For a number of years the sole purpose of vehicle headrests was for the comfort of the occupant. The headrest could be adjusted up and down in most cases, and moved fore and aft in some expensive models. A typical headrest consists of a notched rod that may be straight or bent in a “U” shape and held in the car seat's guide tube. Foam and trim covers are placed on top of the rod (the headrest assembly) to give head and neck support and passenger comfort. The notches placed along the length of the rod help in moving the headrest assembly up and down, and locking the headrest in a specific place depending upon the occupant's height.
The headrests that move fore and aft are typically of a riveted design (4-way). The headrest is made in two parts. The upper section has welded brackets and a pair of notched rods. The rods are attached to the upper section with rivets and a friction pack comprising a wave washer, a flat washer and a rubber or plastic washer. The upper section pivots on the pair of rods at riveted joints. The upper section is foamed and trimmed for the headrest. The friction on the riveted joints control the movement of the upper section with respect to the lower notched rods.
The problem with existing designs is that efforts to move the headrest depend upon the dimensional tolerances of seat frame components. While 4-way headrests allow movement in both the up and down directions as well as fore and aft, they depend upon the friction on the rivet to keep in place and for movement. Increasing friction causes higher efforts, while reducing friction allows the upper section to fall since there is no locking mechanism.
With new regulations, headrests are becoming a part of the overall safety restraint system in the vehicles, and are being used as a protection device for whiplash in case of an accident. This requires the headrest to lock in a specific position and not move (at least in the aft direction) unless an activation device is used to move it from one position to another.
The present invention provides a head restraint system that overcomes some of the above-described problems of the related art. The invention allows the occupant to lock the headrest in a specific position. The headrest can be moved forward with minimal effort, while moving the headrest in the opposite direction requires a pushbutton activation. The invention also combines up and down motions and eliminates the effort issues related to seat frame dimensional tolerances.
The following prior art is related to this technology: U.S. Pat. Nos. 4,830,434 issued May 16, 1989 to Keiichi Ishida and Takami Terada for “Adjustable Headrest Device for Vehicle”; 5,669,668 issued Sep. 23, 1997 to Andrew Leuchtmann for “Folding Headrest in Particular for Motor Vehicles” and 6,045,181 issued Apr. 4, 2000 to Noriyuki Ikeda and Moriyuki Eguchi for “Adjustable Headres”
Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains, upon reference to the following drawings.