Ammunition and explosives – Igniting devices and systems – Ignition or detonation circuit
Reexamination Certificate
2002-05-30
2003-11-18
Carone, Michael J. (Department: 3641)
Ammunition and explosives
Igniting devices and systems
Ignition or detonation circuit
C102S200000, C102S218000, C280S735000
Reexamination Certificate
active
06647886
ABSTRACT:
FIELD OF THE INVENTION
THE PRESENT INVENTION relates to a vehicle safety system, and more particularly relates to a vehicle safety system which incorporates a plurality of safety devices, such as air-bags or safety-belt pre-tensioners, which are activated by means of a squib
BACKGROUND OF THE INVENTION
Many vehicle safety systems incorporate a plurality of safety devices, such as air-bags or safety-belt pre-tensioners, with each device being activated by means of a squib. Also, many vehicle safety systems include one or more sensors, some of which may be simple switches, to determine the condition of various parts of the safety system before active parts of the safety system are activated or deployed. For example, a safety-belt buckle may incorporate a switch which indicates whether the buckle is, or is not, in use. Information concerning the status of the buckle may be very relevant in deciding, in an accident situation, whether to deploy a pre-tensioner associated with a safety-belt adapted to be connected to that buckle.
A typical safety device, such as an air-bag or a pretensioner, may comprise a squib resistor which is embedded within a pyrotechnic charge. When the safety device is to be deployed, an electric current from a power source is passed through the squib resistor which ignites the pyrotechnic charge. The pyrotechnic charge generates gas which inflates the air-bag or actuates the pretensioner.
In order to minimise any risk of inadvertent deployment of the safety device, the circuit which is utilised to connect the squib to the power source should incorporate two switches, with one switch being provided on each side of the squib. It is to be appreciated that in such a situation if, and only if, both switches are closed, will a current pass through the squib to ignite the squib. It is intended that the switches will be closed in response to signals from appropriate sensors which indicate that an accident is likely to occur or is occurring. Thus there is a minimum risk that the safety devices in the vehicle will be inadvertently deployed, for example as a result of a spurious current.
FIG. 1
of the accompanying drawings is a circuit diagram which illustrates a typical prior proposed vehicle safety system.
FIG. 1
illustrates three squib resistors
1
,
2
,
3
each of which is associated with a respective safety device. The first squib resistor has one end which is connected by means of a first switch
4
to one pole of a capacitor
5
, the other pole of which is connected to earth by means of a rail
6
. The other end of the squib resistor
1
is connected by means of a switch
7
to a rail
8
which is also connected to earth.
The second squib resistor
2
has a first end which is connected by means of a switch
9
to one pole of a capacitor
10
, the other pole of the capacitor
10
being connected to earth by means of the rail
6
. The other end of the squib resistor
2
is connected, by means of a switch
11
, to the rail
8
which is also connected to earth. The third squib resistor
3
is provided, at one end, with a switch
12
which is connected to one pole of a capacitor
13
, the other pole of which is connected to earth by means of the rail
6
. The other end of the squib resistor
3
is provided with a switch
14
which is connected to earth by the rail
8
.
The switches (
4
,
9
,
12
and
7
,
11
,
14
) are each individually controlled by a control unit
15
.
It is to be appreciated that initially the capacitors
5
,
10
and
13
will be charged. If, for example, the control unit causes the switches
4
and
7
to be closed, the capacitor
5
will be discharged through the resultant circuit which comprises the switch
4
, the squib
1
, the switch
7
, the rail
8
and the rail
6
. The safety device associated with the squib resistor
1
will thus be deployed. If other appropriate combinations of switches are closed, other safety devices will be actuated.
FIG. 2
is a circuit diagram which illustrates a modified embodiment of the safety system shown in FIG.
1
. Referring to
FIG. 2
, three squib resistor
21
,
22
,
23
are provided, each of which is associated with a respective safety device. One end of the squib resistor
21
is connected by means of a switch
24
to a rail
25
, the rail
25
being connected to a source of potential
26
, such as a source of positive potential. The other end of the squib resistor
21
is connected directly to a rail
27
which is connected by means of a single switch
28
to a line
29
which is connected to a further source of potential
30
, such as a source of negative potential.
The second squib resistor
22
has one end connected by means of a switch
31
to the rail
25
, and has the other end connected directly to the rail
27
. The third squib resistor
23
has one end connected by means of a switch
32
to the rail
25
, and has the other end connected directly to the rail
27
.
The switches (
24
,
31
,
32
and
28
) are all individually controlled by a control unit
33
. If the control unit
33
closes the switch
28
, and then closes one of the switches
24
or
31
or
32
, current will flow through a selected squib resistor
21
,
22
or
23
, depending upon precisely which of the three switches
24
,
31
,
32
has been closed, thus deploying the respective safety device.
It is to be appreciated that in the arrangement shown in
FIG. 1
, the number of switches is equal to twice the number of squib resistors. In the arrangement shown in
FIG. 2
, the number of switches is equal to the number of squib resistors plus one. Switches are expensive to manufacture, and the present invention seeks to provide a safety system for a vehicle which will operate satisfactorily, but in which manufacturing costs are reduced.
SUMMARY OF THE INVENTION
According to one aspect of this invention there is provided a safety system for a motor vehicle, the safety system incorporating at least one safety device adapted to be activated in the event that an accident should occur, the safety device being provided with at least one element selected from the group comprising an electric activator for activating the safety device and a sensor to sense a parameter related to the safety device, there being a plurality of said elements in the complete safety system, the safety system further comprising first conductive means consisting of at least one first conductor and a first group of a plurality of switches, each switch of the first group being connected to a said first conductor, and second conductive means consisting of at least one second conductor, and a second group of a plurality of switches, each switch of the second group being connected to a said second conductor, the elements being connected in circuit, with each element being connected between one switch of the first group of switches and one switch of the second group of switches, the arrangement being such that at least one switch in each group is connected to at least two elements, with each of said two elements being connected to different switches of the other group of switches.
Preferably as least some of said elements are electric activators constituted by squibs in the form of a resistor associated with respective pyrotechnic charges.
Conveniently each said element is connected to a unique combination of one switch from the first group of switches and one switch from the second group of switches.
Advantageously at least one element is in the form of an electric activator constituted by a solenoid.
Conveniently the first conductive means are connected to at least one source of the first potential and the second conductive means are connected to at least one source of a potential which is opposite to said first potential.
At least some of the elements may be constituted by sensors such as switches or resistors, and a switching arrangement may be provided to connect each sensor in circuit with a parameter sensor, such as an ohm meter.
Conveniently at least some of said electrical activators are connected in series with a command controlled switch, the sys
Bourcart Denis
Darraba Roger
Demersseman Bernard
Anderson Chad
Autoliv Development AB
Blackner H. A.
Carone Michael J.
Kinberg Robert
LandOfFree
Vehicle system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Vehicle system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vehicle system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3166703