Four-Way Manual Automotive Seat Adjustment Assembly

The present invention relates to automotive vehicle seating and, more particularly, to automotive vehicle seats equipped with manual four-way adjustment assemblies.

Traditionally, only expensive luxury type vehicles have been equipped with seating that is adjustable in multiple directions in addition to fore and aft. Recent consumer demand, however, has made it increasingly important for automobile manufacturers to offer enhanced seat adjustment capability on less expensive vehicles. The cost and weight penalties associated with conventional power seat adjustment systems makes their application in smaller, less expensive vehicles impractical. Accordingly, the use of manual seat adjustment mechanisms is dictated for such applications.

Many different manual seat adjustment mechanisms have been proposed. However, there remains a need for a manual seat adjustment mechanism that is relatively simple in design and construction and therefore inexpensive to manufacture, is durable, and yet is light in weight, quiet, and easy to operate.

It is the primary object of the present invention to provide a four-way manual seat adjustment assembly that satisfies these criteria. In particular, the present invention discloses an improved mechanism for manually adjusting the position of a vehicle seat in either the up and down directions or the fore and aft directions. The present invention, in general, comprises a pair of stationary tracks defining a substantially horizontal plane. Elongated carriages are slidably coupled with the tracks and move longitudinally thereon. A mechanism is coupled with the tracks and carriages which enables selective movement of the carriages longitudinally along the tracks. Also, a vertical adjustment mechanism is provided that is coupled with the seat assembly to enable vertical adjustment of the seat assembly.

The vertical adjustment mechanism includes a pair of quadrants or lift links that are rotatably journalled to the seat frame members fastened to the underside of the seat bottom. The seat frame members are pivotably mounted at their rearward end to the carriages. A pair of pivot pins is fixedly attached to the quadrants/lift links and journalled to a pair of brackets that is in turn slidably mounted to the forward ends of the carriages. Vertical movement of the seat frame members relative to the carriages raises and lowers the pivot point of the quadrants/lift links, thereby causing the quadrants/lift links to rotate. The slidable mounting brackets take up the horizontal movement of the pivot pins as the quadrants rotate. A locking mechanism including a pawl that is engagable with teeth on the quadrants is provided to secure the seat frame in a selected vertical position. In addition, plastic bushings are provided at each of the various pivot points in the preferred embodiment to provide smoothness of operation and to minimize the amount of noise generated by the mechanism when operated.

From the following specification in connection with the accompanying drawings, other objects and advantages of the present invention will become apparent to those skilled in the art.

FIG. 1 is a top plan view of a four-way seat assembly in accordance with the present invention;

FIG. 2 is a sectional view taken along line 2--2 of the four-way seat assembly shown in FIG. 1;

FIG. 3 is a sectional view taken along line 2--2 similar to that of FIG. 2 with the seat assembly in a second position;

FIG. 4 is a sectional view taken along line 2--2 similar to that of FIG. 2 with the seat assembly in a third position;

FIG. 5 is a sectional view taken along line 5--5 in FIG. 2;

FIG. 6 is a side elevation view of the four-way seat assembly in accordance with the present invention;

FIG. 7 is a side elevation view similar to FIG. 6 with the seat assembly in a second position; and

FIG. 8 is a side elevation view similar to FIG. 6 with the seat assembly in a third position.

Referring to the drawings, particularly FIGS. 1 and 4, a manually operable four-way seat adjustment assembly is illustrated and designated with the reference numeral 10. The four-way seat adjustment assembly 10 includes a pair of track members 12 and 14, carriages 16 and 18, a horizontal adjustment mechanism 20, seat frame members 22 and 24, and a vertical adjustment mechanism 26.

The rails 12 and 14 are elongated, U-shaped in cross-section, and include mounting members 28 for securing the rails 12 and 14 to the floor of a vehicle. A pair of carriages 16 and 18 are slidably mounted to the rails 12 and 14, respectively, for relative movement in the fore and aft directions. In addition, seat frame members 22 and 24, which are bolted via mounting pads 56 to the underside of the seat bottom, are in turn pivotably mounted at their rearward ends by pins 62 to carriages 16 and 18 for providing up and down movement of the seat.

The carriages 16 and 18 are elongated and have an overall rectangular shape in cross-section with a channel along one of the sides thereof to enable the rails 12 and 14 to be slidably positioned within the carriages 16 and 18 as seen in FIG. 5. Rollers 36, of the ball type, are positioned between the carriages 16 and 18 and the rails 12 and 14 to enable movement of the carriages 16 and 18 along the rails 12 and 14 in a substantially horizontal plane.

The horizontal adjustment mechanism 20 which provides selective fore and aft slidable movement of the carriages 16 and 18 on the rails 12 and 14 includes a handle 38 fixably secured to a crossbar 40. The crossbar 40 is rotatably secured to a torsion bar 42 and includes a pair of downturned flanges 44 and 46 which are secured to biasing linkages 48 and 50, respectively. Biasing linkages 48 and 50 are secured to levers 32 and 34, respectively. Also, biasing springs 52 and 54 are secured between the levers 32 and 34, respectively, and the carriages 16 and 18.

