GB2041065A - Reclining and emergency latch mechanism for vehicle seats - Google Patents

Abstract

In a latch mechanism for controlling movement of a pivoted vehicle seat back under all operating conditions of the vehicle, the seat back is pivotable about a pivot pin (16) rearwardly to a reclining position and forwardly to facilitate entry to the rear seat of the vehicle. A clutch quadrant (24) is also mounted on the pivot pin and is used to control the adjusted position of the seat back. A spring loaded latch (18) latches the seat back at any desired reclining position. A normally locked inertia or emergency latch (40, 54, 56) is provided to maintain the seat back in the locked condition relative to the sear cushion during normal vehicle operation as well as upon deceleration of the vehicle yet automatically opens to provide for forward pivoting movement of the seat back when the vehicle is in the static condition. <IMAGE>

Description

SPECIFICATION Reclining and emergency latch mechanism for vehicle seats The present invention relates to a latch mechanism for controlling pivoting of a seat back of a vehicle seat.

Seats having reclining backs are increasingly popular in motor vehicles. When such seats are employed in two door motor vehicles, the latch mechanism therefore preferably latches the seat back against both undesired rearward and undesired forward pivotal movement relative to the seat cushion.

With respect to reclining movement, manually operated reclining latch mechanisms for holding the seat back in a desired reclining position are known. However, such manually operated latches are generally unsatisfactory in that they latch only at relatively widely spaced incremental reclining positions or, if infinitely adjustable, are heavy and cumbersome and relatively expensive. To overcome this situation, the reclining latch mechanism of the instant invention is substantially infinitely adjustable and of simple and inexpensive construction.

With respective to forward pivotal movement of the seat back, normally open emergency latches have been heretofore proposed which latch upon rapid decleration of the vehicle. See, for example, U.S. Patent No.

4,010,979. Preferably, however, the emergency latch for the seat back is normally latched so as to eliminate the time lag between the advent of deceleration and lockup.

It also desirable to provide means to both automatically and manually open the emergency latch to permit forward movement of the seat back to facilitate entry to or exit from the back seat of the vehicle.

According to the present invention, there is provided a latch mechanism for controlling pivoting of a vehicle seat back relative to a vehicle seat cushion, said mechanism comprising: a pivot pin joining said seat cushion and seat back for relative rotation; a clutch quadrant supported by said pivot pin for rotation relative to both said seat cushion and seat back; means adjacent said seat cushion for controlling rotation of said clutch quadrant relative to said seat cushion comprising a pair of releasable infinitely adjustable dogs having biting edges engageable with said clutch quadrant; a manual release handle extending generally normal to the axis of rotation of said seat back and clutch quadrant; cam means on said release handle engageable with said dogs to bias said dogs to an open condition; and means on said seat back for controlling rotation of said seat back relative to said clutch quadrant.

The invention will be further described with reference to the accompanying drawings, in which: Figure 1 is a schematic side elevational view of a vehicle seat incorporating an embodiment of the present invention; Figure 2 is an enlarged side elevational view of the seat shown in Fig. 1 with the seat cover and other portions removed to show the details of the latch mechanism; Figure 3 is a side elevational view, similar to Fig. 2, showing the seat back in the fully reclined position; Figure 4 is a side elevational view, similar to Fig. 2, showing the seat back in the forwardmost condition to facilitate access to or exit from the rear seat of a vehicle; Figure 5 is a side elevational view, similar to Fig. 2, showing the seat back in the latched condition due to vehicle deceleration;; Figure 6 is a side elevational view, similar to Fig. 2, showing the inertia latch biased to the release position by the manual release; Figure 7 is a view taken in the direction of the arrow "7" of Fig. 2; Figure 8 is a view taken generally along the line 8-8 of Fig. 2; Figure 9 is a view taken generally along the line 9-9 of Fig. 2.

Referring to the drawings, Fig. 1 shows, in schematic fashion, a vehicle seat assembly 10, incorporating a latch mechanism in accordance with the present invention. The seat assembly 10 is of the "bucket" type conventionally found in the front seat of two-door motor vehicles and comprises a seat cushion 1 2 and a seat back 14. The seat back 1 4 is supported for pivotal movement relative to the seat cushion 1 2 as by a pin 1 6 so as to permit the seat back 14 to be folded forwardly to provide access to the rear seat of the associated vehicle as weil as to be folded rearwardly to a desired reclining position.A latch mechanism, indicated generally by the reference numeral 18, is provided for controlling reclining movement of the seat back 14, for preventing forward pivotal movement of the seat back 14 due to sudden vehicle deceleration and for accommodating desired forward movement of the seat back 1 4.

In Figs. 2 through 9, the upholstery of the seat cushion 1 2 and seat back 1 4 have been omitted and only the structural components necessary to an understanding of the invention have been illustrated.

