GB2313911A - Acceleration sensor apparatus for vehicles - Google Patents
Acceleration sensor apparatus for vehicles Download PDFInfo
- Publication number
- GB2313911A GB2313911A GB9713178A GB9713178A GB2313911A GB 2313911 A GB2313911 A GB 2313911A GB 9713178 A GB9713178 A GB 9713178A GB 9713178 A GB9713178 A GB 9713178A GB 2313911 A GB2313911 A GB 2313911A
- Authority
- GB
- United Kingdom
- Prior art keywords
- vehicle
- sensor bracket
- sensor
- acceleration
- acceleration sensor
- 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.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/34—Belt retractors, e.g. reels
- B60R22/36—Belt retractors, e.g. reels self-locking in an emergency
- B60R22/40—Belt retractors, e.g. reels self-locking in an emergency responsive only to vehicle movement
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/34—Belt retractors, e.g. reels
- B60R22/36—Belt retractors, e.g. reels self-locking in an emergency
- B60R22/40—Belt retractors, e.g. reels self-locking in an emergency responsive only to vehicle movement
- B60R2022/401—Belt retractors, e.g. reels self-locking in an emergency responsive only to vehicle movement with adjustable sensor
- B60R2022/402—Belt retractors, e.g. reels self-locking in an emergency responsive only to vehicle movement with adjustable sensor automatically adjustable to keep a vertical position, e.g. irrespective of seat or vehicle tilting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R22/00—Safety belts or body harnesses in vehicles
- B60R22/18—Anchoring devices
- B60R22/26—Anchoring devices secured to the seat
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Automotive Seat Belt Assembly (AREA)
Abstract
An acceleration sensor for a vehicle is provided in which vehicle acceleration, caused by a collision for instance, causes movement of an inertial body 34 which in turn causes the locking of a seat belt retractor R and the sensor is also capable of locking the seat belt retractor R in the event of the vehicle tilting more than a predetermined angle. A sensor bracket 30 is swingably supported in a sensor housing 10 for rotation about axis O . The sensor housing 10 is fixed to a part of the vehicle body such as a seat back. The inertial body 34 is movably supported in a depression formed in the sensor bracket 30. Upper and lower weights 28 and 72 maintain the sensor bracket 30 in an upright condition so that acceleration of the vehicle in a predetermined direction can be detected regardless of the tilt of the vehicle. If the vehicle tilts by more than a predetermined amount then lobes 70 attached to the sensor bracket 30 engage with a locking member 66 causing a tooth 68 of the locking member 66 to engage a gear 64 of the retractor R and prevent further release of seat belt webbing.
Description
ACCELERATION SENSOR APPARATUS FOR A VEHICLE
The present invention relates to an acceleration sensor apparatus for a vehicle which is used with an air bag, a retractor for a seat belt apparatus and the like, provided in the vehicle.
Generally, a vehicle is provided with a variety of measures against an unusually large acceleration imposed thereon. Examples of such measures include deployment of an air bag, and the locking of a retractor of a seat belt apparatus to prevent a webbing from further being released from the retractor. Thus, air bag and retractor apparatuses have an acceleration sensor apparatus to detect accelerations acting on a vehicle that are greater than a predetermined value.
In various apparatuses each having an acceleration sensor apparatus, the acceleration sensor apparatus is mounted at a predetermined angle in relation to a vehicle body. For example, in a seat belt retractor, the acceleration sensor apparatus is mounted on a center pillar of the vehicle body cr on a seat cushion at a predetermined angle of installation. Also, in an air bag apparatus, the acceleration sensor apparatus is mounted in a steering panel or an instrument panel at a predetermined angle of installation.
As described above, a conventional acceleration sensor apparatus is mounted at a predetermined angle in relation to a vehicle body. When an acceleration sensor for detecting an acceleration in a predetermined direction is mounted in a movable portion of a vehicle, for example, in a retractor mounted to a seatback of a reclining seat, the angle of the acceleration sensor may vary in some cases. That is, when an occupant tilts the seatback to adjust his/her sitting posture, the orientation of the acceleration sensor apparatus of the retractor alters, resulting in a failure to detect an acceleration in a predetermined direction. As a result, an acceleration in a wrong direction will be detected.
Further, a retractor may be required to be locked to thereby prevent a webbing from further being released from the retractor when the vehicle body is tilted more than a predetermined angle.
n view of the foregoing fact, it is an object of the present invention to provide an acceleration sensor apparatus for a vehicle capable of properly detecting an acceleration acting on a vehicle body even when the mounted orientation of the sensor apparatus changes, and capable of providing an output operation when the vehicle body tilts more than a predetermined angle.
The present invention provides an acceleration sensor apparatus for a vehicle wherein an inertial body is inertially moved according to a vehicle acceleration, comprising: a sensor bracket which supports the inertial body and is swingably supported in a vehicle; a lower weight which is mounted on the sensor bracket, has a center of gravity located below a swing center of the sensor bracket, and is adapted to maintain the sensor bracket at a present position regardless of a tilt of the vehicle; and an upper weight which is lighter than the lower weight, is mounted on the sensor bracket, and has a center of gravity located above the swing center of the sensor bracket.
