A webbing retractor which, when a webbing is drawn out instantaneously, prevents the drawing out of the webbing by operating a lock mechanism. In addition, when a vehicle is decelerated suddenly, the drawing out of the webbing is also instantaneously prevented by causing a pawl to engage with a lock wheel preventing the lock wheel from rotating. The webbing retractor includes a lever which is swung in such a manner as to be movable between a first position in which the pawl is made unengageable with the lock wheel and a second position in which the pawl is made engageable with the lock wheel. The webbing retraction also includes a lever swing member which causes the lever to be located in the first position as the take-up shaft rotates in a webbing taking-up direction and to be situated in the second position as the take-up shaft rotates in a webbing draw-out direction. Accordingly, the pawl is prevented from engaging with the lock wheel at a take-up limit of the webbing.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a webbing retractor which, during a sudden 
deceleration of a vehicle, is capable of instantaneously stopping the 
rotation of a take-up shaft in a webbing drawing-out direction by the 
operation of a lock mechanism which results from a lock wheel and the 
take-up shaft undergoing relative rotation due either to the engagement, 
with the lock wheel, of a pawl operated by sensing the sudden 
deceleration, or the sudden drawing out of the webbing at the time of 
sudden deceleration. 
2. Description of the Related Art 
Among webbing retractors that are mounted on vehicles, there is a type 
(which is called WSIR) which is adapted to operate a lock mechanism by 
sensing a sudden drawing out of the webbing and then making it possible to 
instantaneously prevent the drawing out of the webbing. 
With this type of webbing retractor, when the webbing is drawn out suddenly 
by the occupant's inertia during a sudden deceleration of the vehicle, a 
delay in rotation normally occurs in a lock wheel which follows the 
rotation of a take-up shaft. This causes the lock mechanism to operate, 
thereby keeping the occupant in a restricted state by instantaneously 
preventing the drawing out of the webbing. 
The cancellation of the lock mechanism operation is effected by rotating 
the take-up shaft by a small amount in a direction in which the webbing is 
taken up. 
At this juncture, when the occupant unfastens the webbing, the take-up 
shaft is urged in the webbing take-up direction by means of an urging 
means. When the occupant releases the webbing, there is a case where the 
webbing is taken up quickly. In this case, since the rotation of the 
take-up shaft stops suddenly at a take-up limit of the webbing, relative 
rotation occurs in the lock wheel with respect to the take-up shaft due to 
inertia. Therefore, the state becomes identical to that in which the 
webbing is drawn out suddenly. 
As a result, the lock mechanism is actuated which prevents the take-up 
shaft from rotating in the webbing draw-out direction. To cancel this 
state, it is necessary to rotate the take-up shaft by a small amount in 
the webbing taking-up direction, as described above. However, since a 
major portion of the webbing has already been taken up, there are cases 
where the cancellation is cumbersome and takes time. 
In order to overcome the aforementioned drawback, a webbing retractor has 
been developed as disclosed in Japanese Utility Model Laid-Open No. 
95058/1987. The webbing retractor is arranged in such a manner that a 
displacing member is disposed on a rotating member rotating integrally 
with the take-up shaft. The lock wheel is prevented from rotating in the 
webbing take-up direction relative to the take-up shaft by causing the 
displacing member to be engaged with the lock wheel as the take-up shaft 
rotates in the webbing take-up direction. In addition, the displacing 
member is disengaged from the lock wheel as the take-up shaft rotates in 
the webbing draw-out direction, permitting the take-up shaft to rotate in 
the webbing draw-out direction relative to the lock wheel. 
On the other hand, there is another type of webbing retractor (VSIR) which 
is adapted to prevent the lock wheel from rotating by means of a pawl 
actuated by sensing a sudden deceleration of the vehicle, whereby a delay 
in operation normally occurs in the lock wheel which rotates by following 
the rotation of the take-up shaft so as to instantaneously prevent the 
drawing out of the webbing. 
