Hood latch crash opening prevention

Abstract

The present invention relates to a hood latch system for a vehicle comprising a hood having a striker, the system comprises: a spring loaded claw rotatable between an engaged position in which the striker is locked in place by the claw, and an open position in which the striker is disengaged from the claw, and a main pawl rotatable between a first position in which the claw is held in place by the main pawl in the engaged position and a second position in which the claw is released by the main pawl whereby the claw is allowed to rotate into the open position. When the main pawl is caused to be activated for rotating from the first position to the second position by a crash acceleration force, the main pawl is configured to prevent the striker from being released.

Claims

1. A hood latch system for a vehicle comprising a hood having a striker attached to an inside of the hood, the hood latch system comprising: a spring loaded claw pivotally attached to an assembly base, the claw is rotatable between an engaged position, in which said striker is locked in place by engagement with said claw, and an open position, in which said striker is disengaged from said claw, a main pawl pivotally attached to said assembly base and attached to a Bowden cable, wherein, under an influence of a normal operation force acting on the Bowden cable, the main pawl is rotatable between a first position, in which the claw is held in place by said main pawl in the engaged position, and a second position, in which said claw is released by said main pawl, whereby said claw is allowed to rotate into said open position, and an inertia pawl rotatable with respect to the main pawl between a blocking position in which the inertia pawl blocks the main pawl from rotating from said first position to said second position, causing the main pawl to prevent the claw from rotating to the open position, and a non-blocking position, in which the main pawl is allowed to rotate from said first position to said second position, wherein said inertia pawl is spring loaded by an inertia pawl spring and is arranged to rotate in a plane generally perpendicular to a rotation plane of the main pawl, the inertia pawl is biased by the inertia pawl spring to be in the non-blocking position when the main pawl is under the influence of the normal operation force acting on the Bowden cable attached to the main pawl, wherein when the main pawl is caused to be activated for rotation by a crash acceleration force caused by a crash event, the inertia pawl is configured to rotate to the blocking position, wherein said crash acceleration force is higher than said normal operation force acting on the Bowden cable, wherein said inertia pawl comprises a blocking portion configured to be biased away from the rotation plane of the main pawl by said inertia pawl spring in said non-blocking position of the inertia pawl when the main pawl is under the influence of the normal operation force acting on the Bowden cable attached to the main pawl, and wherein during said crash event when the main pawl is caused to be activated for rotation from said first position to said second position by said crash acceleration force, said inertia pawl spring is configured to allow the inertia pawl to rotate to the blocking position such that the blocking portion intersects the rotation plane and a trajectory of the rotation of the main pawl from said first position to said second position, whereby the main pawl is prevented by the blocking portion of the inertia pawl from rotating into the second position to release the claw to the open position.

2. The hood latch system according to claim 1, wherein said inertia pawl is pivotally attached to the assembly base.

3. The hood latch system according to claim 1, wherein the main pawl is spring loaded by a main pawl spring around a rotation axis thereof and is biased by the main pawl spring towards the first position, and wherein, when the main pawl is caused to be activated for rotation from said first position to said second position by said crash acceleration force, said inertia pawl is configured to rotate such that said blocking portion intersects the rotation plane and the trajectory of the rotation of the main pawl before the main pawl has rotated into the second position to release the claw to the open position.

4. A vehicle, comprising: a hood having a striker attached to an inside of the hood, and a hood latch system comprising: a spring loaded claw pivotally attached to an assembly base, the claw is rotatable between an engaged position, in which said striker is locked in place by engagement with said claw, and an open position, in which said striker is disengaged from said claw, a main pawl pivotally attached to said assembly base and attached to a Bowden cable, wherein, under an influence of a normal operation force acting on the Bowden cable, the main pawl is rotatable between a first position, in which the claw is held in place by said main pawl in the engaged position, and a second position, in which said claw is released by said main pawl, whereby said claw is allowed to rotate into said open position, and an inertia pawl rotatable with respect to the main pawl between a blocking position in which the inertia pawl blocks the main pawl from rotating from said first position to said second position, causing the main pawl to prevent the claw from rotating to the open position, and a non-blocking position, in which the main pawl is allowed to rotate from said first position to said second position, wherein said inertia pawl is spring loaded by an inertia pawl spring and is arranged to rotate in a plane generally perpendicular to a rotation plane of the main pawl, the inertia pawl is biased by the inertia pawl spring to be in the non-blocking position when the main pawl is under the influence of the normal operation force acting on the Bowden cable attached to the main pawl, wherein when the main pawl is caused to be activated for rotation by a crash acceleration force caused by a crash event, the inertia pawl is configured to rotate to the blocking position, wherein said crash acceleration force is higher than said normal operation force acting on the Bowden cable, wherein said inertia pawl comprises a blocking portion configured to be biased away from the rotation plane of the main pawl by said inertia pawl spring in said non-blocking position of the inertia pawl when the main pawl is under the influence of the normal operation force acting on the Bowden cable attached to the main pawl, and wherein during said crash event when the main pawl is caused to be activated for rotation from said first position to said second position by said crash acceleration force, said inertia pawl spring is configured to allow the inertia pawl to rotate to the blocking position such that the blocking portion intersects the rotation plane and a trajectory of the rotation of the main pawl from said first position to said second position, whereby the main pawl is prevented by the blocking portion of the inertia pawl from rotating into the second position to release the claw to the open position.

