Information
-
Patent Grant
-
6591465
-
Patent Number
6,591,465
-
Date Filed
Wednesday, February 28, 200124 years ago
-
Date Issued
Tuesday, July 15, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Sandy; Robert J.
- Rodriguez; Ruth C.
Agents
-
CPC
-
US Classifications
Field of Search
US
- 280 733
- 280 751
- 280 748
- 280 8011
- 280 8012
- 280 808
-
International Classifications
-
Abstract
A latching apparatus for an inflatable belt device which achieves reduction in the gas leakage without losing the smoothness of insertion of a tongue into a buckle, or which achieves reduction in the manufacturing cost and the weight of the latching apparatus. A tongue and a buckle of a latching apparatus for an inflatable belt device have pipes (a tongue pipe, a buckle pipe), through which gas for deploying an inflatable belt flows. The end of the buckle pipe is covered by a buckle cap which is broken when an inflator is actuated. The buckle cap is biased upwardly by a spring fitted around the buckle pipe. A space between the pipes is eliminated by the buckle cap, thereby achieving the reduction in gas leakage. Therefore, the need for excess gas is eliminated, thereby enabling miniaturization of the inflator.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a latching apparatus for an inflatable belt device which achieves reduction of gas leakage without losing the smoothness of insertion of the tongue into the buckle, or reduction in the manufacturing cost and the weight of the latching apparatus. More particularly, the present invention relates to a latching apparatus for an inflatable belt device comprising a tongue and a buckle through which gas generated from an inflator is supplied to a cushion.,
Currently, a seat belt is the most commonly used as a device for restraining an occupant in a vehicle seat in the event of emergency. A typical seat belt device comprises a shoulder webbing to be extended diagonally across the chest from the shoulder to the waist of an occupant, a lap webbing to be extended across the lap in front of the waist of the occupant, the shoulder webbing and the lap webbing being integral as one strip. The proximal end of the shoulder webbing is connected to a seat belt retractor. The retractor prevents the shoulder belt from being withdrawn when an abnormal deceleration is exerted on a vehicle. When locked, the shoulder belt blocks the frontward movement of the occupant.
In recent years, seat belt devices have been refined to further intensify the function of protecting occupants by adding the following techniques:
(1) a pretensioner which rapidly remove slack from the webbing in the event of emergency to achieve initial restraint of the occupant; and
(2) an energy absorbing mechanism (hereinafter, referred to as “EA mechanism”) which allows the webbing to be gradually withdrawn to absorb inertia energy of the occupant when the tension on the webbing exceeds a predetermined value.
However, there remains a need for achieving more soft protection of the occupant by reducing the pressures to the shoulder and the chest of the occupant.
In order to meet this need an inflatable belt device has been developed. The conventional inflatable belt device is a seat belt, of which a portion of a shoulder webbing that touches the shoulder and chest of an occupant's body is composed of an inflatable bag. For example, the bag may be inflated to have a diameter of 14 cm in order to function as an air cushion, thereby softening the pressure exerted on the occupant's body. The bag is shortened in the longitudinal direction when inflated in order to remove the slack from the webbing. In this manner, the inflatable belt also functions as a seat belt pretensioner. Furthermore, the inflatable belt device can also function as an EA mechanism by gradually exhausting gas in the bag at appropriate times. It is expected that inflatable belt devices will increase in popularity due to their improved safety capacity as compared to current seat belt devices.
In general, an inflatable belt device may include a latching apparatus for connecting a seat belt device and a vehicle body. The latching apparatus generally comprises a buckle connected to a vehicle body (e.g. seat frame) and a tongue connected to an end of the inflatable belt. The buckle has a tongue latching mechanism for allowing detachable latching of the tongue.
Inflators for inflating a bag of an inflatable belt device generally include two types. One type is connected to an upper portion of the bag (arranged above the shoulder of the occupant) and the other type is connected to an lower portion of the bag (arranged below the lap of the occupant). In some of the second type of inflators, gas generated by the inflator is supplied into the bag through a buckle. The buckle and a tongue have gas passages, respectively, through which gas generated by the inflator is passed. These passages are designed to communicate with each other when the tongue is inserted to the buckle.
SUMMARY OF THE INVENTION
The inflatable belt mentioned above may be improved in several ways. In order to improve the smoothness of insertion of tongue into the buckle, a suitable clearance should be formed between the tongue and a tongue insertion opening of the buckle in the normal used state of a seat belt. In order to minimize gas leakage, gas generated by the inflator should be supplied into the bag through the passages of the buckle and the tongue without gas leakage when the inflatable belt is deployed (in the event of vehicle collision). Furthermore, easy detachment of the tongue from the buckle should be allowed after the vehicle collision.
