CA1047016A - Seat belt retracting and winding device - Google Patents
Seat belt retracting and winding deviceInfo
- Publication number
- CA1047016A CA1047016A CA271,435A CA271435A CA1047016A CA 1047016 A CA1047016 A CA 1047016A CA 271435 A CA271435 A CA 271435A CA 1047016 A CA1047016 A CA 1047016A
- Authority
- CA
- Canada
- Prior art keywords
- spring
- seat belt
- ratchet
- winding
- ratchet wheel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Automotive Seat Belt Assembly (AREA)
Abstract
SEAT BELT RETRACTING AND WINDING DEVICE
ABSTRACT OF THE DISCLOSURE
A seat belt retracting and winding device in which a seat belt may be automatically retracted and wound on a winding reel under restoring or unwinding spring force of spiral springs. A cylindrical ratchet wheel is coaxially rotatably supported on a shaft of a winding reel, and is covered with a case attached to one of the side plates of a frame of the device.
There are provided a first spiral spring disposed in a doughnut-shaped space defined between the case and the ratchet wheel, and a second spiral spring disposed in the ratchet wheel. The first spring has one end fixed to the case and the other end fixed to the ratchet wheel, while the second spring has one end fixed to the ratchet wheel and the other end fixed to the shaft of the reel. The ratchet wheel is formed with a plurality of ratchet teeth on its periphery, and a ratchet is pivotally disposed in the case for releasable engagement with the ratchet wheel teeth.
While the seat belt is being paid out both the first and the second springs are wound, however, after the seat belt has been fastened to the vehicle occupant the engagement of the ratchet with the ratchet wheel locks the ratchet wheel against rotation, thereby preventing the first spring from exerting the un-winding spring force to the winding reel, thus reducing unpleasant restraining force applied to the vehicle occupant.
ABSTRACT OF THE DISCLOSURE
A seat belt retracting and winding device in which a seat belt may be automatically retracted and wound on a winding reel under restoring or unwinding spring force of spiral springs. A cylindrical ratchet wheel is coaxially rotatably supported on a shaft of a winding reel, and is covered with a case attached to one of the side plates of a frame of the device.
There are provided a first spiral spring disposed in a doughnut-shaped space defined between the case and the ratchet wheel, and a second spiral spring disposed in the ratchet wheel. The first spring has one end fixed to the case and the other end fixed to the ratchet wheel, while the second spring has one end fixed to the ratchet wheel and the other end fixed to the shaft of the reel. The ratchet wheel is formed with a plurality of ratchet teeth on its periphery, and a ratchet is pivotally disposed in the case for releasable engagement with the ratchet wheel teeth.
While the seat belt is being paid out both the first and the second springs are wound, however, after the seat belt has been fastened to the vehicle occupant the engagement of the ratchet with the ratchet wheel locks the ratchet wheel against rotation, thereby preventing the first spring from exerting the un-winding spring force to the winding reel, thus reducing unpleasant restraining force applied to the vehicle occupant.
Description
~47~6 ~ `
BACKGROUND OF T~E INVENTION
FIELD O~ THE INVENTION
The present invention relates to a seat belt retracting and winding device of the type in which a sea-t belt may be automatically retracted and wound on a winding reel under restoring or unwinding spring force of spiral springs, and more particularly to a seat belt retracting and winding device which may exert a reduced retracting and winding force to the seat belt after it has been fastened to the vehicle occupant.
BRIE~ DESCRIPTION O~ PRIOR ART
There have conventionally been known seat belt retracting and winding devices which contain only one spiral spring having its one end attached to a shaft of a windlng rool and the other end attached to the body of a retractor. In these devices, when the ;~
seat belt is paid out and thus the winding reel is rotated, the spiral spring is wound to exert an un-winding or restoring spring force to the seat belt, thereby retracting and winding the latter onto the winding reel. Generally the spiral spring used in these devices exerts an increased unwinding spring ~ ~ -force to the seat belt according to the increase in length of the seat belt paid out. Therefore, when the seat belt is paid out in larger length and fastened to the occupant, ths winding spring force of the -~
spiral spring exerts a large restraining or tightening force to the seat belt. Such large restraining force 70~
1 not only brings about an uncomfortable feeling to the occupant but also prevents his smooth movement. In cases where the large restraining force is exerted to the driver9 the movement of the driver is restricted so that the safe driving operations will be adversely affected.
In the conventional devices of the type in which a lap belt and a shoulder belt are made of a continuous webbing and winding means is disposed on the shoulder belt side, it is necessary to pay out the seat belt in particularly larger length, so that the restraining force exerted to the occupant becomes very large. Further, in a passive seat belt system in which the length of the seat belt paid out is ;
further increased, the occupant experiences much more uncomfortable restraining force.
In the seat belt retracting and winding devices of the type described, it is desirable to reduce the unwinding spring force of the spiral spring in order that the restraining force exerted to the occupant may be reduced. However, the reduced spring force brings about a disadvantage such that the seat belt is not completely retracted and wound on the winding reel wheh the seat belt is unfastened or released.
SUMMARY OF T~E IN~ENTION
It is therefore a primary object of the present invention to provide an improved seat belt retracting and winding device which avoids the aforesaid disadvantages experienced with the conventional devices 7Q~6 o~ the type described.
According to one aspect of the present invention there is provided a seat belt retracting and winding device comprising a frame; a winding reel rotatably supported by said frame; spring means connected between said frame and said winding reel and including a first spring and a second spring;
said winding reel being adapted to wind thereon a seat belt with a spring force of at least one of said first and second springs; and means for controlling the combina-tion of spring forces of said first and second springs and operable in response to the rotation of said winding reel for causing said spring means to operate selectively under a first operative condition and a ;
second operative condition exerting larger and smaller spring forces, res-pectively, on said seat belt, whereby the winding force exerted on said seat belt is reduced when said spring means is operated under said second operative condition.
According to another aspect of the present invention there is pro-vided a seat belt retracting and winding device comprising: a frame; spring ~-means fixed at its one end to said frame and including a first spiral spring and a second spiral spring; a seat belt; a winding reel rotatably supported by said frame and connected to said spring means; said winding reel being adapted to wind thereon said seat belt with aspring force of at Ieast one of said first and second spiral springs; clutch means operatively connecting one end of said first spiral spring with one end of said second spiral spring, and operable selectively under a first operative condition and a second -operative condition; said clutch means changing over said operative condi-tions to control the composition or combination of spring forces of said first and second spiral springs; and control means operatively connected to said winding reel to detect the winding of said sea~ belt to thereby actuate said clutch means; said clutch means being changed over to operate under said first operative condition to thereby reduce the winding force exerted on said seat belt when the seat belt having been paid out is retracted and wound.
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Accordlng to a further aspect of the present invention there is provided a seat belt retracting and winding device comprising: a frame having two side plates, a winding reel rotatably supported in said side plates and including an integral shaft, a seat belt wound on said winding reel, said seat belt being fixed at its inner end to said winding reel, a cup-shaped case attached to one of said side plates, a ratchet wheel rotatably supported on said shaft, said ratchet wheel having a plurality of ratchet teeth formed on the periphery thereof, a first spiral spring having one end fixed to said case and the other end fixed to said ratchet wheel, a second spiral spring having one end fixed to said shaft and the other end fixed to said ratchet wheel, a ratchet operatively releasably engaging the ratchet tee~h on said ratchet wheel, and co-operative means operable in response to the rotation of said winding reel to bring said ratchet into engagement with the ratchet teeth on said ratchet wheel thereby locking the same against rotation, whereby when said seat belt is paid out and fastened to the vehicle occupant : :
the unwinding spring force of said first spring is not exerted to said wind-ing reel while the unwinding spring force of only said second spring is exerted thereto. ~ -In the accompanying drawings:-Figure 1 is a sectional view taken along the line I-I of Figure 2, illustrating a first embodiment of a seat belt retracting and winding device in accordance with the present invention;
- 3a -~7(1 ~6 1 Fig. 2 is a cross sectional view taken along the line II - II of Fig. l;
Fig. 3 is a cross sectional view taken along the line III - III of Fig. l;
Fig. 4 is a cross sectional view taken along the line IV - IV of Fig. 1, illustrating the engagement of a shaft of a winding reel wi-th a ratchet wheel when a seat belt is completely retracted and wound on a ~;~
winding reel;
Fig. 5 is a cross sectional view similar to Fig. 4, illustrating the engagement of the shaft with the ratchet wheel when the seat belt is paid out;
Fig. 6 is an explanative view illustrating the engagement of an operating lever with a lever of a leaf spring shown in Fig. 3;
Figs. 7 and 8 are explanative views simllar to Figo 6, illustrating the engagement of the operating ~;
lever with a friction disk in different positions;
Fig. 9 is a sectional view taken along the line IX - IX of Fig. 11, illustrating a second embodi-ment of the present invention;
Figs. lO(A) and lO(B) are top and side views, respectively, of a ratchet wheel shown in Fig. 9;
Fig. 11 is a cross sectional view taken along the line XI - XI of Fig. 9;
Fig. 12 is a cross sectional view taken along the line XII - XII of Fig. 9, illustrating the engage-ment of a shaft of a winding reel with a ratchet wheel when a seat belt is completely retracted and wound on a windi~g reel;
: . . . ~ . :
.: : . :
~0~7~6 1 Fig. 13 is a cross sectional view similar to Fig. 12, illustrating the engagement of the shaft with the ratchet wheel when the seat belt is paid out;
Fig. 1~ is a cross sectional view taken along the line XIV - XIV of Fig. 9, showing an operating lever engaged with a lever of a leaf spring;
Figs. 15 and 16 are cross sectional views similar to Eig. 14, showing the operating lever engaged with a friction disk in different positions;
Fig. 17 is a sectional view taken along the ; line XVII - XVII of Eig. 18, illustrating a third embodiment of the present invention;
Fig. 18 is a cross sectional view taken along the line XVIII - ~III of Fig. 17;
Fig. 19 is a cross sectional view taken along the line XIX - XIX of Fig. 17, showing a ratchet ~-engaged with a cam gear member; and Fig. 20 is a cross sectional view similar ;~
to Fig. 19, showing the ratchet engaged with a ratchet wheel.
Same or similar reference numerals are used to designate same or similar parts throughout the figures.
DESCRIPTION OF THE PREFERRED EM13ODIME:~TS
First Embodiment, Figs. 1 through 8 Referring to Figs. 1, 2 and 3, a frame 1, which is the main body of a seat belt retracting device in accordance with the present invention, is formed by the press operation from a thick steel plate, and has ' . ~ .
~04~
1 side plates la and lb and a mounting hole lc for anchoring the frame 1 to the floor of an automotive vehicle. A shaft 2b of a winding reel 2 is rotatably supported in bush bearings ld and le made of teflon `
or the like and attached to the side plates la and lb The reel 2 includes flanges 2c and 2d and a spool 2a made integral with the shaft 2b. The inner end of a seat belt 3 is securely attached to the spool 2a while the other end is attached to an anchor or a buckle (not shown). As shown in Fig. 3, ratchet teeth are formed in the flanges 2c and 2d. In case of the rapid deceleration of the vehicle, seat belt locking means (not shown) engages the ratchet teeth for locking the seat belt 3, thereby protecting the vehicle occupant.