As the handle 38 is moved upward, the lever teeth (not shown) disengage from the notches 30 in rails 12 and 14 to enable the carriages 16 and 18 to move fore and aft in the horizontal plane defined by the rails 12 and 14 (see FIGS. 2 5). When the handle 38 is released, the lever teeth (not shown) engage the rail notches 30 locking the seat in a desired horizontal position.

The vertical adjustment mechanism 26 includes a pair of quadrants 76 and 78 which also serve as lifting links for adjusting the front height of the seat frame members 22 and 24 relative to the carriages 16 and 18. The quadrants 76 and 78 are fixedly secured to opposite ends of a torsion bar 80 that is journalled to the seat frame members 22 and 24. The torsion bar serves to keep the rotational position of the two quadrants 76 and 78 synchronized.

The quadrants 76 and 78 are in turn coupled to the carriages 16 and 18 to support the front end of the seat frame members 22 and 24 by a pair of support pins 86 fixedly attached to the quadrants. The support pins 86 ext arcuate slots 66 formed in the seat frame mounting members 22 and 24 and are journalled to a corresponding pair of mounting brackets 72 mounted for slidable movement along the carriages 16 and 18. As best shown in FIG. 5, the mounting brackets 72 are configured so as to form an internal rectangular-shaped channel 84 that is adapted to receive the carriages 16 and 18 to accommodate relative sliding movement therebetween along the longitudinal axes of the carriages 16 and 18. The length of the mounting brackets 72 is sufficient to prevent binding between the brackets and the carriages 16 and 18. The support pins 86 are journalled through bores 68 formed in raised portions 70 of the mounting brackets 72 and are rotationally secured therein by fasteners 88. The mounting brackets 72 in the preferred embodiment are made from a strong dimensionally stable. polymeric material, such as nylon, to reduce the sliding friction between the mounting brackets 72 and the carriages and also to minimize the amount of noise generated thereby. In addition, the raised portions 70 of the mounting brackets 72 are preferably reinforced with integral ribs 75 (FIGS. 6-8) to enable the mounting brackets to withstand the torque loading imposed thereon when a seat occupant leans backward against the seat back.

The vertical adjustment assembly 26 further includes a handle 90 fixably secured to the torsion bar 42. The torsion bar 42 is journalled for rotational movement to the seat frame members 22 and 24. A pair of locking pawls 92 and 94 is also fixably secured to the torsion bar 42 and is adapted to pivot when the handle 90 is raised. The locking pawls 92 and 94 include apertures 96 for receiving and engaging the teeth 81 on the quadrants 76 and 78. Also, a helical spring 98 provides a biasing force against the handle 90 to return the handle 90 to its original position. The spring 98 is coupled between the seat frame member 22 and torsion bar 42 by flanges 100 and 102, respectively.

The vertical adjustment mechanism 26 functions as follows. When the handle 90 is pulled in an upward direction against the bias of spring 98, the locking pawls 92 and 94 are released, thereby disengaging apertures 96 from the teeth 81 of quadrants 76 and 78 as seen in phantom in FIG. 2. With the locking pawls 92 and 94 disengaged from teeth 81, the seat frame members 22 and 24 are free to move vertically, either up or down, with respect to the carriages 16 and 18 (See FIGS. 6-8).

For discussion purposes and to illustrate the vertical movement of the seat frame members. FIG. 6 illustrates the seat frame member 24 in a first or down position. FIG. 7 illustrates the seat frame member 24 in a second or intermediate position, and FIG. 8 illustrates the seat frame member 24 in a third or up position.

As the seat frame members 2? and 24 begin to move vertically from the down position in FIG. 6 to the up position shown in FIG. 8, the pivot points of the quadrants 76 and 78 are also raised. This movement causes the quadrants 76 and 78 to rotate due to the fact that the quadrants 76 and 78 are tied at a point radially spaced from their pivot points to the mounting brackets 72 by the support pins 86. It will be noted, however, that as the quadrants 76 and 78 rotate with the upward movement of the seat frame members 22 and 24, the support pins 86 are displaced initially in a forward direction, as illustrated in FIG. 7, and thereafter in a rearward direction, as shown in FIG. 8. This horizontal displacement of the support pins 86 is accommodated by the slidable connection between the mounting brackets 72 and the carriages 16 and 18. Upon attaining the desired seat height position, the handle 90 is released and the locking pawls 92 and 94 re-engage the teeth on the quadrants 76 and 78 to lock the seat in position.

Thus, it will be appreciated that by tying the support pins 86 directly to the quadrants 76 and 78, the quadrants 76 and 78 serve not only to secure the selected vertical position of the seat, but also function as lift links to raise and lower the seat frame 22 and 24. Moreover, it will further be appreciated that the present invention is designed to operate smoothly and quietly with a minimum of effort. In this regard, it is further to be noted that the present invention preferably includes plastic bushings at the pivot points of the torsion bar 80 and latch handles 38 and 90 to reduce noise and enhance ease of operation.

While the above description constitutes the preferred embodiment of the invention, it will be appreciated that the invention is susceptible to modification, variation, and change without departing from the proper scope or fair meaning of the accompanying claims.