Head rest lock

A head rest lock enables the adjusting of the elevational position of a head rest of a vehicle seat having sleeves that serve as vertical guides for support posts having lock notches therein, the notches providing a plurality of vertical height adjustment positions. The sleeves include a lock latch for manually activating the adjustable height mechanism and ribs which prevent inadvertent rotation of said sleeve. The head rest lock is mountable to a bracket or directly to a seat back frame.

TECHNICAL FIELD 
This invention relates to a headrest for a motor vehicle seat and more 
particularly to an head rest lock for adjusting the elevational position 
of a headrest of a vehicle seat. 
BACKGROUND OF THE INVENTION 
There exist a large variety of headrests which are conventionally mounted 
on one or two support posts that are inserted into guide sleeves, tubes or 
brackets affixed to the seat back frame structure. Generally, some sort of 
adjustment mechanism is provided to enable variable vertical positioning 
of the headrest and to prevent inadvertent removal of the headrest from 
the seatback. 
One such particular type of headrest is one which comprises two support 
posts which can be easily introduced into sleeves fixed to the framework 
tube of the backrest and then locked in position by a clip or the like 
engaged, on one hand, in a slot of the sleeve and, on the other hand, in a 
recess extending around the perimeter of the corresponding support post. 
Such an assembly is simple, however, there exist problems of a deformation 
or breakage of the support posts and unwanted rotation of the sleeves 
which both limits the ability to have precise locking and places the 
adjustment latches in a less than optimal positions for manual employment. 
SUMMARY OF THE INVENTION 
Accordingly, an object of this invention is to provide a device for 
adjusting the elevational position of a headrest that provides optimum 
durability and strength. 
Another object of the present invention is to provide a device for 
adjusting the elevational position of a headrest which includes an 
adjustment latch which is fixed and free from inadvertent rotational 
movement. 
In order to achieve the above and other objects, there is provided 
according to the present invention a device for adjusting the elevational 
position of a head rest of a seat for a vehicle which includes a support 
post having lock notches therein, and sleeves securely mounted around the 
support posts. The lock notches are located only on one side of the 
support post for optimum support post strength, and do not extend 
completely around the perimeter of the support post, thereby weakening 
support post strength. The sleeves have lock clips mounted therein which 
are snappingly fitable within the lock notches of the support posts and of 
which are activated by manually pushing a lock latch that is pivotally 
mounted in the sleeve. A headrest bracket is fixably attached to the top 
of the support posts while the bottom of the support posts which are 
enclosed by the sleeves and are securely anchored in a seatback bracket or 
seatback frame. The sleeves include rotational lock ribs which fit into 
rotational lock notches of the seat back bracket or seat back frame, 
thereby preventing the sleeves and integral lock latches from inadvertent 
rotational movement. The sleeves also include position ribs which lock the 
sleeves to the seatback bracket or frame to prevent inadvertent removal of 
the headrest from the seatback. 
The above and other related objects and features of the invention will be 
apparent from a reading of the following description of the disclosure 
found in the accompanying drawings and novelty thereof pointed out in the 
appended claims.

DETAILED DESCRIPTION OF THE INVENTION 
This invention will now be described in detail with reference to FIG. 1, 
which shows an or headrest lock 10 which includes a headrest bracket 12, a 
pair of support posts 14 and 16, a pair of sleeves 18 and 20, and a 
seatback bracket 22. 
As seen in FIGS. 1 and 5-8, headrest bracket 12 includes a central portion 
24 and a narrow top and bottom portion 26 and 28 respectively, both 
portions 26 and 28 being perpendicular to central portion 24. Headrest 
bracket 12 also has a pair of apertures 30a and 30b in each end of its top 
portion 26. Aperture 30b has a substantially semi-circular shape with a 
straight side 31b. A pair of corresponding round apertures 32a and 32b are 
in each end of the bottom portion 28 of headrest bracket 12. 
Support post 14 has a round cross-section and is extends through aperture 
32a with its top end terminating in apertures 30a, 30b. In this preferred 
embodiment, support post 14 is fixedly attached to headrest 12 by a weld. 
The top of post 14, which fits into aperture 30a, is preferably formed 
with a reduced diameter portion thereby providing a circumferential ridge 
on which bracket portion 26 partially rests. This provides for mechanical 
support, machining to relatively close tolerances and better contact for 
bonding the post 14 in the aperture 30a, as, for example, by welding. 
Support post 16 preferably has a round cross-section and has a plurality of 
lock notches 34 along one side. As seen in FIGS. 1, 5, 6, 12 and 13, the 
top of support post 16 has a straight edged cut-out portion 35 leaving a 
straight edge surface 35b in the support post 16. The straight edge 
cut-out portion has a corresponding shape to aperture 30b and is fixably 
positioned in aperture 30b. Straight edge surface 35b fits against 
straight side 31b of aperture 30b. The remaining round cross-section 
portion of support post 16 extends through aperture 32b. 
Sleeves 18 and 20 include an integral head portion 36, position ribs 37, 
38, 39 and 40, rotational lock rib 41, and bores 42 and 43 respectively. 