A cup-shaped case 4, which is molded from suitable synthetic resin, is attached to the side plate lb, and a ratchet wheel 5 is rotatably supported between a shaft bearing hole 4d formed at the center of the case 4 and the bush bearing le. The ratchet wheel 5 includes a large-diameter cylindrical section and a small-diameter cylindrical section, and ratchet teeth ~ ~
5a are formed around the outer periphery of the large ~ ~ ?
diameter section as shown in ~ig. 2. One end of a first spiral spring 6 is attached to the small diameter section 5b while the other end of the first spiral spring 6 is attached to the case 4 so that when the ratchet wheel 5 rotates, the first spiral spring 6 is wound around the small-diameter cylindrical section 5b.
One end 7a of a second spiral spring 7, which is ' .
;.:~
16)~7~6 1 disposed in the large-diameter section, is inserted and attached into a slit 2f of the shaft 2b (See Fig. 2) while the other end 7b is attached to the inner wall of the large-diameter section. The spring force of the second spring 7 is a weaker than that of the first spring 6. As shown Figs. 4 and 5, a projection 2e is provided at one end (the left end in Fig. 1) of the shaft 2b for engagement with a stopper 5c provided on the inner wall o~ the small-diameter section.
The projection 2e engages the stopper 5c as shown in Fig. 4 when the seat belt 3 is retracted and completely wound around the reel 2, while they engage with each other as shown in Fig. 5 when the belt 3 is paid out. More particularly, when the belt 3 is retracted and completely wound around the reel 2, the shaft 2b is exerted with the spring force of the second spring 7 in a directlon opposite to that indicated by an arrow A in Fig. 4 so that the projection 2e engages the stopper 5c as shown in Fig. 4. On the other hand, when the seat belt 3 is paid out, the shaft 2b is rotated in a direction indicated by the arrow A in Fig. 4, and only the second spring 7 is wound up be-cause it is weaker in spring force than the first spring 6. At this time, -the rotation of the ratchet wheel 5 with respect to the case 4 is not permitted so that the projection 2e comes to engage the stopper 5c as shown in Fig. 5. When the seat belt 3 is paid out, the shaft 2b is rotated in the direc-tion indicated by the arrow A in Fig. 5 with the projection 2e kept in :
: :
~L~47~
1 engagement with the stopper 5c so that the ratchet wheel 5 is rotated and consequently the first spring is wound up around the small-diameter section 5b. It should be noted that at this time there exists no relative rotation between the shaft 2b and the ratchet wheel 5 so that the second sprine 7 is no longer wound up. ' :
A doughnut-shaped leaf spring 8 and a fric-tion disk 9 are carried by the shaft 2b between the side plate lb of the frame 1 and the flange 2d of the reel 2. The leaf spring 8 9 which is made of, for instance, phosphor bronze, includes three spring legs 8a and a lever 8b as shown in Figs. 3, 6, 7 and 8. The lever 8b is radially outwardly extended and 15 is placed between a retraction stopper lf and an ~-extension stopper lg both of which project from the side plate lb of the frame 1 toward the friction disk 9 so that the angular displacement of the lever 8b ~
,...
is limited between the stoppers lf and lg. The friction disk 9 is pressed against the flange 2d under the ; biasing force of the leaf spring 8, and rotates in unison with the reel 2. ~ portion of the periphery ~-of the friction disk 9 is somewhat radially outwardly ' bulged to form a cam portion 9a (See Fig. 6), and the ; 25 most radially outwardly bulged point is stepped to form a stopper portion 9b (See Fig. 3).
A ratchet 11 for selective engagement at its locking pawl llb with the teeth 5a of the ratchet wheel 5 is attached to one end (on the side of the ~0 case 4) of a shaft lla rotatably supported in and '~ ' ' :, .
... . . . .
~(~47~L6 1 extending through the side plate lb (See ~ig. 2), while an operating lever llc having its loc~ing pawl lld engaged with the periphery of the friction disk 9 is attached to the other end (on the side of the disk 9) of the shaft lla (See Fig. 3). Therefore the operating lever llc moves or swings in unison with the ratchet 11. As shown in Fig. 3, the operating lever llc is pressed against the peripheral surface of the friction disk 9 under -the biasing force of a leaf spring 12 having one end thereof attached to the side plate lb. When the pawl lld of the operating lever llc engages the stopper portion 9b of the fric-tion disk 9 as shown in Fig. 39 the locking pawl llb of the ratchet 11 is moved away from the teeth 5a of the ratchet wheel 5, so that the locking pawl llb becomes out of engagement with the teeth 5a as shown in Fig. 2.
The friction resistance Fl between the friction disk 9 and the flange 2d, the friction resistance F2 between the leaf spring 8 and the friction disk 9 and the friction resistance F3 between the side p]ate lb and the leaf spring 8 have the follow-ne relation:
F1 > F2 > F3 Therefore when the belt 3 is paid out and thus the flange 2d is rotated, the leaf spring 8 as well as the fric-tion disk 9 rotates in unison with the flange 2d, but after the lever 8b of the leaf spring 8 has engaged the extension stopper lg, only the friction disk 9 rotates in unison with the flange 2d.
~470~ ~
1Next the mode of operation ~ith the first embodiment of the present invention with the above construction will be described. When the seat belt 3 is retracted and completely wound around the reel 2, the projection 2e of the shaft 2b engages the stopper 5c of the ratchet wheel 5 as shown in Fig. 4 9 and the operating lever llc is held in a raised position by the lever 8b of the leaf spring 8 as shown in Fig. 6.
As a result, the locking pawl llb of the ratchet 11 -is moved away from the teeth 5a of the ratchet wheel 5 as shown in Fig. 2.
When the occupant pays out the belt 3, the latter is unwound from the reel 2 so that the flange , . ~
2d and the shaft 2b are rotated in the direction in-15 dicated by the arrow A in Figs. 6 and 4. The friction ~ ~;
disk 9 and the leaf spring 8 rotate in unison with the flange 2d so that, as shown in Fig. 7, the lever 8b .:
is disengaged from the pawl lld of the operating lever , llc and consequently the pawl lld is pressed against the peripheral surface of the friction disk 9 under :: ~
the biasing force of the leaf spring 12. The locking pawl 11b of the ratchet 11, which swings in unison with the operating lever llc, engages the teeth 5a of ; ~ -the ratchet wheel 5. However, as is clear from ~ig.
BACKGROUND OF T~E INVENTION
FIELD O~ THE INVENTION
The present invention relates to a seat belt retracting and winding device of the type in which a sea-t belt may be automatically retracted and wound on a winding reel under restoring or unwinding spring force of spiral springs, and more particularly to a seat belt retracting and winding device which may exert a reduced retracting and winding force to the seat belt after it has been fastened to the vehicle occupant.
BRIE~ DESCRIPTION O~ PRIOR ART
There have conventionally been known seat belt retracting and winding devices which contain only one spiral spring having its one end attached to a shaft of a windlng rool and the other end attached to the body of a retractor. In these devices, when the ;~
seat belt is paid out and thus the winding reel is rotated, the spiral spring is wound to exert an un-winding or restoring spring force to the seat belt, thereby retracting and winding the latter onto the winding reel. Generally the spiral spring used in these devices exerts an increased unwinding spring ~ ~ -force to the seat belt according to the increase in length of the seat belt paid out. Therefore, when the seat belt is paid out in larger length and fastened to the occupant, ths winding spring force of the -~
spiral spring exerts a large restraining or tightening force to the seat belt. Such large restraining force 70~
1 not only brings about an uncomfortable feeling to the occupant but also prevents his smooth movement. In cases where the large restraining force is exerted to the driver9 the movement of the driver is restricted so that the safe driving operations will be adversely affected.
In the conventional devices of the type in which a lap belt and a shoulder belt are made of a continuous webbing and winding means is disposed on the shoulder belt side, it is necessary to pay out the seat belt in particularly larger length, so that the restraining force exerted to the occupant becomes very large. Further, in a passive seat belt system in which the length of the seat belt paid out is ;
further increased, the occupant experiences much more uncomfortable restraining force.
In the seat belt retracting and winding devices of the type described, it is desirable to reduce the unwinding spring force of the spiral spring in order that the restraining force exerted to the occupant may be reduced. However, the reduced spring force brings about a disadvantage such that the seat belt is not completely retracted and wound on the winding reel wheh the seat belt is unfastened or released.
SUMMARY OF T~E IN~ENTION
It is therefore a primary object of the present invention to provide an improved seat belt retracting and winding device which avoids the aforesaid disadvantages experienced with the conventional devices 7Q~6 o~ the type described.
According to one aspect of the present invention there is provided a seat belt retracting and winding device comprising a frame; a winding reel rotatably supported by said frame; spring means connected between said frame and said winding reel and including a first spring and a second spring;
said winding reel being adapted to wind thereon a seat belt with a spring force of at least one of said first and second springs; and means for controlling the combina-tion of spring forces of said first and second springs and operable in response to the rotation of said winding reel for causing said spring means to operate selectively under a first operative condition and a ;
second operative condition exerting larger and smaller spring forces, res-pectively, on said seat belt, whereby the winding force exerted on said seat belt is reduced when said spring means is operated under said second operative condition.
According to another aspect of the present invention there is pro-vided a seat belt retracting and winding device comprising: a frame; spring ~-means fixed at its one end to said frame and including a first spiral spring and a second spiral spring; a seat belt; a winding reel rotatably supported by said frame and connected to said spring means; said winding reel being adapted to wind thereon said seat belt with aspring force of at Ieast one of said first and second spiral springs; clutch means operatively connecting one end of said first spiral spring with one end of said second spiral spring, and operable selectively under a first operative condition and a second -operative condition; said clutch means changing over said operative condi-tions to control the composition or combination of spring forces of said first and second spiral springs; and control means operatively connected to said winding reel to detect the winding of said sea~ belt to thereby actuate said clutch means; said clutch means being changed over to operate under said first operative condition to thereby reduce the winding force exerted on said seat belt when the seat belt having been paid out is retracted and wound.