As a result of the above-described structure being employed, even when a part of the vehicle on which the sensor bracket is mounted is tilted, the lower weight is adapted to maintain the sensor bracket at its original position, so that the sensor, bracket detects an acceleration in a fixed direction. Also, even when a great acceleration acts on the acceleration sensor apparatus, inertial forces acting on the upper and lower weights function to maintain the sensor jacket at its original position. Thus, the acceleration sensor apparatus can always detect an acceleration in a predetermined direction relative to a vehicle body.
Preferably, an accommodation section for accommodating t least the upper or lower weight is formed in the sensor bracket.
The above-described structure facilitates the work of mounting the upper or lower weight onto the sensor bracket to thereby provide an inexpensive product.
Further, the present invention provides an acceleration sensor apparatus for a vehicle comprising: a sensor housing fixed on a seatback of a reclining seat of a vehicle; a sensor bracket supported swingably about an axis which is substantially parallel to an axis of tilting the seatback, the sensor bracket being swingable relative to the sensor housing; an inertial body having a spherical shape and supported so as to be movable within a predetermined range in a support depression formed in the sensor bracket; an output member for locking a seat belt retractor gear in an interlocking relation with the inertial body's ascending movement along a slope of the support depression upon reception of an acceleration acting on a vehicle; an upper weight located above a swing center axis of the sensor bracket and adapted to cancel a swing of the sensor bracket induced by an acceleration acting on the sensor bracket to thereby bring the sensor bracket to a standstill; and a lower weight for bringing a center of gravity of an entire body supported swingably about the swing center axis of the sensor bracket to a position lower than the swing center axis.
As a result of the above-described structure being employed, even when an occupant tilts a seatback of a reclining seat, the center-of-gravity setting means causes the sensor bracket to swing relative to the sensor housing fixed on the seatback to thereby maintain the sensor bracket at its original position. Also, when a great acceleration acts on the acceleration sensor apparatus, an inertial force acting on the upper weight located above the swing center axis causes the sensor bracket to be maintained at its original position, and thus only the inertial body moves along the surface of the support depression. This movement of the inertia body is output from the acceleration sensor apparatus by means of the output member. In this manner, an acceleration can be properly detected by the acceleration sensor apparatus.
Preferably, there is provided a forcibly driving member that drives the output member when a tilt of a vehicle reaches a predetermined value. As a result of this structure being employed, when an entire vehicle body tilts more than a predetermined angle, the forcibly driving member drives the output member to thereby lock a retractor, and thus webbing is restrained from further being released.
Preferably, the forcibly driving member is a projection which integrally projects from the sensor bracket. As a result of this structure being employed, when a vehicle body tilts more than a predetermined angle, the sensor bracket relatively swings more than a predetermined angle.
Consequently, the integral projection from the sensor bracket drives the output member to thereby lock the retractor as described above.
FIG. I is an exploded perspective view of an
acceleration sensor apparatus for a vehicle according to a
first embodiment of the present invent ion;
FIG. 2 is a side view taken along line II-II of FIG. 1,
showing a state tat a sensor bracket is in its original
position;
FIG. 3 is a side view taken along line II-II of FIG. 1,
showing a state that the sensor bracket is tilted from its
original position;
FIG. 4 is a side view that corresponds to the side view
taken along line II-II of FIG. 1 and shows another example of forcibly driving member used in the acceleration sensor
apparatus according to the first embodiment;
FIG. 5 is a front view showing a main portion of the
forcibly driving member of FIG. 4;
FIG. 6 is a side view that corresponds to the side view
taken along line II-II of FIG. 1 and shows still another
example of the forcibly driving member used in the
acceleration sensor apparatus according to the first
embodiment;
FIG. 7 is a front view showing a main portion of the
forcibly driving member of FIG. 6;
FIG. 8 is a side view showing an output interlock member
and an interlock stopper member of the acceleration sensor
apparatus according to the first embodiment;
FIG. 9 is an exploded perspective view of an
acceleration sensor apparatus for a vehicle according to a
second embodiment of the present invention;
FIG. 10 is a vertical sectional view for illustrating the relation between an inertial body and a support depression of a sensor bracket of the acceleration sensor apparatus of the present invention when the sensor bracket is in its original position;
FIG. 11 is a sectional view for illustrating the relation between an inertial body and a support depression of a sensor bracket of the acceleration sensor apparatus of the present invention when the sensor bracket is tilted; and
FIG. 12 is a schematic side view of a reclining seat whose seatback is provided with the acceleration sensor apparatus of the present invention.
FIG. 1 shows an acceleration sensor apparatus for a vehicle according to a first embodiment of the present invention which is employed as an acceleration sensor for use with a retractor for a seat belt apparatus.
As shown in FIG. 12, a retractor R used in this seat belt apparatus is located at an upper portion of a seatback B of a reclining seat S within a vehicle, and is provided with a sensor housing 10 fixed therein. As shown in FIG. 1, the sensor housing 10 includes a sensor bracket 12 and a support and pivot structure for attaching an output member of an output mechanism thereto.
