move radially inward of the tops
of teeth to guiding surfaces 37 extending between and separating
adjacent teeth. With the pawl noses radially inward and ad-
; jacent or touching the guiding surfaces 37 continued rotation
~f the teeth 29 in the belt-extending direction abuts base
portions 39 of the teeth against the pawl noses 35. Thus,
the pawls are timed and are closed to prevent their hitting
the radially outer ends of the teeth and shearing them, as
might occur, when a large force and a fast extending accel
eration of the seat belt occurs during an accident by throwing
104S6(~6
the occupant's body with a large force against the seat belt
17.
In accordance with another embodiment of the inven-
tion, the inertia means 23 may be prevented from operating
and blocking a turning of the reel 16 during an initial fast
unwinding of the belt. That is, if the occupant should sudden-
ly accelerate a fully retracted belt with an acceleration be-
yond the predetermined rate when extending the belt to a
buckling position, a means 40, as will be explained in connec-
tion with FIGURES 10 and 11, prevents operation of the inertiameans 23 to lock the belt reel as the seated occupant may
resent such a stopping of the belt extension. Thus, the oc-
cupant may reach for the belt and initially extend the belt
with a rapid motion which would, without the means 40, cause
the inerLia means 23 to lock the belt during its initial ex-
tension to a position about the occupant. As will be explained
in greater detail, the illustrated hold-out means 40 is not
effective to prevent locking of the reels when the extended
belt receives a slight retraction as will occur during a
buckling or securing of the belt about the occupant. There-
fore, in the event of a subsequent sudden acceleration of the
occupant's body beyond the predetermined rate, the inertia
means 23 would cause a locking of the retractor agains~ belt
extension to its maximum length. Also, as will be explained
in detail, the preferred hold-out means 40 will be overcome
with a very high acceleration as may occur with an accident,
e.g., two G's or more.
Referring now in greater detail to the various elements
of the retractor 11, the support means 13 comprises a gener-
ally U-shaped casing having a bottom wall or base 41 al~d up-
standing parallel side walls 42 and ~3 inte~xal therewit'l along
lower edges 45 of the side wa]ls. The side walls 42 and 4~
_ q_
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have respective outer surfaces 54 and inner surfaces 56.
The reel means 15 includes a spindle 49 which spans these side
walls and is journaled in apertures 47 therein. The spindle
49 is held against axial movement as by a threaded nut ~0
thereon (as best seen in FIGURE 1) abutted against the out
wardly facing sur~ace 54 of the side wall 42 and a nut 51
threaded on the opposite end of the spindle and disposed adja-
cent the outer surface 54 of the side wall 43. In this manner,
the spindle is journaled for rotation be.ween the side walls
42 and 43 about an axis generally horizontal, as viewed herein,
and parallel to the base 41. As will be explained, the re-
tractor 11 may be disposed in various planes and will still
operate successfully.
The reel 16 for winding the seat belt 17 is carried
by the spindle 49 and is fixed thereto to rotate with the
spindle. The reel 16 comprises a generally C-shaped cross
- section cylindrical reel hu~ 57 having a longitudinally ex-
tending slotted opening 59 to receive looped end 61 of the
belt for fastening to the spindle 49~ Th~ interior of the
2Q generally circular hub is spaced from the spindle 49 to
accommodate the thickness of web of the seat belt 17. In
this instance, a pair of ratchet wheels 32 are fixed to oppo-
site ends of the reel hub 57 and provide parallel guide flanges
for guiding the longitudinally extending edges 63 of the seat
belt to wind neatly on the hub when the belt is retracted.
To assure that the hub 57 and the ratchet wheels 32 move with
the spindle 49, the spindle 49 may be keyed to the ratchet
wheels by having a hexagonal cross section for insertion into
a hexagonally shaped opening 65 (FIGUR~ 3) in each of the
ratchet wheels 32.
The reel 16 is biased to wind the seat b~lt in the
counterclockwise direction, as seen in FIGUR~ 3 by the biasin~
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means 19 which is in the form o~ a spiral spring 70 which
has an inner small end 71 fastened to an end of the spindle
as by a fastener 73, as seen in FIGURE 1. The opposite large
end of the spiral spring is connected by a hook end 74 to a pin
75 projecting inwardly from the inner surface 56 of the side
wall 43 to which the pin is fastened. Thus, the spring urges
the spindle 49 to turn counterclockwise as viewed in FIGURE 3
to wrap the belt 17 on the reel hub with the spindle turning
within the apertures 47 in the side walls 42 and 43.
The ratchet wheels 32 may be in various configurations
as may the teeth 2g which are sometimes referred to as shoul-
ders. Preferably, the teeth 29 are spaced equally and cir-
cumferentially about the rotational axis of the reel 16 and
axe separated by elongated slide surfaces 37 which undersides
5 152 of the pawl noses 35 may abut and slide along until abut-
ting an ~pstanding radially outwardly extending tooth 29.
! In this irstance, t~e slide surfaces 37 are generally flat
and planar, althouyh they may be arcuate, and separate eight
ratchet teeth.
To distribute the forces equally between the ratchet
wheels 32, the pawl means 25 is provided with a pair of pawls
26 each of which extends outwardly and upwardly, in this in-
stance, lrom a common connecting flat bar 76 of the pawl rneans.