Affixed to the frame of the seat cushion 1 2 is a seat cushion bracket 22, which pivotally supports a clutch quadrant 24 by means of the pivot pin 1 6. The clutch quadrant 24 is pivotally supported by the pin 1 6 for rotation relative to the seat cushion bracket 22 as well as to a seat back bracket 26. Clockwise or reclining rotation of the quadrant 24 relative to the seat cushion bracket 22 is stopped after a predetermined angular displacement by engagement of a pin 27 therein with the end portion of an arcuate slot 28 in the bracket 22. Counterclockwise rotation of the quadrant 24 relative to the seat cushion bracket is stopped by engagement of a shoulder 29 on the quadrant 24 with a flange 30 on the bracket 22.

Clockwise rotation of the seat back bracket 26 relative to the quadrant 24 is stopped by engagement of the bracket 26 with a pin 31 in the quadrant 24. Counterclockwise rotation of the seat back bracket 26 is normally limited by engagement of the bracket 26 with a flange 32 on the bracket 22.

The latch mechanism 1 8 comprises an inertia member cage 40 formed of, for example, plastics or the like. The cage 40 is supported for rotation relative to the seat back bracket 26 by a pivot pin 42. The inertia member cage 40 carries a transversely extending latch pin 44 that is adapted to cooperate with a shoulder 46 on the quadrant 24 and the edges of an arcuate slot 48 in the seat back bracket 26 to limit forward rotation of the seat back 14 upon rapid deceleration of the vehicle. It is to be noted that the pin 44 extends across two spaced portions 26a and 26b, of seat back bracket 26 (Fig 7), so that no load is placed on the inertia member cage 40.

The inertia member cage 40 is formed with an internal track 54 for the acceptance of a generally disc-shaped inertia member 56 which is rollable therealong, as will be described.

Fig. 2 shows the latch mechanism 1 8 in its normal or latched and upright condition denoted by the full line condition "C" in Fig. 1.

In this condition, the inertia member 56 is positioned to the right of the pivot pin 42 that supports the cage 40 in which position the weight of the inertia member 56 causes the inertia member cage 40 to be biased clockwise about the pin 42. However, rotation of the inertia member cage 40 is limited by engagement of a boss or shoulder 58 thereon with an abutment 60 on the quadrant 24 thereby normally maintaining the pin 44 in alignment with the shoulder 46 on the clutch quadrant 24 so as to be engageable therewith.

As best seen by comparing Figs. 2 and 5, if an associated vehicle decelerates suddenly or is driven rearwardly, as might occur when a standing vehicle is struck headon by a vehicle travelling in the opposite direction, the inertia member 56 rolls along the track 54 effecting a counterclockwise bias on the inertia member cage 40 thereby holding the pin 44 at the lower end of the track 48 so that it is maintained in a position to engage the shoulder 46 on the quadrant 24.Thus, when the vehicle is subject to a deceleration force, forward pivotal movement of the seat back 14 relative to the clutch quadrant 24 and seat cushion bracket 22 about the pivot pin 1 6 is stopped at the broken line position "B" of Fig. 1, assuming the quadrant 24 is latched relative to the bracket 22 in the position shown in Fig. 2 The inertia member cage 40 is positively held in the aforesaid latched position until deceleration ceases and the inertia member 56 returns to the position shown in Fig. 2.It is to be noted that while the bias on the inertia member cage 40 reverses when the seat back 1 4 moves from the "C" position to the "B" position of Fig. 1, the pin 44 on the inertia member cage 40 is maintained in the locked position shown in Fig. 2, due either to engagement of the boss 58 thereon with the abutment 60 on the clutch quadrant 24 or the weight transfer due to movement of the inertia member 56. Thus, the seat back 14 is normally maintained in the latched condition.

Stated in another manner, the pin 44 does not have to move to a latched position in order to effect locking of the seat back 14 relative to the seat 1 2 upon the occurrence of deceleration of the vehicle.

As best seen in Fig. 6, when the vehicle is in the static condition, or is not subject to deceleration forces, and it is desired to move the seat back 14 forward relative to the seat 1 2 to the broken line position "A" in Fig. 1, thereby to facilitate access to the rear seat of the vehicle, the first increment of rotation of the seat back 14 from the "C" position towards the "B" position of Fig. 1, permits the inertia member cage 40 to rotate clockwise, as seen in Fig. 6 of the drawings, under the clockwise bias of the inertia member 56. When the cage 40 rotates clockwise, the pin 44 is raised within the track 48 in the bracket 26 so as to clear the shoulder 46 on the quadrant 24 permitting the seat back 14 to be pivoted forwardly to the "A" position.

