Ammunition and explosives – Igniting devices and systems – Ignition or detonation circuit
Reexamination Certificate
1998-08-10
2001-06-05
Poon, Peter M. (Department: 3643)
Ammunition and explosives
Igniting devices and systems
Ignition or detonation circuit
C102S249000, C102S252000, C102S274000, C280S734000, C089S132000
Reexamination Certificate
active
06240848
ABSTRACT:
The invention concerns a device as set forth in the classifying portion of claim
1
.
A device of that kind serves for the firing of a pyrotechnic propellent composition, in particular of a gas generator. Propellent compositions of that kind are used in particular in motor vehicles in order to drive components, for example a piston or a rotary piston in a tube or a housing so that safety components on the vehicle are moved from a normal position into a safety position. For example a telescopic steering column is reduced in length by drive devices of that kind. It is also known for safety belts which bear loosely against the body of the vehicle occupants to be tightened by means of pyrotechnically operated belt tensioners. It is also known for a filling gas to be produced by means of a fired propellent composition, for filling air bags. To fire the respective propellent compositions, it is known to drive a firing or striker pin in its axial direction by means of a drive spring. There is also a locking means which holds the drive spring and therewith the firing pin in the rest position. In the event of excessive acceleration a sensor mass is moved, by which the locking means is released so that the drive force of the spring can act on the firing pin (EP 0 529 501 A1). {EP-A-642 958 describes a trigger mechanism for a motor vehicle safety device. It comprises an ignition pin urged towards the detonator by a spring, a mass and its biassing spring as wall as a pivotable trigger lever which holds the pin in position with a hook arrangement and is prevented from pivoting by contact with the mass. During sudden acceleration, the mass moves relative to its casing allowing the trigger lever to pivot so releasing the ignition pin.
U.S. Pat. No. 5,431,102 relates to a mechanical acceleration sensor including a sensor casing, a weight, a spring-loaded firing pin and a latch lever, each being movably mounted in the sensor casing in such a manner as to either translate along an axis or to rotate about an axis. The latch lever is moved by inertial movement of the weight allowing the firing pin to perform a percussive firing action by the spring load.
In the mechanical sensors which have heretofore been proposed, including the above described sensors no firing actuating means movable with respect to the firing pin has been described providing an accurate alignment of the firing pin with a firing opening and compensating production tolerances.}
The object of the invention is to provide a device of the kind set forth in the opening part of this specification, which is acceleration-sensitive, comprises mechanical components, and can be universally employed.
In accordance with the invention that object is attained by the characterising features of claim
1
.
The drive spring can be held in a prestressed rest position by means of the locking lever which is supported at a stationary location, in particular of the sensor housing. A torque acts on the locking lever, in the direction of its release position, due to the prestressing of the drive spring. In the rest position, that is to say below a given triggering threshold, the sensor mass provides that the release moment which acts on the locking lever is carried at an abutment which in particular can be provided on the sensor mass.
Preferably, besides a first support location which is supported in particular on a firing pin actuating means and with which the drive force of the drive spring is carried, the locking lever may have a second support location which, as viewed in the drive direction, is displaced outwardly and which is supported stationarily, in particular on the sensor housing. That arrangement ensures that for release of the locking lever, which is caused by the moved sensor mass, the locking means is moved into its release position by the drive force of the drive spring and at the same time the drive force of the spring is utilised for the firing procedure.
For that purpose the locking lever may have a third support location which bears against an abutment, in particular on the sensor mass.
Preferably the locking lever is in the form of a double-sided locking lever whose axis, which is not stationary, is formed by the first support location or is in the immediate vicinity of the first support location, and in which the second and third support locations are provided at the two sides of the lever.
Preferably a ring is provided on the firing pin as the firing pin actuating means. It is displaceable by the drive force of the drive spring towards the firing pin.
In the rest condition the firing ring bears against the first support location of the locking lever under the prestressing effect of the drive spring.
When the locking means is released, the ring which can be in the form of a striker or firing ring is moved towards an anvil on the firing pin and is impacted thereagainst. Due to the impact, the firing pin is accelerated towards the firing means for the propellant and upon impact thereof fires the propellant.
For guidance of the striker ring the firing pin may have a shank along which the striker ring is accelerated towards the anvil by the drive spring.
The firing pin is mounted with its shank on the sensor housing, at the end which is opposite to the firing tip. That mounting configuration ensures that the firing pin is mounted with its tip that projects out of the sensor housing, movably in a radial direction with respect to its axis, at its end that is opposite to the firing tip. That arrangement provides for accurate alignment of the firing pin with a firing opening in a housing which can be fitted on to the sensor housing and in which the propellant is disposed. The alignment with the firing opening ensures that the firing tip of the firing pin impinges precisely on the firing device of the propellant upon acceleration thereof by the drive spring. Production tolerances can be compensated by virtue of that design configuration, and this arrangement always guarantees that the firing pin is aligned with the propellant firing device.
It is also possible for the firing pin actuating means to be pivotable about an axis, the drive spring acting on the firing pin actuating means by way of a lever arm. As in the first embodiment the firing pin is held in a pre-positioned condition with respect to the firing device and the firing pin actuating means can be impacted on to the pre-positioned firing pin. In that respect the impact surface on the firing pin may be of relatively large size so that production tolerances in regard to alignment of the firing pin with respect to the firing device do not have a detrimental effect.
The drive spring and the firing pin actuating means may also comprise one piece. For that purpose the drive spring is in the form of a leaf spring which is subjected to a prestressing effect and on which the firing pin actuating means is possibly integrally formed.
REFERENCES:
patent: 4573706 (1986-03-01), Breed
patent: 4771914 (1988-09-01), Kaneda et al.
patent: 4819960 (1989-04-01), Breed
patent: 4927172 (1990-05-01), Motozawa
patent: 5149134 (1992-09-01), Fohl
patent: 5188393 (1993-02-01), Fohl
patent: 5328204 (1994-07-01), Kawaguchi et al.
patent: 5431102 (1995-07-01), Nishizawa
patent: 5454322 (1995-10-01), Sakamoto et al.
patent: 5483846 (1996-01-01), Sakamoto et al.
patent: 490987 (1919-01-01), None
patent: 314716 (1919-10-01), None
patent: 0376446 (1923-05-01), None
patent: 1177525 (1964-09-01), None
patent: 2709339A1 (1977-09-01), None
patent: 0 642 958 (1995-03-01), None
patent: 2 273 647 (1994-06-01), None
Ludwig Thomas
Specht Martin
Bergin James S.
Breed Automotive Technology Inc.
Poon Peter M.
Seitzman Markell
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