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::
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~0~701~
Accordlng to a further aspect of the present invention there is provided a seat belt retracting and winding device comprising: a frame having two side plates, a winding reel rotatably supported in said side plates and including an integral shaft, a seat belt wound on said winding reel, said seat belt being fixed at its inner end to said winding reel, a cup-shaped case attached to one of said side plates, a ratchet wheel rotatably supported on said shaft, said ratchet wheel having a plurality of ratchet teeth formed on the periphery thereof, a first spiral spring having one end fixed to said case and the other end fixed to said ratchet wheel, a second spiral spring having one end fixed to said shaft and the other end fixed to said ratchet wheel, a ratchet operatively releasably engaging the ratchet tee~h on said ratchet wheel, and co-operative means operable in response to the rotation of said winding reel to bring said ratchet into engagement with the ratchet teeth on said ratchet wheel thereby locking the same against rotation, whereby when said seat belt is paid out and fastened to the vehicle occupant : :
the unwinding spring force of said first spring is not exerted to said wind-ing reel while the unwinding spring force of only said second spring is exerted thereto. ~ -In the accompanying drawings:-Figure 1 is a sectional view taken along the line I-I of Figure 2, illustrating a first embodiment of a seat belt retracting and winding device in accordance with the present invention;
- 3a -~7(1 ~6 1 Fig. 2 is a cross sectional view taken along the line II - II of Fig. l;
Fig. 3 is a cross sectional view taken along the line III - III of Fig. l;
Fig. 4 is a cross sectional view taken along the line IV - IV of Fig. 1, illustrating the engagement of a shaft of a winding reel wi-th a ratchet wheel when a seat belt is completely retracted and wound on a ~;~
winding reel;
Fig. 5 is a cross sectional view similar to Fig. 4, illustrating the engagement of the shaft with the ratchet wheel when the seat belt is paid out;
Fig. 6 is an explanative view illustrating the engagement of an operating lever with a lever of a leaf spring shown in Fig. 3;
Figs. 7 and 8 are explanative views simllar to Figo 6, illustrating the engagement of the operating ~;
lever with a friction disk in different positions;
Fig. 9 is a sectional view taken along the line IX - IX of Fig. 11, illustrating a second embodi-ment of the present invention;
Figs. lO(A) and lO(B) are top and side views, respectively, of a ratchet wheel shown in Fig. 9;
Fig. 11 is a cross sectional view taken along the line XI - XI of Fig. 9;
Fig. 12 is a cross sectional view taken along the line XII - XII of Fig. 9, illustrating the engage-ment of a shaft of a winding reel with a ratchet wheel when a seat belt is completely retracted and wound on a windi~g reel;
: . . . ~ . :
.: : . :
~0~7~6 1 Fig. 13 is a cross sectional view similar to Fig. 12, illustrating the engagement of the shaft with the ratchet wheel when the seat belt is paid out;
Fig. 1~ is a cross sectional view taken along the line XIV - XIV of Fig. 9, showing an operating lever engaged with a lever of a leaf spring;
Figs. 15 and 16 are cross sectional views similar to Eig. 14, showing the operating lever engaged with a friction disk in different positions;
Fig. 17 is a sectional view taken along the ; line XVII - XVII of Eig. 18, illustrating a third embodiment of the present invention;
Fig. 18 is a cross sectional view taken along the line XVIII - ~III of Fig. 17;
Fig. 19 is a cross sectional view taken along the line XIX - XIX of Fig. 17, showing a ratchet ~-engaged with a cam gear member; and Fig. 20 is a cross sectional view similar ;~
to Fig. 19, showing the ratchet engaged with a ratchet wheel.
Same or similar reference numerals are used to designate same or similar parts throughout the figures.
DESCRIPTION OF THE PREFERRED EM13ODIME:~TS
First Embodiment, Figs. 1 through 8 Referring to Figs. 1, 2 and 3, a frame 1, which is the main body of a seat belt retracting device in accordance with the present invention, is formed by the press operation from a thick steel plate, and has ' . ~ .
~04~
1 side plates la and lb and a mounting hole lc for anchoring the frame 1 to the floor of an automotive vehicle. A shaft 2b of a winding reel 2 is rotatably supported in bush bearings ld and le made of teflon `
or the like and attached to the side plates la and lb The reel 2 includes flanges 2c and 2d and a spool 2a made integral with the shaft 2b. The inner end of a seat belt 3 is securely attached to the spool 2a while the other end is attached to an anchor or a buckle (not shown). As shown in Fig. 3, ratchet teeth are formed in the flanges 2c and 2d. In case of the rapid deceleration of the vehicle, seat belt locking means (not shown) engages the ratchet teeth for locking the seat belt 3, thereby protecting the vehicle occupant.
A cup-shaped case 4, which is molded from suitable synthetic resin, is attached to the side plate lb, and a ratchet wheel 5 is rotatably supported between a shaft bearing hole 4d formed at the center of the case 4 and the bush bearing le. The ratchet wheel 5 includes a large-diameter cylindrical section and a small-diameter cylindrical section, and ratchet teeth ~ ~
5a are formed around the outer periphery of the large ~ ~ ?
diameter section as shown in ~ig. 2. One end of a first spiral spring 6 is attached to the small diameter section 5b while the other end of the first spiral spring 6 is attached to the case 4 so that when the ratchet wheel 5 rotates, the first spiral spring 6 is wound around the small-diameter cylindrical section 5b.
One end 7a of a second spiral spring 7, which is ' .
;.:~
16)~7~6 1 disposed in the large-diameter section, is inserted and attached into a slit 2f of the shaft 2b (See Fig. 2) while the other end 7b is attached to the inner wall of the large-diameter section. The spring force of the second spring 7 is a weaker than that of the first spring 6. As shown Figs. 4 and 5, a projection 2e is provided at one end (the left end in Fig. 1) of the shaft 2b for engagement with a stopper 5c provided on the inner wall o~ the small-diameter section.
The projection 2e engages the stopper 5c as shown in Fig. 4 when the seat belt 3 is retracted and completely wound around the reel 2, while they engage with each other as shown in Fig. 5 when the belt 3 is paid out. More particularly, when the belt 3 is retracted and completely wound around the reel 2, the shaft 2b is exerted with the spring force of the second spring 7 in a directlon opposite to that indicated by an arrow A in Fig. 4 so that the projection 2e engages the stopper 5c as shown in Fig. 4. On the other hand, when the seat belt 3 is paid out, the shaft 2b is rotated in a direction indicated by the arrow A in Fig. 4, and only the second spring 7 is wound up be-cause it is weaker in spring force than the first spring 6. At this time, -the rotation of the ratchet wheel 5 with respect to the case 4 is not permitted so that the projection 2e comes to engage the stopper 5c as shown in Fig. 5. When the seat belt 3 is paid out, the shaft 2b is rotated in the direc-tion indicated by the arrow A in Fig. 5 with the projection 2e kept in :
: :
~L~47~
1 engagement with the stopper 5c so that the ratchet wheel 5 is rotated and consequently the first spring is wound up around the small-diameter section 5b. It should be noted that at this time there exists no relative rotation between the shaft 2b and the ratchet wheel 5 so that the second sprine 7 is no longer wound up. ' :
A doughnut-shaped leaf spring 8 and a fric-tion disk 9 are carried by the shaft 2b between the side plate lb of the frame 1 and the flange 2d of the reel 2. The leaf spring 8 9 which is made of, for instance, phosphor bronze, includes three spring legs 8a and a lever 8b as shown in Figs. 3, 6, 7 and 8. The lever 8b is radially outwardly extended and 15 is placed between a retraction stopper lf and an ~-extension stopper lg both of which project from the side plate lb of the frame 1 toward the friction disk 9 so that the angular displacement of the lever 8b ~
,...
is limited between the stoppers lf and lg. The friction disk 9 is pressed against the flange 2d under the ; biasing force of the leaf spring 8, and rotates in unison with the reel 2. ~ portion of the periphery ~-of the friction disk 9 is somewhat radially outwardly ' bulged to form a cam portion 9a (See Fig. 6), and the ; 25 most radially outwardly bulged point is stepped to form a stopper portion 9b (See Fig. 3).
A ratchet 11 for selective engagement at its locking pawl llb with the teeth 5a of the ratchet wheel 5 is attached to one end (on the side of the ~0 case 4) of a shaft lla rotatably supported in and '~ ' ' :, .
... . . . .
~(~47~L6 1 extending through the side plate lb (See ~ig. 2), while an operating lever llc having its loc~ing pawl lld engaged with the periphery of the friction disk 9 is attached to the other end (on the side of the disk 9) of the shaft lla (See Fig. 3). Therefore the operating lever llc moves or swings in unison with the ratchet 11. As shown in Fig. 3, the operating lever llc is pressed against the peripheral surface of the friction disk 9 under -the biasing force of a leaf spring 12 having one end thereof attached to the side plate lb. When the pawl lld of the operating lever llc engages the stopper portion 9b of the fric-tion disk 9 as shown in Fig. 39 the locking pawl llb of the ratchet 11 is moved away from the teeth 5a of the ratchet wheel 5, so that the locking pawl llb becomes out of engagement with the teeth 5a as shown in Fig. 2.
The friction resistance Fl between the friction disk 9 and the flange 2d, the friction resistance F2 between the leaf spring 8 and the friction disk 9 and the friction resistance F3 between the side p]ate lb and the leaf spring 8 have the follow-ne relation:
F1 > F2 > F3 Therefore when the belt 3 is paid out and thus the flange 2d is rotated, the leaf spring 8 as well as the fric-tion disk 9 rotates in unison with the flange 2d, but after the lever 8b of the leaf spring 8 has engaged the extension stopper lg, only the friction disk 9 rotates in unison with the flange 2d.
~470~ ~
1Next the mode of operation ~ith the first embodiment of the present invention with the above construction will be described. When the seat belt 3 is retracted and completely wound around the reel 2, the projection 2e of the shaft 2b engages the stopper 5c of the ratchet wheel 5 as shown in Fig. 4 9 and the operating lever llc is held in a raised position by the lever 8b of the leaf spring 8 as shown in Fig. 6.
As a result, the locking pawl llb of the ratchet 11 -is moved away from the teeth 5a of the ratchet wheel 5 as shown in Fig. 2.
When the occupant pays out the belt 3, the latter is unwound from the reel 2 so that the flange , . ~
2d and the shaft 2b are rotated in the direction in-15 dicated by the arrow A in Figs. 6 and 4. The friction ~ ~;
disk 9 and the leaf spring 8 rotate in unison with the flange 2d so that, as shown in Fig. 7, the lever 8b .:
is disengaged from the pawl lld of the operating lever , llc and consequently the pawl lld is pressed against the peripheral surface of the friction disk 9 under :: ~
the biasing force of the leaf spring 12. The locking pawl 11b of the ratchet 11, which swings in unison with the operating lever llc, engages the teeth 5a of ; ~ -the ratchet wheel 5. However, as is clear from ~ig.
2, the locking pawl llb slides over the inclined surface of the tooth 5a so that the pawl llb may not prevent or lock the rotation of the ratchet wheel 5. ~ ;;
The lever 8b of the leaf spring 8, having disengaged from the pawl lld of the operating lever llc, engages the extension stopper lg on the side plate - 10- ~ , :,.
,' ' .' ' ;' ' . - ' ' ' ~,: ~ ' . ' ' ~
.. . . .
.,. ~ .
1 lb as shown in Fig. 7. Thereafter the leaf spring 8 slips over the friction disk 9; that is, the former cannot rotate in unison with the latter so that the former is held in the position shown in Fig. 7. ~s shown in Fig. 3, when the flange 2d is further rotated so that the friction di~sk 9 may make almost one rota-tion from the initial position shown in Fig. 6, the pawl lld of the operating lever llc engages the stopper portion 9b of the friction disk 9 as shown in Fig. 3.
