U.S. patent application number 11/695789 was filed with the patent office on 2007-10-04 for harness pretensioning device for child safety seat.
Invention is credited to Said Nakhla.
Application Number | 20070228787 11/695789 |
Document ID | / |
Family ID | 38557734 |
Filed Date | 2007-10-04 |
United States Patent
Application |
20070228787 |
Kind Code |
A1 |
Nakhla; Said |
October 4, 2007 |
HARNESS PRETENSIONING DEVICE FOR CHILD SAFETY SEAT
Abstract
A child safety device for a vehicle including a seat and a
harness, a sensor for providing an indication of a vehicle crash,
and a take up assembly linked to sensor and the webbing to take up
the webbing in response to the indication from the sensor.
Inventors: |
Nakhla; Said; (Charlotte,
NC) |
Correspondence
Address: |
ADAMS EVANS P.A.
Suite 2350 Charlotte Plaza, 201 South College Street
CHARLOTTE
NC
28244
US
|
Family ID: |
38557734 |
Appl. No.: |
11/695789 |
Filed: |
April 3, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60744240 |
Apr 4, 2006 |
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Current U.S.
Class: |
297/250.1 |
Current CPC
Class: |
B60N 2/2812 20130101;
B60R 22/1958 20130101 |
Class at
Publication: |
297/250.1 |
International
Class: |
A47C 1/08 20060101
A47C001/08 |
Claims
1. A child safety device for a vehicle, comprising: (a) a seat and
a harness comprising webbing for securing an occupant in the seat;
(b) a sensor for providing an indication of a vehicle crash; and
(b) a take up assembly linked to sensor and the webbing to take up
the webbing in response to the indication from the sensor.
2. A child safety device according to claim 1 wherein the take up
assembly is located under the seat.
3. A child safety device according to claim 1 wherein the take up
assembly comprises a spring loaded pivot bar.
4. A child safety device according to claim 3 wherein the pivot bar
rotates to take up the webbing.
5. A child safety device according to claim 4 further comprising a
ratchet mechanism for preventing the pivot bar from returning to an
original position.
6. A child safety device according to claim 1 wherein the webbing
comprises an adjuster strap.
7. A child safety device according to claim 6 wherein the take up
device takes up the adjuster strap.
8. A child safety device according to claim 1 wherein the sensor
comprises a spring.
Description
TECHNICAL FIELD AND BACKGROUND OF THE INVENTION
[0001] This invention relates to a harness pretensioning device and
related apparatus for a child safety seat. Child safety seats have
a harness that includes a pair of shoulder straps that extend from
the back rest of the seat across the shoulders of the seat
occupant, and a crotch strap that extends upwardly from the seat
bottom to a point between the legs of the seat occupant. The
shoulder straps extend downwardly and have respective latch members
that interconnect with a latch affixed to the crotch strap that
extends upwardly through a slot from below the seating surface. In
many seat designs the shoulder straps pass through slots in the
latch and attach to the seat at the waist level to form a pair of
straps that extends around the waist of the seat occupant to form a
lap belt.
[0002] A tensioning strap extends through an opening in the front
of the seating surface. When the shoulder straps are latched into
the latch, the tensioning strap is pulled to place the shoulder
straps in tension so that they fit securely against the anterior
aspect of the upper torso of the seat occupant. Any significant
slack in the harness can increase the risk of injury by subjecting
the seat occupant to an initial rapid, unrestrained acceleration
before the shoulder straps are tensioned by the forward movement of
the seat occupant and bring the seat occupant to an almost
instantaneous stop. It is the g-loading on the seat occupant that
results from the sudden acceleration and then instantaneous
stopping that has the potential for injury. This is due to the fact
that in the event of an impact, such as from an automobile
collision, the harness must be placed under tension before it can
act to restrain the seat occupant.
[0003] Users require instruction to properly position and restrain
the seat occupant. Lack of attention or training may result in the
harness straps being too loose. This is particularly so when the
seat occupant is wearing bulky or several layers of clothing,
whereby the straps seem under proper tension but, in fact, are too
loose to offer the necessary protection.
[0004] There is a need for a device that is adapted to pretension
the harness in the event of a crash so that the seat occupant has
the proper level of protection. While it is preferable, of course,
that the harness be correctly tensioned from the outset, a
self-acting pretensioning device is desirable to place the harness
in proper tension at an early stage of an incipient crash. In
addition, the pretensioning device can be made to self-destruct in
the event it is used, thus providing a load-limiting feature to the
seat.
SUMMARY OF THE DISCLOSURE
[0005] Therefore, it is an object of the invention to provide a
pretensioning device and related apparatus for a child safety
seat.
[0006] It is another object to provide a child safety seat that has
a pretensioning device that applies tension to the harness straps
in the event of a crash.
[0007] It is another object to provide a child safety seat that has
a pretensioning device that self-destructs to provide an indication
that the seat has been damaged as the result of a crash and should
not be further used.
[0008] These and other objects of the present invention are
achieved in the preferred embodiments disclosed below by providing
a child safety device for a vehicle including a seat and a harness
including webbing for securing an occupant in the seat, a sensor
for providing an indication of a vehicle crash, and a take up
assembly linked to sensor and the webbing to take up the webbing in
response to the indication from the sensor.
[0009] In another preferred embodiment of the invention, the take
up assembly is located under the seat.
[0010] In another preferred embodiment of the invention, the take
up assembly includes a spring loaded pivot bar.
[0011] In another preferred embodiment of the invention, the pivot
bar rotates to take up the webbing.
