U.S. patent number RE29,594 [Application Number 05/715,029] was granted by the patent office on 1978-03-28 for automatic locking acceleration actuated vehicle safety belt retractor.
This patent grant is currently assigned to Takata Kojyo Co., Ltd.. Invention is credited to Takezo Takada, deceased, by Juichiro Takada, heir.
United States Patent |
RE29,594 |
Takada, deceased , et
al. |
March 28, 1978 |
Automatic locking acceleration actuated vehicle safety belt
retractor
Abstract
An automatic locking vehicle safety belt retractor includes a
shaft on which is affixed a belt take up reel having similar first
ratchet wheels at its opposite ends. A spring retracted transverse
pawl member includes pawl teeth which are rockable with the pawl
member into and out of braking engagement with the ratchet wheels
and the pawl member is drive coupled to an internally toothed
second ratchet wheel rockably mounted on the shaft. A fly wheel is
freely rotatable on the shaft within the second ratchet reel and
carries a spring retracted second pawl swingable into engagement
with the second ratchet wheel and a cam wheel is rotatable with the
shaft and engages a cam follower on the second pawl to advance the
second pawl upon rotation of the cam wheel relative to the fly
wheel. The numbers of teeth on the second ratchet wheel and on each
of the first ratchet wheels are equal and the cam and ratchet
wheels are so angularly related that when the retractor is braked,
the pawls fully engage respective ratchet teeth.
Inventors: |
Takada, deceased; Takezo (LATE
OF Hikone, JA), Takada, heir; by Juichiro (Tokyo,
JA) |
Assignee: |
Takata Kojyo Co., Ltd. (Tokyo,
JA)
|
Family
ID: |
26352884 |
Appl.
No.: |
05/715,029 |
Filed: |
August 17, 1976 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
441534 |
Feb 11, 1974 |
03897024 |
Jul 29, 1975 |
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Foreign Application Priority Data
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Feb 12, 1973 [JA] |
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48-16530 |
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Current U.S.
Class: |
242/383.4 |
Current CPC
Class: |
B60R
22/405 (20130101) |
Current International
Class: |
B60R
22/34 (20060101); B60R 22/405 (20060101); A62B
035/02 (); B65H 075/48 () |
Field of
Search: |
;242/17.4R,17.4E
;280/744-747 ;297/388 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gilreath; Stanley N.
Assistant Examiner: Jillions; John M.
Attorney, Agent or Firm: Wolder, Gross & Yavner
Claims
I claim:
1. An automatic locking safety belt retractor comprising a shaft, a
take-up reel mounted on and rotatable with said shaft and spring
biased to in a belt rewind direction, a safety belt connected to
and retractable by and withdrawable from said reel, a first ratchet
wheel rotatable with said reel, a first pawl mounted for movement
between positions engaging and disengaging said first ratchet
wheel, a second ratchet wheel mounted on and rotatable relative to
said shaft, a fly wheel rotatably mounted on said shaft, a second
pawl mounted on said fly wheel and movable therewith and movable
relative to said fly wheel between positions engaging and
disengaging said second ratchet wheel, a cam member mounted on and
rotatable with said shaft and engagable with said second pawl
whereby rotation of said cam member a predetermined angle in
advance of said fly wheel by the rotation of said shaft in response
to a predetermined pull on said belt effects the actuation of said
second pawl by said cam member into engagement with said second
ratchet wheel to forwardly rock said second ratchet wheel, and
actuating means drive coupling said second ratchet wheel and said
first pawl whereby forward rocking of said second ratchet wheel
advances said first pawl into engagement with said first ratchet
wheel to lock said reel against belt withdrawal rotation, said
first and second ratchet wheels having equal numbers of ratchet
teeth.
2. The retractor of claim 1 wherein said first and second ratchet
wheels and said cam member are so angularly related that said first
and second pawls when actuated to their engaged positions engage
the base portions of corresponding ratchet teeth of the respective
first and second ratchet wheels.
3. The retractor of claim 1, including a first spring resilient
biasing said first pawl toward its ratchet disengage position and a
second spring resiliently biasing said second pawl toward its
ratchet disengage position.