There is a demand to incorporate the functions of such a webbing retractor 
(VSIR) into a webbing retractor (WSIR) which is capable of preventing the 
rotation of the lock wheel in the webbing take-up direction relative to 
the take-up shaft at a take-up limit of the webbing in the same way as 
Japanese Utility Model Laid-Open No. 95058/1987. 
In this case, however, when the rotation of the take-up shaft is stopped 
suddenly at the take-up limit of the webbing, there is the possibility of 
the pawl becoming engaged with the lock wheel due to a shock occurring at 
that time. In addition, if the webbing is subsequently drawn out in that 
state, the webbing drawing-out force can be imparted to the pawl via the 
lock wheel, possibly causing damage to the pawl. 
SUMMARY OF THE INVENTION 
Accordingly, an object of the present invention is to provide a webbing 
retractor which is capable of preventing a webbing drawing-out force from 
being imparted to the pawl even if the webbing is drawn out from a take-up 
limit of the webbing, thereby overcoming the above-described drawback of 
the conventional art. 
To this end, according to the present invention, there is provided a 
webbing retractor for taking up a webbing worn by a seat occupant of a 
vehicle, comprising: a take-up shaft by which the webbing is retained and 
which is urged in a direction in which the webbing is taken up; a lock 
wheel axially supported by the take-up shaft and adapted to be rotatable 
relative to the take-up shaft; lock means which is interposed between the 
take-up shaft and the lock wheel and which operates so as to prevent the 
take-up shaft from rotating in a direction in which the webbing is drawn 
out; a pawl which is engaged with the lock wheel at the time of a sudden 
deceleration of the vehicle and causes the lock wheel and the take-up 
shaft to rotate relative to each other so as to operate the lock means; a 
rotating member adapted to rotate integrally with the take-up shaft; a 
displacing member, which is supported by the rotating member, is moved to 
a first position by the rotation of the take-up shaft in the webbing 
take-up direction, and is engaged with the lock wheel so as to prevent 
rotation of the lock wheel relative to the take-up shaft, is moved to a 
second position by the rotation of the take-up shaft in the draw-out 
direction and is disengaged from the lock wheel so as to permit the 
relative rotation of the lock wheel; a lever which is swingable between a 
third position, in which the engagement of the pawl with the lock wheel is 
prevented, and a fourth position, in which the engagement of the pawl with 
the lock wheel is permitted; and lever swinging means which causes the 
lever to be located in the third position when the take-up shaft rotates 
in the take-up direction and causes the lever to be located in the fourth 
position when the take-up shaft rotates in the draw-out direction. 
In accordance with the present invention having the above-described 
arrangement, at the time when the webbing is taken up, the lever is swung 
to the first position by the lever swinging means to make the pawl 
unengageable with the lock wheel, so that even if the rotation of the 
take-up shaft is stopped suddenly at a take-up limit of the webbing and a 
shock is thereby generated, the pawl is prevented from engaging with the 
lock means as a result of that shock. 
Accordingly, even if the webbing is drawn out from the take-up limit of the 
webbing, this drawing-out force is prevented from being imparted to the 
pawl via the lock wheel. 
The above and other objects, features and advantages of the present 
invention will become more apparent from the following detailed 
description of the invention when read in conjunction with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the accompanying drawings, a description will now be given of 
the preferred embodiments of the present invention. 
FIG. 1 is a perspective view of a webbing retractor in accordance with a 
first embodiment of the present invention. 
A frame 10 has a pair of legs which extend from opposite sides of a base 
portion thereof and in parallel with each other. A take-up shaft 20 is 
rotatably supported by the legs 12, 14. An end of a webbing 23 for 
restraining a seat occupant is retained by the take-up shaft 20. 
One longitudinal end portion of the take-up shaft 20 projects outwardly 
from the leg 12. An inner end of a spiral spring 27 is retained by this 
projecting portion. An outer end of the spiral spring 27 is retained by a 
spring cover 29 secured to the leg 12 and accommodates the spiral spring 
27. As a result, the arrangement is such that the take-up shaft 20 is 
rotatively urged in the direction of arrow A in FIG. 1 by the urging force 
of the spiral spring 27 so as to take up the webbing 23 in the form of 
rolled layers. 
