Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2000-12-04
2003-11-04
Walsh, Donald P. (Department: 3653)
Winding, tensioning, or guiding
Reeling device
With spring motor
Reexamination Certificate
active
06641076
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a webbing take-up device for use in a seat belt apparatus for protecting a vehicle occupant in the event of a vehicular emergency, in which an ELR mode and an ALR mode can be properly switched. In the ELR mode, an ELR prevents a take-up shaft from rotating in the direction in which the webbing is unwound, only in the event of a vehicular emergency. In the ALR mode, an ALR always prevents the webbing from being unwound, after a predetermined amount of the webbing has been unwound.
2. Description of the Related Art
In a webbing take-up device with which a vehicle is equipped, there is provided a locking mechanism for, when necessary, preventing the webbing from being unwound.
The locking mechanism comprises an ELR (i.e., Emergency Locking Retractor) and an ALR (i.e., Automatic Locking Retractor). Ordinarily, taking-up and unwinding (pulling-out) of the webbing is possible. In the event of a vehicular emergency, the ELR detects the state of emergency by an acceleration detection means and instantaneously prevents a take-up shaft from rotating in the direction in which the webbing is unwound. The ALR continually prevents further unwinding of the webbing after a predetermined amount of the webbing has been unwound.
In the ELR, a locking wheel is provided so as to follow the rotation of the take-up shaft in the direction in which the webbing is unwound, and an elastic body is inserted between the locking wheel and the take-up shaft. Therefore, in a normal state, the locking wheel and the take-up shaft integrally rotate. As a result, since it is possible to freely take up or unwind the webbing from the take-up shaft when the vehicle is in a state of normal travelling, a vehicle occupant can freely change his or her posture. In the event of vehicular emergency, an acceleration detection means prevents the locking wheel from rotating, and, due to the delayed rotation of the locking wheel relative to the take-up shaft, a locking member which rotates with the take-up shaft is guided and moved to mesh with ratchet teeth of a frame. As a result, the take-up shaft is prevented from rotating so that the webbing is stopped from unwinding.
On the other hand, in the ALR, an ALR pawl prevents the locking wheel from rotating due to unwinding of the webbing in a predetermined amount (therefore, in this state, the locking member which rotates together with the take-up shaft meshes with the ratchet teeth of the frame), and, thereafter, further unwinding of the webbing from the take-up shaft is not allowed so that the vehicle occupant can be securely restrained.
A webbing take-up device in which the ELR and the ALR are jointly provided has already been proposed by the same applicant of the present invention (for example, Japanese Patent Application Laid-Open (JP-A) No. 10-244905, Japanese Utility Model Application Publication (JP-Y) No. 7-47239, and the like).
In a webbing take-up device of this type, the ELR and ALR can be switched as needed. That is, when the webbing take-up device is between a state in which an entire amount of the webbing has been taken up by the take-up shaft and a state in which a predetermined amount of the webbing has been unwound, an ALR lever which is allowed to engage with the locking wheel by means of an urging force is compellingly disengaged from the locking wheel, and further engagement is prevented, and the locking member is controlled by the acceleration detecting means (that is, the ELR operative state). On the other hand, when the webbing take-up device is in a state in which a predetermined amount of the webbing has been unwound (for example, an entire amount of the webbing has been unwound), the ALR lever is compellingly engaged with the locking wheel so as to prevent further unwinding of the webbing (that is, the ALR operative state).
Accordingly, a single webbing take-up device is able to function as either the ELR or the ALR, according to the situation.
In a webbing take-up device of this type, there has been a drawback in that, in a state in which both taking up and unwinding of the webbing are possible (namely, in the ELR state), when a vehicle occupant to whom the webbing has been harnessed stoops or the like, the webbing take-up device may unintendedly and unnecessarily be switched to a state in which the webbing is prevented from unwinding (namely, the ALR state), which may make the vehicle occupant feel unpleasant.
In this case, it is possible to conceive of setting the overall length of the webbing to be much longer than the length required for ordinary use to harness the vehicle occupant, so that unnecessary switching from the ELR mode to the ALR mode may be prevented. However, simply setting the overall length of the webbing to be long may lead to increases in the size and cost of the device.
SUMMARY OF THE INVENTION
In view of the aforementioned, it is an object of the present invention to provide a webbing take-up device in which unintended and unnecessary switching from an ELR mode to an ALR mode can be prevented.
In accordance with a first aspect of the present invention, here is provided a webbing take-up device which operates in one of an ELR mode in which, in only a case of a vehicular emergency, a rotating of a take-up shaft of a webbing in a direction in which the webbing is unwound is prevented, and an ALR mode in which, after a predetermined amount of the webbing is unwound, an unwinding of the webbing is always prevented, wherein: a switching from the ELR mode to the ALR mode is carried out by, in the ELR mode, unwinding an entire amount of the webbing; taking up a predetermined amount of the webbing from a state in which the entire amount of the webbing is unwound; unwinding the entire amount of the webbing from a state in which the predetermined amount of the webbing is taken-up; and taking up the predetermined amount of the webbing from the state in which the entire amount of the webbing is unwound, in serial order; and a switching from the ALR mode to the ELR mode is obtained by, in the ALR mode, taking up a predetermined amount of the webbing.
In accordance with a second aspect of the present invention, there is provided a webbing take-up device comprising: a take-up shaft which takes up a webbing for restraining a vehicle occupant; a locking device which can engage with the take-up shaft to prevent the take-up shaft from rotating in a direction in which the webbing is unwound; a locking wheel which following rotates around the take-up shaft, and, when stops rotating, which guides the locking device such that the take-up shaft is prevented from rotating; an acceleration detecting means which detects a state of a vehicle emergency, and which stops the locking wheel from rotating; an ALR pawl which is able to move so as to switch between a state in which the ALR pawl engages with the locking wheel so as to prevent the locking wheel from rotating, and a state in which the ALR pawl is spaced from the locking wheel so as to allow the locking wheel to rotate; a reduction mechanism which operates due to an intermittent motion, comprising a driving gear which rotates integrally with the take-up shaft and a reduction gear which meshes with the driving gear; a disc control member which is provided with a braking operational portion which engages with the ALR pawl so as to keep the ALR pawl spaced from the locking wheel, and an intermediate holding surface which is disposed adjacent to the braking operational portion and which engages with the ALR pawl so as to keep the ALR pawl spaced from the locking wheel; and a cam member which is rotated by the reduction mechanism in an interlocking manner, and which is provided with a first pressing surface and a second pressing surface for pressing the disc control member, and which engages with the ALR pawl so as to keep the ALR pawl spaced from the locking wheel, wherein the webbing take-up device operates in one of an ELR mode or an ALR mode, the switching between the ELR mode or the ALR mode being carried
Hashimoto Masakazu
Mori Shinji
Sumiyashiki Akira
Cole Thomas W.
Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho
Nixon & Peabody LLP
Rodriguez Joseph C
Walsh Donald P.
LandOfFree
Webbing take-up device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Webbing take-up device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Webbing take-up device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3151120