An inflatable belt device that satisfies the above points may include a buckle having a gas passage of which one end is positioned inside the buckle so as not to project in the normal used state. The gas passage is arranged to project into the tongue only at the start of vehicle collision and to return to the inside of the buckle by pressure inside the bag during a period between the vehicle collision and the end of the vehicle collision.
In order to cope with a vehicle collision of relatively long period of time (for example, a roll-over that needs to restrain an occupant for several seconds of time), it is required to increase the capacity (molecular amounts of gas) of the inflator to maintain the pressure in the bag. However, the size and the weight of the inflator are increased with increase in the capacity of the inflator, thus also increasing the manufacturing cost. The inflator should be designed to have enough capacity to account for any gas leakage between the buckle and the tongue.
The present invention has been made to solve the aforementioned problems by providing a latching apparatus for an inflatable belt device which achieves reduction in the gas leakage without losing the smoothness of insertion of a tongue into a buckle, and which achieves reduction in the manufacturing cost and the weight of the latching apparatus.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below.
FIG. 1
is a sectional view showing the structure of a latching apparatus for an inflatable belt device of the embodiment, in a state that a tongue is latched to a buckle.
FIG. 2
is an enlarged sectional view of the buckle in a state that the tongue is released.
FIG. 3
is a sectional view showing the connecting relation among an inflatable belt, the tongue, and an upper portion of the buckle of the inflatable belt device.
FIG. 4
is a perspective view showing the appearance of the tongue and the buckle.
FIG. 5
is a front view showing the entire structure of the latching apparatus for the inflatable belt device of the embodiment.
FIG. 6
is a view showing a rear side of the latching apparatus in a state that a cover of the buckle is removed.
FIG. 7
is a schematic perspective view showing the entire structure of the inflatable belt device according to an embodiment of the present invention and also showing its bag deployed state.
FIG. 8
is a perspective view, partially cutaway, showing the structure of this embodiment of the latching apparatus for the inflatable belt device according to the present invention,
FIG. 8
showing a state that a buckle and a tongue are separated away.
FIG. 9
is a front view, partially cutaway, showing the entire structure of the latching apparatus for the inflatable belt device shown in FIG.
8
.
FIGS.
10
(A)-
10
(C) are enlarged sectional views showing the joint portion between a buckle pipe and a tongue pipe in the latched state of the latching apparatus.
FIGS.
11
(A),
11
(B) are enlarged sectional views showing the flow of gas at the joint of the pipes in the latched state of the latching apparatus for the inflatable belt device.
FIG. 12
is a front view showing a variation of the latching apparatus for the inflatable belt device shown in FIG.
8
.
FIGS.
13
(A) through
13
(C) are enlarged views showing a joint portion between a buckle pipe and a tongue pipe of the latching apparatus shown in FIG.
12
.
DETAILED DESCRIPTION
Although references are made below to directions, such as left, right, up, down, etc., in describing the drawings, they are reference relative to the drawings (as normally viewed) for convenience. These directions are not intended to be taken literally or limit the present invention in any form.
In
FIG. 7
, an occupant
11
is shown in a state sitting on a seat
1
. The seat
1
includes a seat squab
5
on which the occupant
11
sits and a seat back
3
. Arranged below the seat squab
5
is a seat frame
7
for supporting the seat
1
and connecting the seat
1
to a vehicle body.
An inflatable belt device
21
comprises the following components: an inflatable belt
31
which is extended diagonally across the chest from the shoulder to the waist of the occupant
11
when the occupant
11
puts on the inflatable belt device
21
; a shoulder webbing
25
which is connected to the upper end of the inflatable belt
31
and is composed of a band-like webbing just like a webbing of a normal seat belt; a deflector
27
for deflecting the shoulder webbing
25
; a retractor
23
for winding up the shoulder webbing
25
and for stopping the shoulder webbing
25
from being withdrawn in the event of emergency; a tongue
33
which is connected to a lower end portion of the inflatable belt
31
to connect the inflatable belt
31
to the vehicle body through a buckle
35
; the buckle
35
which is fixed to the seat frame
7
through an inflator
39
and an anchor bracket
37
; the inflator
39
for generating gas for inflating the inflatable belt
31
; a lap webbing
41
which is extended across the lap of the occupant; a retractor
43
for winding up the lap webbing
41
and for stopping the lap webbing
41
from being withdrawn in the event of emergency; and an acceleration sensor and an electric circuit for actuating the inflator
39
in the event of emergency.