Consequently, the rotation of the friction disk 9 in the direction indicated by the arrow A is prevented while the reel 2 is rotated as the seat belt 3 is paid out.
When the seat belt 3 is started to be paid out, the projection 2e on the shaft 2b is in engagement with the stopper 5c on the ratchet wheel 5 as shown in Fig. 4 so that the second spring 7, which is weaker in spring force than the first spring 6, is wound.
When the shaft 2b makes almost one rotation (through ~ ) as shown in ~ig. 4, the projection 2e engages the stopper 5c as shown in ~ig. 5 so that the rotation of the shaft 2b is transmitted to the ratchet wheel 5.
As a result, the first spring 6 is then wound. During the winding of the first spring 6, the relative rota-tion between the shaft 2b and the ratchet wheel 5 isprevented so that the second spring 7, which has been already wound by almost one rotation of the shaft 2b, '~
may be pre~ented from being further wound.
When the seat belt 3 is paid out in the manner described above and fastened to restrain the 1 occupant, the belt 3 is ~omewhat slacked. There~ore, the belt 3 is retracted by the first and second springs 6 and 7 to eliminate the slacks. That is, the flange 2d of the reel 2 is rotated in the direction opposite to that indicated by the arrow A shown in ~ig. 3, so that both the leaf spring 8 and the friction disk 9 rotate in this direction in unison with the flange 2d.
As a result, when the belt 3 is retracted a little, the relative position between the operating lever llc and the friction disk 9 changes from the position shown in Fig. 3 to the position shown in ~ig. 8. At the latter position~ the pawl lld of the operating lever llc is disengaged from the stopper portion 9b of the friction disk 9, and thus is made slidable over the peripheral surface of the disk 9. The locking pawl llb of the ratchet 11, which swings in unison with the operating lever llc, engages the teeth 5a of the ratchet wheel 5 and consequently the ratchet wheel 5 is rotated in the direction opposite to that indicated by A in Fig. 2. As a result, the locking pawl llb locks the rotation of the ratchet wheel 5. Under this condition, the restoring or unwinding spring force of the first spring 6 is not exerted to the shaft 2b of the reel 2, and only the unwinding spring force of the second spring 7 is exerted to the shaft 2b in a direction in which the belt 3 is retracted and wound around the reel 2. Therefore the tension of the belt
The lever 8b of the leaf spring 8, having disengaged from the pawl lld of the operating lever llc, engages the extension stopper lg on the side plate - 10- ~ , :,.
,' ' .' ' ;' ' . - ' ' ' ~,: ~ ' . ' ' ~
.. . . .
.,. ~ .
1 lb as shown in Fig. 7. Thereafter the leaf spring 8 slips over the friction disk 9; that is, the former cannot rotate in unison with the latter so that the former is held in the position shown in Fig. 7. ~s shown in Fig. 3, when the flange 2d is further rotated so that the friction di~sk 9 may make almost one rota-tion from the initial position shown in Fig. 6, the pawl lld of the operating lever llc engages the stopper portion 9b of the friction disk 9 as shown in Fig. 3.
Consequently, the rotation of the friction disk 9 in the direction indicated by the arrow A is prevented while the reel 2 is rotated as the seat belt 3 is paid out.
When the seat belt 3 is started to be paid out, the projection 2e on the shaft 2b is in engagement with the stopper 5c on the ratchet wheel 5 as shown in Fig. 4 so that the second spring 7, which is weaker in spring force than the first spring 6, is wound.
When the shaft 2b makes almost one rotation (through ~ ) as shown in ~ig. 4, the projection 2e engages the stopper 5c as shown in ~ig. 5 so that the rotation of the shaft 2b is transmitted to the ratchet wheel 5.
As a result, the first spring 6 is then wound. During the winding of the first spring 6, the relative rota-tion between the shaft 2b and the ratchet wheel 5 isprevented so that the second spring 7, which has been already wound by almost one rotation of the shaft 2b, '~
may be pre~ented from being further wound.
When the seat belt 3 is paid out in the manner described above and fastened to restrain the 1 occupant, the belt 3 is ~omewhat slacked. There~ore, the belt 3 is retracted by the first and second springs 6 and 7 to eliminate the slacks. That is, the flange 2d of the reel 2 is rotated in the direction opposite to that indicated by the arrow A shown in ~ig. 3, so that both the leaf spring 8 and the friction disk 9 rotate in this direction in unison with the flange 2d.
As a result, when the belt 3 is retracted a little, the relative position between the operating lever llc and the friction disk 9 changes from the position shown in Fig. 3 to the position shown in ~ig. 8. At the latter position~ the pawl lld of the operating lever llc is disengaged from the stopper portion 9b of the friction disk 9, and thus is made slidable over the peripheral surface of the disk 9. The locking pawl llb of the ratchet 11, which swings in unison with the operating lever llc, engages the teeth 5a of the ratchet wheel 5 and consequently the ratchet wheel 5 is rotated in the direction opposite to that indicated by A in Fig. 2. As a result, the locking pawl llb locks the rotation of the ratchet wheel 5. Under this condition, the restoring or unwinding spring force of the first spring 6 is not exerted to the shaft 2b of the reel 2, and only the unwinding spring force of the second spring 7 is exerted to the shaft 2b in a direction in which the belt 3 is retracted and wound around the reel 2. Therefore the tension of the belt
3; that is, the restraining or tightening force exerted to the occupant is dependent only upon the unwinding spring force of the second spring 7.
1(;1 47~16 1 ~urthermore, as described above, the spring force of the second spring 7 is selected to be weaker than that of the first spring 6, and the second spring 7 has been wound only by almost one rotation of the shaft 2b. Therefore the tension exerted to the occupant is reduced and stabilized so that the occupant may experience no unpleasant restraining force and may freely move his body for operating a switch or the like. As described above, when the occupant is using the seat belt 3, the tension of the belt is produced only by the second spring 7 so that the tension may be freely adjusted.
In case of the sudden deceleration of the vehicle due to a collision or the like, the locking means (not shown) immediately engage the ratchet gears formed in the flanges 2c and 2d of the reel 2 to prevent sudden extension o~ the seat belt 3 so that the belt may securely restrain the occupant from the secondary collision in the vehicle chamber.
Mext the mode of the retraction of the seat belt 3 when the occupant unfastens or release it will be described. Immediately before the seat belt is i released, the pawl lld of the operating lever llc is in engagement with the lever 8b of the leaf spring 8 -~
as shown in Fig. 8, while the locking pawl llb of the ratchet 11 is in engagement with the teeth 5a of `~
the ratchet wheel 5 so that the unwinding spring force of the first spring 6 is not exerted to the shaft 2b as described above. When the seat belt 3 is unfastened, the unwinding spring force of the second spring 7 is -, . . . , . :
.
-~
.
~ ,: . ' -, , :
470~L~
1 exerted to the reel 2 in a direction indicated by the arrow B in ~ig. 8. As described above, the friction resistance Fl between the friction disk 9 and the flange 2d is higher th~n the resistance F2 between the friction disk 9 and the leaf spring 8, so that the friction disk 9 rotates in unison with the flange 2d in the direction indicated by the arrow B, but the rotation of the leaf spring 8 in the direction B is prevented by the engagement of the lever 8b with the pawl lld of the operating lever llc. When the flange 2d has made almost one rotation under the unwinding spring force of the second spring 7, the latter is ; '~
substantially unwound or released so that no unwinding ~ ~-force is exerted by the second spring 7 to the reel ! `
2, but the friction disk 9 is returned to the initial position shown in Fig. 6. That is, in unison with the rotation in the direction B of the reel 2 under the unwinding spring force of the second spring 7, the `
friction disk 9 rotates in the direction indicated -by the arrow B in Fig. 8, and before the friction disk 9 makes one rotation, the pawl lld of the operating `
lever llc is raised by the cam portion 9a of the fric- ~ `
tion disk 9 into the position shown in Fig. 6. In ::.:. , :
the latter position, the lever 8b of the leaf spring -::: ,, 8 engages the retraction stopper lf so that -the leaf spring 8 is held in the position shown in Fig. 6 regardless of further rotation of the friction disk 9. When the pawl lld of the operating lever llc is raised as shown in Fig. 6, the locking pawl llb of ~o the ratchet 11 is disengaged from the teeth 5a of the :. ~ .. . , `- ' . :
~ . : , .' ::' ~ ' ' ':
, 1 ratchet wheel 5 as shown in Fig. 2 so that the s~cond spring does not produce substantial unwinding ~orce.
However, the strong unwinding force of the first spring 5 is now exerted to the reel 2 so that the belt 3 is rapidly retracted and wound around the reel 2. The friction resistances exerted by the friction disk 9 and the leaf spring 8 to the flange 2d are sufficiently lower as compared with the unwinding forces of the first and second springs 6 and 7 so that the friction resistances will not adversely affect the seat belt retracting operation.
Second Embodiment, Figs. 9 through 16 The second embodiment shown in ~igs. 9 through 16 is substantially similar in construction to the first embodiment described above so that only the parts different from those of the first embodiment will be described. Referring to Figs. lOA and lOB, the ratchet wheel 5, which is rotatably supported on the flange of the bush bearing le attached to the side plate lb, has ratchet teeth 5a formed on the periphery thereof. The ratchet wheel 5 has six protrusions 5b, 5c, 5d, 5f and 5e formed by punching or the like. The protrusions 5b, 5c and 5d are angularly spaced apart from each other by 90, and the protrusions 5b are angularly spaced apart by 180 while the protrusions 5c and 5d are angularly spaced apart by 180. The protrusions 5b and 5d are positioned on a common inscribed circle (indicated by a phantom line in Fig. lOA) whose center coincides with that of the ratchet wheel 5, while the ~Q~7~6 1 protrusion 5c lies radially inside of the circle. The protrusions 5f and 5e are formed on circumferentially both sides of the protrusion 5d.
One end 6a of a spiral spring 60 which is housed within the case 4 is inserted and fixed in a slit 4b formed in the inner wall of the case 4 while ~ ~;
the other or inner end 6b is inserted and fixed in the slit 2f of the shaft 2b. The spring 60 is wrapped around the protrusions 5b through 5f as shown in ~ig.
11, and two radially inwardly extending projections 6c of the spring 60 sandwitch the protrusion 5d so that not only the spring 60 is securely attached to the ratchet wheel 5 but also it is livided into an outer or a first spring section 6 and an inner or a second spring section 7. The unwinding spring force of the second spring 7 is directly transmitted to the ;
shaft 2b while the unwinding spring force of the first spring 6 is indirectly transmitted to the shaft 2b through the ratchet wheel 5. ;~
As shown in Figs. 12 and 13, the shaft 2b ..
is formed with an integral flange 2h at an inner end ;~
of its small diameter portion on which the spring 60 is wound, and the flange 2h has a radial projection 2e.
