CA1055380A - Adjustable vehicle seat providing pitch compensation - Google Patents

Abstract

VEHICLE SEAT

Abstract of the Disclosure An adjustable seat having air spring support and providing for pitch compensation and limitation, automatic maintenance of height adjustment, and rapid and economical back inclination adjustment.

Description

3 Bactc~round of the Invention l;

5, This invention relates to an improved seating assembly ~ for use in vehicles such as trucks and buses.
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8 The drivers of heavy vehicles who spend many hours 9 in them need seating that is both comfortable and is an aid to safety. They need seating that can be adjusted to their own 11 size and preferences and is adequately cushioned. Accordingly, 12 many sea~ing arrangements have been designed which enable fore-13 and-a~t adjustabi~ity, which provide a suitable cushioning 14 action to the seat, and which provide for adjustment of the back.
' 16 The present invention is an advance on these earlier 17 inventions and relates particularly to a seat which is supported ~8 upon an air spring and in which compressed air is used to adjust 19 the seat height.

2~ ' 21 It is very important that the adjustment of the seat 22- height be coupled with an arrange~ent for maintaining the seat 23 at the height to which it is set, even when the driver gets out 24 Of his seat or when he sits down rather heavily in ît. Some . .
- ~5 seats are so made that when the driver begins to get out of the 26 seat, the cushioning air forces the seat upwardly, making it 27 difficult for the driver to get out- and even more difficult for 28 him to get back in. The present invention is directed to solution - 29 of this problem.

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~ Another problem encountered with seats o~ this type . . . ~.
2 and relatively unsolved, for little attention has been given to

3 this problem, i~ that of response of the seat to pitch.
- '~ 4 - ~, In a passenger automobile, the passengers a~e ideally i~ -; ~ 6 located for riding comfort: low in the chassis and n~arly 7 midway between the axles. Vertical displacements of the wheels, ~ , 8 due to bumps, tend to induce vertical displacements of the ';- 9 passengers, and no pitch component is introduced. In a large - 10 truck, however, and especially in a cab-over-engine type of ~ 1 vehicle, the occupant is located high above the axles in a cab i' 12 that is supported on a rather narrow footing. As a result of ~ .
';: 13 this top-heavy arrangement, vertical displacements of the axles , . .
14 tend to i~duce horizontal displacements of ~he cab. In addition, ~ . ... ~
the long frame rails of a truck deflect considerably under load.
- . 16^ This up-and-down flexing of the frame rails provides one of the ; . -.
17 main vibratory inputs into the cab. As the rails flex, the front 1~ and rear othe cab move up and down unequally. Since the driver 19 is situated above the cab mounts, he senses a ore-aft vibration.

21 The end result of all t~is i$ that the driver experi-Z2 ences a persistent "backslap" from the seat. This can be 23 particularly bad even on apparently smooth roads such as freeways.
24 The even spacing of dividers between concrete slabs will often . . .
cause this kind of vibratory response in a vehicle, because a 26 resonance is created.
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28 The present in~ention provides or the seat to move 29 som~what under either forward or backward pitch in order to stay with the driver better about a position to which t~e ~ri~er has 31 set his normal position. However, as one leaves this centerpoint ~ . , , . . .

10553~0 1 1 in either direction the movement o the seat is opposed more and 2 more, so that there is a gradual but thorough snubbing o~ the 3 pitch within a desired distance. This is ~m important feature