The inflatable belt device
21
is characterized by the structure of the gas passages of the tongue
33
and the buckle
35
. The structure will be described in detail with reference to FIG.
1
through FIG.
6
.
As shown in
FIG. 5
, the latching apparatus
100
of the inflatable belt device
21
comprises the tongue
33
and the buckle
35
. The inflator
39
is connected to a lower portion of the buckle
35
by screws. Disposed on the lower end of the inflator
39
is an anchor bracket
37
.
As shown in
FIG. 4
, the tongue
33
has a tongue plate
33
a
to be inserted into the buckle
35
, a hanger portion
33
c,
and a tongue pipe
33
d.
The tongue plate
33
a
is engaged with a latch
131
of a tongue latching mechanism
110
in the buckle
35
as described later. The hanger portion
33
c
is formed with a slit
33
e
. The lap webbing
41
, described further below, is inserted through the slit
33
e.
The tongue pipe
33
d
is provided at the center in the width direction of the tongue
33
. As shown in
FIG. 3
, connected to the upper end of the tongue pipe
33
d
is a gas inlet
77
(described further below) for the inflatable bag
53
. The tongue pipe
33
d
has a gas passage
33
b
formed inside thereof. As shown in
FIG. 3
, the gas passage
33
b
is formed to communicate with the inside of the bag
53
. As shown in FIG.
1
and
FIG. 3
, a tongue cap
34
made of aluminum is fitted in a lower end opening of the tongue pipe
33
d
. The tongue cap
34
is depressed into the gas passage
33
b
of the tongue pipe
33
d
and is engaged with an edge of the lower end opening of the tongue pipe
33
d
. The tongue cap
34
is designed to give way or rupture when confronted by the gas emitted by the inflator
39
. The tongue cap
34
also functions as a screen gate for preventing dust from invading into the tongue pipe
33
d.
As shown in FIG.
1
and
FIG. 2
, the buckle
35
comprises an outer cover
101
. The cover
101
is formed at its upper portion with an upper opening
35
d
for the insertion of the tongue plate
33
a
. The tongue latching mechanism
110
is provided inside the cover
101
for engaging the tongue plate
33
a
when inserted. The cover
101
is provided at its upper portion with a release button
35
a
. As the button
35
a
is depressed, the tongue latching mechanism
110
is released so as to push out the tongue
33
upwardly.
As shown in
FIG. 6
, the tongue latching mechanism
110
comprises a buckle base
111
made of steel. The buckle base
111
functions as a main rigid member against a force drawing out the inflatable belt
31
. The buckle base
111
is a substantially U-shaped member having a base plate
113
and two side plates
115
. The base plate
113
is formed with two slits
113
a
parallel to each other. Projections
165
of an ejector
161
, further described below, fit and slide into the slits
113
a
. The base plate
113
is formed at its lower portion with a cutout
113
b
into which an external stopper
175
of an inflator connecting member (duct)
171
, described later is fitted. Screws
114
for fixing a buckle pipe
181
and screws
116
for fixing an inflator connecting member are screwed into the base plate
113
.
The latch
131
is held between the side plates
115
of the buckle base
111
. The latch
131
presses down the tongue plate
33
a
when the tongue
33
is latched (see FIG.
1
). As shown in
FIGS. 1
,
2
, and
6
, the latch
131
has a pivot portion
133
and a movable portion
135
. The pivot portion
133
of the latch
131
has lateral protrusions
133
a
. The protrusions
133
a
function as a pivot axis for the latch
131
. The movable portion
135
of the latch
133
is formed with left-side and right-side windows
135
a
as shown in FIG.
6
. The windows
135
a
are closed by a sliding member
141
when the tongue
33
is latched (as shown in
FIG. 1
) and are opened when the tongue
33
is not latched (as shown in FIG.
2
). In the opened state, pawls (not shown) of the side plates
115
enter into the windows
135
a.
The back (a right-side surface in FIG.
1
and
FIG. 2
) of the latch
131
is formed with a tongue engaging projection
137
. The engaging projection
137
is engaged with the tongue plate
33
when the tongue
33
is latched (as shown in FIG.
1
). The latch engaging projection
137
has a tapered portion
137
a
formed on an upper portion thereof. In addition, the latch
131
has a spring hook
138
formed on the upper end thereof. Attached to the spring hook
138
is a spring
104
for connecting and biasing the latch
131
and a sliding member
141
. The latch
131
and the release button
35
a
are connected and biased by a button spring
107
. The connecting state among the ends of the button spring
107
, the latch
131
, and the release button
35
a
is schematically shown. The button spring
107
biases the release button
35
a
in the downward direction and biases the latch
131
to stand upright.
