1. Field of the Invention
The invention relates to seat assemblies for an automotive vehicle. More particularly, the invention relates to a mechanism for automatically adjusting the position of a head restraint in response to pivotal movement of a seat back relative to a seat cushion.
2. Description of Related Art
Automotive vehicles include seat assemblies for supporting an occupant in the vehicle. The seat assemblies include a seat cushion and a seat back. Typically, the seat back is pivotally coupled to the seat cushion by a recliner mechanism to allow for pivotal movement of the seat back between a plurality of reclined seating positions. Each reclined seating position corresponds to a particular seat back recline angle.
The seat assemblies also commonly include a head restraint which provides added comfort for the seat occupant's head. In addition to the comfort feature, the head restraint also provides a safety feature. Namely, the head restraint provides needed head support during rear end collisions which reduces the likelihood of whiplash type injuries. Typically, the head restraint is one of three types. The first type is an “integral” head restraint, which is formed as part of a top portion of the seat back and is non-adjustable. The second type is an “adjustable” head restraint, which consists of a separate cushion that is mounted to the top portion of the seat back and includes some type of height adjustment mechanism to provide vertical adjustment of the head restraint to accommodate seat occupants of varying heights. Some adjustable head restraints also provide horizontal adjustment to allow the head restraint to be moved closer to or farther away from the seat occupant's head. The third type is an “active” head restraint, which deploys toward the seat occupant's head in the event of a collision to minimize the potential for whiplash.
The National Highway Traffic Safety Administration recently revised Federal Motor Vehicle Safety Standard (FMVSS) 202, which governs head restraints. The new standard, known as FMVSS 202a, establishes a requirement for the fore-aft position of the head restraint. Basically, a fore-aft distance between the head restraint and the back of the seat occupant's head should not exceed fifty-five (55) millimeters when measured with an occupant torso angle of twenty five (25) degrees. This fore-aft distance is commonly referred to as “backset.”
One problem with the previously mentioned types of head restraints is the head restraint moves with the seat back during adjustment of the seat back between the plurality of reclined seating positions. Therefore, if the seat assembly is designed with a backset distance of 55 millimeters when the occupant torso angle is at 25 degrees, as the seat back is pivoted forward toward a more upright seating position the head restraint will move closer to the seat occupant's head, potentially creating discomfort for the occupant. The reverse occurs when the seat back is pivoted rearward toward a more reclined seating position, i.e., the head restraint will move farther away from the seat occupant's head. Alternatively, if the seat assembly is designed with a backset distance of 55 millimeters when the seat back is in an upright seating position, as the seat back pivots rearward the head restraint will move farther away from the seat occupant's head and potentially create discomfort for the occupant.
Therefore, there is a need to provide a mechanism for automatically adjusting the position of a head restraint in response to pivotal movement of a seat back to maintain a specified distance between the head restraint and a seat occupant's head to minimize potential occupant discomfort.
According to one aspect of the invention, a seat assembly is provided for supporting a seat occupant in an automotive vehicle. The seat assembly includes a seat cushion and a seat back operatively coupled to the seat cushion for selective pivotal movement of the seat back relative to the seat cushion between a plurality of reclined seating positions. The seat back includes a seat back frame. A head restraint is coupled to the upper end of the seat back frame and includes a front surface for supporting a head of the seat occupant. A backset distance is defined between the front surface of the head restraint and the seat occupant's head. An adjustment mechanism operatively interconnects the seat back frame and the seat cushion for automatically tilting the seat back in response to pivotally adjusting the seat back in order to maintain the backset distance. As the seat back pivots rearward the seat back tilts forward thereby moving the head restraint toward the seat occupant's head. As the seat back pivots forward the seat back tilts rearward thereby moving the head restraint away from the seat occupant's head.
In one embodiment of the invention, the adjustment mechanism includes a pair of eccentric bearings operatively coupled between the seat back and seat cushion. Rotation of the eccentric bearings in response to pivotally adjusting the seat back translates a lower end of the seat back forwardly and rearwardly along an arcuate path thereby tilting the seat back to maintain the backset distance between the front surface of the head restraint and the seat occupant's head constant.