The projection 2e is formed integral with the flange 25 2h in a manner that it is rotatable within the inscribed ;
circle passing the inner sides of -the protrusions 5b and 5d, however, it is engageable with the protrusion 5c which is formed radially inside of the circle.
Next the mode of operation of the second embodiment will be described. When the belt 3 is :.
.. . .
.: , ~ ' ~
.. . ' ' ' , ' . . .
~047~1~
1 retracted and wound around the reel 2, the spring 60 still has some unwinding spring force. Therefore, the belt 3 is completely wound around the reel 2 under this residual unwinding force of the spring 60, and the projection 2e of the shaft 2b is in engagement with the protrusion 5c (to be referred to as the "stopper" hereinafter in this specification) of the ratchet wheel 5 as shown in Fig. 12. The shaft 2b is biased in the direction opposite to that indicated by the arrow A in Fig. 12 under the residual unwinding force of the spring 60. The operating lever llc is `
held in the raised position as shown in Fig. 14 as the lever 8b of the leaf spring 8 raises the lever llc against the leaf spring 12. As a result, the ratchet 11, which swings in unison with the driving lever llc, is moved away from the teeth of the ratchet wheel 5 as with the case of the first embodiment.
When the occupant pays out the belt 3, the ~-~
flange 2d and the shaft 2b of the reel 2 are rotated in the direction indicated by the arrow A in Figs. 12 and 14. The friction disk 9 and the leaf spring 8 are also rotated in the sa~e direction in unison with the flange 2d so that the pawl lld of the operating lsver llc is disengaged from the lever 8b of the leaf spring 8 and consequently pressed against the peri~
pheral surface of the friction disk 9. As a result, the locking pawl llb of the ratchet 11, which swings is unison with the operating lever llc, engages the ratchet wheel 5. As is clear from Fig. 11, the locking pawl llb only slides on the slanted surface of the teeth ... , .-. .. -. . ... .
- . . . .
. .
. . ~ ' ' :, . . ... ,:
1047~16 1 retracted and wound around the reel 2, the spring ~0 still has some unwinding spring force. Therefore, the belt 3 is completely wound around the reel 2 under this residual unwinding force of the spring 60, and the projection 2e of the shaft 2b is in engagement with the protrusion 5c (to be referred to as the "stopper" hereinafter in this specificat.ion) of the ratchet wheel 5 as shown in Fig. 12. The shaft 2b is ;
biased in the direction opposite to that indicated by the arrow A in ~ig. 12 under the residual unwinding force of the spring 60. The operating lever llc is held in the raised position as shown in Fig. 14 as the ~ i~A'',.' lever 8b of the leaf spring 8 raises the lever llc against the leaf spring 12. As a result, the ratchet 11, which swings in unison with the driving lever llc, is moved away from the teeth of the ratchet wheel 5 ;
as with the case of the first embodiment.
When the occupant pays out the belt 3, the flange 2d and the shaft 2b of the reel 2 are rotated ..
in the direction indicated by the arrow A in Figs. 12 and 14. The friction disk 9 and the leaf spring 8 are also rotated in the sa~e direction in unison with the flange 2d so that the pawl lld of the operating ~;
lever llc is disengaged from the lever 8b of the leaf -25 spring 8 and consequently pressed against the peri- ~-pheral surface of the friction disk 9. As a result, the locking pawl llb of the ratchet 11, which swings is unison with the operating lever llc, engages the ratchet wheel 5. As is clear from Fig. 11, the locking pawl llb only slides on the slanted surface of the teeth - . . -, , ~ , . . . :
. , . .: : :
~47~)~L6 1 already wound by almost Pne rotation of the shaft 2b, may be prevented from being further wound.
When the seat belt 3, which has been paid out in the manner described above, is fastened to restrain the occupant, it has some slack. Therefore the belt 3 is retracted by the spring 60 to eliminate the slack of the belt 3. That is, the flange 2d of the reel 2 is rotated in the direction opposite to -that indicated by the arrow A n Fig. 15 so that both - 10 the leaf spring 8 and the friction disk 9 are caused - ~ ;
to rotate in the same direction. When the belt 3 is retracted to eliminate the slack, the relative position between the operating lever llc and the friction disk ~-9 changes from the position shown in Fig. 15 to that shown in Fig. 16. More particularly, the pawl lld of the operating lever llc is disengaged from the ;~ ;
stopper portion 9b of the friction disk 9, and slldes on the peripheral surface of the friction disk 9.
Therefore the locking pawl llb of the ratchet 11 which .:
swings in unison with the operating lever llc comes to engage the teeth 5a of the ratchet wheel. Since ~ -~
the ratchet wheel 5 is rotated in the direction opposite to that indicated by the arrow A in ~ig. 11, the lock-ing pawl llb locks the rotation of the ratchet wheel ~-5. As a result, the unwiding spring force of the first spring 6 is not exerted to the reel 2, but the unwinding spring force of the second spring 7 is exerted to the shaft 2b of the reel 2 in the direction in which the belt 3 is retracted and wound. Therefore the tension of the belt 3; that is the restraining force :: :
- 19 - ~
.
~47~6 1 exerted upon the occupant is dependent upon the un-winding spring force of only the second spring 7 so that the occupant may be restrained under the stable belt tension. As with the case of the first embodiment, locking mean~ (not shown) immediately engage the r~tchet teeth of the flanges 2c and 2d of the reel 2 in case of a collision of the vehicle or the like so that the seat belt ~ may be positively prevented from being suddently paid out.
~ext the mode of operation for retracting and ;~
winding the belt will be described. Immediately before the belt is unfastened, the locking pawl lld of the lever llc is in engagement with the lever 8b of the leaf spring as shown in Fig. 16 while the locking pawl llb of the ratchet 11 is in engagement with the tooth 5a of the ratchet wheel 5, so that the un-winding spring force of the first spring 6 is not exerted to the shaft 2b as described above. The pro-jection 2e of the shaft 2b is in a position indicated by a broken line in Fig. 1~. When the seat belt is unfastened or released, the unwinding force of the ,~
second spring 7 is exerted to the reel 2 in the direction ~ in Fig. 16 so that the shaft 2b is rotated in the direction opposite to the direction A in Fig. 1,. Since the friction resistance F1 between the friction disk 9 and the flange 2d is higher than the friction resistance F2 between the friction disk 9 and the leaf spring 8, the friction disk 9 rotates ~;
in the direction ~ as the flange 2d is rotated in ~0 the same direction in Fig. 16. When the reel -: , , - , ~47~3~6 :::
1 2 and hence its shaft 2b makes almost one rotation under the unwinding spring force of the second spring ~ `
7; that is~ when the projection 2e of the shaft 2b turns from the position indicated by the broken line `
in Fig. 13 to the position shown in Fig. 12, the second spring 7 is substantially unwound or released so that no further returning ~orce is transmitted to the reel 2. When the reel 2 and hence its flange 2d make almost one rotation as described above, the friction disk 9 is rotated to the position shown in Fig. 14. More particularly, when the reel 2 is rotated under the unwinding force of the second spring 7 in the direc-tion B in Fig. 16, the friction disk 9 is also rotated ~-in the same direction. Before the friction disk 9 makes ;
one rotation, its cam portion 9a raises the pawl lld of the operating Iever llc so that~the lever llc is dlsplaced from the position shown in Fig. 16 to the position shown in Fig. 14. As is clear from Fig. 14, ~
the lever 8b of the leaf spring 8 engage retrac- -tion stopper lf so that the leaf spring 8 is held in the po ition shown in Fig. 14 regardless of further rotation of the friction disk 9. When the lever llc is raised by the lever 8b of the leaf spring 8, the ratchet 11 which swings in unison with the operating 25 lever llc is disengaged from the ratchet wheel 5 as ;
shown in Fig. 11 so that the unwinding spring force of the first spring 6 is transmitteid to the reel 2 -and the belt 3 is completely wound around the reel 2.
- 21 -- ;
~' "' ,~
, . ., . . , , :
; - - .,. ~ . : . .
~047V16 ~ ~
1 Third E~bodiment, Figs. 17 through 20 The third embodiment shown in Figs. 17 through 20 is substantially similar in construction to the first embodiment so that only those parts different from those of the first embodiment will be described. A
cup-shaped ratchet wheel 5 is rotatably supported on the shaft 2b within the cup-shaped case 4 a-ttached to the side plate lb of the frame 1. One end of the second spring 7 which is housed within the cylindrical portion 5g of the ratchet wheel 5 is inserted and fixed in the slit 2f of the shaft 2b while the other end is inserted and fixed in the slit 5h of the wall of the cylindrical portion 5g. One end 6b of the first spring 6 which is housed within the doughnut-shaped space defined between the case 4 and the ratchet wheel 5 is joined to the other end of the second spring 7 at the slit 5h while the other end is inserted and fixed in the slit 4b of the case 4. As with the case ;~
of the first embodiment, the first spring 6 is stronger than the second spring 7. The left end portion of the sha~t 2b extends through the ratchet wheel 5 and the terminates in a gear 2g. An arcuate projection 4c ~;
(See Figs. 17 and 19) is projected outwardly from the left end surface of the case 4, and is fitted into the annular groove of a doughnut-shaped cam gear member 13 so as to guide the rotation of the member 13. The member 13 includes an internal gear 13a in mesh with ;
the gear 2g of the shaft 2b and a circular cam 13b having an opening 13c. The ratchet 11 is pivotally supported on a shaft or a pin lla which is fixed to , . .
, . . .
.
~47~
1 the left end surface of the case ~, and a lever llc is outwardly extending from the ratchet 11 at a right angle and slides over the peripheral surface of the cam 13b as best shown in Fig. 19. The ratchet 11 is normally pressed against the teeth 5a of the ratchet wheel 5 under the biasing force of a spring (not shown).
When the cam gear member 13 rotates and the opening 13c of the cam 13b comes into a position located below the lever llc, the ratchet llc is pushed down by the spring (not shown) as shown in Fig. 20 so that the locking pawl llb of the ratchet 11 engages the ratchet wheel 5. These member 13 and the ratchet 11 are covered by a cover 14 attached to the case 4.
~ext the mode of operation of the third embodi-15 ment will be described. When the seat belt 3 is com~ ~ ~
pletely wound around the reel 2, the ratchet 11 i~ held -~ `
in the raised position by the cam 13b as shown in Fig. `~
19. When the belt 3 is paid out by the occupant, it is unwound from the reel 2, and the cam gear member ;~
13 in mesh with the gear 2g of the shaft 2b is rotated in the direction indicated by the arrow A in Fig. 19.
As the belt 3 is paid out, the shaft 2b of the reel -~
2 is rotated in the direction A in Fig. 18 so that both the first and second spiral springs 6 and 7 are wound.
25 The spring constant of the first spring 6 is larger ;~
than that o~ the second spring 7 so that first the second spring 7 is almost wound. After the second spring 7 has been wound, the rotation in the direction A of the shaft 2b is transmitted to the cylindrical section 5g of the ratchet wheel 5 through the wound . '`" ' _ 23 -.:
-~ , . ' ~047016 1 second spring 7 so that the first spring 6 is wound.