As shown in FIG. 1, a support plate 14 projects from the sensor housing 10 at a middle portion within the interior
thereof. A small cylindrical axial pin 16 stands on the
planar surface of the support plate 14 at the central portion
thereof. The axial pin 16 forms a part of a swing center
axis 0 that pivotably supports the sensor bracket 12. A
bearing concave 18 is formed at one end of the sensor housing
10 so as to be positioned on the swing center axis 0. As
shown in FIG. 12, the swing center axis 0 is in parallel with
a swing center axis 01 which extends through a seat base
member 124 and about which seatback B swings.
A shaft 20 for pivotably supporting the output member is integrally provided at the other end of the sensor housing 10.
Further, a clearance recess 22 for housing a part of the
output mechanism is formed in the sensor housing 10 between
the support plate 14 and the shaft 20.
As shown in FIG. 1, in the sensor bracket 12 housed in
the sensor housing 10 having the above-described structure,
free-ended side portions 24 and 36 stand in parallel with
each other at both ends of a bottom plate portion 30,
respectively forming a generally U-shape as viewed from the
side. An arm 26 projects from the outer surface of the free
ended side portion 24 and extends along the swing center axis
0, wherein it is bent upward at a right angle from the middle portion thereof, thus forming a hook-like shape. An upper
weight 28 is integrally attached to the free end portion of
the arm 26.
The upper weight 28 having a predetermined weight is
made of metal or other materials and is integrally attached to the arm 26.
In the sensor bracket 12, a conical support depression 32 is formed in the top surface of the bottom plate portion 30, i.e. the planar surface of the bottom plate portion 30 located on the side facing the swing center axis 0, such that the center of the support depression 32 coincides with the center of the top surface. The support depression 32 has a
V-shaped vertical section having a predetermined angle of slope. An inertial body 34 having a predetermined height is movably placed in the support depression 32. The inertial body 34 is spherical, and is made of metal. Accordingly, upon being subjected to a predetermined horizontal acceleration, the inertial body 34 ascends along the slope of the support depression 32.
In the sensor bracket 12, a semicircular opening 38 is cut through the end of the free-ended side portion 36. An output interlock member 40 is disposed such that it passes through the opening 38. As shown in FIG. 8, the output interlock member 40 is composed of a driven portion 42 and a connection portion 44 that are integrated to form a bent shape. The driven portion 42 has a circular end section 46 that is integrally formed at the tip end of a rectangular plate portion thereof. A spherical concave is formed in the planar surface of the circular end section 46 on the side that faces the bottom plate portion 30. The inertial body 34 is held between the spherical concave formed in the circular end section 46 and the support depression 32 formed in the
bottom plate portion 30.
A bearing bore portion 48 is formed at an intermediate
portion of the output interlock member 40, i.e. at the base
portion of both the driven portion 42 and the connection
portion 44. An axial pin 50 inserted into the bearing bore
portion 48 is pivotably inserted into a bearing bore portion
formed in the free-ended side portion 36 of the sensor
bracket 12. Thus, the output interlock member 40 is
pivotably mounted on the free-ended side portion 36.
In the above-described structure, the driven portion 42 \extends from its base portion supported by the axial pin 50,
and protrudes over the bottom plate portion 30 through the
opening 38. Accordingly, the opening 38 limits a swinging
movement of the driven portion 42 about the axial pin 50.
Thus, when the inertial body 34 held between the spherical
concave formed in the driven portion 42 and the support
depression 32 ascends along the slope of the support
depression 32 to a predetermined height, the driven portion
42 is prevented from swinging any further about the axial pin
50. That is, the driven portion 42 prevents the inertial
body 34 from further ascending along the slope of the support
depression 32. Hence, the inertial body 34 is maintained
between the support depression 32 and the spherical concave
formed in the circular end section 46 of the driven portion
42.
As described above, as the inertial body 34 ascends
along the slope of the support depression 32, the driven portion 42 swings in the direction of arrow A shown in FIG 1.
This causes the connection portion 44 to also swing in the direction of arrow A. As shown in FIGS. 1 and 8, the connection portion 44 extends from the bearing bore portion 48 of the output interlock member 40 and is bent into the shape of a letter L as viewed from the side. A spherical interlock head 52 is integrally formed at the free end of the connection portion 44. An interlock stopper member 54, which is a part of the output mechanism, is engaged in an interlocking manner with the interlock head 52.
The interlock stopper member 54 is shaped like a hook. A cylindrical bearing bore 58 is formed in a shaft support portion 56 having a rectangular cross-section, at an intermediate portion thereof. One end of the bearing bore 58 is blocked with a small cylindrical cover 60.
The bearing bore 58 opens at a side wall of the shaft support portion 56. The shaft 20 of the sensor housing 10 is inserted into the bearing bore 58 so as to pivotably support the interlock stopper member 54. An interlock projection 62 having an L-shaped cross-section integrally projects from one end section of the shaft support portion 56 of the interlock stopper member 54, whose end section corresponds to the interlock head 52 of the output interlock member 40. The interlock head 52 of the connection portion 44 is held between the shaft support portion 56 and the interlock projection 62.
In the interlock stopper member 54, a stopper member 66
integrally projects from the other end section of the shaft
support portion 56, whose end section is located on the side
closer to a retractor gear 64. The free end portion of the
stopper member 56 is formed into a U shape as viewed from the
side and extends toward the retractor gear 64. An acute
latch tooth 68 is integrally formed at the free end portion
of the stopper member 66.