In another embodiment of the invention, the adjustment mechanism includes a pair of V-shaped links in place of the eccentric bearings. The V-shaped links are operatively coupled between the seat back and seat cushion. Rotation of the V-shaped links in response to pivotally adjusting the seat back translates the lower end of the seat back forwardly and rearwardly along the arcuate path thereby tilting the seat back to maintain the backset distance between the front surface of the head restraint and the seat occupant's head constant.
Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a seat assembly for use in an automotive vehicle is generally shown at 10 in
The seat assembly 10 also includes a pair of spaced recliner mechanisms, generally indicated at 40, operatively coupling the seat back 14 and seat cushion 12. The recliner mechanisms 40 provide selective pivotal adjustment of the seat back 14 about a first pivot axis 42 relative to the seat cushion 12 between a plurality of reclined seating positions defined generally between an upright seating position, shown in
The seat back frame 22 of the seat back 14 is operatively coupled to the pair of spaced apart recliner mechanisms 40 as is described below. The seat back frame 22 includes a pair of spaced apart and parallel frame tubes 54. The frame tubes 54 extend between lower and upper ends, thereby defining a lower end 56 of the seat back frame 22 adjacent the lower portion 34 of the seat back 14 and an upper end 58 of the seat back frame 22 adjacent the upper portion 36 of the seat back 14. A head restraint 60 is fixedly secured to the upper end 58 of the seat back frame 22 by a pair of spaced apart posts 61 (one shown) extending therebetween. The head restraint 60 includes a front supporting surface 62 for supporting the seat occupant's head. It is contemplated that the posts 61 may be slidably coupled to the upper end 58 of the seat back frame 22 for providing vertical height adjustment of the head restraint 60 relative to the upper portion 36 of the seat back 14.
With the seat occupant seated in the seat assembly 10, a distance between the back of the seat occupant's head and the front supporting surface 62 of the head restraint 60 is referred to as “backset” and is shown as B in
In order to maintain the backset distance B constant at 55 millimeters as the seat back 14 is pivotally adjusted between the upright seating position and the fully reclined seating position, an adjustment mechanism, generally shown at 63, is provided. The adjustment mechanism 63 automatically adjusts the position of the head restraint 60 in response to pivotal movement of the seat back 14. For example, the head restraint 60 moves toward the back of the seat occupant's head as the seat back 14 pivots rearward toward the fully reclined seating position. Conversely, the head restraint 60 moves away from the back of the seat occupant's head as the seat back 14 pivots forward toward the upright seating position. Because the head restraint 60 is fixedly secured to the upper end 58 of the seat back frame 22, the adjustment of the head restraint 60 toward and away from the seat occupant's head is accomplished by tilting the seat back 14 as the seat back 14 is pivotally adjusted.
The adjustment mechanism 63 is operatively coupled between the lower end 56 of the seat back frame 22 and the B-brackets 46, as described below in more detail. The adjustment mechanism 63 includes first and second eccentric bearings, generally indicated at 64, 65. In the embodiment shown, the first 64 and second 65 bearings are substantially the same and only the first bearing 64 will described herein in detail. The first bearing 64 includes a first cylindrical portion 66 defining a bearing surface 68 that is disposed in a circular aperture 70 extending through one of the A-brackets 44. The first bearing 64 rotates about a rotation axis 72 that is coincident with the geometric center of the first cylindrical portion 66, as shown in
A torsion spring 80 is disposed around the second cylindrical portion 74 of the first bearing 64 and extends between a first end 82 engaging a notch (not shown) in the second cylindrical portion 74 and a second end 83 engaging a notch 84 in the respective A-bracket 44. The torsion spring 80 biases the first bearing 64 in a clockwise direction (when viewed from the Figures).