As shown in FIG.
1
and
FIG. 2
, slidably fitted to the left side of the latch
131
(the left side in FIG.
1
and
FIG. 2
) is a sliding member
141
. The sliding member
141
has lateral protrusions
143
. The protrusions
143
close the windows
135
a
(see
FIG. 6
) of the latch
131
when the tongue
33
is latched (in the state shown in
FIG. 1
) and are positioned below the windows
135
a
of the latch
131
so that the windows
135
a
are opened when the tongue
33
is not latched (in the state shown in FIG.
2
). The sliding member
141
has a spring hook
145
formed substantially at its central portion. A spring
104
is disposed between the spring hook
145
and the spring hook
138
of the latch
131
. By this spring
104
, the slider
141
is biased upwardly (toward the position where the windows
135
a
are closed). The sliding member
141
is formed at its upper end with a humulus-like contact portion
147
. The contact portion
147
comes in contact with the inner side of the release button
35
a
when the tongue
33
is latched (as shown in FIG.
1
).
The ejector
161
having a U-like shape in its plan view is held inside the buckle base
111
in such a manner that the ejector
161
can slide along the vertical direction. The ejector
161
is formed to have a dimension larger than the outer diameter of the buckle pipe
181
. The ejector
161
has two projections
165
, as shown in
FIG. 6
, formed on the edge of the opening inside the U-like shape. The projections
165
are slidably fitted in the slits
113
a
of the buckle base
111
. The ejector
161
has an arc-like contact portion
167
formed on the upper end of a surface, opposite to the projections
165
, (the left-side surface in FIG.
1
and
FIG. 2
) of the ejector
161
. The lower end of the tongue plate
33
a
comes in contact with the contact portion
167
when the tongue
33
is latched. The ejector
161
has spring holes (not shown) fitted to the upper ends of springs
108
, described further below.
As shown in FIG.
1
and
FIG. 2
, the buckle pipe
181
is disposed between the base plate
113
and the ejector
161
substantially at the center of the inside of the buckle base
111
. The buckle pipe
181
is fixed to the base plate
113
of the buckle base
111
by screws
114
. The buckle pipe
181
is a gas passage through which gas spouted out from the inflator
39
passes into the inflatable belt
31
.
A buckle cap
103
made of aluminum is put on the upper end of the buckle pipe
181
. The buckle cap
103
is formed with tear lines (not shown). The upper end of the buckle pipe
181
is normally closed by the buckle cap
103
. When the inflatable belt device is actuated, however, the buckle cap
103
is broken along its tear lines by gas pressure generated by the inflator
39
. As shown in
FIG. 1
, there is a clearance (over stroke) C between the inner surface of the buckle cap
103
and the upper end of the buckle pipe
181
, and this clearance absorbs the tolerance among parts and backlash during the insertion of the tongue
33
.
The buckle cap
103
is biased upwardly by the spring
185
fitted around the buckle pipe
181
. Because of the biasing force of the spring
185
, the upper end of the buckle pipe
181
and the lower end of the tongue pipe
33
d
of the tongue
33
are closely in contact with each other when the tongue
33
is latched. The upper end of the inflator
39
is connected to the lower end of the buckle pipe
181
via an O-ring
189
.
To prevent the buckle cap
103
from coming off the buckle pipe
181
, a flange (not shown) of the buckle cap
103
is stopped by pawls (not shown) extending from the buckle base
111
.
This embodiment is designed so that the tongue pipe
33
d
of the tongue
33
and the buckle pipe
181
of the buckle
35
are coaxially aligned and connected to each other substantially at the center in the width direction when the tongue
33
is latched. At this point, in the joint portion between the pipes
33
d
and
181
, the buckle cap
103
is biased toward the tongue cap
34
by the spring
185
so that a space between the pips
33
d
and
181
is eliminated. Since the space is eliminated, gas leakage during the operation of the inflator
39
can be reduced.
As shown in FIG.
1
and
FIG. 2
, a holder
151
is disposed inside the buckle base
111
below the latch
131
and the sliding member
141
. The holder
151
has projections
155
formed on a right side portion thereof (the right side in FIG.
1
and
FIG. 2
) to project upwardly. The springs
108
are fitted around the projections
155
. The upper ends of the springs
108
are fitted to the spring holes (not shown) formed in the bottom of the ejector
161
. The ejector
161
is biased upwardly by the biasing force of the springs
108
so that the ejector
161
is risen when the tongue
33
is not latched, as shown in FIG.
2
.