4. The retractor of claim 3 comprising a mounting bracket including
a pair of transversely spaced side walls, said shaft extending
between and projecting beyond and journalled to said side walls, a
pair of said first ratchet wheels disposed at opposite ends of said
reel proximate the confronting faces of said bracket side walls, a
transverse cross bar extending between and rockably supported by
said bracket side walls proximate said first ratchet wheels, and a
pair of said first pawls located on said cross bar and rockable
between positions engaging and disengaging respective first ratchet
wheels.
5. The retractor of claim 4 wherein said fly wheel, second ratchet
wheel, said second pawl and said cam member are located on said
shaft along the outside face of one of said bracket side walls.
6. The retractor of claim 4, wherein said second ratchet wheel is
internally toothed and is cap shaped and provided with an end wall
journalled on said shaft, and fly wheel and second pawl being
disposed within the space delineated by said second ratchet
wheel.
7. The retractor of claim 4, wherein said second ratchet wheel end
wall has a radially extending slot formed therein, and said
actuating means comprises a lever engaging and rockable with said
cross bar and provided with a follower element remote from said
cross bar slideably engaging said slot.
8. An emergency locking type vehicle safety belt retractor,
comprising a U-shaped frame 1; a shaft mounted intermediate the
upright sides of the U-shaped frame, said shaft loosely carrying on
one outside of the frame, a cap-shaped latch wheel with internal
teeth, an inertia wheel fitted with a pawl, a cam wheel press
fitted on the shaft, a spring washer fitted on the shaft, and a
stop plate also fitted on the shaft; ratchet wheels provided to
both insides of the U-shaped frame and having the same number of
teeth as those of the latch wheel; a belt-winding reel press fitted
on the shaft; a pawl plate mounted intermediate the upright sides
of the frame and in the proximity of the ratchet wheels; and a pawl
plate actuating plate transversely extending from an end part of
pawl plate; wherein, when the vehicle is subjected to an abrupt
impact or sudden change in the operating state, said inertia wheel
operates to rotate with the cam wheel, but with a time lag when the
belt is suddenly extracted, the pawl on the inertia wheel thus
engaging with the latch wheel to rotate the latter, thereby
engaging the pawl plate with the ratchet wheels through the pawl
plate actuating plate and preventing further reeling out of the
safety belt; and wherein the number of teeth of the ratchet wheels
is equal to that of the latch wheel to make the pivot angle of the
ratchet wheels and that of the latch wheel equal to each other to
synchronize the movement of the ratchet wheels with that of the
pawl plate by adequate selection of the angle of operation of the
latch wheel and the fulcrum distance of the pawl plate and the pawl
plate actuating plate. .Iadd. 9. An automatic locking safety belt
retractor comprising a rotatable take-up reel spring biased in a
belt rewind direction, a safety belt connected to and retractable
by and withdrawable from said reel, a first ratchet wheel rotatable
with said reel, a first pawl mounted for movement between positions
engaging and disengaging said first ratchet wheel, a second ratchet
wheel coaxial with and rotatable relative to said first ratchet
wheel, a second pawl rotatable with said first ratchet wheel and
movable between positions engaging and disengaging said second
ratchet wheel and normally urged to said ratchet wheel disengage
position, actuating means for urging said second pawl into
engagement with said second ratchet wheel, and means drive coupling
said second ratchet wheel and said first pawl whereby rocking of
said second ratchet wheel advances said first pawl into engagement
with said first ratchet wheel to lock said reel against belt
withdrawal rotation, said retractor being characterized by said
first and second ratchet wheels having equal numbers of ratchet
teeth..Iaddend..Iadd. 10. The retractor of claim 9 wherein said
actuating means includes means responsive to a predetermined
rotational parameter of said reel for motivating said actuating
means..Iaddend. .Iadd. 11. The retractor of claim 9 wherein said
first and second ratchet wheels, said first and second pawls, said
actuating means and said drive coupling means are so related that
said first pawl when advanced to its ratchet wheel engage position
engages the base portion of a tooth of the first ratchet
wheel..Iaddend. .Iadd. 12. An automatic locking safety belt
retractor comprising a shaft, a take-up reel mounted on and
