GB2120093A

GB2120093A - Double latch adjustable seat assembly

Info

Publication number: GB2120093A
Application number: GB08313967A
Authority: GB
Inventors: Randall T Murphy; Ernest L Peterson
Original assignee: Lear Siegler Inc
Current assignee: Lear Siegler Inc
Priority date: 1982-05-20
Filing date: 1983-05-20
Publication date: 1983-11-30
Also published as: AU1179283A; FR2527062A1; JPS58206428A; GB8313967D0; DE3316173A1

Abstract

Means for independently adjusting the height of the front and rear of a vehicle seat includes a pair of sector-shaped toothed (30, 36) lever arms (20, 22) pivoted (23, 31, 28, 35) to a base (10) and to a seat support (12); a pair of pivoted (42, 45) toothed (44, 50) latch plates (40, 46); and a pair of biased (64) pivoted (53, 55) camming plates (49, 51) for selectively locking the latch plates to the lever arms. A pivotal (54) control link (52) is operable by way of an actuator mechanism (66) to selectively disengage the camming plates from the latch plates for, in turn, selectively disengaging the latch plates from the associated lever arms. The lever arms (20, 22) and a second pair of opposite lever arms are interconnected by torsion bars for synchronous operation. <IMAGE>

Description

SPECIFICATION Double latch adjustable seat assembly This invention relates to automotive seat assemblies and more particularly to automotive seat assemblies in which the front and rear of a seat support are independently adjustable in elevation relative to the base.

The prior art discloses manually adjustable seat assemblies in which the front and rear of a seat support member are independently adjustable in elevation relative to a base. Forexample,the U.S.

Patent of Posh, 3,460,793 discloses an assembly in which a base and a seat support member are interconnected by at least one pair of lever arms which are pivotally connected to both the base and seat support member at longitudinally spaced points, such thatthe angular disposition of each lever arm adjusts the elevation between either the front or rear portion ofthe seat support relative to the base. The lever arms are latchable in desired angular dispositions by means of a latch assembly, including a pairofsubstantially horizontal latch plates which are pivotable about a substantially vertical axis to selectively engage notches in the inward ends ofthe lever arms. A control arm is interconnected with the latch plates to permit the latch plates to be selectively disengaged from the associated lever arms.

Likewise, the U.S. Patent of Homier et al 3,692,271 discloses a seat assembly having at least one pair of lever arms which are pivotally interconnected between a base and a seat support and which extend inwardlytoward each other,togetherwith a pair of latch plates which are pivotally connected to the seat supportfor rotation about axestranverse of the base and selectivelyengageablewith the inwardlyextend- ing ends of the lever arms to permit rotation thereof when engaged.A control link is pivotallyconnected to the seat support and is connected through lost motion connections to the latch plate such that rotation of the control link aboutthe transverse axis causes one or the other of the latch plates to pivot aboutthe transverse axis to effect a disengagement of one of the latch plates from the associated lever arm. The lever arms are provided with tapered notches or slots and each latch plate is provided with a tooth which fits into the notches such that rotation of the latch plate withdraws the tooth from the tapered slot.

In the U.S. Patent of Robinson 3,669,398 there is disclosed an adjustable seat assembly having two sets of levers on each side of the assembly. Control links and latching plates are secured on opposite sides of the seat assemblyforselectively allowing the levers to pivot to thereby adjust the vertical position of seat support members. Atorsion bar is connected to the levers atthe rear ofthe assembly. The torsion bar urgesthe rear levers to pivot in a manner two raise the rear portion of the seat support members.

Other seat assemblies generally ofthetypetowhich this invention relates are disclosed by the U.S Patents of Robinson et al 3,662,984, Holdampf et al 3,572,624, Heyl Jr.3,109,622, Posh 3,181,831, Robinson 3,405,900 and Homier 3,055,627.

An object ofthe present invention is to provide an improved adjustable seat assembly including a latch mechanism which is simple in fabrication, assembly and operation, and which produces a large amount of frictional resistance when engaged and a small amount of frictional resistance when disengaged.