The holder
151
has two guide poles
153
arranged along the width direction (the depth direction in FIG.
1
and
FIG. 2
) to stand upwardly on a left side portion thereof (the left side in FIG.
1
and FIG.
2
). Guide holes (not shown) of the release button
35
a
slide along the guide poles
153
. Springs
106
are fitted around the guide poles
153
, respectively. The upper ends of the spring
106
are in contact with the bottom of the release button
35
a
. The release button
35
a
is biased upwardly by the biasing force of the springs
106
.
As shown in FIG.
1
and
FIG. 2
, the cylindrical duct
171
is attached to the buckle base
111
below the holder
151
. The duct
171
is formed in its lower inner surface with an internal thread
171
a
(see FIG.
1
and FIG.
2
). Screwed into this internal thread
171
a
is an external thread
39
a
(see FIG.
1
and
FIG. 2
) formed in an upper end portion of the inflator
39
. The duct
171
has the external stopper
175
formed on an end portion thereof as shown in FIG.
6
. The external stopper
175
is formed in a drum-like shape with a neck portion and is fitted to the cutout
113
b
of the base plate
113
of the buckle base
111
. Force of drawing the tongue is transmitted to the duct
171
and the inflator
39
through this joint portion. The duct
171
and the buckle base
111
are fixed to each other by the screws
116
.
As shown in FIG.
1
and
FIG. 2
, the upper end of the inflator
39
is connected to the lower end of the buckle pipe
181
of the buckle
35
via the duct
171
. When the inflator
39
is ignited in the event of vehicle collision, the inflator
39
spouts out gas for deploying the bag toward the gas passage
35
c
of the buckle
35
. The gas is emitted into the hollow portion of the bag through the tongue pipe
33
d
(see
FIG. 3
) of the tongue
33
after passing through the inside of the buckle pipe
181
.
The upper end portion of the inflator
39
is tapered and has the external thread
39
a
formed in the outer surface thereof. The external thread
39
a
is screwed into the internal thread
171
a
of the duct
171
. The inflator
39
includes a propellant and an initiator (not shown) therein. The anchor bracket
37
is provided at the lower end of the inflator
39
as shown in FIG.
5
. The bracket
37
is fixed to the seat frame by bolts or the like. Though the anchor bracket
37
is formed integrally with the body of the inflator
39
in this embodiment, it may be formed separately from the inflator and may be connected by bolts or clamps. It should be noted that the inflator
39
and the bracket
37
may be connected by crimping.
As shown in
FIG. 3
, the inflatable belt
31
is composed of three layer elements. The three layer elements in the order from the inside to the outside are: a bag
53
, a mesh webbing
51
, and a cover
81
. The bag
53
is made by forming (bonding, sewing) for example, nylon plain wave fabric, on which silicone resin is coated, into an envelope shape. The bag
53
is covered by the mesh webbing
51
from the outside. The mesh webbing
51
is formed by knitting, for example, polyester yarns into a cylindrical shape. When the bag
53
is deployed, the mesh webbing
51
expands along the outer surface of the bag
53
. At this point, the mesh webbing
51
shrinks in the longitudinal direction, thereby removing slack from the webbing and imparting pre-tension on the webbing. It should be noted that the bag
53
itself also shrinks in the longitudinal direction during its deployment.
The mesh webbing
51
is covered by the cover
81
from the outside. The cover
81
may be made of polyester plain wave fabric. The cover
81
is torn during the deployment of the bag
53
. The cover
81
is used for accommodating the inflatable belt
31
in a compact form and for making the inflatable belt
31
comfortable to the occupant.
The bag
53
has the gas inlet
77
formed in the lower end thereof. The lower end of the mesh webbing
51
is sewn to the end of the lap webbing
41
by sewing (sewing portion
52
).
The inflatable belt
31
and the tongue
33
are connected to each other by the following method. That is, as shown in
FIG. 3
, the tongue pipe
33
d
of the tongue
33
is inserted into the gas inlet
77
of the bag
53
. The tongue pipe
33
d
and the gas inlet
77
are fastened and fixed by a clamping band
79
. The lap webbing
41
connected to the mesh webbing
51
by sewing is passed through the slit
33
e
of the hanger portion
33
c.
Hereinafter, the actions of the inflatable belt device
21
having the aforementioned construction will be described with reference to FIG.
1
and
FIG. 2
mainly.
When the tongue
33
is not latched to the buckle
35
, as shown in
FIG. 2
, the ejector
161
is pressed upwardly by the biasing force of the springs
108
so that it is in an upward position. At this point, the side of the ejector
161
is in contact with the engaging projection
137
of the latch
131
so that the latch
131
tilts leftward.