At opposite ends of the connecting bar 76, a pair of pivot
lugs 77 project outwardly and into trianguiar shaped apertures
79 in the respective side walls 42 and 43. More specifically,
th-~ lugs 77 project outwardly from vertically extending end
walls 81 of the connecting bar with the end walls 81 posi-
tioned adjacent the inner surfaces 56 of the respecti~e side
walls ~2 and 43 to hold the pawls 26 against longitudinal
movement and thereby from misalignment with the-ratchet
~heels 32. _ 9_
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As best seen in FIGURES 4, 5 and 6, it is preferred
that the pawls 26 be biased to a non-blocking or non-locking
position by a biasing spring 83 having an upper end secured to
a hook 84 extending upwardly and rearwardly from the connecting
bar 76. An opposite lower end of the spring 83 is secured
to a pin 85 fastened to the side wall 42. The spring 83 is
a contractile spring and biases a lower rounded end 89 on each
pivot lug 77 to abut a lower rounded corner 91 at the bottom
of the respective aperture 79. The rotational movement of
the pawls 26 is limited to the angular relationship between
the inclined side walls of the triangular apertures 79.
Integral with the cross bar 76 of the pawl means is a pawl
actuating finger 93 which is connected at one end thereof to
the cross bar 76. The actuating finger 93 has a free end 95
which projects toward an inertia wheel 100 to be actuated there-
- by, as will be described.
In accordance with the present invention ! the inertia
means 23 comprises an inertia member in the form of inertia
wheel 100 which is mounted for both longitudinal and rotational
2Q movement with respect to the reel 16 and the spindle 49. ~he
illustrated inertia wheel is a generally bell-shaped member
.and is made of a dense material to provide the desired mass
which when accelerated at the predetermined rate overcomes
frictional resistances and a spring force from an inertia
wheel spring 102, as will be explained in greater detail, to
pivot the pawl means against the force of the spring 83. The
inertia wheel generally has an outer projecting flange 155
which is annular and projects toward an adjacent one of the
ratchet wheels 32. A generally annular wall 103 extends
radially between the laterally projecting flange 155 and has
an inner portion connected by a series of spokes 105, as best
seen in FIGURE 7, to an inner circular hub 107 in which is
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mounted a bearing 109. In this instance, the bearing 109
is a plastic sleeve forced into the hub 107. The bearing 10
has a central aperture 111 which encircles a smooth cyli.n-
drical surface 113 of the spindle 49, as best seen in FIGURE
3, for freely turning relative thereto in either a clockwise
or counterclockwise direction.
For the purpose of rotating the inertia wheel 100
and sliding it longitudinally relative to the reel means 15,
the inertia wheel 100 is coupled to the reel means 15 by a
cam means 114 which includes cam grooves 115 formed in each
of three extensions 117 of tne spool hub 57. Each of the
three extensions is generally curved arcuately about the
axis of ro~ation of the spindle 49 and is spaced from the
spindle 49. The extensions 117 project through three spaced
openings in the ratchet wheel 32 adjacent the inertia wheel
100. In a similar manner, three extensions of the reel hub
1 57 project into the other ratchet wheel 32 to prevent rela-
tive movement between the ratchet wheels 32 and the reel hub 57.
To cause both a rotational and longitudinal movement
of the inertia wheel 100, the cam grooves 115 are formed with
. curved walls 119 which are inclined to the longitudinal axis
and also extend in an arcuate direction for a limited number
of degrees. For example, the cam grooves may be inclined
between 30 and 45 to the axis of rotation. The cam grooves
have open outer ends to receive therein the spokes 105 of the
inertia wheel 100. When three of the six spokes 105 are in-
serted into the three cam grooves 115, the remaining three
spokes 105 are each positioned in a respective space 121
between adjacent axial extending walls 123 of adjacent exten-
sions 117 As will be explained, these other spokes 105
in the spaces 121 will abut the walls 123 to limit the rota-
tional mov~ment of the inertia wheel relative to the extensions
I I _
~04~606
and as a result term.inate the thrust from the cam surfaces
forcing the inertia wheel outwardly from the adjacent ratchet
wheel.
The cam wheel 100 is urged to a position closely
adjacent the ratchet wheel 32 to position its spokes 105 in
abutting engagement with bottom end walls 127 of the cam grooves`
115 by the spring means 102 which, in this instance, is in the
form of a leaf spring body 131 having flexed spring legs 133.
There are three spring legs 133, in this instance, which pro-
ject toward the inertia wheel 100 and act through a brakingmeans in the form of a bra~e disk 135 which engages the annular
- wall 103 of the inertia member 100. The legs 133 are flexed
so that the inertia member is urged in this instance to the
right as viewed in FIGURE 3 to a position adjacent the ratchet
wheel 32. This acts to stabilize the inertia wheel in a posi-
tion perpendicular to the axis of the spindle 49. The spring
member 131 is provided with a central aperture 137 for sur-
rounding the cylindrical surface 113 of the spindle 49.
To prevent rotation of the spring body 131 with turning
-of the inertia wheel 100, the spring body is formed with an
: anchor leg 139 with an offset end 141 seated within a notch
143 in the stationary casing side wall 42.
The braking disk 135 functions to dampen the oscilla-
tory movement of the inertia wheel 100 and to prevent any
bounce thereof as might cause a misoperation of the retractor.