The gear ratio between the teeth of the gear 2g of the shaft 2b and the teeth of the internal gear 13a is so selected that when the belt 3 is fully paid out, the cam gear member 13 makes almost one rotation from the position shown in Fig. 19. Therefore the ratchet 11 is in the position shown in ~ig. 20 when the belt 3 is fully paid out and fastened. More particularly, as the belt 3 is paid out, the cam gear member 13 makes almost one rotation in the direction A from the position shown in Fig. 19 so that the open-ing 13c of the cam 13b is brought to the position opposite to the lever llc extending from the ratchet 11. Therefore the ratchet 11 is pushed down under the biasing force of the spring (not shown) so that its locking pawl llb eng&ges the tooth 5a of the ratchet wheel 5 as shown in Fig. 20. Thus when the seat belt ~ is fastened, the unwinding spring force of the first spring 6 is exerted to the ratchet wheel 5 in the direction B1 in Fig. 20 while the unwinding spring force of the second spring 7 is exerted to the shaft 2b in the direction B2 in Fig. 20. However, the rota-tion in the direction B of the ratchet wheel 5 is prevented by the engagement of the locking pawl llb of the ratchet 11 with the tooth 5a of the ratchet wheel 5 so that the unwinding spring force of the first spring 6 is not transmitted to the shaft 2b of the reel 2. Therefore only the unwinding spring force of the second spring 7 is transmitted to the shaft 2b in the direction in which the belt 3 is retracted and _ 24 -~7~
1 wound. As a result, the tension of the belt is reduced when the belt is fastened so that the occupant has less feeling of being restrained.
In case of a collision or the like, locking means (not shown) immediately engages the ra-tchet teeth formed in the flanges 2c and 2d of the reel 2 to prevent rapid paying out of the belt 3, thereby securely restraining the occupant as with the case of the first and second embodiments.
~ext the mode of retracting and winding the seat belt will be described. When the belt is unfastened or released, the shaft 2b is rotated in -the direction B2 under the unwinding spring force of the second spring 7 so that the cam gear member 13 is rotated in the direction B3 in Fig. 20. Therefore the slanting surface 13d at one side of the opening 13c of the cam 13b contacts th~ lever llc of the ratchet 11 and raises the lever llc over the peripheral surface of the cam 13b. The locking pawl llb of the ratchet 11 is there~
20 fore disengaged from the teeth 5a of the ratchet wheel ~:r'-, ' 5 so that the ratchet wheel 5 initiates to rotate in ~
the direction B2 under the unwinding spring force of ;~ ~ -the first spring 6. Then, the rotation of the ratchet wheel 5 is transmitted to the shaft 2b through the 25 second spring 7, and the unwinding spring force of the -~
first spring 6 rotates the reel 2 to retract and wind the belt 3 around the reel 2. -`':
'.: . . . : .
- ?
.
1(;1 47~16 1 ~urthermore, as described above, the spring force of the second spring 7 is selected to be weaker than that of the first spring 6, and the second spring 7 has been wound only by almost one rotation of the shaft 2b. Therefore the tension exerted to the occupant is reduced and stabilized so that the occupant may experience no unpleasant restraining force and may freely move his body for operating a switch or the like. As described above, when the occupant is using the seat belt 3, the tension of the belt is produced only by the second spring 7 so that the tension may be freely adjusted.
In case of the sudden deceleration of the vehicle due to a collision or the like, the locking means (not shown) immediately engage the ratchet gears formed in the flanges 2c and 2d of the reel 2 to prevent sudden extension o~ the seat belt 3 so that the belt may securely restrain the occupant from the secondary collision in the vehicle chamber.
Mext the mode of the retraction of the seat belt 3 when the occupant unfastens or release it will be described. Immediately before the seat belt is i released, the pawl lld of the operating lever llc is in engagement with the lever 8b of the leaf spring 8 -~
as shown in Fig. 8, while the locking pawl llb of the ratchet 11 is in engagement with the teeth 5a of `~
the ratchet wheel 5 so that the unwinding spring force of the first spring 6 is not exerted to the shaft 2b as described above. When the seat belt 3 is unfastened, the unwinding spring force of the second spring 7 is -, . . . , . :
.
-~
.
~ ,: . ' -, , :
470~L~
1 exerted to the reel 2 in a direction indicated by the arrow B in ~ig. 8. As described above, the friction resistance Fl between the friction disk 9 and the flange 2d is higher th~n the resistance F2 between the friction disk 9 and the leaf spring 8, so that the friction disk 9 rotates in unison with the flange 2d in the direction indicated by the arrow B, but the rotation of the leaf spring 8 in the direction B is prevented by the engagement of the lever 8b with the pawl lld of the operating lever llc. When the flange 2d has made almost one rotation under the unwinding spring force of the second spring 7, the latter is ; '~
substantially unwound or released so that no unwinding ~ ~-force is exerted by the second spring 7 to the reel ! `
2, but the friction disk 9 is returned to the initial position shown in Fig. 6. That is, in unison with the rotation in the direction B of the reel 2 under the unwinding spring force of the second spring 7, the `
friction disk 9 rotates in the direction indicated -by the arrow B in Fig. 8, and before the friction disk 9 makes one rotation, the pawl lld of the operating `
lever llc is raised by the cam portion 9a of the fric- ~ `
tion disk 9 into the position shown in Fig. 6. In ::.:. , :
the latter position, the lever 8b of the leaf spring -::: ,, 8 engages the retraction stopper lf so that -the leaf spring 8 is held in the position shown in Fig. 6 regardless of further rotation of the friction disk 9. When the pawl lld of the operating lever llc is raised as shown in Fig. 6, the locking pawl llb of ~o the ratchet 11 is disengaged from the teeth 5a of the :. ~ .. . , `- ' . :
~ . : , .' ::' ~ ' ' ':
, 1 ratchet wheel 5 as shown in Fig. 2 so that the s~cond spring does not produce substantial unwinding ~orce.
However, the strong unwinding force of the first spring 5 is now exerted to the reel 2 so that the belt 3 is rapidly retracted and wound around the reel 2. The friction resistances exerted by the friction disk 9 and the leaf spring 8 to the flange 2d are sufficiently lower as compared with the unwinding forces of the first and second springs 6 and 7 so that the friction resistances will not adversely affect the seat belt retracting operation.
Second Embodiment, Figs. 9 through 16 The second embodiment shown in ~igs. 9 through 16 is substantially similar in construction to the first embodiment described above so that only the parts different from those of the first embodiment will be described. Referring to Figs. lOA and lOB, the ratchet wheel 5, which is rotatably supported on the flange of the bush bearing le attached to the side plate lb, has ratchet teeth 5a formed on the periphery thereof. The ratchet wheel 5 has six protrusions 5b, 5c, 5d, 5f and 5e formed by punching or the like. The protrusions 5b, 5c and 5d are angularly spaced apart from each other by 90, and the protrusions 5b are angularly spaced apart by 180 while the protrusions 5c and 5d are angularly spaced apart by 180. The protrusions 5b and 5d are positioned on a common inscribed circle (indicated by a phantom line in Fig. lOA) whose center coincides with that of the ratchet wheel 5, while the ~Q~7~6 1 protrusion 5c lies radially inside of the circle. The protrusions 5f and 5e are formed on circumferentially both sides of the protrusion 5d.
One end 6a of a spiral spring 60 which is housed within the case 4 is inserted and fixed in a slit 4b formed in the inner wall of the case 4 while ~ ~;
the other or inner end 6b is inserted and fixed in the slit 2f of the shaft 2b. The spring 60 is wrapped around the protrusions 5b through 5f as shown in ~ig.
11, and two radially inwardly extending projections 6c of the spring 60 sandwitch the protrusion 5d so that not only the spring 60 is securely attached to the ratchet wheel 5 but also it is livided into an outer or a first spring section 6 and an inner or a second spring section 7. The unwinding spring force of the second spring 7 is directly transmitted to the ;
shaft 2b while the unwinding spring force of the first spring 6 is indirectly transmitted to the shaft 2b through the ratchet wheel 5. ;~
As shown in Figs. 12 and 13, the shaft 2b ..
is formed with an integral flange 2h at an inner end ;~
of its small diameter portion on which the spring 60 is wound, and the flange 2h has a radial projection 2e.
The projection 2e is formed integral with the flange 25 2h in a manner that it is rotatable within the inscribed ;
circle passing the inner sides of -the protrusions 5b and 5d, however, it is engageable with the protrusion 5c which is formed radially inside of the circle.
Next the mode of operation of the second embodiment will be described. When the belt 3 is :.
.. . .
.: , ~ ' ~
.. . ' ' ' , ' . . .
~047~1~
1 retracted and wound around the reel 2, the spring 60 still has some unwinding spring force. Therefore, the belt 3 is completely wound around the reel 2 under this residual unwinding force of the spring 60, and the projection 2e of the shaft 2b is in engagement with the protrusion 5c (to be referred to as the "stopper" hereinafter in this specification) of the ratchet wheel 5 as shown in Fig. 12. The shaft 2b is biased in the direction opposite to that indicated by the arrow A in Fig. 12 under the residual unwinding force of the spring 60. The operating lever llc is `
held in the raised position as shown in Fig. 14 as the lever 8b of the leaf spring 8 raises the lever llc against the leaf spring 12. As a result, the ratchet 11, which swings in unison with the driving lever llc, is moved away from the teeth of the ratchet wheel 5 as with the case of the first embodiment.
When the occupant pays out the belt 3, the ~-~
flange 2d and the shaft 2b of the reel 2 are rotated in the direction indicated by the arrow A in Figs. 12 and 14. The friction disk 9 and the leaf spring 8 are also rotated in the sa~e direction in unison with the flange 2d so that the pawl lld of the operating lsver llc is disengaged from the lever 8b of the leaf spring 8 and consequently pressed against the peri~
pheral surface of the friction disk 9. As a result, the locking pawl llb of the ratchet 11, which swings is unison with the operating lever llc, engages the ratchet wheel 5. As is clear from Fig. 11, the locking pawl llb only slides on the slanted surface of the teeth ... , .-. .. -. . ... .
- . . . .
. .
. . ~ ' ' :, . . ... ,:
1047~16 1 retracted and wound around the reel 2, the spring ~0 still has some unwinding spring force. Therefore, the belt 3 is completely wound around the reel 2 under this residual unwinding force of the spring 60, and the projection 2e of the shaft 2b is in engagement with the protrusion 5c (to be referred to as the "stopper" hereinafter in this specificat.ion) of the ratchet wheel 5 as shown in Fig. 12. The shaft 2b is ;
biased in the direction opposite to that indicated by the arrow A in ~ig. 12 under the residual unwinding force of the spring 60. The operating lever llc is held in the raised position as shown in Fig. 14 as the ~ i~A'',.' lever 8b of the leaf spring 8 raises the lever llc against the leaf spring 12. As a result, the ratchet 11, which swings in unison with the driving lever llc, is moved away from the teeth of the ratchet wheel 5 ;
as with the case of the first embodiment.