The other end of the take-up shaft 20 projects outwardly from the leg 14, 
and a fork end portion 20A is formed at this projecting portion. Disposed 
around the fork end portion 20A are a pair of lock plates 24, 25 which 
constitute parts of a lock mechanism, as also shown in FIG. 2. These lock 
plates 24, 25 are each formed into a substantially C-shaped configuration 
in which a substantially U-shaped notch 26 is formed in a central portion 
thereof. The fork end portion 20A of the take-up shaft 20 is situated in 
these notches 26. Both of the notches 26 are formed in such a manner that, 
as shown in FIG. 2, the breadth thereof (vertical length as viewed in the 
drawing) is slightly greater than the breadth (ditto) of the fork end 
portion 20A, so that the lock plates 24, 25 are rotatable by a 
predetermined angle relative to the take-up shaft 20. 
Claw portions 28, 30 are respectively formed at one end of the lock plates 
24, 25 in such a manner as to oppose the lock teeth of an internal ratchet 
wheel 32 which is secured to the leg 14 and, together with the lock plates 
24, 25, constitute the lock mechanism. 
Furthermore, returning to FIG. 1, two pairs of pins 34, 36 are respectively 
provided on the lock plates 24, 25 in such a manner as to project 
therefrom, and are respectively inserted in elongated holes 40 formed in a 
lock wheel 38. The lock wheel 38 is axially supported by a small-diameter 
shaft portion 20B projecting from an axially central portion of the 
take-up shaft 20. Thus, the lock wheel 38 is rotatable relative to the 
take-up shaft 20. A rotor 42 is disposed about the axis of this lock wheel 
38 on the side remote from the side where the lock plates 24, 25 are 
provided. 
The rotor 42 is fitted over a distal end of the small-diameter shaft 
portion 20B which passes through the lock wheel 38 and is hence rotatable 
integrally with the take-up shaft 20. A torsion coil spring 44 is 
interposed between the rotor 42 and the lock wheel 38. 
The torsion coil spring 44 urges the lock wheel 38 relative to the rotor 42 
in the draw out direction of the webbing (in the opposite direction of 
arrow A in FIG. 1). By means of this urging force, as shown in FIG. 2, the 
pins 34, 36 of the lock plates 24, 25 are held at the ends of the 
elongated holes 40. In consequence, the claw portions 28, 30 are spaced 
apart from the internal ratchet wheel 32 and, at the same time, the lock 
wheel 38 (see FIG. 1) is prevented from rotating further relative to the 
rotor 42 in the direction of drawing out the webbing. 
In addition, when the take-up shaft 20 rotates in the webbing drawing-out 
direction relative to the lock wheel 38 by deforming the torsion coil 
spring 44 against its urging force, the lock wheel 38 undergoes a delay in 
rotation relative to the take-up shaft 20, and the take-up shaft 20 
presses the lock plates 24, 25. Consequently, with their pins 34, 36 
guided by the elongated holes 40, the lock plates 24, 25 move in the 
longitudinal direction of the elongated holes 40 and cause their claw 
portions 28, 30 to be engaged with the internal ratchet wheel 32, as shown 
in FIG. 3. This movement of the lock plates 24, 25 can also occur when the 
lock wheel 38 deforms the torsion coil spring 44 against its urging force 
and causes the take-up shaft 20, rotating in the webbing take-up 
direction, to rotate further in that direction. 
As one can see in FIG. 1, a pin 61 is provided on the rotor 42 at a 
position offset from the center of its rotation. A hold lever 60, which is 
a displacing member, is pivotally supported by the pin 61 in such a manner 
as to be swingable. The hold lever 60 has a pawl 60A formed at one end 
thereof. The pawl 60A is opposed to a notch 62 formed on an inner 
periphery of a recessed portion of the lock wheel 38. The pawl 60A is 
adapted to move into or out of the notch 62 of the lock wheel 38 as the 
hold lever 60 swings about the pin 61. 