5. The vehicle according to claim 4, wherein said inertia pawl is pivotally attached to the assembly base.

6. The vehicle according to claim 4, wherein the main pawl is spring loaded by a main pawl spring around a rotation axis thereof and is biased by the main pawl spring towards the first position, and wherein, when the main pawl is caused to be activated for rotation from said first position to said second position by said crash acceleration force, said inertia pawl is configured to rotate such that said blocking portion intersects the rotation plane and the trajectory of the rotation of the main pawl before the main pawl has rotated into the second position to release the claw to the open position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing example embodiments of the invention, wherein:

(2) FIG. 1 conceptually illustrates a vehicle comprising a hood latch system;

(3) FIG. 2a-d conceptually illustrate a hood latch system according to embodiments of the invention;

(4) FIG. 3a-b conceptually illustrate another hood latch system according to embodiments of the invention;

(5) FIG. 4a-d conceptually illustrate yet another hood latch system according to embodiments of the invention; and

(6) FIG. 5a-c conceptually illustrate a further hood latch system according to embodiments of the invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(7) In the present detailed description, various embodiments of the system according to the present invention are mainly described with reference to a vehicle in the form of a car having a hood in the front of the car. However, the present invention may equally be used with other vehicles such as trucks, buses, etc., and having various locations for the hood not necessarily being in the front of the vehicle. Thus, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person. Like reference characters refer to like elements throughout.

(8) FIG. 1 illustrates a vehicle in the form a car 1 comprising a hood 2 and a hood latch system 100. The hood 2 comprise a striker 3 attached on the inside of the hood 2. The striker 3 is arranged such that it falls into a slot 4 (see e.g. FIG. 2a) in the hood latch system in which a claw 104 (see e.g. FIG. 2a) is arranged to lock the striker 3 in place in the slot 4 such that the hood 2 is held in a closed position. The striker 3 may be released from the inside of the vehicle by means of pulling a cable, e.g. a Bowden cable which causes the claw to release the striker. Various embodiments of a hood latch system will now be described in detail with reference to FIGS. 2a-5c.

(9) FIGS. 2a-d conceptually illustrates one embodiment of a hood latch system 100. In FIG. 2a, the hood latch system is shown with the claw 104 in an engaged position in which the striker 3 is locked in place by the claw 104. The claw 104 is held in its engaged position by a main pawl 102. Both the spring loaded claw 104 and the main pawl 102 are pivotally attached to an assembly base 106 such that they may rotate about a respective rotation axis 114 and 116 (see FIG. 2b). The claw 104 comprises a slot 110 in which the striker is adapted to fit and be held in place when the claw 104 is in this engaged position. The slot is oriented at least partly sideways when the claw 104 is in the engaged position (FIG. 2a) such that the striker 3 cannot be released upwards out from the slot 110.

(10) The claw 104 is spring loaded and biased towards the open position, in other words, if the pawl 102 releases the claw 104, the claw 104 will rotate under the influence of the spring force from the engaged position (FIG. 2a), to the open position (FIG. 2c), counter-clockwise as seen in the perspective shown in FIGS. 2a-d.

(11) Starting from FIG. 2a, the main pawl 102 is in a first position in which the claw 104 is held in its engaged position locking the striker 3 in place such that the hood is held closed. The main pawl 102 comprises a claw holding portion in the form of a holding shoulder 108 adapted to mechanically make contact with a contact surface 118 of the claw 104. The holding shoulder 108 faces the contact surface 118 in a direction at least partly opposite a tangent of the rotation direction of the claw 104 for rotating from the engaged position to the open position. Consequently, the contact between the holding shoulder 108 of the pawl 102 and the contact surface 118 of the claw 104 prevent the claw 104 from rotating from the engaged position to the open position under the influence of the spring force acting on the claw 104.

(12) In FIG. 2b, the main pawl 102 has been rotated about its rotation axis 116 by a force acting on the Bowden cable 107. The main pawl 102 is caused to rotate in counter-clockwise direction. The rotation of the main pawl 102 moves the holding shoulder 108 sideways whereby the contact surface 118 of the claw 104 is exposed. The main pawl 102 is now in its second position in which the claw 104 is free to rotate under the influence of the spring force, from the engaged position (FIGS. 2a-b) to its open position illustrated in FIG. 2c.