As the interlock stopper member 54 pivots on the shaft
20 in the direction of arrow B, the latch tooth 68 of the
stopper member 66 moves in the direction of arrow C. As a result, the latch tooth 68 engages with a tooth space of the
retractor gear 64 to thereby lock the retractor gear 64.
This causes the inertia lock mechanism of the retractor R to
operate (description of the inertia lock mechanism is omitted
because it is publicly known). Consequently, a reel-up shaft
for reeiing up a seat belt webbing W stops rotating to
thereby restrain the webbing W from further being released.
As shown in FIGS. 2 and 3, in the sensor bracket 12,
forcibly driving members 70 are provided on the free-ended
side portion 36 in the vicinity of both lateral ends of the
opening 38 in such a manner as to project in radial
directions from the swing center axis 0. Each of the
forcibly driving members 70 is a small rectangular projection
having a rounded tip end portion. The forcibly driving
members 70 are arranged so as to function in the following
manner. When the sensor bracket 12 rotates about the swing
center axis 0 by a predetermined angle, the tip end portion of one of the forcibly driving members 70 abuts the bottom surface of the stopper member 66 at a central portion thereof, thus pushing up the stopper member 66, as shown in FIG. 3.
This causes the interlock stopper member 54 to pivot about the shaft 20 in the direction of arrow B. As a result, the latch tooth 68 formed at the free end portion of the stopper member 66 engages with a tooth space of the retractor gear 64.
In the sensor bracket 12 swingably supported about the swing center axis 0, the output interlock member 40, which is part of the output mechanism, the upper weight 28 provided on the arm 26, the forcibly driving members 70, and the inertial body 34 are arranged as described above. In order to maintain these members at their original positions shown in
FIG. 1 with respect to the swing center axis 0 regardless of a tilt of the seatback B, a lower weight 72 is provided on the bottom plate portion 30 at the side opposite the support depression 32. The lower weight 72 functions as a center-ofgravity setting means.
As a result of provision of the lower weight 72, the center of gravity of the sensor bracket 12 and its attachments is positioned below the swing center axis 0 onward the bottom plate portion 30. Thus, a vertical axis V cf the support depression 32 is maintained in the vertical direction to thereby maintain the inertial body 34 at the deepest position in the support depression 22. Also, when an acceleration in the longitudinal direction of a vehicle as indicated by arrow FR in FIG. 1 acts on the sensor bracket 12, an inertial force induced by the acceleration and acting on
the upper weight 28 prevents the sensor bracket 12 from
rotating about the swing center axis 0, thereby maintaining
the sensor bracket 12 at its original position shown in FIG.
1.
The upper weight 28 is intended to cancel an inertial force acting below the swing center axis 0 on an assembly of the sensor bracket 12, the output interlock member 40, and the lower weight 72. Accordingly, the deflected distance of the upper weight 28 from the swing center axis 0 and the weight of the upper weight 28 may be determined so as to cancel this inertial force. When the mass of elements other than the upper and lower weights 28 and 72 is ignorably small as compared with the mass of both the weight 28 and the lower weight 72, for example, when the upper weight 28, the lower weight 72, and the inertial body 34 are made of metal, other elements are made of a synthetic resin, with the inertial body 34 being located on the swing center axis 0, the upper weight 28 and the lower weight 72 may be designed to meet the following relation. When the upper weight 28 and the lower weight 72 are located at the distances L1 and L2, respectively, away from the swing center axis 0 and have weights W1 and 'S2, respectively, these parameters may be determined so as to meet the following: Wl < W2 and substantially W1 x L1 = W2 x L2.
As a result, when seatback B is tilted for reclination, the lower weight 72 functions to bring the sensor bracket 12 back to its original position. When an acceleration in the direction of arrow FR acts on the vehicle, inertial forces of the upper and lower weights 28 and 72 cancel each other to thereby maintain the sensor bracket 12 at its original position. In a case where the mass of elements other than the upper and lower weights 28 and 72 is not ignorable, individual elements may be manufactured so as to satisfy the above-described expression, where L1 is a distance from the swing center axis 0 to the center of gravity of an upper mass located above the swing center axis 0, and L2 is a distance from the swing center axis 0 to the center of gravity of a lower mass located below the swing center axis 0.
The center-of-gravity setting means may assume a variety of constructions so long as the center of gravity of an assembly of the sensor bracket 12, the output interlock member 40, and the lower weight 72 is located below the swing center axis 0 through employment of the center-of-gravity setting means. For example, the thickness of the bottom plate portion 30 of the sensor bracket 12 may be increased to increase the weight thereof. Alternatively, the swing center axis 0 may be posItioned in the vicinity of the free ends of both the free-ended side portions 24 and 36.
As a result of installation of the lower weight 72 at the bottom plate portion 30 of the sensor bracket 12, even when the sensor housing 10 relatively rotates about the swing center axis 0, gravity acting on the lower weight 72 causes the sensor bracket 12 to maintain its original position shown
in FIG. 1.