rotatable with said shaft and spring biased to rotate in a belt
rewind direction, a safety belt connected to and retractable by and
withdrawable from said reel, a first ratchet wheel rotatable with
said reel, a first pawl mounted for movement between positions
engaging and disengaging said first ratchet wheel, a second ratchet
wheel mounted on and rotatable relative to said shaft, a support
wheel mounted on said shaft, a second pawl mounted on said support
wheel and means responsive and movable relative to said support
wheel in response to a predetermined rotational parameter of said
reel for moving said second pawl between positions engaging and
disengaging said second ratchet wheel whereby a predetermined pull
on said belt effects the actuation of said second pawl into
engagement with said second ratchet wheel to forwardly rock said
second ratchet wheel, and means drive coupling said second ratchet
wheel and said first pawl whereby forward rocking of said second
ratchet wheel advances said first pawl into engagement with said
first ratchet wheel to lock said reel against belt withdrawal
rotation, said first and second ratchet wheels having equal numbers
of ratchet teeth..Iaddend. .Iadd. 13. The retractor of claim 12
wherein said first and second ratchet wheels, said first pawl, said
second pawl moving means and said drive coupling means are so
related that said first pawl when actuated to its engaged position
engages the base portion of a tooth of the first ratchet
wheel..Iaddend. .Iadd. 14. The retractor of claim 12 including a
first spring resiliently biasing said first pawl toward its ratchet
disengage position and a second spring resiliently biasing said
second pawl toward its ratchet disengaging position..Iaddend..Iadd.
15. The retractor of claim 14 comprising a mounting bracket
including a pair of transversely spaced side walls, said shaft
extending between and projecting beyond and journalled to said side
walls, a pair of said first ratchet wheels disposed at opposite
ends of said reel proximate the confronting faces of said bracket
side walls, a transverse cross bar extending between and rockably
supported by said bracket side walls proximate said first ratchet
wheels, and a pair of said first pawls located on said cross bar
and rockable between positions engaging and disengaging respective
first ratchet wheels..Iaddend..Iadd. 16. The retractor of claim 15
wherein said support wheel, second ratchet wheel, and said second
pawl are located on said shaft along the outside face of one of
said bracket side walls..Iaddend..Iadd. 17. The retractor of claim
15, wherein said second ratchet wheel is internally toothed and is
cap shaped and provided with an end wall journalled on said shaft,
and said support wheel and second pawl being disposed within the
space delineated by said second ratchet wheel..Iaddend..Iadd. 18.
The retractor of claim 15, wherein said second ratchet wheel end
wall has a radially extending slot formed therein, and said
actuating means comprises a lever engaging and rockable with said
cross bar and provided with a follower element remote from said
cross bar slideably engaging said slot..Iaddend.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to improvements in vehicle
safety belt retraction devices, and it relates particularly to an
improved automatic locking safety belt retractor reel which
responds to a belt withdrawal exceeding a predetermined rate.
In order to restrain a vehicle seat occupant against forward motion
in the event of a sharp or rapid slowing of the vehicle's forward
motion, such as that accompanying a collision or similar occurrence
while affording free and unhampered movement to the seat occupant,
under normal vehicle conditions it is a common practice to take up
the safety belt by a spring biased retractor reel which permits
free withdrawal of the safety belt except under rapid vehicle
deceleration conditions, under which conditions the reel is
automatically locked against belt withdrawal. One type of such reel
responds to the belt withdrawal speed exceeding a predetermined
rate to lock the reel against further withdrawal. While the reel
may respond to any desired belt pull, it should advantageously
respond to the pull exceeding 0.3 G. This type of reel which has
been heretofore available possesses numerous drawbacks and
disadvantages. They are complicated, bulky, expensive devices of
limited application, difficult and inconvenient to install, and of
little versatility and adaptability.
SUMMARY OF THE INVENTION
It is a principal object of the present invention to provide an
improved vehicle safety belt retrator.
Another object of the present invention is to provide an improved
automatic locking vehicle safety belt retractor reel.