To latch the tongue
33
to the buckle
35
, the tongue plate
33
a
of the tongue
33
is inserted into the upper opening
35
d
of the buckle
35
. At this point, the lower edge of the tongue plate
33
a
comes in contact with the contact portion
167
of the ejector
161
. The ejector
161
is depressed against the biasing force of the springs
108
. Then, as shown in
FIG. 1
, the ejector
161
is lowered below the engaging projection
137
of the latch
131
and the tongue plate
33
a
is also lowered below the engaging projection
137
so that the projection
137
enters into a tongue plate hole
33
x
of the tongue plate
33
a
. In this way, the tongue plate
33
a
and the latch
131
are latched. The latch
131
is biased by the button spring
107
so as to stand upright as shown in FIG.
1
. At this point, the sliding member
141
is biased by the compressing force of the spring
104
to move upwardly so as to close the windows
135
a
(
FIG. 6
) of the latch movable portion
135
. This configuration prevents the latch
131
from tilting leftward and prevents the tongue plate
33
a
from coming off.
When the buckle
35
and the tongue
33
are connected to each other, as shown in
FIG. 1
, the tongue pipe
33
d
of the tongue
33
and the buckle pipe
181
of the buckle
35
are aligned coaxially and connected to each other substantially at the center in the width direction. The buckle cap
103
on the upper end of the buckle pipe
181
is biased upwardly by the spring
185
and is thus pressed against the tongue cap
34
of the lower end of the tongue pipe
33
d
. Therefore, the upper end of the buckle pipe
181
and the lower end of the tongue pipe
33
d
are connected closely to each other. It should be noted that the tolerance among parts and backlash during the insertion of the tongue
33
can be absorbed by the clearance C inside the buckle cap
103
.
When gas is emitted out from the inflator
39
, the gas breaks the buckle cap
103
on the upper end of the buckle pipe
181
along the tear lines, further breaks the tongue cap
34
, and is supplied into the bag
53
through the tongue pipe
33
d
. Since there is no space between the upper end of the buckle pipe
181
and the lower end of the tongue pipe
33
d
, i.e. these are closely connected, it achieves the reduction in gas leakage during the actuation of the inflator
39
.
Hereinafter, another embodiment of the latching apparatus for the inflatable belt device according to the present invention will be described with reference to FIG.
8
through
FIG. 13. A
feature of the latching apparatus
200
of this embodiment that differs from the latching apparatus
100
of the aforementioned embodiment is that the gas passages of the tongue and the buckle are arranged on a side not the center.
In the respective drawings, the up and down direction when the apparatus is installed in a vehicle is indicated by arrows.
As shown in FIG.
8
and
FIG. 9
, the latching apparatus
200
of this embodiment comprises a tongue
210
and a buckle
240
. Disposed below the buckle
240
is an anchor bracket
205
.
The tongue
210
has an outer casing
212
. The tongue
210
is provided at its lower end with a tongue plate
211
which is inserted into the buckle
240
. The tongue plate
211
is latched to a tongue latching mechanism
250
of the buckle
240
. A hanger portion
213
is arranged inside the casing
212
. The hanger portion
213
has a slit
213
a
through which the lap webbing
41
is passed just like the aforementioned embodiment.
In the casing
212
, a tongue pipe
215
is disposed on a side of the tongue plate
211
and the hanger portion
213
. The tongue pipe
215
is fixed to the casing
212
by rivets
216
. The gas inlet
77
of the bag is connected to the upper end of the tongue pipe
215
by a band
217
in the same manner as the aforementioned embodiment. The inside of the tongue pipe
215
communicates with the inside of the bag in the same manner as the aforementioned embodiment described above. The lower end of the tongue pipe
215
projects outside the casing
212
. A tongue cap
218
made of aluminum is fitted on the lower end opening of the tongue pipe
215
. This tongue cap
218
has a bottom
218
a
formed in a concave spherical shape. The bottom
218
a
is formed with tear lines. The tongue cap
218
also functions as a screen gate or protective cover for preventing dust from invading into the tongue pipe
215
.
The buckle
240
has an outer casing
242
. The casing
242
is formed at its upper portion with an upper opening
242
a
into which the tongue plate
211
is inserted. The tongue latching mechanism
250
for latching the inserted tongue plate
211
is disposed in the casing
242
. A release button
242
b
is provided at the upper portion of the casing
242
. As the button
242
b
is depressed, the tongue latching mechanism
250
is released so as to pushed out the tongue
210
upwardly.