When the occupant pays out the belt 3, the flange 2d and the shaft 2b of the reel 2 are rotated ..
in the direction indicated by the arrow A in Figs. 12 and 14. The friction disk 9 and the leaf spring 8 are also rotated in the sa~e direction in unison with the flange 2d so that the pawl lld of the operating ~;
lever llc is disengaged from the lever 8b of the leaf -25 spring 8 and consequently pressed against the peri- ~-pheral surface of the friction disk 9. As a result, the locking pawl llb of the ratchet 11, which swings is unison with the operating lever llc, engages the ratchet wheel 5. As is clear from Fig. 11, the locking pawl llb only slides on the slanted surface of the teeth - . . -, , ~ , . . . :
. , . .: : :
~47~)~L6 1 already wound by almost Pne rotation of the shaft 2b, may be prevented from being further wound.
When the seat belt 3, which has been paid out in the manner described above, is fastened to restrain the occupant, it has some slack. Therefore the belt 3 is retracted by the spring 60 to eliminate the slack of the belt 3. That is, the flange 2d of the reel 2 is rotated in the direction opposite to -that indicated by the arrow A n Fig. 15 so that both - 10 the leaf spring 8 and the friction disk 9 are caused - ~ ;
to rotate in the same direction. When the belt 3 is retracted to eliminate the slack, the relative position between the operating lever llc and the friction disk ~-9 changes from the position shown in Fig. 15 to that shown in Fig. 16. More particularly, the pawl lld of the operating lever llc is disengaged from the ;~ ;
stopper portion 9b of the friction disk 9, and slldes on the peripheral surface of the friction disk 9.
Therefore the locking pawl llb of the ratchet 11 which .:
swings in unison with the operating lever llc comes to engage the teeth 5a of the ratchet wheel. Since ~ -~
the ratchet wheel 5 is rotated in the direction opposite to that indicated by the arrow A in ~ig. 11, the lock-ing pawl llb locks the rotation of the ratchet wheel ~-5. As a result, the unwiding spring force of the first spring 6 is not exerted to the reel 2, but the unwinding spring force of the second spring 7 is exerted to the shaft 2b of the reel 2 in the direction in which the belt 3 is retracted and wound. Therefore the tension of the belt 3; that is the restraining force :: :
- 19 - ~
.
~47~6 1 exerted upon the occupant is dependent upon the un-winding spring force of only the second spring 7 so that the occupant may be restrained under the stable belt tension. As with the case of the first embodiment, locking mean~ (not shown) immediately engage the r~tchet teeth of the flanges 2c and 2d of the reel 2 in case of a collision of the vehicle or the like so that the seat belt ~ may be positively prevented from being suddently paid out.
~ext the mode of operation for retracting and ;~
winding the belt will be described. Immediately before the belt is unfastened, the locking pawl lld of the lever llc is in engagement with the lever 8b of the leaf spring as shown in Fig. 16 while the locking pawl llb of the ratchet 11 is in engagement with the tooth 5a of the ratchet wheel 5, so that the un-winding spring force of the first spring 6 is not exerted to the shaft 2b as described above. The pro-jection 2e of the shaft 2b is in a position indicated by a broken line in Fig. 1~. When the seat belt is unfastened or released, the unwinding force of the ,~
second spring 7 is exerted to the reel 2 in the direction ~ in Fig. 16 so that the shaft 2b is rotated in the direction opposite to the direction A in Fig. 1,. Since the friction resistance F1 between the friction disk 9 and the flange 2d is higher than the friction resistance F2 between the friction disk 9 and the leaf spring 8, the friction disk 9 rotates ~;
in the direction ~ as the flange 2d is rotated in ~0 the same direction in Fig. 16. When the reel -: , , - , ~47~3~6 :::
1 2 and hence its shaft 2b makes almost one rotation under the unwinding spring force of the second spring ~ `
7; that is~ when the projection 2e of the shaft 2b turns from the position indicated by the broken line `
in Fig. 13 to the position shown in Fig. 12, the second spring 7 is substantially unwound or released so that no further returning ~orce is transmitted to the reel 2. When the reel 2 and hence its flange 2d make almost one rotation as described above, the friction disk 9 is rotated to the position shown in Fig. 14. More particularly, when the reel 2 is rotated under the unwinding force of the second spring 7 in the direc-tion B in Fig. 16, the friction disk 9 is also rotated ~-in the same direction. Before the friction disk 9 makes ;
one rotation, its cam portion 9a raises the pawl lld of the operating Iever llc so that~the lever llc is dlsplaced from the position shown in Fig. 16 to the position shown in Fig. 14. As is clear from Fig. 14, ~
the lever 8b of the leaf spring 8 engage retrac- -tion stopper lf so that the leaf spring 8 is held in the po ition shown in Fig. 14 regardless of further rotation of the friction disk 9. When the lever llc is raised by the lever 8b of the leaf spring 8, the ratchet 11 which swings in unison with the operating 25 lever llc is disengaged from the ratchet wheel 5 as ;
shown in Fig. 11 so that the unwinding spring force of the first spring 6 is transmitteid to the reel 2 -and the belt 3 is completely wound around the reel 2.
- 21 -- ;
~' "' ,~
, . ., . . , , :
; - - .,. ~ . : . .
~047V16 ~ ~
1 Third E~bodiment, Figs. 17 through 20 The third embodiment shown in Figs. 17 through 20 is substantially similar in construction to the first embodiment so that only those parts different from those of the first embodiment will be described. A
cup-shaped ratchet wheel 5 is rotatably supported on the shaft 2b within the cup-shaped case 4 a-ttached to the side plate lb of the frame 1. One end of the second spring 7 which is housed within the cylindrical portion 5g of the ratchet wheel 5 is inserted and fixed in the slit 2f of the shaft 2b while the other end is inserted and fixed in the slit 5h of the wall of the cylindrical portion 5g. One end 6b of the first spring 6 which is housed within the doughnut-shaped space defined between the case 4 and the ratchet wheel 5 is joined to the other end of the second spring 7 at the slit 5h while the other end is inserted and fixed in the slit 4b of the case 4. As with the case ;~
of the first embodiment, the first spring 6 is stronger than the second spring 7. The left end portion of the sha~t 2b extends through the ratchet wheel 5 and the terminates in a gear 2g. An arcuate projection 4c ~;
(See Figs. 17 and 19) is projected outwardly from the left end surface of the case 4, and is fitted into the annular groove of a doughnut-shaped cam gear member 13 so as to guide the rotation of the member 13. The member 13 includes an internal gear 13a in mesh with ;
the gear 2g of the shaft 2b and a circular cam 13b having an opening 13c. The ratchet 11 is pivotally supported on a shaft or a pin lla which is fixed to , . .
, . . .
.
~47~
1 the left end surface of the case ~, and a lever llc is outwardly extending from the ratchet 11 at a right angle and slides over the peripheral surface of the cam 13b as best shown in Fig. 19. The ratchet 11 is normally pressed against the teeth 5a of the ratchet wheel 5 under the biasing force of a spring (not shown).
When the cam gear member 13 rotates and the opening 13c of the cam 13b comes into a position located below the lever llc, the ratchet llc is pushed down by the spring (not shown) as shown in Fig. 20 so that the locking pawl llb of the ratchet 11 engages the ratchet wheel 5. These member 13 and the ratchet 11 are covered by a cover 14 attached to the case 4.
~ext the mode of operation of the third embodi-15 ment will be described. When the seat belt 3 is com~ ~ ~
pletely wound around the reel 2, the ratchet 11 i~ held -~ `
in the raised position by the cam 13b as shown in Fig. `~
19. When the belt 3 is paid out by the occupant, it is unwound from the reel 2, and the cam gear member ;~
13 in mesh with the gear 2g of the shaft 2b is rotated in the direction indicated by the arrow A in Fig. 19.
As the belt 3 is paid out, the shaft 2b of the reel -~
2 is rotated in the direction A in Fig. 18 so that both the first and second spiral springs 6 and 7 are wound.
25 The spring constant of the first spring 6 is larger ;~
than that o~ the second spring 7 so that first the second spring 7 is almost wound. After the second spring 7 has been wound, the rotation in the direction A of the shaft 2b is transmitted to the cylindrical section 5g of the ratchet wheel 5 through the wound . '`" ' _ 23 -.:
-~ , . ' ~047016 1 second spring 7 so that the first spring 6 is wound.
The gear ratio between the teeth of the gear 2g of the shaft 2b and the teeth of the internal gear 13a is so selected that when the belt 3 is fully paid out, the cam gear member 13 makes almost one rotation from the position shown in Fig. 19. Therefore the ratchet 11 is in the position shown in ~ig. 20 when the belt 3 is fully paid out and fastened. More particularly, as the belt 3 is paid out, the cam gear member 13 makes almost one rotation in the direction A from the position shown in Fig. 19 so that the open-ing 13c of the cam 13b is brought to the position opposite to the lever llc extending from the ratchet 11. Therefore the ratchet 11 is pushed down under the biasing force of the spring (not shown) so that its locking pawl llb eng&ges the tooth 5a of the ratchet wheel 5 as shown in Fig. 20. Thus when the seat belt ~ is fastened, the unwinding spring force of the first spring 6 is exerted to the ratchet wheel 5 in the direction B1 in Fig. 20 while the unwinding spring force of the second spring 7 is exerted to the shaft 2b in the direction B2 in Fig. 20. However, the rota-tion in the direction B of the ratchet wheel 5 is prevented by the engagement of the locking pawl llb of the ratchet 11 with the tooth 5a of the ratchet wheel 5 so that the unwinding spring force of the first spring 6 is not transmitted to the shaft 2b of the reel 2. Therefore only the unwinding spring force of the second spring 7 is transmitted to the shaft 2b in the direction in which the belt 3 is retracted and _ 24 -~7~
1 wound. As a result, the tension of the belt is reduced when the belt is fastened so that the occupant has less feeling of being restrained.
In case of a collision or the like, locking means (not shown) immediately engages the ra-tchet teeth formed in the flanges 2c and 2d of the reel 2 to prevent rapid paying out of the belt 3, thereby securely restraining the occupant as with the case of the first and second embodiments.
~ext the mode of retracting and winding the seat belt will be described. When the belt is unfastened or released, the shaft 2b is rotated in -the direction B2 under the unwinding spring force of the second spring 7 so that the cam gear member 13 is rotated in the direction B3 in Fig. 20. Therefore the slanting surface 13d at one side of the opening 13c of the cam 13b contacts th~ lever llc of the ratchet 11 and raises the lever llc over the peripheral surface of the cam 13b. The locking pawl llb of the ratchet 11 is there~
20 fore disengaged from the teeth 5a of the ratchet wheel ~:r'-, ' 5 so that the ratchet wheel 5 initiates to rotate in ~
the direction B2 under the unwinding spring force of ;~ ~ -the first spring 6. Then, the rotation of the ratchet wheel 5 is transmitted to the shaft 2b through the 25 second spring 7, and the unwinding spring force of the -~
first spring 6 rotates the reel 2 to retract and wind the belt 3 around the reel 2. -`':
'.: . . . : .