The brake disk 135 also serves to apply a retarding force to
the inertia wheel to assist in its being retrograded relative
to the reel extension and in this manner acts with wheel's
inertia. ~ence, the retarding force of the braking disk on
the inertia wheel may be thought of as a "false" inertia or
"pseudo-inertia". The illustrated braking disk may be made
of a plastic material in fricti.onal contact with the annular
-la- .
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wall 103 of the inertia member 100. The illustrated braking
disk 135 is formed with three radially extending slots 143,
each receiving therein a respective spring leg 133 which
acts to prevent rotation of the braking disk. An annular
laterally projecting flange 145 is formed on one side of
the brake disk to fit into a circular groove 147 on the
inertia wheel 100 to assure that the braking disk stays
properly centered. An arcuate cut-out 148 is made on the
bottom side of the brake disk 135 to accommodate the pawl
actuatlng finger 93 of the pawl means.
For the purpose of actuating the pawl means 25 to
bring the pawl noses 35 into operational relationship with
the ratchet wheels 32, the inertia wheel 100 is provided ~ith
pawl actuating means which may take various forms such as,
for example, sloped projections or teeth 150. The illustrated
teeth 150 are in the form of short metal projections or pro-
! tuberances which are equally spaced from one another angularly
about the annular wall 103 and equidistantly from the rotation-
al axis of the inertia wheel 100. At rest, the spring 102
urges the inertia wheel 100 to the right with the spokes 105
abutting the bottom walls 127 of the cam grooves 115 at which
position the teeth 150 lie in a plane spaced from the pawl
actuating finger 93. For example, the teeth 150 may be spaced
about 0.030 inch longitudinally of the spindle 49, to the
right as viewed in the drawings, from the pawl actuating
finge~ ~3. In this instance, there are eight teeth 150 having
centers spaced at 45 with a leading surface 151 disposed to
engage the pawl finger 93 and pivot the pawl noses 35 toward
the slide surfaces 37 of the ratchet wheels 32. The teeth
are of a very limited arcuate extent and are spaced apart
and are angularly related to the spokes 105 on the same
inertia wheel and thereby positioned in a predetermined
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angular relationship relative to the ratchet teeth 29 as
will be explained.
In the preferred embodiment of the invention, the
occupant may, after the seat belt is extended, make the belt
tensionless by exerting a sharp pull on the belt to extend
it under acceleration sufficiently to cause the inertia means
23 to operate and render the pawls 26 operative to hold the
reel against the urging of the spring force from the biasing
means 19 where~y the belt will be relieved of tension and
may lie limp on the occupant. More specifically, the sharp
pull causes the inertia wheel 100 to lag in rotation relative
to the reel and to be cammed by cam surfaces 119 longitudinally
to abut a projection lS0 against the pawl finger 93 and to
pivot the pawl noses 35 to adjacent or touching the guide
surfaces 37 between ratchet teeth 29. Before the inertia
wheel 100 returns from its outward position, the adjacent
ratchet teet~ 29 turn to abut the pawl noses which are now
in the closed position, thereby stopping further belt exten-
sion. Preferably, the pawl noses 35 abut the reversely in-
clined teeth walls 153 which capture and hold the pawl noses
35 and even drive the pawl noses inwardly toward the bases
of the ratchet teeth.
During this time, the inertia wheel 100 returns toward
its position adjacent the closest one of the ratchet wheels
32, and the annular flange 155 on the inertia wheel is super-
posed over a tang 160, as best seen in FIGURE 9, on the pawl
26 disposed adjacent the inertia wheel 100~ With the f~ange
155 overlying the tang 160, relaxation of the seat belt 17
allows pawl noses 35 to separate from the inclined teeth walls
153, and the pawls 26 begin to pivot under the urging of the
spring 83 to shift the tang 160 outwardly to abut the slide
along the flange wall 155 as the reel biasing spring 70 turns
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the reel 16, ratchet wheels 32 and inertia wheel 100 in
the rewind direction. This brings an adjacent notch 163 of
a series of notches 163 formed in the inner wall of the flange
155 into alignment with the tang 160. Under the urging of
the pawl biasing spring 83, the tang 160 will snap into the
aligned notch 163. The flange 155 serves to limit ~urther
turning of the pawl means 25 towards its release position
under the urging of the pawl biasing spring 83.
The tang~160 is, in this instance, a small protuberance
projecting laterally from a side wall 171 of the pawl 26 toward
the inertia wheel 100 and spaced inwardly from the pawl nose 35
which is on an extremity of the pawl 26. In this instance,
the cooperating notches 163 extend radially outwara and are
cut in the interior sur~ace o~ the flange 155 and also extend
laterally of the flange to open in an annular side wall 165
~ on the inertia wheel. The notches are positioned in the flange
! 155 at circumferentiaIly spaced locatio~s to assure that the
tang ~60 slides into a notch 163 before the surface 37 of the
preceding ratchet tooth 29 returns to abut the undersurfaces
152 ~FIGURE 6) of the pawls 26. The tang 160 and an aligned
notch 163 serve as detent means for detenting the inertia
wheel 100 and reel 16 to hold the extended belt portion 21
tensionless.