Still another object of the present invention is to provide a
safety belt retraction reel which automatically locks against belt
withdrawal when the belt is withdrawn under a pull exceeding a
predetermined value.
A further object of the present invention is to provide a device of
the above nature, characterized by its high reliability, great
compactness, low cost, ease and convenience of installation, and
great versatility and adaptability.
In a sense, the present invention contemplates the provision of an
automatic locking safety belt retractor comprising a shaft, a
take-up reel mounted on and rotatable with the shaft, and spring
biased in a belt rewind direction, a safety belt, connected to and
retractable by and withdrawable from the reel, a first ratchet
wheel rotatable with the reel, a first pawl mounted for movement
between positions engaging and disengaging the first ratchet wheel,
a second ratchet wheel mounted on and rotatable relative to the
shaft, a fly wheel rotatably mounted on the shaft, a second pawl
mounted on the fly wheel and movable therewith and movable relative
to the fly wheel between positions, engaging and disengaging the
second ratchet wheel, and a cam member mounted on and rotatable
with the shaft and engagable with the second pawl, whereby rotation
of the cam member a predetermined angle in advance of the fly wheel
by the rotation of the shaft at a predetermined acceleration in
response to a predetermined pull on the belt effects the actuation
of the second pawl by the cam member into engagement with the
second ratchet wheel to forwardly rock the second ratchet wheel,
and actuating means drive coupling the second ratchet wheel and the
first pawl whereby forward rocking of the second ratchet wheel
advances th first pawl into engagement with the first ratchet wheel
to lock the reel against belt withdrawal rotation, the first and
second ratchet wheels having equal numbers of ratchet teeth. In
addition, the cam member and the first and second ratchet wheels
are angularly related about the shaft, so that the first and second
pawls simultaneously engage the bases of ratchet teeth on the first
and second ratchet wheels respectively.
In the preferred form of the retractor, the shaft is journalled
between the side walls of a U-shaped bracket which rockably
supports a cross bar having a pair of first pawls which are
proximate a pair of first ratchet wheels at opposite ends of the
reel. The second ratchet wheel is internally toothed and surrounds
the fly wheel and the second pawl which is pivotally mounted on the
fly wheel. The means coupling the first pawl carrying cross bar and
the second ratchet wheel, includes a transverse leg extending from
the bar and engaged by an arm which includes a pin slideably
engaging a radial slot in an end wall of the second ratchet
wheel.
The improved retractor reel is rugged, simple, reliable,
inexpensive and compact, and is simple and convenient to install
even in restricted and limited spaces. The control components which
require close tolerances may be injection molded of polymeric
resin.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of an automatic locking belt
retractor embodying the present invention;
FIG. 2 is a fragmentary front elevational view thereof;
FIG. 3 is a side elevational view;
FIG. 4 is a sectional view taken along line X--X in FIG. 2, showing
the retractor in its normal operating condition;
FIG. 5 is a view similar to FIG. 4, showing the retractor in its
locked condition;
FIG. 6 is a side elevational view of another embodiment of the
present invention;
FIG. 6' is a perspective view of a component thereof; and
FIG. 7 is a side elevational view of a further embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, particularly FIGS. 1 to 5 thereof
which illustrate a preferred embodiment of the present invention,
the reference numeral 1 generally designates a U-shaped bracket or
frame which constitutes the main support body of the retractor by
which it is securely mounted to the floor or seat, or other
suitable portion of the automotive vehicle. A shaft 3 having
secured thereto reel 4 is rotatably mounted between the upright
side walls of the frame 1, the reel 4 being attached, in turn, to
one end of a safety belt 2. A cap-shaped return spring cover 5 and
a helical return spring 6 are located on the outside face of a side
wall of the U-shaped frame 1, the ends of return spring 6 being
fastened to the cover 5 and the shaft 3 and operative to keep the
safety belt 2 wound up on the reel 4 by its resilient recoiling
force. Ratchet wheels 7,7' are fitted or otherwise secured to both
ends of the reel 4 proximate the frame side walls.
