Hood elevation system
A hood elevation system for a vehicle includes an actuator configured to selectively move at least a portion of a vehicle hood between an elevated and a retracted position. The hood elevation system also includes a self-locking mechanism configured to allow movement of the hood between the elevated and retracted positions initiated by the actuator, but to resist retraction of the hood as a result of certain loads applied to the hood. The self-locking mechanism thus enables repeated elevation and retraction of the hood. In a preferred embodiment, the self-locking mechanism is configured to deform, thereby absorbing energy from an impact to the hood.
1. A vehicle comprising:
a hood configured to extend above and over a front compartment;
a support member operatively connected to the hood;
an actuator configured to selectively raise and lower the hood by extending and retracting the support member, respectively;
a locking mechanism operatively interconnecting the actuator and the support member and sufficiently configured to resist downward movement of the hood caused by a force exerted on the hood during a vehicle impact while allowing downward movement of the hood initiated by the actuator;
an outer tube characterized by an inner surface;
an inner member operatively connected to the support member and located within the outer tube for translation in an extension direction in which the support member is extended and in a retraction direction in which the support member is retracted;
a ramp on the inner member facing the inside surface of the outer tube, the distance between the ramp and the inside surface of the outer tube being greater at a first end of the ramp than at a second end of the ramp;
a rolling element between the ramp and the inside surface of the outer tube; and
a retainer member configured to restrict relative movement of the roller element toward the second end of the ramp during movement of the support member caused by the actuator, and thereby prevent the roller element from wedgingly engaging the inside surface of the outer tube.
2. The vehicle of claim 1 , wherein the locking mechanism is configured so that the movement of the inner member in the retraction direction caused by a force exerted on the hood results in relative movement between the ramp and the retainer member whereby the ramp drives the roller element into wedging engagement with the inside surface thereby to restrict relative movement between the ramp and the outer tube.
3. The vehicle of claim 2 , further comprising a shear element configured to substantially rigidly interconnect the inner member and the retainer member for unitary movement when the force exerted on the hood is below a predetermined magnitude, and to allow relative movement between the inner member and the retainer member when the force is above the predetermined magnitude.
4. The vehicle of claim 3 , wherein the shear element is configured to break when the force exceeds the predetermined magnitude.
5. The vehicle of claim 1 , further comprising at least one controller; and at least one sensor configured to monitor at least one vehicle condition and transmit sensor signals indicative of said at least one vehicle condition to said at least one controller;
wherein said at least one controller is configured to determine whether the sensor signals indicate the presence of said at least one predetermined vehicle condition and to cause the actuator to raise at least a portion of the hood in response to the sensor signals indicating the presence of said at least one predetermined vehicle condition.
6. A vehicle comprising:
a hood configured to extend above and over a front compartment;
a support member operatively connected to the hood;
an actuator configured to selectively raise and lower the hood by extending and retracting the support member, respectively;
a locking mechanism operatively interconnecting the actuator and the support member and sufficiently configured to resist downward movement of the hood caused by a force exerted on the hood during a vehicle impact while allowing downward movement of the hood initiated by the actuator; and
material sufficiently positioned with respect to the locking mechanism to receive at least part of the force and being plastically deformable when the force exceeds a predetermined magnitude.
7. The vehicle of claim 6 , wherein the material is a shape memory material.
8. A method comprising:
monitoring a possibility of a vehicle impact;
raising a vehicle hood in response to determining that the possibility of impact is higher than a predetermined amount; and
lowering the vehicle hood in response to the possibility of impact being below the predetermined amount for a predetermined duration of time;
wherein said monitoring the possibility of vehicle impact includes monitoring a vehicle operating environment for at least one predetermined condition indicative of an elevated risk of vehicle collision.
9. A vehicle comprising:
a hood configured to extend above and over a front compartment;
a support member operatively connected to the hood;
an actuator operatively connected to the support member and configured to selectively raise and lower at least a portion of the hood by extending and retracting the support member;
a locking mechanism operatively interconnecting the support member to the actuator and including an outer tube characterized by an inner surface,
an inner member operatively connected to the support member and supported within the outer tube for translation in an extension direction in which the support member is extended and in a retraction direction in which the support member is retracted,
a ramp on the inner member facing the inside surface of the outer tube, the distance between the ramp and the inside surface of the outer tube being greater at a first end of the ramp than at a second end of the ramp,
a rolling element between the ramp and the inside surface of the outer tube, and
a retainer member configured to at least partially extend between the roller element and the second end of the ramp during movement of the support member caused by the actuator to restrict relative movement of the roller element and the ramp and thereby prevent the roller element from wedgingly engaging the inside surface of the outer tube; and
wherein the locking mechanism is configured so that movement of the inner member in the retraction direction caused by a force exerted on the hood results in relative movement between the ramp and the retainer member whereby the ramp drives the roller element into wedging engagement with the inside surface.