~hen the tang 160 is in a notch 163, the inertia wheel
100 is held by the pawl 26 against rotation by the reel biasing
means 19 as would retract the seat belt. More specifically,
the tang 160 holds the inertia wheel 100, and its spokes 105
hold reel extensions 117, the reel hub 57 and the reel spindle
49 against turning. The spring 102 urges the spokes lCS to
remain in their longitudinal inward positions adjacent the
near ratchet wheel 32 and holds inertia wheel 100 from shifting
longitudinally outward and releasing the -tang 160.
I 5 -
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To release the belt from tensionless state to a
tensioned state, the inertia wheel flange 155 and its notch
163 are shifted longitudinally on the reel 16 to uncover the
tang 160 whereby the pawl spring 83 pivots the paw's 26 to
the non-bloc~ing position spaced from the ratchet teeth 29.
More specifically, a pull on the seat belt causes the spindle
49 and reel 16 to turn relative to the inertia wheel 100 for
the tang 160 in the notch 163 prevents the inertia wheel from
rotating. Thereby the reel extensions 117 with the camming
surfaces 119 cam the inertia wheel spokes 105 to shift them
longitudinally outward from the tang 160. After the inertia
wheel 100 shifts to uncover the tang 160, the pawls 26 move
to release the ratchet teeth 29 and, upon release of the beli,
; the reel biasing means 19 becomes e~fective to tension the
belt about the occupant. If the belt buckle is released, the
belt is wound upon the reel 15.
To further facilitate an understanding of the tLming
operation of the pawls 26 relative to the ratche~ teeth 32, a
brief explanation o~ an inertia locking operation will be given,
whether occasioned by an accident or in order to place the belt
in its tensionless condition. With the belt extended in tension
about a person and a sharp pull extending the belt with an
acceleration over .7 G will cause the inertia means 23 to
operate as the belt tu~ns the reel 16 relative to the inertia
wheel 100. The inertia of the wheel 100 causes it to lag,
aided by the "psuedo-inertia" of the brake disk 135 whereby
the cam surfaces 119 on the reel extensions 117 cam the spokes
105 longitudinally outward of the adjacent ratchet wheel 32.
After the inertia wheel 100 has turned about 7.5 relative
to the ra~chet wheel, it will have been displaced longitudin-
ally aDout .030 inch to turn one of its teeth 150 into initial
engagement with the pawl finger 93. The force of the pawl
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spring 83 is usually greater than this initial impact from
the tooth 150. As a result the pawls 26 remain open in their
position spaced from the ratchet teeth 29. As the reel 16
continues to rotate relative to the inertia wheel 100 through
about another 3 or 4, the inertia wheel displaces longitu-
dinally to its maximum longitudinal displacement of approx-
imately .090 inch at which time the spokes 105 of the inertia
wheel 100 abut hub walls 123 of the reel extensions 117, where-
upon the inertia wheel 100 and ratchet wheels 32 may no longer
rotate relative to each other. A continued turning of the
reel 16 and inertia wheel 100 in the belt extending direction
through an angle of approximately another 6 1/2 is sufficien-t
to pivot the pawl finger 93 against the force of the pawl spring
B3 to rotate the pawls 26 through an anqle of about 7 1/2 by
; 15 the time the pawl -finger 93 has separated from the tooth 150.
The tooth 150 continues turning past the pawl finger. During
the camming of the pawl finger 93, the pawls 26 rotate to the
closed position in which the underlying sur~aces of the pawls
are generally parallel to guide surfaces 37 on the ratchet
wheels 32 and spaced slightly thereabove. As the teeth 2g are
spaced 45 apart and the teeth 150 operate about one-half or
less than this amount of turning, the pawl noses 35 will usu-
ally be at about the center of the guide surfaces 37 when the
teeth 150 leave the pawl finger 93. If the camming action
of the cams on the pawl finger 93 is made with considerable
force, the pawl noses 35 may pivot to abut the guide suxfaces
37. In any event, the ratchet wheels 32 are turning with
such speed that the pawls 26 cannot reverse their direction
of movement and travel outwardly from ratchet wheels 32 ~mder
the urging OL- the pawl spring 83 be~ore the inclined te~th
walls 153 abut the pawl noses 35. In this instance, the
ratchet teeth 29 rotate about another 10 be~ore abutting the
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pawl noses 35. This stops the rotation of the reel 15,
preventing further extension of the belt, thus retaining
the occupant in his seat in the event of an accident.
At the same time, this action holds the pawls 26
against outward pivotal movement from the teeth 29. Before
the pawls 26 can separate from the ratchet teeth 29 and pivot
outwardly, the inertia wheel 100 will have returned under
the urging of the spring 102 by winding down the cam grooves
115 to a position to trap the pawl tang 160 beneath the inertia
wheel flange wall 155. Upon release o~ the acceleratiny force,
the retractor is in its tensionless condition. Upon release
of tension in the belt, the reel 16 is free to be turned
slightly in the retracting direction, for example, by about
15 under the urging of reel rewind spring 19. As the ratchet
wheel turns, it carries the inertia wheel 100 with it and turns
a notch 163 into an aligned overlying relationship with the
tana 160 which upon a slight pivotin~ of the pawl 26 under the
urging of pawl spring 83 pivots outwardly into the aligned
notch 163. As explained previously, the pawl tang 160 holds
- the inertia wheel which acts through the cam surfaces 119 of
the reel extensions 117 to hold the reel 16 and spindle 49
against turning in the retraction direction under the urging
of the reel biasing spring 70. Thus, the extended belt is held
free of tension of the reel spring 70 and the extended belt
is tensionless.