A pawl member 8 is mounted in proximity to the ratchets 7,7' and
includes a cross bar rockably engaging opposing segment shaped
openings 9,9' formed in the side walls of the frame 1 and pawl
teeth 10,10' projecting from the cross bar of the pawl member 8 and
engageable with ratchet teeth 7,7'. A return spring 11 engages one
end of the cross bar of the pawl member 8 and resiliently biases
the pawl member 8 out of meshing engagement with the ratchet teeth
7,7' by the pawl teeth 10,10'. A cap-shaped ratchet latch wheel 12
made of a polymeric resin material and having the same number of
internal ratchet teeth as those of each of the ratchet wheels 7,7'
is mounted on the portion of shaft 3 projecting beyond the opposite
side wall of the frame 1 and is rockable and restricted against
axial movement by an E-shaped ring 13. The outer surface of the end
wall of the latch wheel 12 has several bosses 14, by which the
latch wheel 12 is rotatable with reduced friction on the
confronting face of the side wall of the frame 1.
An elongated opening or slot 15 is formed in the end wall of the
ratchet wheel 12 for coupling to a bent part or transverse tongue
17 on the pawl member 8 by engagement with an end pin 18 located on
a pawl member actuating arm 16, to which the bent part 17 of the
pawl member 8 is secured as by spot welding. Thus, the pawl member
8 is actuated by the rotation or rocking of the latch wheel 12. An
inertia.Iadd. , support .Iaddend.or fly wheel 20 made of metal is
freely rotatably carried by shaft 3 inside of the latch wheel 12
and held by an E-shaped ring 13' against axial displacement on the
shaft. The inertia wheel 20 has small holes 21,21', and a stepped
pin 22' is suitably anchored in the hole 21' while another stepped
pin 22 registers with a fulcrum opening 24 in a pawl 23 and is
suitably anchored in the hole 21, the pawl 23 thus being lightly
slideable on the surface of the inertia wheel 20. The free end part
of the pawl 23 has a spring engaging aperture 25, by which a
tension spring 26 connected to stepped pin 22 is retained. The pawl
23 is normally resiliently urged or biased by spring 26 towards a
cam wheel 27, later to be described, and out of meshing engagement
with the latch wheel 12. The cam wheel 27, an undulate ring spring
28 and a stopper plate 29 are fitted to the shaft 3 and retained
thereon by the E-shaped ring 13". The cam wheel 27 is made of a
polymeric resin material and press fitted on the shaft 3. Segment
shaped peripherally extending camming recesses 30 are formed in the
surface of the cam wheel 27 facing to the inertia wheel 20.
As the inertia wheel 20 is rotated with rotation of cam wheel 27
but with a time lag, the camming recesses 30 act on the inwardly
directed cam follower part 31 of the pawl 23, thereby rotating the
pawl 23 outwardly and urging the pawl 23 into engagement with a
ratchet tooth of the latch wheel 12. The cam wheel 27 is urged
towards the inertia wheel 20 by the ring spring 28 backed by the
stop plate 29 and constrained by the E-shaped ring 13'. The inertia
wheel 20 has a light surface contact with the cam wheel 27 to keep
the inertia wheel 20 from oscillation. The pawl 23 and the cam 30
are also uniformly maintained in their normal positions to prevent
fluctuations in the sensitivity of the inertia system. In order to
synchronize the operation of the ratchet wheels 7,7' with that of
the latch wheel 12 under conditions of locking operation, the latch
wheel 12 is turned partially counter-clockwise until the pawl teeth
10,10' of the pawl member 8 are in full meshing engagement with
corresponding teeth of the ratchet wheels 7,7', that is, with the
bases of the teeth, and the cam wheel 27 is then adjustably turned
partially counter-clockwise until the pawl 23 is in complete
engagement with the bottom or base of a tooth of the latch wheel
12. The cam wheel 27 is mounted fast on the shaft 3 in this
position.