Thus, the pin 44 is automatically moved out of the normal or latched condition to accommodate forward movement of the seat back 14 but only when there are no deceleration forces operative on the vehicle. At this time the inertia member 56 is at the right or lowermost portion of its track 56 and exerting a clockwise bias on the inertia member cage 40.

The foregoing description of operation of the inertia locking portion of the latch mechanism 1 8 presupposes positive positioning of the quadrant 24 relative to the seat cushion bracket 22 and seat 12.

An emergency release lever 62 is supported for rotation by the pin 1 6. In the event of vehicle upset, at which time the normal clockwise bias on the inertia member 56 on the cage 40 might reverse, counterclockwise rotation of the release lever 62 brings a cam surface 64 thereof into engagement with the pin 44 so as to bias it upwardly and condition the seat back 14 for forward movement. The release lever 62 is normally biased to the position shown in Fig, 2 by a spring 66 which extends between a bracket 68 on the lever 62 and an aperture 70 on the bracket 26.

As best seen by comparing Figs. 2 and 3, provision for reclining movement of the seat back 14 is achieved by controlling movement of the quadrant 24 relative to the seat cushion bracket 22. As discussed hereinbefore, the end position "D" of clockwise movement of the seat back 14 relative to the quadrant 24 is defined by engagement of the pin 27 in the seat cushion bracket 22 with the end 28 of the slot in the quadrant 24. Concomitantly, rotation of the seat back bracket 26 relative to the quadrant 24 is limited by engagement of the pin 31 on the quadrant 24 with the bracket 26.

Latching of the seat back 14 at any desired reclining position intermediate the heretofore described end positions thereof, is achieved by latching of the quadrant 24 relative to the seat cushion bracket 22 and seat 1 2. As best seen in Fig. 8, a pair of dogs 80 and 82 are pivotally supported by a pin 83 on the seat cushion bracket 22. The dogs 80 and 82 have biting edge portions 86 and 88, respectively, which engage a face 89 of an arcuate segment 90 of the quadrant 24 in biting engagement. It is to be noted that the arcuate segment 90 of the quadrant 24 is backed up by the seat cushion bracket 22 which, in turn, is backed up by the pin 83 which supports the dogs 80 and 82. The pin 83 is journaled in a pair of ears 91 and 92 (Fig. 2) on the bracket 22.Thus, it will be seen that assembly for latching the quadrant 24 relative to the seat cushion bracket 22 is positively supported, relatively simple, and lightweight in construction. The dogs 80 and 82 are normally biased to the locked condition relative to the quadrant 24 by a spring 93 which extends between apertures 94 and 95 thereon, respectively.

As best seen in Fig. 8, the dog 80 has a cam portion 96 thereon which is engaged by a flange 97 on a manual operator 98. Similarly, a flange 100 on the operator 98 engages the dog 82. Thus, upon counterclockwise rotation of the operator 98 about a supporting pin 102, the dogs 80 and 82 are biased to an open condition relative to the arcuate segment 90 of the quadrant 24.

In operation, reclining movement of the seat back 14 is initiated by a downward push on a handle portion 104 of the operator 98 which effects release of the biting edges 86 and 88 on the dogs 80 and 82, respectively, from the face 89 of the arcuate segment 90 of the quadrant 24, conditioning the quadrant 24 for rotation relative to the bracket 22 about the supporting pin 1 6. Thereafter, a rearward push in the seat back 1 4 is transmitted to the quadrant 24 through the pin 31 thereon causing the quadrant 24 to rotate clockwise with the seat back 14 to a desired reclining position. Release of the operator 98 allows the biting edges 86 and 88 of the dogs 80 and 82 to re-engage the face 89 on the arcuate segment 90 of the quadrant 24 and lock the seat back 14 at a desired reclining position.

Forward movement of the seat back 14 is achieved by a similar procedure, movement of the seat back 14 being effected by a spring 106 that extends between a flange 108 on the seat bracket 22 and the pin 1 6 on the seat back bracket 26.

Claims (3)

1. A latch mechanism for controlling pivoting of a vehicle seat back relative to a vehicle seat cushion, said mechanism comprising: a pivot pin joining said seat cushion and seat back for relative rotation; a clutch quadrant supported by said pivot pin for rotation relative to both said seat cushion and seat back; means adjacent said seat cushion for controlling rotation of said clutch quadrant relative to said seat cushion comprising a pair of releasable infinitely adjustable dogs having biting edges engageable with said clutch quadrant; a manual release handle extending generally normal to the axis of rotation of said seat back and clutch quadrant; cam means on said release handle engageable with said dogs to bias said dogs to an open condition; and means on said seat back for controlling rotation of said seat back relative to said clutch quadrant.

2. A latch mechanism in accordance with claim 1 and including means on said seat back for releasing said controlling means thereon to permit rotation of said seat back to said seat cushion.

3. A latch mechanism constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.