In the event the belt is in the tensionless condition
at the time of an accident, the occupant's body will extend
the belt rapidly under an acceleration above about .7 G. This
quickly turns the adjacent ratchet teeth 29 through an arc of
about less than 15 to abut the pawl noses 35, which are al-
ready down in a closed position, against the inclined walls
153 of the teeth before the spring 83 can act to withdraw the
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pawls 26 after the tang 160 is released. The inclined walls
153 may drive the pawl noses further inwardly to the bases
of the teeth. This locking of ratchet teeth 29 and pawls
26 holds the belt against complete extension as may allow
the belt wearer to hit a window, steering wheel or the like.
The retractor thus locks in the event of accident irrespective
of whether it is in its tensionless condition.
When it is desired to return from the tensionless
state to the tensioned state for the belt, the occupant need
merely pull on the belt to extend the same sufficiently to
shift the inertia wheel 100 to release tang 160, whereupon the
pawl spring 83 will pivot the pawls 26 to their open non-
blocking position. More particularly, the pull on the belt
- may be slow or fast, intentional or unintentional, so long as
it is not so fast as to abut the pawls 26 against the teeth
29 before the spring 83 can withdraw the pawls 26 after re-
lease of the tano 160. It will be appreciated th2t inertia
wheel 100 is held by the tang 160 against turning with reel
during this belt extension. As belt is protracted, the spokes
105 are cammed longitudinally by the cam surfaces 117 within
~ - less than 15 of ratchet wheel turning to release the tang
; 160, whereupon the spring 83 withdraws the pawls 26.
In accordance with another embodiment of the invention,
the inertia locking retractor may be made without the tension-
less feature by removing the tang 160 from the pawl 26. The
operation described above will be generally the same except
that the inertia wheel flange 155 cannot capture and hold the
pawls 26 from being returned by the pawl spring 83. Even
though the inertia wheel 100 has returned to adjacent the
left ratchet wheel 32 before tension in the belt is released,
the release of the belt tension allows the reel spring 70 to
turn the ratchet teeth 29 in the retracting direction and
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from abutment with the inclined surfaces 37 whereupon the
pawls 26 will be unimpeded in pivoting past the inertia wheel
flange 155 to the release or open position spaced from inertia
wheel 100 and ratchet wheels 32. Therefore, the seat belt
retracting spring 19 is free to turn the reel in the retracting
direction until the belt is taut about the occupant. Thus,
it will be seen that the inertia locking retractor may be
by sim~le modifications changed from the tensionless to the
tension kind.
In accordance with another embodiment of the invention,
the inertia means 23 is disabled after an initial slight ex-
tension of the belt so that a sudden jerk or snap on the belt
is ineffective to block further belt extension of the belt.
During securement of the belt about occupant, a slight re-
tracting movement of the reel will occur whereupon the inertia
means 23 is again enabled to operate and lock further belt ex-
tension ~ in the ~a~e of an acc;~ent. ~ ch embodiment of the
invention is illustrated in FIGURES 10-19. Because this embodi-
ment of the invention operates substantially in the manner
described above for the embodiment of the invention illus-
trated in FIGURES 1-9, it will not be described in such detail
except for the description of the hold-out means 40 and the
inertia means 23. As will be explained in greater detail,
a slight retraction of the extended belt 17 occurring at the
time of buckling the belt sections toge~her deactivates the
hold-out means 40, thereby allowing the inertia means 23 to
operate the pawl means 25 to lock the reel 16 against further
belt extension if there should be an accident. Also, as will
be explained in greater detail, the retractor illustrated in
FIGURES 10-19 is constructed with parts which can be readily
assembled and economically produced as required for a commer-
cially acceptable seat belt retractor.
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Very generally, the seat belt retractor illustrated in
FIGURES 10-19 comprises a U-shaped frame 181 having a central
base 182 spanning a pair of upstanding flanges 183.and 184
on which is journaled a rotatable reel supporting spindle 185.
A coiled power spring 187 is mounted in a spring housing 188
fastened to upstanding flange 183 for turning the reel 16 in the
rewind direction. One end of the spring 187 is secured to the
upstanding flange 183, and its other end is secured to the adja-
cent one of the pairs of ratchet wheels 32 for the reel. In
this embodiment of the invention, the inertia means 23 is dis-
posed outwardly of the upstanding flange 184 and is protected by
a cover or housing 193. As will be explained, the inertia means
23 pivots pawl means 25 against the force of a biasing spring
197 secured to the frame base 182 to bring pawl nose 199 of a
pair of pawls 200 into position for abutting the teeth of the
respective ratchet wheels 32. As will be explained in greater
detail ! the operation and timing of ;nertia me~ns ~3 and p~w~
means 25 is substantially the same as hereinbefore described for
the embodiment of the invention as illustrated in FIGURES 1-9.
Referring now in greater detail to the inertia means
23 illustrated in FIGURES 10-13 and 19, it comprises a cam
means 114 having an inertia cam or cam member 201 which is
keyed to a ratchet wheel 32 by three radially extending lugs
202 (FIGURE 19) which are fitted into three complementary
radially extending slots 203 in the ratchet wheel 32. The
lugs 202 are attached to a rear small diameter cylindrical
portion 204 which projects through a suitable opening in the
upstanding flange 184. The ratchet wheel has a central opening
205 through which projects a threaded end 206 of the reel
spindle 185 which supports the reel for rotation. The hub
of the reel is connected to the ratchet wheel 32 at slots
in the manner previously described in connection with FIGURES
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1-9. A threacled nut 208 is threaded on end 206 of the spindle
185 to hold the cam member 201 against shifting longitudinally
outward of the ratchet wheel 32.