Another object ofthis invention is to provide an improved adjustable seat assembly including a latch mechanism which is light-weight and has moving parts, yet at the same time hasthe required strength and locking abilityto provideefficientoperation of the seat assembly.

Afurther object of the invention isto provide an improved adjustable seat assembly including a latch mechanism which is relatively easy to adjust.

In carrying out the above objects and other objects of this invention, an adjustable seat assembly constructed in accordance with the present invention includes a base, a seat support, and first and second sector-shaped lever arms, each being pivotal ly connected at one end ofthe base for rotation about an axis transverse the base. The other ends ofthe lever arms extend inwardlytoward each other. Atransverse rod means pivotally connects each ofthefirst and second lever arms at points mediate the ends thereof to the seat support at longitudinally spaced points along the seat supportfor independently adjusting the elevation between the spaced points and the base by rotation of the lever arms.First and second latch plates are pivotally connected to the seat support for rotation about respective transverse axes and are selectively engageable with the other ends of the first and second lever arms respectively to prevent rotation thereof when engaged. First and second camming plates are pivotally connected to the seat supportfor rotation about respective transverse axes at points mediate the ends thereof and are selectively engageablewith the first and second latch plates respectivelyto positively lockthe first and second latch plates to the first and second lever arms, respectively. A single control link is pivotally connected to the seat support and has lost motion connections to the first and second camming plates.An actuator is connected to the control linkfor pivoting the control link to selectively disengage both ofthe latch plates from the lever arms. The other ends ofthe lever arms each have formed thereon a first plurality of teeth and the latch plates each have formed thereon a second plurality of teeth which are selectively engageable with any first plurality of the second plurality ofteeth on the associated lever arm.

Each of the first and second lever arms may be latched inthethird plurality of angulardispositions.

Preferably, the first and second lever arms are disposed adjacent one side ofthe base and third and fourth lever arms are disposed adjacentthe other side of the base in laterally corresponding relationship to thefirstand second lever arms. Each of the third and fourth lever arms are pivotally connected at one end of the base for rotation about the transverse axes.

Preloaded first and second torque members connect the first and second lever arms to the third and fourth lever arms, respectively, for synchronizing rotation thereof Also preferably, spring counterbalancing means is connected to the second torque memberfor counter balancing rotation ofthe second torque member.

The objects, features and advantages of the present invention are readily apparentfrom the following detailed description ofthe best mode when taken in connection with the accompanying drawings FIGURE lisa side view of an illustrative embodi mentoftheinvention in a lowered position; FIGURE 2 is a side view of the assembly of FIGURE 1 in a raised position; and FIGURE 3 is a plan view ofthe illustrative embodiment.

Referring to FIGURES 1 through 3 ofthe drawings, the illustrated adjusted seat assembly comprises a base or base portion 10 which is adapted to be mounted on the floor 11 of a vehicle. A seat support 12 carries a seat 14 having a backrest portion 16. The elevation between the front and rear portions of the seat support 12 and the base 10 are adjustable by means of an adjuster mechanism 18 which is disposed between the base 10 and the seat support 12.

The adjuster mechanism 18 includes a pair of sectorially-shaped lever arms 20 and 22. The lever arm 20 has a narrow outer end thereof connected to the base 10 by a pin or rivet 23 through a bent mounting bracket24having a groove 25formed therein and receiving the pin 23 to permit angular displacement of the lever arm 20 relative to the base 10 about an axis transversethe base 10. The lever arm 20 is independently pivotally connected at 28 by a pin 29 as shown in FIGURE 3to the seat support 12. The arcuate inwardlyfacing end ofthe lever arm 20 has formed thereon a plurality of teeth 30, preferably fifteen in number,which permitthe lever arm 20 to be latched in any one of a plurality of angular dispositions relative to the base 10.

Similarly, the lever arm 22 is pivotally connected at its outerendtothe base10 bya pin orrivet31 through a bent mounting bracket 32 having a groove 33 formed therein and receiving the pin 31. The lever arm 22 is also independently pivotally connected to the seat support 12 at35 by a pivot or pin 34, as shown in FIGURE 3. The lever arm 22 has formed on its arcuate, inwardlyfacing end thereof a plurality ofteeth 36 which correspond to the teeth 30 in the lever arm 20.