In FIG. 1, the forcibly driving member 70 according to
the first embodiment having the above-described structure is
provided at the free-ended side portion 36 of the sensor
bracket 12. However, as shown in FIGS. 4 and 5, the forcibly
driving member 70 may integrally project from the shaft
portion of the arm 26 which extends along the swing center
axis 0. When the sensor bracket 12 rotates about the swing
center axis 0 by a predetermined angle, the tip of the
forcibly driving member 70 projecting from the arm 26 \directly engages a tooth space of the retractor gear 64 to
thereby prevent the retractor gear 64 from rotating.
Further, as shown in FIGS. 6 and 7, the forcibly driving
member 70 may be integrally projected from a driven gear 76
which engages a driving gear 74 mounted on the arm 26. The
tip end of the forcibly driving member 70 engages a tooth
space of the retractor gear 64 to thereby prevent the
retractor gear 64 from rotating. As a matter of fact, a
mechanism for interlocking the sensor bracket 12 and the
forcibly driving member 70 may employ a variety of structures.
Next will be described the operation of the acceleration
sensor apparatus according to the first embodiment.
When the seatback B of the reclining seat S is tilted,
the sensor housing 10 of the acceleration sensor apparatus of
the retractor R mounted on the seatback B relatively tilts
about the swing center axis 0.
In this case, as a result of the action of the lower weight 72 serving as center-of-gravity setting means, the sensor bracket 12 swingably supported about the swing center axis 0 is maintained at its original position as before seatback B is tilted. That is, the sensor bracket 12 relatively rotates about the swing center axis 0 to thereby remain at its original position.
When an acceleration perpendicular to the swing center axis 0 is imposed on the sensor bracket 12 swingably supported about the swing center axis 0, an inertial force induced by the acceleration acts on the lower weight 72.
At the same time, an inertial force induced by the acceleration acts on the upper weight 28 fixed to the sensor bracket 12 via the arm 26. Thus, the inertial force acting on the upper weight 28 cancels the above-described inertial force acting on the lower weight 72. As shown in FIG. 10, this prevents the sensor bracket 12 from swinging about the swing center axis 0.
At this time, since the center of the inertial body 34 is located on the swing center axis 0, the inertial body 34 is free from any restraint from the upper weight 28. Thus, the inertial body 34 ascends along the slope of the support depression 32, causing the driven portion 42 of the output interlock member 40 to swing in the direction cf arrow A. In an interlocking relation with this swing of the driven portion 42, the connection portion 44 of the output interlock member 40 presses the interlock projection 62 of the interlock stopper member 54 in the direction of arrow A to
thereby rotate the interlock stopper member 54 about the
shaft 20 in the direction of arrow B. As a result, the latch
tooth 68 of the stopper member 66 rises in the direction of
arrow C and engages a tooth space of the retractor gear 64 to
thereby lock the retractor gear 64. This actuates a stopper
mechanism of an unillustrated retractor apparatus and thereby
restrains the webbing from further being released from a
retractor.
When a reclining seat's seatback provided with the
above-described acceleration sensor apparatus according to \the first embodiment is tilted within a tilt angle range of
12 degrees to 27 degrees, for example, to a predetermined
tilt angle of 15 degrees to 20 degrees, the forcibly driving
member 70 operates to lock the retractor gear 64. This
locking operation is described in detail below. When the
seatback provided with the acceleration sensor apparatus is tilted to a predetermined angle, the sensor housing 10 also
tilts accordingly. At this time, the center-of-gravity
setting means causes the sensor bracket i2 to tilt about the
swing center axis 0 to thereby maintain the sensor bracket 12
at its original position. Because of the resultant relative
rotation between the sensor bracket 12 and the sensor housing
10, the interlock stopper member 54 pivotably supported on
the shaft 20 of the sensor housing 10 rotates relative to the
forcibly driving member 70 of the sensor bracket i2. As a
result, a part of the stopper member 66 of the interlock
stopper member 54 abuts against the forcibly driving member 70, which thus causes the interlock stopper member 54 to rotate about the shaft 20 in the direction of arrow B.
Consequently, the latch tooth 68 of the stopper member 66 moves in the direction of arrow C and engages a tooth space of the retractor gear 64 to thereby lock the retractor gear 64. This actuates an unillustrated retractor apparatus to restrain webbing from further being released. In the first embodiment shown in FIG. 1, two forcibly driving members 70 are provided on the sensor bracket 12 in rotation symmetry with respect to the swing center axis 0.
Accordingly, even when the sensor bracket swings about the swing center axis 0 either clockwise or counterclockwise, it is possible to lock the retractor gear 64 through movement of the interlock stopper member 54.
For other embodiments of the forcibly driving members 70 shown in FIGS. 4 to 7, only when the sensor bracket 12 swings clockwise in FIGS. 4 and 6, the forcibly driving member 70 directly engages a tooth space of the retractor gear 64 to thereby restrain the retractor gear 64 from rotating.
Next will be described the relation between the inertial body 34 and the support depression 32 of the sensor bracket 12. In FIG. 10, the sensor bracket 12 is in its original position, i.e. the slope of the support depression 32 forms a predetermined angle Sl with the horizontal plane. In this state, upon reception of an acceleration in the direction of arrow FR, the inertial body 34 ascends along the slope of the support depression 32 in the direction of arrow FR to thereby
move an unillustrated output interlock member as expected.