Furthermore, the rotor 42 is provided with a cylindrical portion 50 about 
the center of its rotation. A cam 52 is pivotally supported by the 
cylindrical portion 50 in such a manner as to be rotatable. The cam 52, 
when rotated about the cylindrical portion 50 relative to the rotor 42, 
swings the hold lever 60 so as to be capable of allowing its pawl 60A to 
move into or out of the notch 62 of the lock wheel 38. 
More specifically, the cam 52 is provided with control pieces 52A, 52B. The 
arrangement is as follows: When the cam 52 is rotated about the 
cylindrical portion 50 relative to the rotor 42 in the webbing draw-out 
direction (in the opposite direction of arrow A), the pawl 60A of the hold 
lever is pressed by the control piece 52A so as to swing the hold lever 60 
about the pin 61 in the direction of arrow B in FIG. 4. This allows its 
pawl 60A to move into the notch 62 of the lock wheel 38. On the other 
hand, when the cam 52 is rotated about the cylindrical portion 50 relative 
to the rotor 42 in the webbing take-up direction (in the direction of 
arrow A), the end of the hold lever 60 opposite to the pawl 60A is pressed 
by the control piece 52B so as to swing the hold lever 60 about the pin 61 
in the opposite direction of arrow B. As a result, the hold lever 60 is 
swung about the pin 61 in the opposite direction of arrow B in FIG. 4, 
thereby allowing its pawl 60A to move out of the notch 62 of the lock 
wheel 38, as shown in FIG. 5. 
The cam 52 is provided with a cylindrical portion 52C around the center of 
its rotation. A friction spring 56, which is a lever swinging means, is 
disposed around the cylindrical portion 52C. The friction spring 56 is a 
leaf spring bent into a V-shaped configuration, and is adapted to press 
and clamp cylindrical portion 52C by means of its legs. 
A pawl 102 is disposed below the lock wheel 38, as shown in FIG. 4. A 
proximal end portion of the pawl 102 is axially supported by a sensor 
bracket 104 secured to the leg 14. An intermediate portion of the pawl 102 
is brought into contact with an upper surface of a sensor ball 106 placed 
in a recess of the sensor bracket 104, the recess having an inclined 
bottom surface. A distal end portion of the pawl 102 is opposed to the 
ratchet teeth formed on an outer periphery of the lock wheel 38. 
The arrangement is as follows: the pawl 102 is pressed and moved upward by 
the sensor ball 106 which rises up the recess of the sensor bracket 104 by 
means of the inertia caused by a sudden deceleration or the like of the 
vehicle. The distal end of the pawl 102 engages the ratchet tooth of the 
lock wheel 38, thereby preventing the lock wheel 38 from rotating in the 
webbing draw-out direction. 
A lever 110 is disposed around the pawl 102, as shown in FIG. 4. The lever 
110 has its proximal end pivotally supported by the leg 14 of the frame 10 
via a pin 112 (shown in FIG. 4) in such a manner as to be swingable. An 
actuating piece 114 opposed to the pawl 102 is formed at an intermediate 
portion thereof. As the lever 110 rotates about the pin 112, the actuating 
piece 114 is brought into or out of contact with the pawl 102, thereby 
causing the pawl 102 to be situated either at the position in which it is 
engageable with the lock wheel 32 or at the position in which it is 
unengageable with the lock wheel 32. A pin 116 is projectingly provided on 
the lever 110 between the actuating piece 114 and the proximal end of the 
lever 110. One end of a tension spring 118 is retained by the pin 116. The 
other end of the tension spring 118 is retained by the leg 14 of the frame 
10 via a pin 120 (shown in FIG. 4) so as to urge the lever 110 around the 
pin 112, preventing the pawl 102 from being engaged with the lock wheel 
38. 