[0012] In another preferred embodiment of the invention, the device
includes a ratchet mechanism for preventing the pivot bar from
returning to an original position.
[0013] In another preferred embodiment of the invention, the
webbing includes an adjuster strap.
[0014] In another preferred embodiment of the invention, the take
up device takes up the adjuster strap.
[0015] In another preferred embodiment of the invention, the sensor
includes a spring.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Embodiments of the invention may be best understood by
reference to the following description in conjunction with the
accompanying drawing figures in which:
[0017] FIG. 1 is a front perspective view of a child safety
seat;
[0018] FIG. 2 is a side view of the child safety seat;
[0019] FIG. 2A is an enlarged side view of a take up assembly for
the child safety seat;
[0020] FIG. 3 is a side view of the child safety seat showing
operation of the take up assembly;
[0021] FIG. 3A is an enlarged side view showing operation of the
take up assembly;
[0022] FIG. 4 is also a side view of the child safety seat showing
operation of the take up assembly;
[0023] FIG. 4A is an enlarged side view of the operation of the
take up assembly;
[0024] FIG. 5 is another side view of the child safety seat showing
operation of the take up assembly;
[0025] FIG. 5A is another enlarged view showing operation of the
take up assembly;
[0026] FIG. 6 is another front perspective view of the child safety
seat;
[0027] FIG. 7 is a front perspective view of an alternative
embodiment of the seat;
[0028] FIG. 8 is a side view of the alternative embodiment of the
child safety seat; and
[0029] FIG. 8A is an enlarged side view of the take up assembly of
the alternative embodiment.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0030] In an embodiment of the invention shown in FIGS. 1-6, a
child safety seat 10 is provided with a sensor 14 positioned on the
seat 10 and adapted to be loaded first in the event of a crash. For
example, a spring, plunger, crushable member or other initiator is
positioned, for example, in the columns of the seat 10 in a
position to be initially loaded in the event of a crash. An
incipient crash compresses the spring, depresses the plunger or
crushes the crushable member to provide actuation to the
pretensioning device. This action initiates a link 24 to a take-up
assembly 26 interconnected with the harness 36 of webbing. The
take-up assembly 26 releases, taking up slack in the harness 36
with sufficient speed that the seat occupant is restrained before
significant, possibly injurious, unrestrained acceleration
commences. It is believed that approximately 12 milliseconds is
available during which to take up slack in the harness 36 before
acceleration of the seat occupant commences.
[0031] Preferred embodiments of the pretensioning device include
either a mechanical, electrical or pyrotechnic interface between
the sensor 14 and the take-up assembly 26. For example, the sensor
14 can trigger an actuator spring or shear pin designed to operate
at a predetermined load, such as 100 lbs. Alternatively, an
electrical circuit can be used to initiate the take-up assembly 26,
the circuit closing and sending a signal to the take-up assembly 26
in response to a load of a predetermined amount on the sensor
14.
[0032] FIGS. 7, 8 and 8A show an alternative embodiment of the seat
including, schematically, the sensor 14 in the form of a spring
linked to the pivot bar 40. Further alternatives include the use of
a piezoresistive element such as a strain gauge and a resistive
element, or a piezocapacitive element using a piezoquartz and a
capacitor. Using these principles will a result in an electrical
signal generation proportional to the load applied. The circuit is
thus designed to operate only upon the generation of a
predetermined minimum strength current based on an applied load
indicative of a crash of sufficient severity to warrant activation
of the take-up assembly 26.
[0033] As noted above, the current generated may be used to close
an electrical or electronic circuit. Alternatively, the current may
be used to fire a pyrotechnic device, i.e., a "squib" or other
pyrotechnic that can either release the take-up assembly 26 or
provide the energy to rotate or displace the take-up assembly 26.
As used herein, the term "squib" refers to a small explosive device
which can be used for shattering, triggering, propelling and
cutting a wide range of pyrotechnic and non-pyrotechnic materials.
The squib may be used to generate a pressurized gas to operate a
small mechanical actuator such as a release cable between the
sensor 14 and the take-up assembly 26, to shear a shear pin, or
similar functions.
[0034] The take-up device 26 may be a spring-loaded pivot bar 40
positioned under the seat 10 that, when activated, releases and
rapidly rotates, carrying with it a length of the adjuster strap 38
of the harness 36. FIGS. 2-6, including 2A-6A, show, sequentially,
operation of pretensioning device, particularly, rotation of the
pivot bar 40, which increases the effective length of an adjuster
strap 38 and instantly applies additional tension to the harness 36
to which it is attached. A linear motion-type device such as a
piston and cylinder assembly, spring or gas-loaded plunger or
similar device may also be used. As noted above, a pyrotechnic
device may be used to supply energy to activate the take-up
mechanism 26.
[0035] A ratchet mechanism 42 prevents the pivot bar 40 from
returning to its original position. Tension is thus maintained on
the harness 36 until the harness latch 48 is released. In one
preferred embodiment of the invention, the pretensioning device is
a "one time" use device, meaning that the child safety seat 10
should be discarded and replaced if a crash of sufficient severity
has occurred to cause activation of the pretensioning device.
[0036] The pretensioning device may be designed to activate at a
given load only when there is insufficient tension on the harness
36, or at a given load without regard to whether the harness 36 is
too loose or at a proper tension. In the latter event, the take-up
device 26 will add only the tension, if any, necessary to bring the
tension on the harness 36 to the proper level, but will also act as
a "one time" use device to provide an indication that the child
safety seat 10 should not be further used, but should be
replaced.
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