By contrast, as shown in FIG. 11, when the sensor
bracket 12 swings clockwise upon reception of an acceleration
in the direction of arrow R, the angle S2 between the slope
of the support depression 32 and the horizontal plane becomes
greater than S1 as shown in FIG. 10. Accordingly, the slope
angle & 2 of the support depression 32 is too large for the
inertial body 34 to ascend along the slope of the support
depression 32. As a result, the inertia body 34 cannot move
the output interlock member 40. Thus, the acceleration Sensor apparatus fails to properly detect an acceleration.
However, in the present embodiment, the upper weight 28
is provided at a position higher than the swing center axis 0
by means of the arm 26. The upper weight 28 functions to
cancel an inertia force acting on the portion of the sensor
bracket 12 located below the swing center axis 0 to thereby
prevent the sensor bracket 12 from s and the detailed description thereof is omitted.
The acceleration sensor apparatus according to the second embodiment has the following structure. A sensor bracket 12 is swingably supported by a sensor housing 10. An inertial body 34 drives an output interlock member 40 pivotably supported by the sensor bracket 12. The thusdriven output interlock member 40 actuates an interlock stopper member 54, which in turn locks a retractor gear 64.
The sensor housing 10 has a box-like shape whose top is open. A support projection 82 projects from the outer surface of each of two side portions 80 and is located at a central position of the outer surface. A through-hole 84 for coupling use is formed in each support projection 82. The sensor housing 10 is mounted on a retractor frame 86. In order to receive the sensor housing 10, an open-ended rectangular opening 88 is formed in one side portion of the retractor frame 86. A through-hole 90 is formed in each projecting portion 92 located on both sides of the opening 88 in such a manner as to align with each through-hole 84 formed in the sensor housing 10. In FIG. 9, due to limited space of llustration, the retractor frame 86 is illustrated in a greater reduced scale than other elements. The support rojectlons 82 of the sensor housing 10 are brought into contact with the corresponding projecting portions 92 such hat the through-holes 84 align with the through-holes 90.
Subsequently, the sensor housing 10 is fixed on the retractor frame 86 through use of unillustrated screws and nuts.
A bearing bore 96 is formed in each of the other opposed
side portions 94 of the sensor housing 10. Each bearing bore
96 is formed such that it is partially open at the end
surface of the side portion 94. A pair of pivotal support
bases 98 stand from the top end surface of one side portion
80. Each pivotal support base 98 is formed into a small
rectangular projection. A bearing bore 100 is formed in each
pivotal support -base 98. Each bearing bore 100 is also cut
such that it partially opens at the end surface of the
bearing base 98.
As shown in FIG. 9, the sensor bracket 12 swingably
supported by the above-described sensor housing 10 has a U
shape as viewed from the front. That is, free-ended side
portions 24 stand in parallel from both ends of a bottom
plate portion 30. A support depression 32 having a V-shaped
cross-section is formed in the planar surface of the bottom
plate portion 30 on the side of a free end of the free-ended
side portion 24. A pair of holder portions 102 integrally
extend from both side edges of the bottom plate portion 30 on
the side opposite to the support depression 32 in a manner
facing each other. A rectangular flat lower weight 72 is
inserted into a pocket 104 formed between the holder portions
102, so that the lower weight 72 and the sensor bracket 12
are attached together into the sensor housing 10.
A bearing bore 106 is formed in each free-ended side
portion 24 of the sensor bracket 12. Each bearing bore 106
is cut such that it partially opens at the end surface of each free-ended side portion 24.
A pocket 108 for accommodating an upper weight 28 is integrally formed on the planar side surface of one freeended side portion 24 on the side opposite to the bottom plate portion 30. The pocket 108 is shaped in a small box whose top is open. The upper weight 28 is inserted into the inner space of the pocket 108. A shaft 110 projects from the outer planar side surface of the pocket 108.
In the other free-ended side portion 24 of the sensor bracket 12, a shaft 112 aligned with the shaft 110 projects from a side surface on the side opposite to the bottom plate portion 30. A pair of forcibly driving members 70 projects from the free end surface of this free-ended side portion 24.
Each forcibly driving member 70 is formed into a quadrant shape. The forcibly driving members 70 are arranged such that they are a predetermined distance apart from each other and such that their flat surfaces face each other. The shafts 110 and 112 are inserted into the bearing bores 96 of the sensor housing 10, so that the sensor bracket 12 is swingably supported by the sensor housing 10.
An output interlock member 40 is pivotably supported by the sensor bracket 12. The output interlock member 40 is formed by a connection portion 44 and a driven portion 42 that are integrated together. The driven portion 42 is formed into a disk-like shape. The surface of the driven portion 42 opposed to the support depression 32 is formed into a substantially spherical concave to receive the
inertia body 34. A pivotal support portion 114 having a
rectangular prism shape is formed at the base end section of
the driven portion 42. The connection portion 44 is a small
projection which integrally projects from the surface of the
driven portion 42 on the side opposite to the inertia body
34. The connection portion 44 has a free-ended arc section.
The thus-structured output interlock member 40 is swingably
supported by the sensor bracket 12 through Insertion of axial pins 116 into the bearing bores 106 of the sensor bracket 12.