An engaging groove 122 for engaging with one leg of the friction spring 56 
is formed at a distal end of the lever 110. 
When the take-up shaft 20 rotates in the webbing draw-out direction, the 
friction spring 56, which is engaged with the lever 110, causes the lever 
110 to swing about the pin 112 against the urging force of the tension 
spring 118, making the pawl 102 engageable with the lock wheel 38. At the 
same time, the friction spring 56 causes the pawl 60A of the hold lever 60 
to move out of the notch 62 of the lock wheel 38 via the cam 52, thereby 
making the lock wheel 38 and the take-up shaft 20 rotatable relative to 
each other. On the other hand, when the take-up shaft 20 rotates in the 
webbing taking-up direction, the friction spring 56 causes the lever 110 
to swing about the pin 112 by means of the urging force of the tension 
spring 118, making the pawl 102 unengageable with the lock wheel 38. At 
the same time, the friction spring 56 causes the pawl 60A of the hold 
lever 60 to move into the notch 62 of the lock wheel 38, thereby making it 
impossible for the take-up shaft to rotate in the webbing drawing-out 
direction relative to the lock wheel 38. 
More specifically, a setting is provided in such a manner that the force 
with which the tension spring 118 urges the lever 110 about the pin 112 is 
greater than the frictional force acting between the cam 52 and the 
rotating rotor 42 and is smaller than the frictional force acting between 
the friction spring 56 and the rotating cam 52. 
By virtue of this setting, when the take-up shaft rotates in the webbing 
draw-out direction (in the opposite direction of arrow A), the cam 52 in 
the state shown in FIG. 4 rotates in the webbing take-up direction (in the 
direction of arrow A) relative to the rotor 42. Due to this relative 
rotation, the hold lever 60 swings about the pin 61 in the opposite 
direction of arrow B, with the result that its pawl 60A moves out of the 
notch 62 of the lock wheel 38, thereby making the lock wheel 38 and the 
take-up shaft 20 rotatable relative to each other. Subsequently, the 
friction spring 56 and the cam 52 rotate relative to each other with the 
amount of rotation of the cam 52 restricted by the hold lever 60. The 
frictional force occurring at this time overcomes the urging force of the 
tension spring 118 and causes the lever 110 to swing about the pin 112, 
thereby making the pawl 102 engageable with the lock wheel 38. Then, while 
the webbing 23 is being drawn out, the relative rotation of the cam 52 and 
the friction spring 56 maintains a state in which the pawl 102 is made 
engageable with the lock wheel 38. The lock wheel 38 and the take-up shaft 
are rotatable relative to each other. When the drawing out of the webbing 
23 is stopped, the lever 110 is urged by the tension spring 118 and is 
swung, as shown in FIG. 6, making the pawl 102 unengageable with the lock 
wheel 38. 
In addition, when the take-up shaft 20 in the state shown in FIG. 6, 
rotates in the webbing taking-up direction, the cam 52 rotates in the 
webbing drawing-out direction (in the opposite direction of arrow A) 
relative to the rotor 42. This relative rotation causes the hold lever 60 
to swing about the pin 61 in the direction of arrow B, and causes its pawl 
60A to move into the notch 62 of the lock wheel 38, making it impossible 
for the lock wheel 38 and the take-up shaft 20 to rotate relative to each 
other. Then, while the webbing 23 is being taken up, the relative rotation 
of the cam 52 and the friction spring 56 maintains a state in which the 
pawl 102 is unengageable with the lock wheel 38, and the lock wheel 38 and 
the take-up shaft 20 are prevented from rotating relative to each other. 
Even after the taking-up of the webbing 23 is stopped, the same state is 
maintained. 
A sensor cover 54 is secured to the leg 14 of the frame 10, and the 
respective parts around the lock wheel 38 are accommodated in the sensor 
cover 54. 