(13) In FIG. 2c, the striker 3 is shown released from the claw 104 and moving upwards. This represents the hood 2 being opened under a normal operation force pulling on the cable 107. In other words, the main pawl 102 rotates from the first position to the second position whereby the claw 104 rotates from the engaged position to the open position to release the striker 3.

(14) In case of an accident a rapid deformation of the Bowden cable 107 may be caused. In such case the main pawl 102 may unintentionally be caused to rotate from its first position to the second position. The force acting on the cable 107 are generally applied rapidly, causing a fast rotation of the main pawl 102 about its rotation axis 116. As is conceptually illustrated in FIG. 2d, the main pawl 102 is configured to, subsequent to having been in its second position (FIG. 2c) in which the claw 104 is released, configured to prevent the striker 3 from being released from the hood latch system 100.

(15) In this exemplary embodiment, the main pawl 102 comprises the holding shoulder 108 and a striker holding portion 120 on opposite sides of the rotation axis 116, i.e. the initial movement of the holding shoulder 108 when the main pawl 102 rotates counter-clockwise is away from the claw 104, whereas the striker holding portion 120 moves towards the opening slot 4 where the striker is held in place by the claw 104. The striker holding portion 120 is hook-shaped and arranged at the end portion of the pawl 102 nearest to the striker 3. The main pawl 102 may rotate past its second position (FIG. 2c) and to a third position illustrated in FIG. 2d. In the event of a crash of certain magnitude causing a rapid deformation of the cable 107, and the rotation of the main pawl 102 is sufficiently fast, the main pawl 102 rotates into the third position faster than the striker 3 can be released from the slot 4 whereby the hook-shaped striker holding portion 120 prevents the striker from being released from the hood latch system 100.

(16) FIGS. 3a-b conceptually illustrate another embodiment of a hood latch system 300. Similar to the above-mentioned embodiment, the hood latch system in FIGS. 3a-b comprises a main pawl 302 pivotally attached to an assembly base 106, and a claw 104 also pivotally attached to the assembly base 106.

(17) In FIG. 3a, the main pawl 302 is in its first position in which the claw holding portion 108 is in contact with the contact surface 118 of the claw 104, thereby preventing the claw 104 from rotating from the shown engaged position in which the striker 3 is held in place in the slot 110 of the claw 104, to the open position in which the striker 3 is released. If the main pawl 302 is rotated to its second position by e.g. pulling on the cable 107, the claw holding portion 108 loses contact with the contact surface 108 of the claw 104 whereby the claw 104 is released by the main pawl 302. Consequently, the claw 104 is rotated under the influence of a spring force from the spring 322 such that the slot 110 becomes oriented upwards whereby the striker 3 is released. The main pawl 302 is spring loaded by a spring 316 which is biased to caused a rotation from the second position to the illustrated first position, i.e. the spring force acts to rotate the main pawl from the second position to the first position.

(18) There is further illustrated an exemplary inertia pawl 310 in FIG. 3a-b. Turning first to FIG. 3a, the inertia pawl 310 is shown in a non-blocking position in which the inertia pawl 310 does not block the main pawl 302 from rotating. The inertia pawl 310 is spring loaded by a spring 312 to be in this non-blocking position. Further, the inertia pawl 310 is rotatable with respect to the main pawl 302 about a rotation axis 324. Under the influence of a crash acceleration force in a direction towards the plane of the assembly base, in which plane the rotation axis 324 for the inertia pawl 310 lies, the moment of inertia for the inertia pawl together with the crash acceleration force overcomes the spring force of the spring 312. Thereby, the inertia pawl 312 rotates in a direction opposite to the biasing direction of the spring 312 to a blocking position as shown in FIG. 3b. After the crash acceleration force has decreased to a sufficiently low level the spring force from the spring 312 forces the inertia pawl 310 back to the non-blocking position.

(19) The inertia pawl 310 illustrated in FIGS. 3a-b is rotatable in a plane perpendicular to the rotation plane of the main pawl 302. The inertia pawl 310 is further arranged such that a blocking portion 314 intercepts the main pawl's 302 rotation in the rotational plane of the main pawl 302 when the inertia pawl is in the blocking position.

(20) Accordingly, when the inertia pawl 310 is in the blocking position as illustrated in FIG. 3b, as caused by a crash acceleration force, then the main pawl 302 is prevented from rotating from the first position to the second position by the blocking portion 314 of the inertia pawl 310. Thereby, the claw 304 is prevented by the main pawl 302 to rotate from the engaged position to the open position to release the striker 3.

(21) FIGS. 4a-d illustrate another possible embodiment of a hood latch system 400. Parts and components in FIG. 4a-d with reference numerals already described with reference to the above-mentioned drawings will not be explained in detail here.