Each ofthe lever arms 20 and 22 carries a pin 37 mediate their respective pivots 28 and 35 and their arcuate inwardlyfacing ends. The pins 37 extend through the leverarms 20 and 22 and travel in arcuate grooves (not shown)formed in the side of the seat support 12 in order to stabilize and limit the motion of the lever arms 20 and 22 relative to their associated latch plates which will be described in greater detail hereinbelow.

Pivotal connections between the lever arms 20 and 22 and the seat support 12 are longitudinally spaced apart. Accordingly, the lever arm 20 controls the elevation ofthe front of the seat.support 12 and the lever arm 22 controlsthe elevation ofthe rear of the seat support 12.

To latch the lever arm 20 in a desired angular disposition, a latch plate 40 is connected by a rivet42 to the seatsupport 12 for angular rotation about an axis which is also transverseto the base 1 O The latch plate 40 has formed thereon a plurality ofteeth 44, preferably five in number, which are adapted to engage or mesh with any of a like plurality ofteeth on the lever arm 20.

A similar latch plate 46 is pivotally connected at 45 to the seat support 12 to permit angular rotation about a horizontal transverse axis. The latch plate 46 carries five teeth 50 which are adapted to engage any set of teeth 36, in the lever arm 22to prevent rotation of the leverarm 22 when so engaged. Preferably, the teeth 30 and 36 have a taper of approximately 55" and the spaced between the teeth have an angle of approximately 60 to permitthe teeth 44 and 50 to be easily withdrawn from the teeth 30 and 36 respectively, when disengagement between the particular leverarm-latch plate combination is desired.

By providing five latching teeth on the latch plates the amount of surface area performing the latching function is substantially increased to ensure a positive lock between the latch plates and the lever arms.

Engagement between the latch plates 40 and 46 and the corresponding lever arms 20 and 22 respectively, is positively secured bycamming plates 49 and 51 respectively. The camming plate 49 is pivotally connected at 53to the seat support 12 for rotation about a transverse axis. Similarly, the camming plate 51 is pivotally connected at 55 to the seat support 12 for rotation about a transverse axis spaced apart from the transverse axis at 53.

Each ofthe latch plates 40 and 46 includes a pair of spaced apa rtfingers 57 and 59 for receiving an end of its corresponding camming plate. Sliding engagement ofthe camming plates 49 and 51 with the corresponding fingers 57 results in unlatching,where- as sliding engagement ofthe camming plates 49 and 51 with their corresponding fingers 59 results in latching.

Engagement between the latch plates 40 and 46,the lever arms 20 and 22 and the camming plates 49 and 51, respectively, is controlled by means of a flat control link 52 which is pivotally connected at 54tothe seat support 12, also for rotation about a transverse axis. The control link 52 has formed thereon a pair of outwardly extending, elongated arms 56 and 58for engaging the camming plates 49 and 51, respectively.

A rivet 60 is carried bythe control link 52 to form a pivotal connection betweenthecontrol link52and one end of an actuator arm 66 which will be described in greater detail hereinafter.

As best shown in FIGURE 3, the camming plates 49 and 51 include bent arms 63 and 65,respectively, which extend upwardly and inwardly from the corres- ponding pivots 53 and 55. An extension spring 64 has its terminal ends in engagementwith the arms 63 and 65 so asto urge the camming plates into engagement with the corresponding fingers 59 ofthe latch plates 40 and 46. Consequently, the latch plates 40 and 46 are urged outwardly away from one another and into engagement with their associated lever arms. Rota tionofthecontrol link52 in one direction about pivot 54 tends to rotate one of the camming plates about its transverse axis and cam the finger 57 of its associated latch plate to, in turn, disengage the latch plate from its associated lever arm. Atthe same time, the other camming plate remains in engagementwiththefinger 59 of its latch plate to, in turn, remain in engagement with its associated lever arm. The pivotal motion of the control link 52 is determined by operator control of theactuatorarm 66 which is also pivotally connected bythe rivet42to the seat support 12 and which extendsoutwardlyand upwardlyfrom the adjuster mechanism 18 to provide access thereto by an occupant ofthe seat 14. The inward end ofthe actuator arm 66 alternately rotates the control link 52 in opposite directions about the pivot 54 upon pivotal movement ofthe arm 66 about the pivotal connection provided bythe rivet 42.