In the webbing retractor in accordance with this embodiment thus 
constructed, the frame 10 is mounted on a chassis via bolts. In a case 
where this retractor is used for a three-point seatbelt of a continuous 
webbing type, an end of the webbing 23 drawn out from the take-up shaft 20 
is retained by the chassis via an anchor member. An intermediate portion 
of the webbing 23 is turned back at a slip joint (not shown) retained by 
the chassis. Furthermore, a tongue plate (not shown) is attached to an 
intermediate portion between the anchor member and the slip joint in such 
a manner as to be longitudinally slidable. Then, when the seated occupant 
draws out the webbing 23 from the take-up shaft 20 and causes the tongue 
plate to engage with a buckle device (not shown) attached to the chassis, 
the webbing is fastened around the occupant's body. 
A description will now be given of the operation of the retractor in 
accordance with this embodiment. 
First, a description will be given of the normal state in which the lock 
mechanism is not in operation. 
In the state in which the webbing 23 has been fully taken up, the take-up 
shaft remains stopped after having rotated in the webbing taking-up 
direction. The relative positional relationships of the retractor 
components are in the state shown in FIGS. 2 and 4. 
In other words, as shown in FIG. 2, the lock mechanism is not operating. 
FIG. 4 shows that the pawl 60A of the hold lever 60 is placed in the notch 
62 provided on the inner periphery of the lock wheel 38, which makes the 
lock wheel 38 and the take-up shaft 20 unrotatable relative to each other. 
At the same time, the pawl 102 is pressed by the lever 110 by means of the 
urging force of the tension spring 118 and is hence made unengageable with 
the lock wheel 38. 
When the drawing out of the webbing 23 in this state is commenced, the cam 
52 rotates relative to the rotor 42 in the webbing taking-up direction (in 
the direction of arrow A). This relative rotation causes the hold lever 60 
to swing about the pin 61 in the opposite direction of arrow B, which, in 
turn, causes its pawl 60A to move out of the notch 62 of the lock wheel 
38, allowing the lock wheel 38 and the take-up shaft 20 to rotate relative 
to each other. Subsequently, the friction spring 56 and the cam 52 rotate 
relative to each other with the amount of rotation of the cam 52 
restricted by the hold lever 60. The frictional force occurring at this 
time overcomes the urging force of the tension spring 118, and causes the 
lever 110 to swing about the pin 112, thereby allowing the pawl 102 to 
engage with the lock wheel 38. While the webbing 23 is being drawn out, 
the relative rotation of the friction spring 56 and the cam 52 maintains a 
state in which the pawl 102 is engageable with the lock wheel 38, and the 
lock wheel 38 and the take-up shaft 20 are rotatable relative to each 
other. When the drawing out of the webbing 23 is stopped, the lever 110 is 
urged by the tension spring 118 and is swung, making it impossible for the 
pawl 102 to engage with the lock wheel 38. 
In the normal state of the vehicle, by following the change in the posture 
of the upper part of the body of the occupant wearing the webbing 23, the 
webbing 23 is drawn out or taken up freely from the take-up shaft 20 and 
does not restrict the occupant. In other words, this is because the normal 
rotation of the take-up shaft 20 does not deform the torsion coil spring 
44, and relative rotation does not occur between the take-up shaft 20 and 
the lock wheel 38. 
When the occupant stops wearing the webbing 23, the webbing 23 is taken up 
by the take-up shaft 20 by the urging force of the spiral spring 27. When 
the taking up of the webbing 23 is commenced, the cam 52 in the state 
shown in FIG. 6 rotates relative to the rotor 42 in the webbing 
drawing-out direction (in the opposite direction of arrow A). This 
relative rotation causes the hold lever 60 to swing about the pin 61 in 
the direction of arrow B, and its pawl 60A moves into the notch 62 of the 
lock wheel 38, thereby making it impossible for the lock wheel 38 and the 
take-up shaft to rotate relative to each other. Then, while the webbing 23 
is being taken up, a state is maintained in which the pawl 102 is made 
unengageable with the lock wheel 38 and the lock wheel 38 and the take-up 
shaft 20 are unrotatable relative to each other, as shown in FIG. 4. Even 
after the taking up of the webbing 23 is stopped, the same state is 
maintained. 