Preferably, the inertia cam 201 is a single integral
generally cylindrical me~ber molded from a plastic material
with three camming grooves or slots 209 which are spaced from
each other by 120 in a generally cylindrical wall 210 having
an axis coaxially aligned with the reel axis. As best seen
in FIGURES 12 and 19, the grooves 209 are formed with spaced
camming walls 211 which are inclined to the longitudinal axis
or direction of the reel. The camming grooves 209 extend in
arcuate direction from an end 212 adjacent the ratchet wheel
32 to an outer opening 213, as best seen in FIGURE 10. The
eamming grooves 209 may extend as shown at 45 to the axis of
rotation and function in the manner as the above-described
camming grooves 115.
! The inertia means 23 illustrated in FIGURES 10-19 com-
prises a multi-piece inertia wheel or member 214 which func-
tions similarly to the above described inertia wheel 100.
~ore spec~fically, the inertia wheel cooperates with the iner-
tia cam 201 and its eamming ~rooves 209 for shifting longitu-
dinally on the inertia cam 201 to a position to actuate the
pawl means 25 to engage the ratchet wheels 32. The iilustra~ed
inertia wheel 214 is formed of three pieces including an inner
ring or member 215 having three radially and inwardly projecting
cylindrical spokes or cam followers in the form of cylindrical
pins 216 spaced at 120 and inserted into the cam grooves 209
in the inertia cam 201. The inner inertia ring 215 has a bore
wall 217, as best seen in FIGURE 19, which slidinyly telescopes
onto the outer surface of the cylindrical wall 210 of the
inertia cam 201 for turning freely relative thereto and/or
freely sliding longitudinally relative to the cylindrical wall
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210 to the extent permitted by the cam slots 209. The inner
inertia ring 215 is preferably moIded in one piece and from
a plastic material with the three pins projecting along radial
lines toward the axis of rotation for the reel 16 and joined
at the radially inner ends to a cylindrical sleeve 218 having
a radially inwardly extending apertured wall 218a which seats
one end of a compression spring 220a. The spring 220a is
compressed between the head 208a of the nut 208 and the end
wall 218a to bias return the inertia wheel 214 to a position
adjacent the ratchet wheel 32. ~he inner end of the nut 208
extends through an opening 218b in the end wall 218a.
Encircling the inner inertia ring 215 is an outer
inertia ring or cylinder 219 which is secured thereto in any
suitable manner as by keying to prevent relative rotation
between the inner ring 215 and outer cylinder 219 which com-
prises the inertia wheel 214. The outer inertia cylinder 219
~! i3 preferably of metal, e.g., steel, to provide a heavy portionof the desired mass for the inertia wheel 214 to cause locking
of the reel at accelerations of the belt above .7 G's. The
outer inertia cylinder 219, as best seen in FIGURES 10, 12
and 19, includes an outer circumf~rential wall 220 encircling
an outer, circular circumferential wall 221 of the inner iner-
tia member 215 and further includes an annular end wall 225
(FIGURE 12) having a central opening 227 therein through which
projects the nut 208. As best seen in FIGURE 12, the end wall
225 of the outer ring 219 is in face-to-face engagement with
an end face 226 of the inner ring 215.
The outer circumferential wall 220 extends in the
longitudinal direction towards the ratchet wheel 32 beyond
opposite face 228 of the inner ring 215 toward the pawl nose
199 to position a series of exposed notches 229 to coopera-te
with a pawl tang 230 on the adjacent pawl 200 to provide a
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- tensionless feature for the retrac~or in the manner that the tang 160 cooperated with the notches 163 to hold the inertia
wheel 100 in the embo~iment of ~IGU~ES 1-9. The no-tches 229
are larger than the notches 163 and extend entirely through
the circumferential wall 220 in contrast to the smaller in-
ternal notches 163 described above. However, the tang 230
is substantially larger than the tang 160 and is of a size
larger than the notch to prevent the tang from passing through
one of the notches. The tang 230 slides along the inner side
of the circumferential wall 220 to abut a notch 229 and hold
the inertia wheel 214 in the manner above described in con- -
nection with FIGURES 1-9.
The pawl actuating means on the inertia wheel 214 is
in the form of a series of circumferentially spaced teeth or
projections 231 on a star wheel 233 comprising the third por-
tion of the inertia wheel 213. The teeth 231 project radially
outward from a central ring 234 and are separated by a series
of arcuate spaces between the teeth. In this instance, the
inertia star wheel 233 is provided with eight equall~ spaced
teeth 231 which have a radial extent of about 0.12 inch beyond
the ring 234. Preferably, leading sides 235 of the teeth 231
will abut a pawl actuating finger and are forme~ with inwardly
: beveled side portions e~tending to trailing sides of the teeth.
The star wheel 233 is also formed of metal and is fastened to
outer cylinder 219 by screws carried by the outer inertia mem-
ber and threaaed into tapped openings in the star wheel 233.