As seen in FIGS. 2-4, sleeve's 20 head portion 36 additionally has a slot 
44 therethrough. Lock clip 46 is attached around the wall of bore 43, a 
portion, described below, engageable with support post 16 through slot 44. 
A lock latch 48 is pivotally mounted by pivot pin 49 to head portion 36 in 
slot 44. One end of lock latch 48 is positioned between clip ends 46a and 
46b. The other end of lock latch 48 extends outside slot 44. Support post 
14 slidably fits inside bore 42. Support post 16 slidably fits inside bore 
43. Sleeves can be formed from a number of plastic materials which provide 
both adequate structural strength, economical forming, resiliency when 
subjected to loads in operation and preferably some level of self 
lubricating properties to permit easy sliding of posts 14, 16 inside bores 
42, 43. 
As seen in FIGS. 1, and 9-11, seat back bracket 22 includes a U-shaped top 
ledge 50 and a U-shaped bottom ledge 52. Top ledge 50 has a pair of 
apertures 54 and 56 therethrough at each of its ends. Similarly, bottom 
ledge 52 has a pair of corresponding apertures 58 and 60 therethrough at 
each of its ends. Apertures 54, 56, 58 and 60 include rotational lock 
slots 54a, 56a, 58a and 60a therein. 
Sleeves 18 and 20 snappingly fit into seat back bracket 22. As seen in 
FIGS. 1, 3 and 4, sleeves 18 and 20 include position ribs 37, 38, 39 and 
40. Position ribs 38 and 40 include incline portions 38a and 40a 
respectively. The diameter of position ribs 37, 38, 39 and 40 are slightly 
larger than the diameter of apertures 54, 56, 58 and 60. This difference 
in diameter size and the tapered shape allows sleeve 18 to be inserted 
through apertures 54 and 58 and sleeve 20 to be inserted through apertures 
56 and 60 whereby top ledge 50 snap fits between position ribs 37 and 38 
of each sleeve 18 and 20. Similarly, when sleeves 18 and 20 are inserted 
into apertures 54 and 58, bottom ledge 52 snap fits between position ribs 
39 and 40. Rotational lock ribs 41 of each sleeve 18 and 20 extend through 
rotational lock slots 54a, 56a, 58a and 60a when sleeves 18 and 20 are 
inserted through apertures 54, 58, 56 and 60 of seat back bracket 22. The 
positioning of rotational lock ribs 41 in slots 54a, 56a, 58a and 60a 
prevents any rotational movement of sleeves 18 and 19 in apertures 54, 58, 
56 and 60. 
The purpose of headrests in vehicles is primarily to support the head of a 
front-facing occupant in a rear-end collision. Rear facing seats having 
headrests, of course, support in the opposite direction. The load thus 
imposed by the acceleration or deceleration is typically on an axis 
perpendicular to brackets 12 and 22 which corresponds to the direction the 
seat is facing. This can be referred to as a seat axis. Rotational locking 
of sleeve 20 permits maximizing strength against these loads because post 
16 need not be grooved around its entire circumference as discussed below. 
When completely assembled, the top of support posts 14 and 16 are welded to 
headrest bracket 24 as the top of the support posts are positioned in 
apertures 30a, 32a, 30b and 32b. The bottom of support posts 14 and 16 fit 
into bores 42 and 43 of sleeves 18 and 20. Sleeves 18 and 20 are snap 
fitted into seat back bracket 22 through apertures 54, 58, 56 and 60. 
In operation, the elevational or vertical position of the headrest is 
adjusted by moving a headrest which is attached to headrest bracket 24 to 
line up with the lock notches generally designated 34, but having two 
different configurations 34a and 34b, so that lock clip 46 engages the 
respective notch 34a or 34b. 
Starting with the clip 46 in the upper of the notches 34a with a beveled 
configuration, the headrest bracket 24 can be raised, displacing the 
spring member in clip 46 so that it slides until clip 46 aligns the next 
lower notch 34a. At this point, lock clip 46 engages the newly adjacent 
lock notch 34a to lock the headrest in a position where it is prevented 
from moving vertically downwardly. In the upper position with notch 34a 
engaged, the headrest is prevented from moving vertically downwardly, as 
described herein in more detail. Bracket 24 can be raised once more until 
clip 46 engages notch 34b. However since notch 34b is square in section, 
clip 46 engaging therein limits movement either in an up or down 
direction. 
To unlock the or headrest lock 10, the operator pushes the portion of the 
lock latch 48 extending outside sleeve's 20 head portion 36 and slot 44 in 
the direction of arrow 62 about pivot pin 49 (As seen in FIG. 2). This 
causes the portion of locking latch 48 extending inside slot 44 to push 
against end 46a of the lock clip 46, thereby, forcing the lock clip out of 
lock notch 34a or 34b. The headrest is now unlocked and may be adjusted 
either up or down. Once the headrest is moved vertically to where the lock 
clip 46 is no longer adjacent to the lock notch 34a or 34b, the lock latch 
may be released and the headrest may be moved up or down until another 
lock notch 34a or 34b along support post 16 comes to a position adjacent 
lock clip 46, whereby, the lock clip 46 will once again snap into the 
adjacent lock notch 34 to lock the headrest in another selected vertical 
position. Thus, it is necessary to actuate latch 48 to either move the 
headrest up or down from alignment of clip 46 with notch 34b or to move 
the headrest down if clip 46 is aligned with notch 34a. From notch 34a, 
the headrest may be raised without actuating latch 48. 