During operation ofthe assembly shown in FI GURES 1 through 3, the adjuster mechanism 18 permits independent adjustment ofthe front and rear elevation ofthe seat support 12 relative to the base 10.

The seat support 12 is adjustable between the lowered elevation position shown in FIGURE 1,andthe raised elevation position shown in FIGURE 2. To permit this adjustment, the actuator arm 66 may be first rotated counter-clockwise about the rivet 42, for example, causing the control link 52 to rotate clockwise about the pivot 54to thereby disengage the biasedcamming plate 49 to, in turn, cam the finger 57 of the latch plate 40, to rotate the latch plate 40 out of engagement with the lever arm 20 by withdrawing the teeth 44 from an upper set of teeth 30 on the lever arm 20. The lever arm 20 is thus free to pivot about the mounting bracket 24 bythe pin and groove combination, thus permitting the front of the seat support 12 to be raised with the assistance of a front torsion rod 70 which is described in greater detail hereinbelow.The occupant of the seat may also assist in this operation simply by leaning back on the backrest portion 16.

After the seat support 12 is placed in the desired elevation relative to the base 10, the actuator arm 66 is released and the spring 64 urges the camming plate 49 to cam againstthe finger 59 and, consequently, the latch plate 40 is cammed outwardly into engagement with the duly selected set ofteeth on the lever arm 20 and, the mechanism 18 is again latched, for example, as shown in FIGURE 2.

Counterclockwise rotation ofthe actuator arm 66 aboutthe rivet 42 does notaffectthe engagement between the latch plate 46 and the lever arm 22 because of the lost motion connection between the control link 52 and the camming plate 51. A clockwise rotation ofthe actuator arm 66 performs a correspond ing function to permitthe rear ofthe seat support 12 to be raised or lowered as desired with the assistance of a reartorsion rod 72 which is described in greater detail hereinbelow. The occupant of the seat may also assist in this operation by leaning forward on the seat 14 As shown in FIGURE 3, a second adjuster mechan ism 18' is disposed on the laterally opposite side if the seat support 12 from the adjuster mechanism 18.

The adjuster mechanism 18' includes a second pair of lever arms 20' and 22' having the outer ends pivotally connected to a base portion 10' by mounting brackets 24' and 32'. The mediate portion of the lever arms 20' and 22' are pivotally connected to the opposite side of the seat support 12 by pins 29' and 34'. To synchronize the operation of the adjuster mechanism 18 and 18', the lever arms 20 and 20' are interconnected by means of a rod-like torque member orfronttorsion rod 70 which extends transversely between the lever arms 20 and 20'. The torsion rod 70 may be welded or otherwise suitably secured to the lever arms 20 and 20' and pivotally mounted on the pins 28 and 28' to permit the pivotal connection 28 as previously described at both sides ofthe seat support 12.

Similarly, the lever arms 22 and 22' and pins 34 and 34' are similarly interconnected by means of a similar torque member or rear torsion rod 72.

Accordingly, rotation ofthe actuator arm 66 to pivot the control link 52, causes thecamming plates 49 and 51 todisengagetheircorresponding latch plates and, consequently, the lever arms on both sides of the apparatus shown in FIGURE 3 rotate. Upward rotation ofthe lever arms 22 and 22' are assisted by the torsion rod 72 which is preloaded.

Mounted on the torsion rod 72 are a pair of spaced apart spring maintaining arms of spring hangers 74 and 76. Opposite ends of torsion springs 78 and 80 are mounted on the hangers 74 and 76, and mounting brackets 75 and 77 fixedly mounted on opposite sides of the seat support 12 near the front of the seat. The springs 78 and 80 counterbalance rotation ofthe torsion rod 72 that the seat assembly, and particularly the rear ofthe seat assembly, can be vertically adjusted in a smooth and efficientfashion.