(22) The hood latch system 400 conceptually illustrated in FIGS. 4a-d comprises a spring loaded pawl activating lever 410 which is pivotally attached to the assembly base 106 with the same rotation axis 416 as the main pawl 402. The spring loaded pawl activating lever 410 may be rotated by e.g. a force applied by pulling on the cable 107 attached to the pawl activating lever 410 at an end portion of the pawl activating lever 410. The pawl activating lever 410 is configured to rotate in a way to latch onto the main pawl 402 during normal operation. When the pawl activating lever 410 has latched onto the main pawl 402, the main pawl is rotated by the pawl activating lever 410 from the first position to the second position. However when the pawl activating lever 410 is rotated fast, the pawl activating lever 410 does not latch onto the main pawl 402 which then maintains in its first position.

(23) In the specific embodiment shown in FIGS. 4a-c the pawl activating lever 410 comprises a protrusion 420 which is adapted to fit into an opening 422 of the main pawl 402. During normal operating conditions, protrusion 420 of the pawl activating lever 410 falls into the opening 422 in the main pawl 402 when the pawl activating lever 410 is rotated about its rotation center 416 as is illustrated in FIG. 4b. The pawl activating lever 410 then causes the main pawl 402 to rotate form the first position to the second position whereby the claw 104 is rotatable from the engaged position to the open position such that the striker 3 can be released.

(24) The pawl activated lever 410 is spring loaded to push towards the main pawl 402, thus the protrusion 420 falls into the opening 422 when the opening 422 and the protrusion 420 coincide. However, under the influence of a crash acceleration force acting in the direction of the tangent of the rotation of the pawl activated lever 410, i.e. in the direction of the force pulling on the cable 107, the rotation of the pawl activating lever may be too fast for the protrusion to be pushed into the opening whereby the main pawl is maintained in the first position, as illustrated in FIGS. 4c-d. In other words, the protrusion 420 of the pawl activated lever 410 rotates past the opening 422 without latching onto the opening whereby the main pawl 402 remains in the first position.

(25) Now turning to FIGS. 5a-b illustrating a hood latch system 500 according to yet another embodiment of the invention. Parts and components in FIG. 5a-b with reference numerals already described with reference to the above-mentioned drawings will not be further explained in detail here. Refer instead to the previous drawings.

(26) The hood latch system 500 shown in FIG. 5a-c comprises an inertia pawl 510 pivotally attached to the main pawl 502. The inertia pawl 510 is spring loaded by a spring 512, the spring is arranged to provide a spring force acting in the same rotational direction as for rotating the main pawl 502 from the first position to the second position, i.e. counter-clockwise as seen from the illustrated perspective. The inertia pawl 510 is rotatable about a rotation axis 517 which is off-center (i.e. not aligned with) from the rotation axis 516 of the main pawl 502. However, the rotation axes 516 and 517 are generally parallel.

(27) Operation of the hood latch system under normal operating force conditions is illustrated in FIGS. 5a-b. In FIG. 5a, the main pawl 502 is in the first position in which the main pawl 502 blocks the claw 104 from rotating from the presently shown engaged position to the open position as described with reference to the above-mentioned drawings. When a normal operating force acts on the cable 107, the inertia pawl 510 follows the rotation of the main pawl 502 as is conceptually illustrated in FIG. 5b. In other words, the spring 512 is not compressed but instead forces the inertia pawl 510 to rotate with the main pawl 502. In FIG. 5b, the main pawl 502 is in the second position whereby the claw 104 has rotated into the open position and the striker 3 has been released.

(28) FIG. 5c illustrate the hood latch system 500 under crash acceleration force conditions which has caused the main pawl 502 to initiate a rotation from the first position towards the second position. However, since the inertia pawl 510 is pivotally attached at an end portion 511 to the main pawl 502 at an off-center location with respect to the rotation axis 516 of the main pawl, the inertia pawl 510 will spatially move also downwards in this case (other direction may also be possible and tailored depending on the location of the blocking element 514). Furthermore, the inertia of the inertia pawl 510 and the spring force are configured such that the spring 512 will be compressed at a threshold acceleration tailored for the event of a crash, whereby the second end portion 513 of the inertia pawl 510 is translated downwards towards a blocking element 514 attached to the assembly base 106. When the second end portion 513 of the inertia pawl 510 meets the blocking portion 514, a further rotation of the main pawl is prevented. In particular, the length of the inertia pawl 510 between its end portions 511 and 513 matches the distance between the blocking element the first end portion 511 before the main pawl 502 has rotated enough to release the claw 104.

(29) The main pawl, the claw, and inertia pawl according to the mentioned embodiments may be made from a rigid material such as a metal or a composite plastic- or carbon-based material.

(30) The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

(31) In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.