Pyrotechnic actuator for retracting a piston

• US 7,735,405 B2
• Filed: 03/14/2008
• Issued: 06/15/2010
• Est. Priority Date: 03/14/2008
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Parks, Brent
• Primary Examiner(s): Hayes; Bret
• Assistant Examiner(s): TILLMAN, JR, REGINALD S
• Application Number:
  US12/048,567
• Publication Number:
  US 20090229485A1
• Time in Patent Office: 823 Days
• Field of Search: 89/11.4, 102/530
• US Class Current: 89/1.14
• CPC Class Codes: B60R 21/34 Protecting non-occupants of a vehicle, e.g. pedestrians B60R19/02 takes precedence
• CPC Class Codes: B60R 21/38 using means for lifting bonnets

Abstract

A safety arrangement for a motor vehicle includes a pyrotechnic actuator for retracting a hinge pin of a vehicle hood. The pyrotechnic actuator includes a housing defining a longitudinal axis and further includes a first end defining an opening. The pyrotechnic actuator additionally includes a piston disposed in the housing for movement along the longitudinal axis between an extended position and a retracted position. The piston carries the pin. The pin at least partially extends from the housing in the extended position. The piston includes a base portion defining a combustion chamber. The pyrotechnic actuator further includes a pyrotechnic charge disposed in the combustion chamber for producing a combustion gas operative to move the piston from the extended position to the retracted position. The combustion chamber is defined by a thin walled member that is sealed to contain the ballistic event.

Claims

1. A pyrotechnic actuator comprising:

a housing;

a combustion chamber located in the housing;

a pyrotechnic charge disposed in the combustion chamber for producing a combustion gas;

an initiator associated with the combustion chamber;

a piston disposed in the housing for movement from an extended position to a retracted position in response to combustion of the pyrotechnic charge, the piston including a proximal portion and a distal portion, the combustion chamber carried at the proximal portion; and

a stationary member disposed within the piston and arranged to engage a stop mechanism positioned within the housing for opposing a combustion force to proximally displace the piston;

wherein the combustion chamber is defined by a thin walled member carried within the piston and arranged to retract with the piston such that the combustion chamber translates with the piston, the piston having a pin at least partially extending from the housing when the piston is in the extended position; and

wherein combustion of the pyrotechnic charge moves the piston to pull the pin completely within the housing.

2. The pyrotechnic actuator of claim 1, wherein the thin walled member is sealed to contain the combustion gas of the pyrotechnic charge.

3. The pyrotechnic actuator of claim 1, wherein the thin walled member carried by the piston and defining the combustion chamber has a first internal volume prior to actuation of the pyrotechnic charge and a second, larger internal volume after actuation of the pyrotechnic charge.

9. The pyrotechnic actuator of claim 1, in combination with a safety arrangement for a motor vehicle having a safety device, the pin operatively associated with the safety device such that the safety device operates in a first manner and when the pin is disassociated from the safety device, the safety device operates in a second manner.

10. The pyrotechnic actuator of claim 9, wherein the pyrotechnic actuator pulls the pin to disassociate the pin from the safety device.

4. A pyrotechnic actuator for pulling a pin, the pyrotechnic actuator comprising:

a housing defining a longitudinal axis and including a distal end defining an opening;

a piston disposed in the housing for movement along the longitudinal axis between an extended position and a retracted position, the piston carrying the pin, the pin at least partially extends from the housing in the extended position, the piston carrying a combustion chamber;

a pyrotechnic charge disposed in the combustion chamber for producing a combustion gas operative to move the piston from the extended position to the retracted position; and

a stationary member disposed within the piston and arranged to engage a stop mechanism positioned within the housing to oppose a combustion force to proximally displace the piston;

wherein the combustion chamber is defined by a thin walled member carried within the piston and arranged to retract with the piston such that the combustion chamber translates with the piston; and

wherein combustion of the pyrotechnic charge moves the piston to pull the pin completely within the housing.

5. The pyrotechnic actuator for pulling a pin of claim 4, wherein the piston includes a distal member defining the pin and a proximal member carrying the combustion chamber.

6. The pyrotechnic actuator for pulling a pin of claim 5, wherein the distal and proximal members of the piston are coupled for common movement between the extended and retracted positions.

7. The pyrotechnic actuator for pulling a pin of claim 4, wherein the thin walled member is operative to substantially contain the combustion gas.

8. The pyrotechnic actuator for pulling a pin of claim 7, wherein the thin walled member carried by the piston and defining the combustion chamber has a first internal volume prior to actuation of the pyrotechnic charge and a second, larger internal volume after actuation of the pyrotechnic charge.

11. The pyrotechnic actuator for pulling a pin of claim 4, in combination with a safety arrangement for a motor vehicle having a safety device, the pin operatively associated with the safety device such that the safety device operates in a first manner and when the pin is disassociated from the safety device, the safety device operates in a second manner.

12. The pyrotechnic actuator for pulling a pin of claim 11, wherein the pyrotechnic actuator pulls the pin to disassociate the pin from the safety device.