While not shown, the base portions 10 and 10' may be provided with track meansto provide longitudinal adjustment of the seat support 12 relative to the floor 11 of the vehicle on which it is mounted. Suitable low-friction bearing material may be disposed between upper and lowertrack members to facilitate longitudinal sliding therebetween.

In summary, the invention has been described with reference to an automotive vehicle seat assembly in which the front and rear portions of a seat support may be independently adjusted to an elevation relative to a seat base by selective operation of a single actuator arm which serves to latch and unlatch the mechanisms which support the seat relative to a base.

Moreover, the seat assembly may be longitudinally adjustable by means oftrackswhich are mounted on a vehicle seat.

While a preferred embodiment of the adjustable seat assembly has been shown and described herein in detail,those skilled in this art will recognize various alternative designs and em bodiments for practicing the present invention as defined by the following

Claims

claims. CLAIMS

1. An adjustable seat assembly comprising: a base; a seat support; first and second sector-shaped lever arms, each being pivotallyconnected at one end to the base for rotation about an axis transverse the base, the other ends ofthe lever arms extending inwardly toward each other; transverse rod means pivotally connecting each of the first and second lever arms at points mediate the endsthereoftotheseatsupportat longitudinally spaced points along the seat support for independently adjusting the elevation between said spaced points and the base by rotation ofthe lever arms; first and second latch plates pivotally connected to the seat support for rotation about respective transverse axes and selectively engageable with the other ends of the first and second lever arms respectively to prevent rotation thereof when engaged;; first and second camming plates pivotally connected to the seat supportfor rotation about respective transverse axes at points mediate the ends thereof and selectively engageable with the first and second latch plates respectively to positively lock the first and second latch plates to the first and second lever arms repectively; a single control link pivotally connected to the seat support and slidably connected to the first and second camming plates; and an actuator mechanism connected to the control link for pivoting thecontrol link to selectively disengage both of the latch plates from the lever arms,the other ends ofthe lever arms each having formed thereon a first plurality of teeth and the latch plates each having formed thereon a second plurality of teeth which are selectively engageable with any first pluralityofthesecond plurality of teeth on the associated lever arm whereby each ofthe first and second lever arms may be latched in a third plurality of angular dispositions.

2. The assembly as claimed in claim 1 including spring means biasing the camming plates into engagementwith the latch plates to positively lockthe latch plates with the leverarms.

3. The asssembly as claimed in claim 1 wherein the control link pivots about a transverse axis and wherein the transverse axes ofthe camming plates are disposed in a plane spaced above the transverse axis ofthecontrol link.

4. The assembly as claimed in claim 2 wherein each of said camming plates includes an arm extending therefrom, said arms being spaced apart, and wherein said spring biasing means interconnects the arms ofthe camming plates for urging the camming plates to cam the teeth of said latch plates into locking engagement with said teeth of said first and second levers.

5. The assembly as claimed in claim 1 wherein each of said first and second latch plates includes a pair of spaced apartfingersforreceiving one end of its respective camming plate, said camming plates camming the latch plates during rotation thereof.

6. The assembly as claimed in claims 1,2,3,4 or 5 wherein the lever arms are disposed adjacent one side of the base and the assemblyfurther includes third and fourth lever arms disposed adjacent the other side ofthe base in laterally corresponding relationship to thefirstand second lever arms, each of the third and fourth lever arms being pivotallyconnected atone end to the base for rotation aboutthe transverse axes, the other ends ofthe lever arms extending inwardly toward one another, means pivotally connecting each ofthethird and fourth lever arms to the seat support at longitudinally spaced points along the seat support for independently adjusting the elevation between said spaced points and the base by rotation ofthe lever arms andfirst and second torque members connecting the first and second lever arms to thethird and fourth lever arms respectively for synchronizing rotation thereof.

7. The assembly as claimed in claim 6 further including spring couterbalancing means connected to said secondtorque memberforcounterbalancing rotation of said second torque member.