The tongue latching mechanism
250
functions in the same basic manner as the tongue latching mechanism
110
described above.
A buckle pipe
245
is disposed on a side of the tongue latching mechanism
250
of the buckle
240
(on the lower side in
FIG. 8
, on the left side in FIG.
9
). The buckle pipe
245
is fixed to a retainer
249
inside the casing
242
by rivets
244
. A buckle cap
248
made of aluminum is fitted on the upper end of the buckle pipe
245
. The buckle cap
248
has a top surface
248
a
which is formed in a convex spherical shape. The top surface
248
a
is formed with tear lines.
As shown in FIGS.
11
(A) and
11
(B), the inner diameter R of the buckle pipe
245
, the inner diameter R′of the tongue pipe
215
, and the inner diameter R″ of the buckle cap
248
are designed to be equal (for example, 9.6 mm). There is a clearance or gap (over stroke) C between the inner surface of the buckle cap
248
and the upper end of the buckle pipe
245
as shown in FIGS.
10
(A) through
10
(C). The clearance C absorbs the tolerance among parts and backlash during the insertion or tilting of the tongue
210
. The buckle cap
248
is biased upwardly by a spring
255
fitted around the buckle pipe
245
. Because of the biasing force of the spring
255
, the upper end of the buckle pipe
245
and the lower end of the tongue pipe
215
are closely in contact with each other when the tongue
210
is latched (in the state shown in FIG.
9
).
In the casing
242
of the buckle
240
, the upper end of the inflator
239
is connected to the lower end of the buckle pipe
245
. The inflator
239
includes a propellant, an initiator (not shown) therein. As the inflator
239
is ignited in the event of vehicle collision, the inflator
239
produces gas for deploying the bag into the buckle pipe
245
. The gas passes into the hollow portion of the bag through the tongue pipe
215
of the tongue
210
after passing through the inside of the buckle pipe
245
.
This embodiment is designed so that the tongue pipe
215
of the tongue
210
and the buckle pipe
245
of the buckle
240
are substantially coaxially aligned and connected to each other at the side of the latching apparatus
200
when the tongue
210
is latched (in the state shown in FIG.
9
). The bottom
218
a
of the tongue cap
218
beneath the lower end of the tongue pipe
215
and the top
248
a
of the buckle cap
248
of the buckle pipe
245
are in closely contact with each other because of the concave spherical shape of the bottom
218
a
and the convex spherical shape of the top
248
a
as clearly shown in FIG.
10
(A). The buckle cap
248
is biased toward the tongue cap
218
by the spring
255
. Therefore, the space between the pipes
215
,
245
is eliminated.
When the tongue
210
tilts rightward relative to the buckle
240
, as shown in FIG.
10
(B), the tongue pipe
215
and the buckle pipe
245
have a tilt angle therebetween so that the tongue pipe
215
and the buckle pipe
245
are not coaxially arranged. However, at this point, the bottom
215
a
of the tongue pipe
215
having the concave spherical shape is followed by the top
245
a
of the buckle pipe
245
because the top
245
a
has the convex spherical shape that is hard to deform against outer force from the above. The same is true for a case that the tongue
210
tilts leftward relative to the buckle
240
as shown in FIG.
10
(C). Therefore, even when there is a tilt between the tongue pipe
215
and the buckle pipe
245
, no space is created between the caps
218
and
248
. It should be noted that the tilt of the buckle cap
248
itself is absorbed by the clearance C in the cap.
The joint portion between the tongue pipe
215
and the buckle pipe
245
is normally closed by the respective caps
218
,
248
as shown in FIG.
11
(A). However, when the inflatable belt is actuated, the caps
218
,
248
are broken along their tear lines by gas pressure produced by the inflator
239
. During this, the clearance at the joint portion is further compressed by the pressure of the gas, thus further reducing the possibility of gas leakage during the actuation of the inflator
239
. After the caps
218
,
248
are broken along their tear lines so as to allow the communication between the tongue pipe
215
and the buckle pipe
245
, the gas from the inflator
239
is supplied into the bag through the inside of the pipes.
Since the inner diameter of the pipes
215
,
245
, and the inner diameter of the buckle cap
248
are equal (R=R′=R″), the flow passage area at the upstream (the tongue pipe
215
) side and the flow passage area at the downstream (the buckle pipe
245
) side relative to the joint portion of the caps
218
,
248
are constant. Even when there is a tilt between the tongue pipe
215
and the buckle pipe
245
, no space is created at the joint portion thereof as mentioned above. Therefore, there is no possibility of turbulence generation in the gas flowing inside the pipes so that the gas can smoothly flow and the gas can reach the inside of the bag without delay.