As described above, the output interlock member 40 is ''pivotably supported by the sensor bracket 12, which in turn
is pivotably supported by the sensor housing 10. An
interlock stopper member 54 is pivotably supported by a pair of the pivotal support bases 98. In the interlock stopper member 54, the free end portion of a stopper member 66 shaped
in a small rectangular plate is curved toward the retractor gear 64 to thereby form a latch tooth 46. A pivotal support portion 118 shaped in a rectangular block is integrally
formed at the base end of the stopper member 66. Axial pins
120 project from both lateral sides of the pivotal support portion 118. An interlock portion 122, which is shaped in a
small rectangle, integrally projects from one lateral side edge of the stopper member 66 at a predetermined position.
The thus-structured interlock stopper member 54 is swingably supported by the sensor housing 10 through
Insertion of the axial pins 120 into the bearing bores 100 of the pivotal support bases 98 of the sensor housing 10.
The thus-structured acceleration sensor apparatus is mounted onto the retractor frame 86 such that the latch tooth 46 of the stopper member 66 is located below the retractor gear 64 in a manner capable of engaging with and disengaging from the retractor gear 64.
An unillustrated retractor R having the above-described retractor frame 86 is structured such that when the retractor gear 64 is locked, a webbing W is restrained from further being released from the retractor R.
Next will be described the operation of the acceleration sensor apparatus according to the second embodiment. The following description assumes that a retractor provided with the vehicle acceleration sensor according to the second embodiment is mounted to a seatback B of a reclining seat S of a vehicle. When the seatback B is tilted for adjustment purpose, the sensor housing 10, together with the retractor frame 86, is tilted. At this time, because of the employment of the lower weight 72, the sensor bracket 12 swings relative to the sensor housing 10 about the shafts 110 aligned with the swing center axis 0 so as to maintain its original position. Accordingly, the slope of the support depression 32 maintains a predetermined angle with the horizontal plane.
When an acceleration In the direction of arrow FR acts on the acceleratIon sensor apparatus according to the second embodiment, an inertial force acting on the upper weight 72 and located above the swing center axis 0 cancels a moment of inertia induced in an assembly of the sensor bracket 12, the lower weight 72, and the output interlock member 40, the center of gravity of which assembly being located below the shafts 110 and 112 aligned with the swing center axis 0.
Thus, the sensor bracket 12 is maintained at its original position.
As a result, only the inertia body 34 moves in a direction opposite to the arrow FR and ascends along the slope of the support depression 32 in a rolling manner. The ascending inertial body 34 lifts the output interlock member 40, and consequently the output interlock member 40 swings in the direction of arrow E. Thus, the connection portion 44 of the output interlock member 40 pushes up the stopper member 66 of the interlock stopper member 54 in the direction of arrow F. This causes the latch tooth 46 of the stopper member 66 to engage a tooth space of the retractor gear 64 to thereby lock the retractor gear 64.
When the retractor gear 64 is locked, an unillustrated retractor functions to restrain the webbing from further being released.
In the acceleration sensor apparatus according to the second embodiment, when the sensor housing 10, together with the retractor frame 86, is tilted within a tilt angle range of 12 degrees to 27 degrees, for example, to a predetermined tilt angle of 15 degrees to 20 degrees, the sensor bracket 12 swings relative to the sensor housing 10. As a result, one of the forcibly driving members 70 of the sensor bracket 12 abuts against the interlock portion 122 of the stopper member 66 to thereby lifts the stopper member 66 in the direction of arrow F. This causes the latch tooth 46 of the stopper member 66 to engage a tooth space of the retractor gear 64 to thereby lock the retractor gear 64. Since the forcibly driving members 70 are arranged in rotation symmetry with respect to the swing center axis 0, even when the sensor bracket 12 relatively swings either clockwise or counterclockwise, one of the forcibly driving members 70 actuates the stopper member 66. Thus, it is possible to reliably restrain the webbing from further being released from a retractor apparatus.
The structure of an acceleration sensor apparatus of the present invention is not limited to the structures of the above-described embodiments. For example, the structure of the acceleration sensor apparatus of the present invention can be applied to an acceleration sensor apparatus in which an inertial body is designed to swing like a pendulum, and the pendulous inertia body actuates an output interlock member so as to detect an acceleration. Moreover, the structure of the acceleration sensor apparatus of the present
invention can be applied to other kinds of acceleration sensor apparatuses such as an acceleration sensor in which an inertial body is substantially cylindrical and arranged vertically, and when the inertiai body is tilted to a predetermined angle, an output interlock member provided at the top portion of the inertial body rises.
An acceleration sensor apparatus for a vehicle according to the present invention can properly detect an acceleration acting on a vehicle body in a predetermined direction even when the mounted orientation of the acceleration sensor apparatus changes relative to the vehicle body, and can provide an output operation when the vehicle body tilts more than a predetermined angle.
Certain features of the hereinbefore described acceleration sensor apparatus are disclosed and claimed in co-pending UK Patent Application No 9701969.9.