At this juncture, if the webbing 23 is taken up very rapidly, the rotation 
of the take-up shaft 20 stops suddenly at the take-up limit of the 
webbing. Consequently, the lock wheel 38 tends to deform the coil spring 
44 by means of the inertia against the urging force of the torsion coil 
spring 44 and rotate further relative to the take-up shaft 20, and at the 
same time the pawl 102 tends to be engaged with the lock wheel 38 due to 
the shock. 
In such a case, however, while the webbing 23 is being taken up, the pawl 
60A of the hold lever 60 moves into the notch 62 provided at the inner 
periphery of the lock wheel 38, as shown in FIG. 4. The result is that a 
state is maintained in which the lock wheel 38 and the take-up shaft are 
prevented from rotating relative to each other. Hence, the lock wheel 38 
is prevented from rotating further relative to the take-up shaft 20. 
In addition, while the webbing 23 is being taken up, the lever 110 presses 
the pawl 102, with the result that the state in which the pawl 102 is made 
unengageable with the lock wheel 38 is maintained, thereby preventing the 
pawl 102 from engaging with the lock wheel 38. 
Accordingly, the possibility of the lock mechanism being operated at the 
take-up limit of the webbing, which would subsequently involve a 
cumbersome operation of further drawing out the webbing 23, is eliminated. 
In addition, even if the webbing 23 is drawn out, the possibility of its 
tensile force being transmitted to the pawl 102 and causing damage to the 
pawl 102 is also eliminated. 
Next, a description will be given of the state in which the lock mechanism 
is operated due to a sudden deceleration of the vehicle. 
During a sudden deceleration of the vehicle, the webbing 23 is drawn out 
from the take-up shaft 20 due to the inertia of the occupant. The 
retractor assumes the state shown in FIG. 5. At this juncture, when the 
webbing 23 is drawn out suddenly from the take-up shaft 20, the take-up 
shaft 20 rotates abruptly. A large force instantaneously acts on the 
torsion coil spring 44 due mainly to the acceleration acting on the lock 
wheel 38, thereby causing the torsion coil spring 44 to be deformed 
against its urging force. As a result, since a delay in rotation occurs in 
the lock wheel 38 relative to the take-up shaft 20, and the lock plates 
24, 25 are pressed by the take-up shaft 20, the claw portions 28, 30 are 
engaged with the internal ratchet wheel 32, as shown in FIG. 3, and 
thereby prevent the take-up shaft 20 from rotating in the webbing draw-out 
direction. This results in the occupant being and restrained by the 
webbing 23. 
In addition, when the vehicle decelerates suddenly, the pawl 102 is swung 
by being pressed by the sensor ball 106 which rises up the recess of the 
sensor bracket 104, the recess having an inclined bottom surface, due to 
the inertia of the deceleration. As a result, the pawl 102 engages the 
lock wheel 38 and prevents the lock wheel 38 from rotating in the webbing 
draw-out direction. Hence, the lock wheel 38 undergoes a delay in rotation 
with respect to the take-up shaft 20 which is further rotated by the 
webbing 23 drawn out by the occupant's inertia due to the sudden 
deceleration of the vehicle. Accordingly, the drawing out of the webbing 
23 is prevented in the same way as described above, so that the occupant 
is restrained by the webbing 23. 
In the foregoing explanation, a description has been given separately with 
respect to one case where the webbing 23 is drawn out suddenly from the 
take-up shaft 20 and another case where the vehicle is decelerated 
suddenly. When the vehicle decelerates suddenly, the pawl 102 is swung and 
the webbing 23 is drawn out suddenly. However, the drawing out of the 
webbing 23 is prevented in both cases. 
FIG. 8 illustrates an essential portion of a second embodiment of the 
present invention. 