An axle or shaft 85 is fixedly secured to the cylindrical boss 78 of the first bearing 64 and extends laterally through the lower end 56 of the seat back frame 22, terminating at a distal end 86. The distal end 86 of the axle 85 is fixedly secured to the cylindrical boss 78 of the second bearing 65, which is rotatably disposed in the circular aperture 70 extending through the other one of the A-brackets 44. As the first 64 and second 65 bearings rotate about the rotation axis 72, the axle 85 moves along the arcuate path thereby translating the lower end 56 of the seat back frame 22 relative to the A-brackets 44.
The first 64 and second 65 bearings are oriented within the apertures 70 so that the arcuate path defines a predetermined amount of fore/aft travel. Therefore, as the first 64 and second 65 bearings rotate about the rotation axis 72, the lower end 56 of the seat back frame 22 translates forwardly and rearwardly depending upon the direction of rotation of the bearings 64, 65. In the embodiment shown, rotation of the bearings 64, 65 in a counterclockwise direction (when viewed from
The second end 50 of each A-bracket 44 includes a generally vertically extending slot 88 for receiving a pin 90 extending laterally from the respective frame tubes 54 of the seat back frame 22, between the lower 56 and upper 58 ends thereof. The pivotal and sliding connection between the pins 90 and slots 88 allow the seat back frame 22, and therefore the seat back 14, to tilt as the lower end 56 of the seat back frame 22 translates forwardly and rearwardly. More specifically, as the lower end 56 of the seat back frame 22 moves rearwardly due to counterclockwise rotation of the first 64 and second 65 bearings, the pins 90 pivot and slide within the slots 88 to allow the upper end 58 of the seat back frame 22 to tilt forwardly, thus moving the upper portion 36 of the seat back 14 and the head restraint 60 toward the seat occupant's head. Conversely, as the lower end 56 of the seat back frame 22 moves forwardly due to clockwise rotation of the first 64 and second 65 bearings, the pins 90 pivot and slide within the slots 88 to allow the upper end 58 of the seat back frame 22 to tilt rearwardly, thus moving the upper portion 36 of the seat back 14 and the head restraint 60 away from the seat occupant's head. Depending on the desired amount of head restraint movement, various adjustments can be made to the offset between the rotation axis 72 and the cylindrical bosses 78, the orientation of the bearings 64, 65 within the apertures 70, and the location of the slots 88 in the A-brackets 44.
On the same side of the seat assembly 10 as the first bearing 64, the adjustment mechanism 63 also includes first 92 and second 94 links for rotatably actuating the bearings 64, 65. The first link 92 is pivotally coupled to the outer surface 76 of the respective A-bracket 44 about a second pivot axis 96. The first link 92 extends between a follower end 98 and a link end 100. The follower end 98 includes a pin 102 extending laterally therefrom. The pin 102 extends laterally inward, toward the seat assembly, and slidably engages a registry component or guide surface 104 that is integrally formed as part of the respective B-bracket 46. The pin 102 is in contact with the guide surface 104 when the seat back 14 is in the upright seating position, as shown in
It is appreciated that the guide surface 104 may be formed such that a variety of backset distances B can be achieved. More specifically, the shape of the guide surface 104 may be any linear or non-linear shape and may include a convex portion 105, such as that shown in
The second link 94 extends between a first end 106 pivotally coupled to the link end 100 of the first link 92 at pivot 107 and a second end 108 pivotally coupled to the second cylindrical portion 74 of the first bearing 64 at pivot 109. The pivotal connection 109 between the second link 94 and the first bearing 64 is offset from the rotational axis 72. The second link 94 causes the first bearing 64 to rotate in response to pivotal movement of the first link 92. When the seat back 14 is pivotally adjusted rearward toward the fully reclined seating position, the first link 92 pivots in the counterclockwise direction as described above, and the link end 100 of the first link 92 pulls the second link 94 downwardly causing the first bearing 64 to rotate in the counterclockwise direction. Conversely, when the seat back 14 is pivotally adjusted forward toward the upright seating position, the torsion spring 80 urges the first bearing 64 to rotate in the clockwise direction pulling the second link 94 upwardly thereby causing the first link 92 to pivot in the clockwise direction. The first end 106 of the second link 94 includes a tab 110 projecting inwardly which abuts an edge of the first link 92 when the seat back 14 is in the upright seating position to stop the clockwise rotation of the first bearing 64.