The ability to fix sleeve 20 against rotation in bracket 22 enables the 
forming of lock notches 34a and 34b to a more advantageous geometry than 
the prior art. The prior art, having a rotatable sleeve used a shallow 
groove completely around the circumference of the post. Because this 
circumferential groove substantially weakened the post, this prior art 
groove was of small section. By both limiting the location of notches 34 
to a single side of post 16 and by aligning notches 34 away from the front 
and rear portions of post 16 where loads would be concentrated, the 
strength of support post 16 is maximized. 
If locking latch 48 is released against the spring pressure of clip 46 when 
post is vertically aligned such that clip 46 abuts the exterior surface of 
post 16 the headrest can be slid until clip 46 comes into engagement with 
notch 34a or 34b. FIG. 12 shows the preferred arrangement with notches 
having profiles 34a for the upper notches and a square profile 34b for the 
bottom notch. The angled or beveled notch 34a permit the headrest bracket 
12 to be slid upwardly without releasing latch 48 but not to slide 
downwardly unless latch 48 disengages clip 46. Bottom notch 34b does not 
permit either upward or downward movement without release of latch 46. 
Notch 34a preferably has a ramp 66 which leads clip 46 to contact face 68 
for a positive lock. Wall 70 supports post 16 vertically. The face 68, 
wall 70, and ramp 68 define a notch axis. As vertical adjustment of 
headrest height to a seat occupant is advantageous this configuration 
which enables more sure locking, particularly where unlocked, released and 
downwardly slid, the invention is an important advance. 
Notch 34b has wall 70b and face 68b. Instead of having ramp 66, square 
notch 341b has wall 72 which is parallel to wall 70b, thereby forming a 
square notch 34b. 
FIG. 14 shows an alternative embodiment. This embodiment is adapted to use 
a square section tube seatback bracket 122. This may, for example be a 
square section tube forming the frame of a seat, such as a bucket seat or 
bench seat for a vehicle, in accordance with known methods of vehicle seat 
construction. The tube 122 has top wall 124 and bottom wall 126, 
interconnected by side walls 128, 130. The arrangement of apertures to 
receive sleeves 18, 20 uses paired apertures of the same configuration, 
however the bottom apertures are not visible in FIG. 14. Apertures 154 and 
156 receive sleeves 18, 20. However, unlike the bracket 22, each aperture 
154 and 156 has two rotational lock slots 154a and 154b and rotational 
lock slots 156a and 156b, respectively. In use in an application such as a 
bench seat which is designed to have a plurality of seating positions, 
apertures 154 and 156 can be preformed in a continuous series of 
apertures, each of identical form. In this manner, production of seat 
frames is more efficient, and the seat upholstery designer can fit either 
sleeve 18 or sleeve 20 in the appropriate aperture. Because of the 
plurality of opposed lock slots 154a, 154b, 156a and 156b, respective ribs 
41, lined up as needed to align clip 46 with the appropriate notches 34a 
and 34b. In this manner, greater manufacturing flexibility is provided, 
while preserving the essential advantages of lining up notches 34a and 34b 
and clips 46 over the prior art annular grooves. 
FIG. 15 shows an improved internally ribbed sleeve 220 include an integral 
head portion 236 with rotational lock rib 241, and bore 243. This head 
portion 236 also has a slot 244 therethrough. As in the other embodiments, 
lock clip 46 is used to engage with support post 16. A lock latch 48 is 
pivotally mounted by pivot pin 49 to head portion 236 in slot 44 in the 
same manner as described with respect to sleeve 20. 
In sleeve 220, support post 16 slidably fits inside bore 243. The 
improvement in sleeve 220 is the use of bearing ribs 246 which directly 
bear on post 16. These provide considerable advantages in manufacturing 
and operation. As described above, sleeves 20 can be formed of a plastic 
material having a level of resiliency and self lubrication. Using a 
material having these properties has advantages in this alternative 
embodiment. Ribs 246 permit forming sleeve 220 with a bore 243 having 
greater clearance with the diameter of post 16 because ribs 246 will 
actually bear and center post 16. Resiliency provided by the material also 
permits a controlled level of distortion of ribs 246 if necessary, while 
the semicircular section of ribs 246 also provides for a needle bearing 
like effect, with contact only along the line on the rib 246 which 
contacts the corresponding line on the surface of post 16. This makes 
forming sleeve move economical and of improved quality because tolerances 
need not be as close as that for sleeve 20. These advantages also apply to 
a similarly configured sleeve corresponding to the non-locking sleeve 18. 
The preceding objects, drawings and description are illustrative of the 
embodiments of the invention, however, it must be understood that these 
particular arrangements merely illustrate and that the invention is to be 
given its fullest interpretation within the terms of the appended claims.