In this embodiment, a weight 140 is attached to an intermediate portion of 
the lever 110. In this embodiment, at the time when the webbing 23 is 
drawn out, the lever 110 swings about the pin 112 against the weight of 
the weight 140 and causes the pawl 102 to be engageable with the lock 
wheel 38. Meanwhile, at the time when the drawing out of the webbing 23 is 
stopped, the webbing 23 is in a state of being taken up, or the take-up 
has stopped. At this time the lever 100 is swung about the pin 112 due to 
the weight of the weight 140, thereby making it impossible for the pawl 
102 to engage with the lock wheel 38. 
FIG. 9 illustrates a third embodiment of the present invention. In this 
embodiment, in addition to the arrangement of the second embodiment, a 
projecting piece 142 is formed at an intermediate portion of the lever 
110, and two pins 144 are projectingly provided on the projecting piece 
142. A leaf spring 146 is interposed between the pins 144 and is retained 
by the leg 14 via pins 145. 
In this embodiment, the lever 110 is swung about the pin 112 while 
deforming the leaf spring 146. When the leaf spring 146 is deformed by a 
predetermined amount, the lever 110 is subsequently swung rapidly by the 
urging force of the leaf spring 146, creating a snap in the operation of 
the lever 110. 
FIG. 10 illustrates a fourth embodiment of the present invention. In this 
embodiment, in addition to the friction spring 56, another friction spring 
148 is pressed against and abuts the outer periphery of the cylindrical 
portion 52C of the cam 52. This friction spring 148 is supported by the 
sensor cover 54 via a holder 149. 
In this embodiment, at the time of drawing out the webbing 23, the cam 52 
rotates in the webbing take-up direction (in the direction of arrow A) 
relative to the rotor 42 due to a frictional force acting between the cam 
52 and the friction spring 148. This rotation causes the hold lever 60 to 
swing about the pin 61 in the opposite direction of arrow B, so that its 
pawl 60A moves out of the notch 62 of the lock wheel 38, thereby making 
the lock wheel 38 and the take-up shaft 20 rotatable relative to each 
other. Subsequently, the lever 110 is swung about the pin 112 by the 
frictional force of the friction spring 56 due to the rotation of the cam 
52, thereby permitting the pawl 102 to engage with the lock wheel 38. 
FIGS. 11 and 12 illustrate a fifth embodiment of the present invention. In 
this embodiment, the friction spring 148 is pressed against and fitted to 
the outer periphery of the friction spring 56. 
Since the operation of this embodiment is basically similar to that of the 
fourth embodiment, a description thereof will be omitted. 
FIGS. 13 and 14 illustrate a sixth embodiment of the present invention. In 
this embodiment, an annular groove 150 (shown in FIG. 14) is formed on the 
outer periphery of the cam 52, and the friction spring 148 is pressed 
against and fitted to the annular groove 150. 
Since the operation of this embodiment is similar to the fourth embodiment, 
a description thereof will be omitted. 
As described above, at the time when the vehicle is decelerated suddenly, 
it is possible to stop the rotation of the take-up shaft in the webbing 
draw-out direction by the engagement, with the lock wheel, of the pawl 
operated by sensing the deceleration or by a sudden drawing out of the 
webbing at that time; relative rotation is caused between the lock wheel 
and the take-up shaft, and the lock mechanism is operated by this relative 
rotation. Furthermore, a displacing member is disposed on a rotating 
member rotating integrally with the take-up shaft, and the displacing 
member is engaged with the lock wheel by the rotation of the take-up shaft 
in the webbing take-up direction. This prevents the lock wheel from 
rotating in the webbing take-up direction relative to the take-up shaft. 
At the same time, the displacing member is disengaged from the lock wheel 
by the rotation of the take-up shaft in the webbing draw-out direction, 
thereby permitting the take-up shaft to rotate in the webbing draw-out 
direction relative to the lock wheel. Accordingly, the present invention 
offers an outstanding advantage in that even if the webbing is drawn out 
from a take-up limit of the webbing, the webbing drawing-out force is 
prevented from being imparted to the pawl.