In a manner similar to that described above in con-
nection with FIGURES 1-9, the spacing of the pawl actuating
teeth 231 on the star wheel 233 of the inertia wheel 214 and
the location of the star wheel 233, cam grooves 209 and pawl
actuating finger 236 relative to ratchet wheels 32 and pawl
nose 199 causes a pivoting of the pawl noses to positions to
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be captured beneath the ratchet teeth 29 and to abut the
base of the ratchet teeth. As stated pxeviously, the tang
230 is similar to but considerably largel- than the tang 160.
It is captured beneath the circumferential wall 220 of the
inertia wheel 214 to slide along the inner surEace of the
circ-~mferential wall until entering one of the notches 22g
which prevents turning of the inertia wheel 214 and hence
limits motion of the inertia cam member 201 and ratchet
wheels 32. Thus, ,he tang 230 operates to hold the reel
16 against turning in the rewind direction under the urging
of the power spring 187 with the seat belt 17 being held
in the tensionless state against the rewind forces from the
power spring 187.
Preferably, a braking disk 249 is mounted coaxially
with the inertia cam 201 and the inertia wheel 214 with one
face 251 thereof in frictional contact with the ring 234 of
i star wheel 233 to provide pseudo inertia and to dampen any
: oscillations of the inertia member, as described hereinbefore
in connection with the braking disk 135. As best seen in
FIGURES 17 an~ 18, the illustrated braking disk is generally
annular with a pair of central collars 253 about a central
opening 254. One collar 253 projects into the central opening
of the adjacent star wheel 233 and the other collar 253 seats
one end of another coiled compression spring 255 (FIGURE 10).
The coiled spring 255 is a compression spring compressed
between an annular wall 257 on the cover 193 and the facing
side of the ~raking disk 249 to provide an axially directed
force on the inertia wheel 214 to cause it to return adjacent
the ratchet wheel 32 and to return the pi.ns 216 to cnds 212
of the cam slots 209. In this connec-tion, th~ braki.ns disk
2~9 and spring 255 runction similarly to the braking disk
135 and spring means 102.
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The preferred hold-out means 40 for preventing op-
- eration o the inertia means 23 during extension of the belt
17 from its fully wound position holds the inertia wheel 214
against longitudinal shi~ting toward the dust cover 193 to
where the teeth 231 thereon would be in a plane to abut the
pawl actuating finger 236 and cause a locking of thc retractor.
It will be recalled that the inertia locking operation will
occur ~or accelerations of the belt above .7 G. However,
such belt accelerations could occur with a sharp pull and fast
acceleration as the occupant pulls the belt toward his body
preparatory to buckling up. The hold-out means 40 allows
the fully wound belt 17 to be accelerated beyond .7 G without
locking after a short initial movement of the bel_ in the
unwinding direction. However, the hold-out means 40 is
deactivated with a slight retraction o~ the belt 17 as occurs
when buckling up, so that a subsequent .7 G acceleration of
belt 17 at the tLme of an accident results in a locking of
the retractor against further belt extension. Of course,
with a .3 G acceleration or less the belt 17 will not operate
the inertia means 23 to lock the reel 16 because the inertia
of the inertia wheel 214 is insufficient to overcome the force
of the springs 220a and 255.
~ or the purpose of blocking longitudinal shifting of
the inertia wheel 214 to its pawl actuating position during
initial unwinding of the belt 17 from the reel 16, the hold-
out means 40 comprises a means 256 (FIGURES 14 and 15) which
shifts with the inertia wheel 214 relative to a stationary
stopping means 258, which blocks the inertia wheel 214 from
shifting to the pawl actuating position to bring teeth 231
into a plane to hit the pawl actuating finger 236. In this
instance, the means 256 comprises tabs 259 Oll the braking
disk 249 which is moved axially by the inertia whe~l 21fi
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1045606
toward the dust cover 193 having the stopping means 258
which, herein, is in the form of a stopping shoulder means
261. Thus, the braking disc 249 functions as a hold-out
member which is frictionally coupled to the inertia wheel
214 and the shoulder means 261 functions as hold-out sur-
faces. The stopping shoulder means 261 is formed integral
with the dust cover and is spaced further from the smallest
diameter, inner circular end wall 260 of the cover than a
bottom wall 262 for each of three adjacent recesses or open-
ings 263. Preferably, three such shoulder means 261 of
limited arcuate extent are formed and when the tabs 259 are
aligned therewith hold the braking disk 249 from shifting
to the extent it will shift when the tabs 259 are aligned
with the openings 263. Only when the tabs are in the open-
ings 263 may the inertia wheel 214 shift axially sufficiently
to bring the teeth 231 to their pawl actuating position.
Thus, depenaing on the angular position of the tabs 259
relative to openings 263, the inertia wheel is either blocked
from or allowed to shift its teeth 231 to the pawl actuating
position.
The natural motion of a person using the seat belt
is to grasp the exposed buckle end or the tongue plate and
give a slight pull on the full retracted belt at an accelera-
tion of less than .3 G and then to pull it with a greater
acceleration. Thus, the inertia wheel 214 turns slightly
initially at this fully wound belt position to bring the
braking disk tabs 259 into position to abut an axially ex-
tending wall 267 and into alignment with the shoulder means
261. The walls 267 extend longitudinally between the shoulder
means 261 and arcuate walls 268 and serve to limit the coun-
terclockwise turning of the disk, as viewed in FIGURE 15.