8. An adjustable seat assembly comprising: a base; a seat support; first and second sector-shaped lever arms, each being pivotallyconnected at one end to the base for rotation about an axis transverse the base, the other ends ofthe lever arms extending inwardlytoward each other; transverse rod means pivotally connecting each of the first and second lever arms at points mediatethe ends thereoftothe seat supportat longitudinally spaced points along the seat supportforindependently adjusting the elevation between said spaced points and the base by rotation ofthe lever arms;; first and second latch plates pivotally connected to the seat supportfor rotation about respective transverse axes and selectively engageable with the other ends of the first and second lever arms respectively to prevent rotation thereof when engaged; first and second camming plates pivotallycon- nected to the seat supportfor rotation about respec tiveaxesatpoints mediate the ends thereof and selectively engageable with the first and second latch plates respectively to positively lock the first and second latch plates to the first and second lever arms respectively; wherein each ofsaid camming plates includes an arm extending therefrom, said arms being spaced apart; a single control link pivotallyconnected to the seat support and slidably connected to the first and second camming plates; and an actuator mechanism connected to the control linkfor pivoting the control link to selectively disengage both ofthe latch plates from the lever arms, the other ends ofthe lever arms each having formed thereon a first plurality of teeth and the latch plates each havinng formed thereon a second plurality of teeth which are selectively engageable with any first plurality ofthe second plurality of teeth on the associated lever arm whereby each ofthe first and second lever arms may be latched in a third plurality of angulardispositons; and spring biasing means interconnecting the arms of the camming platesfor urging the camming plates to cam the teeth of said latch plates into locking engagement with the teeth of said first and second levers.

9. An adjustable seat assembly comprising: a base; aseatsupport; first and second sector-shaped lever arms, each being pivotally connected at one end tothe basefor rotation about an axis transverse the base, the other endsoftheleverarmsextennding inwardlytoward each other, wherein the lever arms are disposed adjacent one side of the base; third andfourth lever arms disposed adjacentthe other side of the base in laterally corresponding relationship to thefirst and second leverarms, each of the third and fourth lever arms being pivotally connected at one end to the base for rotation about the transverse axes, the other ends of the lever arms extending inwardly toward one another;; means pivotally connecting each ofthethird and fourth lever arms to the seat support at longitudinally spaced points along the seat supportfor independently adjusting the elevation between said spaced points and the base by rotation of the lever arms; torque members connecting the first and second lever arms to the third and fourth lever arms respectively for synchronizing rotation thereof; transverse rod means pivotally connecting each of the first and second lever arms at points mediate the ends thereof to the seat support at longitudinally spaced points along the seatsupportfor independently adjusting the elevation between said spaced points and the base by rotation ofthe first and second lever arms;; first and second latch plates pivotally connected to the seat supportfor rotation about respective transverse axes and selectively engageable with the other ends ofthefirst and second lever arms respectively to prevent rotation thereof when engaged; spring means biasing the camming plates into engagement with the latch plates to positively lock the latch plates with the first and second lever arms; first and second camming plates pivotally connected to the seat support for rotation about respective transverse axes at points mediate the ends thereof and selectively engageable with the first and second latch plates respectively to positively lockthe first and second latch plates to thefirstand second lever arms respectively;; a single control link pivotally connected to the seat support and slidably connected to the first and second camming plates; and an actuatormechan:-sm connected to the control linkfor pivoting the control linkto selectively disen gage both ofthe latch platesfromtheflrstandsecond lever arms; the other ends of the first and second lever arms each having formed thereon a first plurality of teeth and the latch plates each having formed thereon a second plurality of teeth which are selectively engageablewith any first plurality ofthe second plurality of teeth on the associated lever arm whereby each ofthefirst and second lever arms may be latched in a third plurality of angular dispositions.

10. Theassemblyasclaimedinclaim9further includinng spring counterbalancing means connected to said second torque memberfor counterbalancing rotation of said second torque member.

11. An adjustable seat assembly substantially as herein described and shown in the accompanying drawings.