- ?
.
Claims (18)
1. A seat belt retracting and winding device comprising:
a frame having two side plates, a winding reel rotatably supported in said side plates and including an integral shaft, a seat belt wound on said winding reel, said seat belt being fixed at its inner end to said winding reel, a cup-shaped case attached to one of said side plates, a ratchet wheel rotatably supported on said shaft, said ratchet wheel having a plurality of ratchet teeth formed on the periphery thereof, a first spiral spring having one end fixed to said case and the other end fixed to said ratchet wheel, a second spiral spring having one end fixed to said shaft and the other end fixed to said ratchet wheel, a ratchet operatively releasably engaging the ratchet teeth on said ratchet wheel, and cooperative means operable in response to the rotation of said winding reel to bring said ratchet into engagement with the ratchet teeth on said ratchet wheel thereby locking the same against rotation, whereby when said seat belt is paid out and fastened to the vehicle occupant the unwinding spring force of said first spring is not exerted to said winding reel while the unwinding spring force of only said second spring is exerted thereto.
a frame having two side plates, a winding reel rotatably supported in said side plates and including an integral shaft, a seat belt wound on said winding reel, said seat belt being fixed at its inner end to said winding reel, a cup-shaped case attached to one of said side plates, a ratchet wheel rotatably supported on said shaft, said ratchet wheel having a plurality of ratchet teeth formed on the periphery thereof, a first spiral spring having one end fixed to said case and the other end fixed to said ratchet wheel, a second spiral spring having one end fixed to said shaft and the other end fixed to said ratchet wheel, a ratchet operatively releasably engaging the ratchet teeth on said ratchet wheel, and cooperative means operable in response to the rotation of said winding reel to bring said ratchet into engagement with the ratchet teeth on said ratchet wheel thereby locking the same against rotation, whereby when said seat belt is paid out and fastened to the vehicle occupant the unwinding spring force of said first spring is not exerted to said winding reel while the unwinding spring force of only said second spring is exerted thereto.
2. A seat belt retracting and winding device as set forth in Claim 1, further comprising means to limit the relative rotation between the shaft of said winding reel and said ratchet wheel to not more than one rota-tion.
3. A seat belt retracting and winding device as set forth in Claim 1, wherein the spring force of said first spiral spring is selected stronger than that of said second spiral spring.
4. A seat belt retracting and winding device as set forth in Claim 1, wherein said cooperative means includes:
a friction disk disposed between a flange of said winding reel and one of said side plates to which said cup-shaped case is attached and rotatably supported on the shaft of said winding reel, said fric-tion disk having on its periphery a bulged portion, spring means interposed between one said side plate and said friction disk for biasing said friction disk against said flange, a shaft extending through one said side plate and having said ratchet attached to one end thereof, and an operating lever attached to the other end of said shaft, said operating lever being movable in union with said ratchet and slidable on the peripheral surface of said friction disk.
a friction disk disposed between a flange of said winding reel and one of said side plates to which said cup-shaped case is attached and rotatably supported on the shaft of said winding reel, said fric-tion disk having on its periphery a bulged portion, spring means interposed between one said side plate and said friction disk for biasing said friction disk against said flange, a shaft extending through one said side plate and having said ratchet attached to one end thereof, and an operating lever attached to the other end of said shaft, said operating lever being movable in union with said ratchet and slidable on the peripheral surface of said friction disk.
5. A seat belt retracting and winding device as set forth in Claim 1, wherein said cooperative means includes;
a cam gear member rotatable in association with the shaft of said winding reel, said member includ-ing on its periphery a cam portion formed with an opening, and a lever secured to said ratchet and slidable on said cam portion during rotation of said member, said lever being brought to a position opposite to said opening and engaged with the ratchet teeth on said ratchet wheel so as to lock the same against rotation when said seat belt is paid out and fastened to the vehicle occupant.
a cam gear member rotatable in association with the shaft of said winding reel, said member includ-ing on its periphery a cam portion formed with an opening, and a lever secured to said ratchet and slidable on said cam portion during rotation of said member, said lever being brought to a position opposite to said opening and engaged with the ratchet teeth on said ratchet wheel so as to lock the same against rotation when said seat belt is paid out and fastened to the vehicle occupant.
6. A seat belt retracting and winding device comprising:
a frame;
spring means fixed at its one end to said frame and including a first spiral spring and a second spiral spring;
a seat belt;
a winding reel rotatably supported by said frame and connected to said spring means;
said winding reel being adapted to wind thereon said seat belt with a spring force of at least one of said first and second spiral springs;
clutch means operatively connecting one end of said first spiral spring with one end of said second spiral spring, and operable selectively under a first operative condition and a-second operative condition;
said clutch means changing over said operative conditions to control the composition or combination of spring forces of said first and second spiral springs; and control means operatively connected to said winding reel to detect the winding of said seat belt to thereby actuate said clutch means;
said clutch means being changed over to operate under said first operative condition to thereby reduce the winding force exerted on said seat belt when the seat belt having been paid out is retracted and wound,
a frame;
spring means fixed at its one end to said frame and including a first spiral spring and a second spiral spring;
a seat belt;
a winding reel rotatably supported by said frame and connected to said spring means;
said winding reel being adapted to wind thereon said seat belt with a spring force of at least one of said first and second spiral springs;
clutch means operatively connecting one end of said first spiral spring with one end of said second spiral spring, and operable selectively under a first operative condition and a-second operative condition;
said clutch means changing over said operative conditions to control the composition or combination of spring forces of said first and second spiral springs; and control means operatively connected to said winding reel to detect the winding of said seat belt to thereby actuate said clutch means;
said clutch means being changed over to operate under said first operative condition to thereby reduce the winding force exerted on said seat belt when the seat belt having been paid out is retracted and wound,
7. A seat belt retracting and winding device as set forth in claim 6, wherein said clutch means includes a ratchet wheel which constitutes a sub-stantial connecting member between said first and second spiral springs, and a ratchet selectively engaged with said ratchet wheel by means of said control means,
8. A seat belt retracting and winding device as set forth in claim 6, wherein said first and second spiral springs are connected in series through said clutch means,
9. A seat belt retracting and winding device as set forth in claim 8, wherein said clutch means includes a ratchet wheel which constitutes a substan-tial connecting member between said first and second spiral springs, and a ratchet selectively engaged with said rathcet wheel by means of said control means,
10. A seat belt retracting and winding device as set forth in claim 6, wherein said control means further detects the winding of said seat belt ex-ceeding a predetermined amount or length, thereby changing over said clutch means to operate under said second operative condition,
11. A seat belt retracting and winding device comprising a frame; a winding reel rotatably supported by said frame; spring means connected between said frame and said winding reel and including a first spring and a second spring; said winding reel being adapted to wind thereon a seat belt with a spring force of at least one of said first and second springs; and means for controlling the combination of spring forces of said first and second springs and operable in response to the rotation of said winding reel for causing said spring means to operate selectively under a first operative condition and a second operative condition exerting larger and smaller spring forces, respectively, on said seat belt, whereby the winding force exerted on said seat belt is reduced when said spring means is operated under said second operative condition.
12. A seat belt retracting and winding device as defined in claim 11, wherein said controlling means includes clutch means for changing over said spring means to operate selectively under said first condition and said second condition, and clutch control means operatively connected to said winding reel to operate said clutch means in accordance with the rotation of said winding reel due to paying out and winding of said seat belt.
13. A seat belt retracting and winding device as defined in claim 12, wherein both of said first and said second springs exert spring forces on said seat belt when said spring means is operated under said first operative condition, and one of said first and second springs exerts spring force thereon when said spring means is operated under said second operative condition.
14. A seat belt retracting and winding device as defined in claim 13, wherein said clutch means is connected between one end of said first spring and one end of said second spring so that said clutch means can connect said first and said second springs in series.
15. seat belt retracting and winding device as defined in claim 14, wherein said clutch means includes a ratchet wheel connected between said one end of said first spring and said one end of said second spring, and a ratchet selectively engaged with said ratchet wheel, the selective engage-ment of said ratchet with said ratchet wheel being controlled in accordance with the rotation of said winding reel.
16. A seat belt retracting and winding device as defined in claim 12, wherein said clutch control means includes a first friction member rotatably supported on a shaft of said winding reel and frictionally engaging the latter, a second friction member rotatably supported on said shaft and frictionally engaging said first friction member, each of said first and second friction members having on its periphery a radially outward extension, and an operating lever operatively ccnnected to said clutch means and adapted to engage with the extensions of said first and second friction members, said operating lever and said extensions being adapted to disengage from each other to contrcl said clutch means such that said spring means is changed over to operate under said second operative condition when the seat belt is wound by a predetermined amount onto said winding reel after it has been paid out, said extension of said first friction member and said operating lever being adapted to engage with each other to control said clutch means such that said spring means is changed over to operate under said first oper-ative condition when said seat belt is wound onto said winding reel by an amount exceeding said predetermined amount.
17. A seat belt retracting and winding device as defined in claim 15, wherein said controlling means includes a friction disk disposed between a flange of said winding reel and rotatably supported on a shaft of said winding reel, said friction disk having on its periphery a bulged portion, a spring member interposed between said frame and said friction disk for biasing said friction disk against said flange, a shaft supported by said frame and having said ratchet attached to one end thereof, and an operating lever attached to the other end of said shaft, said operating lever being movable in union with said ratchet and slidable on the peripheral surface of said friction disk.
18. A seat belt retracting and winding device as defined in claim 12, wherein said clutch control means includes a cam gear member rotatable in association with a shaft of said winding reel, said cam gear member includ-on its periphery a cam portion formed with an opening, and an operating lever connected to said clutch means and slidable on said cam portion during rotation of said cam gear member, said operating lever being brought to a position opposite to said opening and engaged with ratchet teeth on said ratchet wheel so as to lock the latter against rotation when said seat belt is paid out and fastened to the vehicle occupant.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA271,435A CA1047016A (en) | 1977-02-09 | 1977-02-09 | Seat belt retracting and winding device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA271,435A CA1047016A (en) | 1977-02-09 | 1977-02-09 | Seat belt retracting and winding device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047016A true CA1047016A (en) | 1979-01-23 |
Family
ID=4107899
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA271,435A Expired CA1047016A (en) | 1977-02-09 | 1977-02-09 | Seat belt retracting and winding device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1047016A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4478433A (en) * | 1981-11-04 | 1984-10-23 | Nippon Soken, Inc. | Safety seatbelt retractor |
-
1977
- 1977-02-09 CA CA271,435A patent/CA1047016A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4478433A (en) * | 1981-11-04 | 1984-10-23 | Nippon Soken, Inc. | Safety seatbelt retractor |
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