Likewise, end walls 269 extending from the other ends of
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axcuate walls 268 to the bottom walls 262 of the openings
263 limit the clockwise movement, as shown in FIGURE 15,
of the disk.
Following this short initial extension of the belt
17 from the fully wound position, the tabs 259 are aligned
with the shoulder means 261 thereby disabling the inertia
means 23 and allowing belt 17 to be pulled rather sharply
at accelerations which would lock the retractor but for the
hold-out means 40. As the belt 17 is buckled about the
occupant, a slight retraction of the belt 17 naturally occurs
under the movement of the power spring 187 which turns the
inertia wheel 214 as well as the braking disk 249 to bring the
tabs 259 against a longitudinally extending sidewall 269 of
- the recess 263 thereby preventing further turning of the
braking disk 249 and its tabs 259. This assures that the
tabs are aligned with the openings 263 irrespective of any
further retraction of the belt and turning of the inertia
wheel 214 in the rewind direction. Should an accident occur,
the fast acce~eration of the belt 17 operates inertia wheel
214 which moves its pins 216 axially in the cam slots 209
forcing the braking disk 249 axially and deeper into the
openings 263 against the urging of the coil spring 255 be-
fore the tabs 259 turn into alignment with the shoulder
means 261.
If it-is preferred that the hold-out means 40 be
overridden with a very fast acceleration of the belt, e.g.
2 G or above, as such an acceleration is more typical of an
accident than a fast initiàl extension of the belt from a
fully wound condition, then an inclined shoulder means 26ia
such as shown in FIG. 16 may be provided on the dust cover.
This is a fail-safe safety feature to assure that at belt
accelerations of 2 G or more, the inertia means 23 locks
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the reel 16 against further belt extension, even when the
hold-out means 40 is in its hold-out position. To this
end, the shoulder means 261a are inclined at a predetermined
angle relative to the lonyitudinal direction and be-tween the
bottom walls of the recesses 263 and the annular walls 268
and will function as inclined surfaces forcing the tabs 259
in engagement therewith to slide therealong and into the
openings 263 when the inertia wheel 214 applies a force to
the tabs 259 caused by a 2 G or greater acceleration of the
belt 17.
. In accordance with a still further embodiment of
the invention (not shown herein), the illustrated pawl spring
83 or 1~7 is removed and an overcenter spring (not shown~
. is substituted therefor to f~nction to bias the pawls 26 to
an outer release or free position in which the pawls are spaced
. from the ratchet wheels 32 until an inertia wheel tooth 150
I or 231 abuts the pawl finger 93 or 136 and pivots the pawl
means through an intermediate .central or dead position after
which the spring becomes effective to bias the pawl into en-
gagement with the ratchet teeth 29. By having the overcenter
spring ol a predetermined strength and slowly releasing the
belt, it has been found possible to have the ratchet wheels
32 held against turning by friction and the force of the
pawl spring urging the pawls against the ramps on the back
side OJ. the ratchet teeth. This prevents retraction of the
extended belt under the urging of the reel spring 70 or 187.
As a result, the belt will remain tensionless without the
use o~ a tang 160 or 230 and an inertia wheel notch 163 or
229. With the pawls 26 biased against the pawl guide sur-
faces 37, the pawls have been found to exert sufficient force
to prevent more than a slight turnin~ in the withdrawal direc-
tion which merely separateS the noses 35 or 199 from th~
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reversely inclined teeth wall 153. In this em~odiment of
the invention, the pawls 26 will remain biased by the over-
center spring into this position for blocl;ing the extension
of the belt particularly at the time of an accident. To
release the pawls 26 and to shift them through the center
position to where the pawls 26 are free and clear of the
ratchet wheels 32 and are biased in the op2osite direction
to the released position, the operator mus t merely pull the
seat belt to cause the reel means to rotate slightly to abut
the pawl noses 35 or 199 against the inclined tooth walls 153
and then quickly release the belt to allow the reel spring
to rewind the belt at sufficient velocity to cause the ratchet
teeth 29 to hit the pawls 26 with sufficient impact to pivot
the pa~ls 26 to the position spaced from the ratchet wheels
32. Any fast extension of the belt, however, will cause the
inertia wheel 100 or 214 to actuate the pawl finger 93 or
236 to pivot the pawls 26 through the overcenter position
to block the ratchet teeth 29.
From the foregoing, it will be seen that the inertYia
locking retractor may be constructed with or without the
tensionless feature. Also, the retractor may be constructed
either with or without a hold-out means to prevent lockin~ of
the retractor with a fast acceleration of the belt from its
fully wound condition. In any case, the inertia retractor
will be effective to lock belt extension at belt accelerations
above a predetermined acceleration at the time of an accident.
The inertia retractor is simple to release upon a slight
manipulation of the extended belt end. Moreover, the re-
tractor, particularly the embodiment illustrated in FIGURES
10-19, may be construc~ed with low cost components which may
be assembled readily to produce a commercially acceptable
retractor.
30 -
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1~)45606
While a preferred embodiment has been shown and
described, it will be understood that there is no intent
to limit the invention by such disclosure but, rather,
it is intended to cover all modifications and alternate
constructions falling within the spirit and scope of the
invention as defined in the appended claims.