Description will now be made as regard to a variation of caps with reference to FIG.
12
through FIG.
13
(C).
A buckle cap
348
shown in these drawings has a top
348
a
formed in a convex shape having a tapered surface. On the other hand, a tongue pipe cap
318
has a bottom
318
a
formed in a concave shape having a tapered surface. The top
348
a
and the bottom
318
a
are formed with tear lines, respectively, just like the aforementioned embodiments.
According to the buckle cap
348
and the tongue pipe cap
318
having such tapered surfaces, even when the buckle pipe
245
and the tongue pipe
215
are shifted from each other as shown in FIG.
13
(A), the tapered surfaces of the caps
318
,
348
slide relative to each other as shown in FIG.
13
(B) so that the caps
318
,
348
are aligned with each other about the center as shown in FIG.
13
(C). Therefore, no space is created at the joint portion between the buckle pipe
245
and the tongue pipe
215
.
As apparent from the above description, the present invention can provide a latching apparatus for an inflatable belt device which achieves reduction in the gas leakage without losing the smoothness of insertion of a tongue into a buckle, or which achieves reduction in the manufacturing cost and the weight of the latching apparatus.
When the inner diameter of the buckle pipe cap is designed to have substantially the same diameter as the inner diameter of the tongue pipe and the buckle pipe, the flow passage area at the tongue pipe side and the flow passage area at the buckle pipe side are constant. Therefore, there is no possibility of turbulence generation in gas flowing from the inflator to the inside of the bag so that the gas can smoothly flow.
When the top of the buckle pipe cap is formed in a convex spherical shape and the bottom of the tongue pipe cap is formed in a concave spherical shape corresponding to the configuration of the top of the buckle pipe cap, or when the top of the buckle pipe cap is formed in a convex shape having a tapered surface and the bottom of the tongue pipe cap is formed in a concave shape having a tapered surface corresponding to the configuration of the top of the buckle pipe cap, even if there is tilt between the tongue pipe and the buckle pipe, the lower end of the tongue pipe is followed by the upper end of the buckle pipe and these are aligned with each other about the center. Therefore, no space is created at the joint portion between the pipes.
The priority documents, Japanese Patent Application No. 2000-56621 filed Mar. 2, 2000 and No. 2000-347772 filed Nov. 15, 2000 are incorporated by reference herein in their entirety.
Claims
- 1. A latching apparatus for an inflatable belt device comprising:a tongue having a tongue pipe and being connected to an end of an inflatable belt; a buckle having a buckle pipe and configured for being latched together with the tongue; wherein the tongue pipe and the buckle pipe are configured to be substantially coaxially aligned and connected to each other when the tongue is latched to the buckle, so that gas for deploying the inflatable belt may pass from the buckle to the tongue, and wherein a connecting member is provided between the pipes, the connecting member biased in a direction from the buckle toward the tongue to eliminate a space between the pipes.
- 2. The latching apparatus of claim 1, wherein said connecting member comprises:a buckle pipe cap which is fitted on the upper end of said buckle pipe and is configured to break when an inflator is actuated, and a spring for biasing the buckle pipe cap into contact with the lower end of the tongue pipe.
- 3. The latching apparatus of claim 2, wherein the inner diameter of said buckle pipe cap is substantially equal to the inner diameter of said tongue pipe and said buckle pipe.
- 4. The latching apparatus or claim 3, wherein said connecting member further comprises a tongue pipe cap which is fitted on the lower end of said tongue pipe and is configured to rupture when the inflator is actuated.
- 5. The latching apparatus of claim 4, wherein the top of the buckle pipe cap is formed in a convex shape and the bottom of said tongue pipe cap is formed in a concave shape.
- 6. The latching apparatus of claim 4, wherein the top of said buckle pipe cap is formed in a convex spherical shape and the bottom of said tongue pipe cap is formed in a concave spherical shape corresponding to the configuration of the top of said buckle pipe cap.
- 7. The latching apparatus of claim 4, wherein the top of said buckle pipe cap is formed in a convex shape having a tapered surface and the bottom of said tongue pipe cap is formed in a concave shape having a tapered surface corresponding to the configuration of the top of said buckle pipe cap.
Priority Claims (2)
Number |
Date |
Country |
Kind |
2000-056621 |
Mar 2000 |
JP |
|
2000-347772 |
Nov 2000 |
JP |
|
US Referenced Citations (13)
Foreign Referenced Citations (2)
Number |
Date |
Country |
406262997 |
Mar 1993 |
JP |
405112201 |
May 1993 |
JP |