In operation, the backset distance B of the head restraint 60 remains constant as the seat back 14 is pivotally adjusted. As the seat back 14 is pivotally adjusted rearward from the upright seating position, shown in
The opposite movement of the head restraint 60 occurs when the seat back 14 is pivotally adjusted forward. As the seat back 14 is pivotally adjusted forward to return to the upright seating position, shown in
Referring to
The V-link 112 is oriented so that the arcuate path defines a predetermined amount of fore/aft travel. Therefore, as the V-link 112 rotates about the rotation axis 122, the lower end 56′ of the seat back frame 22′ translates forwardly and rearwardly depending upon the direction of rotation of the V-link 112. In the embodiment shown, rotation of the V-link 112 in the counterclockwise direction (when viewed from
Referring to
The slot 88′ at the second end 50′ of each A-bracket 44′ extends between a lower first end 128 and an upper second end 130. In the embodiment shown, the upper second end 130 of the slot 88′ is disposed generally rearward of the lower first end 128. When the seat back 14′ is in the upright seating position the pin 90′ is disposed at the upper second end 130 of the slot 88′, as shown in
The V-link 112 is operatively coupled to the B-bracket 46′ by a linkage including the first 92′ and second 94′ links. The first link 92′ is pivotally coupled to the inner surface 120 of the A-bracket 44′ about the second pivotal axis 96′. The follower end 98′ of the first link 92′ includes the pin 102′ extending laterally therefrom. The pin 102′ extends laterally away from the seat assembly 10′ and slidably engages the guide surface 104′ that is integrally formed as part of the respective B-bracket 46′. The pin 102′ is in contact with the guide surface 104′ when the seat back 14′ is in the upright seating position, as shown in
Referring to
The second link 94′ pivotally connects the first link 92′ and the V-link 112. More specifically, the first end 106′ of the second link 94′ is pivotally coupled to the link end 100′ of the first link 92′ at pivot 107′ and the second end 108′ is pivotally coupled to the first arm 114 of the V-link 112 at pivot 109′. The second link 94′ causes the V-link 112 to rotate in response to pivotal movement of the first link 92′. When the seat back 14′ is pivotally adjusted rearward toward the fully reclined seating position, the first link 92′ pivots in the counterclockwise direction as described above, thereby pulling the second link 94′ downwardly, which in turn causes the V-link 112 to rotate in the counterclockwise direction. Conversely, when the seat back 14′ is pivotally adjusted forward toward the upright seating position, the extension springs 126 bias the lower end 56′ of the seat back frame 22′ forwardly, which urges the V-link 112 to rotate in the clockwise direction, which in turn pulls the second link 94′ upwardly and causes the first link 92′ to pivot in the clockwise direction.
The seat assembly 10′ also includes at least one torsion spring 132 for biasing the seat back 14′ toward the upright seating position and a recliner handle 134 for actuating the disc recliners 52′ between locked and unlocked states, as is well known in the art. More particularly, the torsion spring 132 is disposed about the first pivot axis 42′ and extends between the A-bracket 44′ and the B-bracket 46′ to urge the A-bracket 44′ to pivot in the counterclockwise direction about the first axis 42′ relative to the B-bracket 46′. The recliner handle 134 is operatively coupled to one of the disc recliners 52′ for actuation thereof. A cross-talk tube 136 extends between the disc recliners 52′ for simultaneous actuation of both in response to operation of the recliner handle 134.
In operation, the backset distance B′ of the head restraint 60′ remains constant as the seat back 14′ is pivotally adjusted. As the seat back 14′ is pivotally adjusted rearward from the upright seating position, shown in
The opposite movement of the head restraint 60′ occurs when the seat back 14′ is pivotally adjusted forward. As the seat back 14′ is pivotally adjusted forward to return to the upright seating position, shown in
The invention has been described here in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of words of description rather than limitation. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically enumerated within the description.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CA08/01028 | 5/6/2008 | WO | 00 | 11/6/2009 |
Number | Date | Country | |
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60916630 | May 2007 | US |