In operation, when the safety belt 2 is withdrawn at an ordinary or
normal speed, the reel 4, shaft 3, E-shaped ring 13", ring spring
28, stop plate 29, cam wheel 27, E-shaped ring 13' and inertia
wheel 20 are simultaneously turned with the rotation of the shaft
3. The pawl 23 is pulled by the tension spring 26 and rotated in
unison with the inertia wheel 20, as it is received in the camming
recess 30 of the cam wheel 27. Thus, the latch wheel 12 is
stationary and the pawl member 8 is held disengaged from the
ratchets 7,7' under the influence of the spring 11. The safety belt
2 can then be withdrawn or retracted as desired with the body
movement of the vehicle seat occupant. When a load higher than 0.3
G is suddenly applied to the safety belt 2 by the seat occupant's
forward movement, in the case of some abnormal situation
encountered by the automotive vehicle such as sharp deceleration,
and the safety belt 2 is suddenly withdrawn, the cam wheel 27
starts its rapid rotation with the shaft 3. The inertia wheel 20
starts its rotation with the cam wheel 27, but with a certain time
lag, because the inertia wheel 20 is fitted loosely on the shaft 3
and is made of metallic material and thus has considerable weight.
Thus, the cam follower part 31 of the pawl 23 is pushed upwards by
the face of the camming recess 30 of the cam wheel 27, as shown in
FIG. 5. The pawl 23 is swung outwardly about opening 24 as a
fulcrum and against the force of the spring 26, the free end part
of the pawl 23 thus engaging the ratchet teeth of the latch wheel
12. The pawl 23 is rotated by the rotation of the cam wheel 27
thereby causing the turning of the latch wheel 12 to thereby swing
the pawl teeth 10,10' of the pawl member 8 into engagement with the
ratchet wheels 7,7' and thus bring the rotation of the reel 4 to a
stop. In this locking process, when the pawl 23 is completely
engaged with the ratchet teeth of the latch wheel 12 and the wheel
12 starts its rotation, the latch wheel 12 is synchronized with the
ratchet wheels 7,7', so that the end parts of the pawl teeth 10,10'
are kept in the position of the tooth tips of the ratchet wheels
7,7'. The latch wheel is thus rotated until the pawl teeth 10,10'
are engaged completely with the tooth bottom regions of the ratchet
wheels 7,7'. At this time, the ratchet wheels 7,7' are rotated
simultaneously into complete meshing with the pawl teeth of the
pawl member 8. With the ratchet wheels 7,7' thus engaged with the
pawl teeth 10,10' the reel 4 is locked against belt withdrawal
rotation to keep the safety belt 2 from further extraction, thereby
restraining the occupant in his seat and promoting his safety.
The embodiments of the present invention illustrated in FIGS. 6 to
7 of the drawings differ from that first described only in the
manner of drive coupling the latch wheel 12 to the pawl member 8.
Thus, in the embodiment shown in FIGS. 6 and 6', an acutating lever
16' is enlarged between its end and provided with an opening
rotatably engaging the shaft 3 proximate the end wall of latch
wheel 12. One end of the lever 16' terminates in a thickened yoke
portion 19' which engages the tongue 17 projecting from the end of
the cross bar of pawl member 8 and a pin 18' projects from the
other end of lever 16' into sliding engagement with the slot 15 in
the latch wheel end wall. In the embodiment illustrated in FIG. 7,
a radial projection is integrally formed on the outside peripheral
face of latch wheel 12 and has an enlarged radial recess 12' formed
therein which slideably engages the tongue 17 on pawl member 8, so
that rocking of the latch wheel 12 swings the pawl member 8. In
operation, and in all other constructional details and
relationships, the embodiments last described are similar to that
first described.
The conventional emergency locking and winding mechanisms of the
present type are usually provided with a complicated clutch
mechanism to protect the sensor unit from excessive load
application and prevent the incomplete locking at the time of
operation. This results in the deficiencies and errors in
sensitivity and in increased difficulty in producing a compact
device. With the mechanism of the present invention, the device may
be made highly compact due to omission of the complicated clutch
mechanism as used in the conventional device. Moreover the various
defects as encountered in the conventional apparatus at the time of
emergency may be obviated without any reduction in the reliability
of operation.
While there have been described and illustrated preferred
embodiments of the present invention, it is apparent that numerous
alterations, additions and omissions may be made without departing
from the spirit thereof.
* * * * *