Claims (7)
1. An acceleration sensor apparatus for a vehicle wherein an inertial body is inertially moved according to a vehicle acceleration, comprising:
a sensor bracket which supports said inertial body and is swingably supported in a vehicle;
an output member which is driven through an inertial movement of said inertial body; and
a forcibly driving member for driving said output member when a tilt of a vehicle reaches a predetermined value.
2. An acceleration sensor apparatus for a vehicle according to Claim 1, further comprising:
a lower weight mounted on said sensor bracket, said lower weight having a center of gravity located below a swing center of said sensor bracket and being adapted to maintain said sensor bracket at a present position in spite of a vehicle being tilted; and
an upper weight which is lighter than said lower weight and is mounted on said sensor bracket, said upper weight having a center of gravity located above the swing center of said sensor bracket.
3. An acceleration sensor apparatus for a vehicle according to Claim 2, wherein a sensor housing to which said sensor bracket is swingably attached is supported by a seatback of a reclining seat of a vehicle, and when the seatback is tilted, said lower weight causes said forcibly driving member to relatively rotate to thereby abut against said output member.
4. An acceleration sensor apparatus for a vehicle according to Claim 1, wherein said sensor bracket comprises a bottom plate portion in which a support depression for supporting said inertial body is formed in a planar surface thereof, free-ended portions standing in parallel with each other at both ends of said bottom plate portion, said bottom plate portion and said free-ended portions generally forming a U-like side shape, and an arm projects from an outer surface of said one free-ended portion.
5. An acceleration sensor apparatus for a vehicle according to Claim 2, wherein said upper weight is provided at a tip end of said arm, and said lower weight is provided on a lower side of said bottom plate portion.
6. An acceleration sensor apparatus for a vehicle according to Claim 1, wherein said forcibly driving member is a projection integrally projecting from said sensor bracket.
7. Acceleration sensor apparatus for a vehicle according to Claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP01787196A JP3630818B2 (en) | 1996-02-02 | 1996-02-02 | Acceleration sensor device for vehicle |
JP8017872A JPH09207714A (en) | 1996-02-02 | 1996-02-02 | Acceleration sensor for vehicle |
GB9701969A GB2309785B (en) | 1996-02-02 | 1997-01-30 | Acceleration sensor apparatus for a vehicle |
Publications (3)
Publication Number | Publication Date |
---|---|
GB9713178D0 GB9713178D0 (en) | 1997-08-27 |
GB2313911A true GB2313911A (en) | 1997-12-10 |
GB2313911B GB2313911B (en) | 1999-02-17 |
Family
ID=27268702
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9713178A Expired - Fee Related GB2313911B (en) | 1996-02-02 | 1997-01-30 | Acceleration sensor apparatus for a vehicle |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2313911B (en) |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1515126A (en) * | 1974-05-24 | 1978-06-21 | Peugeot Aciers Et Outillage | Safety belt retractor |
GB1525523A (en) * | 1975-06-02 | 1978-09-20 | Bsg Int Ltd | Safety belt reel locking mechanism |
US4164337A (en) * | 1978-03-16 | 1979-08-14 | General Motors Corporation | Seat belt retractor with pivoted locking mechanism |
US4228969A (en) * | 1977-10-12 | 1980-10-21 | Autoliv Ab | Device in connection with reel mechanisms for safety belts for automobiles |
US4238087A (en) * | 1978-07-04 | 1980-12-09 | Nsk-Warner K.K. | Safety seat belt retractor |
EP0084955A2 (en) * | 1982-01-26 | 1983-08-03 | Britax (Wingard) Limited | Inertia reel |
GB2235124A (en) * | 1989-07-28 | 1991-02-27 | Autoflug Gmbh | Vehicle safety belt system |
US5289986A (en) * | 1990-03-23 | 1994-03-01 | Aisin Seiki Kabushiki Kaisha | Acceleration sensor |
-
1997
- 1997-01-30 GB GB9713178A patent/GB2313911B/en not_active Expired - Fee Related
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1515126A (en) * | 1974-05-24 | 1978-06-21 | Peugeot Aciers Et Outillage | Safety belt retractor |
GB1525523A (en) * | 1975-06-02 | 1978-09-20 | Bsg Int Ltd | Safety belt reel locking mechanism |
US4228969A (en) * | 1977-10-12 | 1980-10-21 | Autoliv Ab | Device in connection with reel mechanisms for safety belts for automobiles |
US4164337A (en) * | 1978-03-16 | 1979-08-14 | General Motors Corporation | Seat belt retractor with pivoted locking mechanism |
US4238087A (en) * | 1978-07-04 | 1980-12-09 | Nsk-Warner K.K. | Safety seat belt retractor |
EP0084955A2 (en) * | 1982-01-26 | 1983-08-03 | Britax (Wingard) Limited | Inertia reel |
GB2235124A (en) * | 1989-07-28 | 1991-02-27 | Autoflug Gmbh | Vehicle safety belt system |
US5289986A (en) * | 1990-03-23 | 1994-03-01 | Aisin Seiki Kabushiki Kaisha | Acceleration sensor |
Also Published As
Publication number | Publication date |
---|---|
GB2313911B (en) | 1999-02-17 |
GB9713178D0 (en) | 1997-08-27 |
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Legal Events
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PCNP | Patent ceased through non-payment of renewal fee |