4 in both driver comfort and safety.
6 The invention also provides for shoc~ absorptlon and 7 fsr the usual fore-and-aft adjustment of the seat.
9 One other problem to which the invention relates is that of providing rapid adjustment o the inclination of the 11 seat back without requiring a more expensive type of seat back.
12 This proble~ may be explained by noting that the back of the seat 13 may be supported by rather lighweight sheet me~al which is 14 i~capable of transmitting major forces. The inclination of the lS back should, however, be adjustable at one location, on either l& side of the seat, without having to adjust the two sides of 17 ~he back separately, which would be extremely undesirable. The 18 invention provides for this and does it with a novel structure 19 having several advantages, which will be explained in the text.
21 Summary of the Invention 22 The invention provides a vehicle seat for use in trucks, 23 buses and other similar vehicles, which affords proper reaction 2~ to pitch, provides for improved adjustment of the air spring and improved retention of the seat to any position to which it is set 26 whether the vehicle seat is occupied or not, and it also provides 27 ~or improved adjustment of the seat back.
28 ~ ' 29 A base assembly is adapted to be s~cured to the floor of the vehîcle. This base assembly includes a base plate and 31 aiso a vertical rear standa`rd havin~ a palr of side walls that 32 support a rear upper horizontal shaft and a rear low~er horizontal ~ 3 -105531~
1 shaft thereacross. The seat proper rests on a seat assembly 2 which is spaced from the base assembly and includes a seat frame 3 having a channel-shaped forward member with a front wall and two 4 rearwardly-extending sidewalls. The front wall has a central S opening, and its sidewalls support a forward upper horizontal 6 shaft and a forward lower horizontal shaft between them. The 7 air spring rests on the base pla~e and is secured to the seat 8 frame, so that in effect the seat assembly is supported by the 9 air spring.
'I O , 11 A lower pivoting assembly is pivoted at its rear end ~2 to the rear lower shaft and at its forward end to the lower 13 forward shaft. An upper pivoting assembly is pivoted at its 14 rear end to the rear upper shaft. A lever assembly comprising a pair o~ lever arms pivoted at their upper ends to the forward 16 upper shaft pivotally carries the forward end of the upper 17 pivoting assembly. The pivot point of the upper pivoting assembly 18 is located below that of the~ lever assembly itself. On the 19 opposite side from the lever assembly, that is, below the upper pivoting assembly, is a plate that joins the two lever arms 2~ together and is generally parallel to the front wall, though not 2~. strictly so, and this plate has a central opening through it 23 that is aligned with a central opening of the front wall.
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A.spring-mounting shaft has an adjustment handle at 26 its forward end,and it extends rearwardly through ~he central 27 opening of the front wall and then through and beyond the 28 ~entral opening of the plate, the plate being spaced rearwardly ~ ;
29 from the front wall. To the rear end of this spring-mounting shaft a bearing washer is adjustably threaded and t:he bearing , .
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1055~380 1 washer is secured against rotation, so that when the shaft is 2 rotated by the adjustment handle, the position of the bearing 3 washer on the shaft is changed. The resistance to pitch is ~; provided by a pair of frustoconical springC; positioned around the spring-mounting shaft. The forward spring is located between 6 and bears on both the front wall and the plate, while a rear 7 spring is located between and bears on both the plate and the 8 bearing washer. Thus, action in either direction is spring-loaded 9 and is spring-loaded by a frustoconical spring, so that it becomes progressively greater as the extremities o~ motion are 11 approached.

i3 The air spring is controlled by a pn~umatic system 14 having a valve which operates both to admit additional air from the compressor to the air spring and, at other times, to bleed 16 the air spring of some of the air already in it. This valve 17 is provided with a plunger which controls the admission of air 18 and the bleeding of the air.

A control arm is mounted pivotally to a pin o~ the upper 21 end of the plunger and is also provided with an arcuate slot 22 through which extends a shaft that is mounted to the body of the 23 valve. The control arm is also attached to the upper end of 24; spring~ whose lower end is attached to the base assem~ly. The control arm extends forwardly of the pivot points~ and its upper 26 surface engages a pin located on a seat adjustment handle. This 27 handle is pivoted to the seat assem~ly frame in such a way that 28 it is automatically locked in position once it is set manually 29 to any desired position by the truck operator.
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- 5 .'''', ' ' 1 When the truck operator gets in a seat and wants to 2 adjust it, he moves the control handle either up or down, thereby 3 lowering or raising the control arm, to causejactuation of the 4 plunger either to send more air in or to bleed some air ~rom the air spring. Once he has done this, the seat is set in a position

6 that is to be retained. Motion u~ward of the¦seat when he removes

7 his weight from it is counteracted by the control arm following

8 the lever arm upwardly with the seat assembly, pivoting about g the shaft mounted on the valve body, and thereby actuating the plunger to bleed air from the air valve, while motion downwardly ¦~
- 11 when the man gets into the empty seat again is followed by actu-12 ation ofthe plunger that moves the plunger to its position of 3 admitting air to the air spring. The action i5 practîcally 14 instantaneous so that there is generally only a light motion.
c 1~ However, if the motion does continue beyond the position in 16 which the valve plunger has moved to its extreme position, then 17 the springs attached to the lever take over, and the lever 18 itself is caused to pivot about the pin on the upper end of the ~9 plunger. The arcuate slot is of sufficient length such that the seat will bottom before the shaft which extends through the 21 slot comes up against the end of the slot.
~2' ; 23 On the seat assembly is provided a fore-and-aft .
24 adjustment enabling the truck driver to set his normal posi~ion and to that the actual seat frame proper is secured and to that 26 ~r~me the back is pivotably mounted.
i' 27 ,l 28 At each side of the seat back a supporting member 29 provides a gear sector which can be interlocked with a gear sector ~ounted on t~e seat frame or on stub shafts attached thereto.
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l A central shaft goes through the supporting members and connects 2 a pair of lockup fing~rs; an adjustment handle is provided 3 enabling disengagement by the lockup fingers of the gear sectors 4 mounted on the seat frame from those on the seat back supporting members, so that the seat back can be moved to any position and 6 then reengaged by operation of this manual handle. The central 7 shaft extending through the two back supporting members together 8 is a key feature which enables a rapid adjustment without acting

9 through the back of the seat itself.

ll Brief Description of the Drawings l2 13 In the drawings:

Fig. l is a view in side elevation of a vehicle seat 16 assembly embod~ing the prineiples of the invention. Various ~ -17 positions of the seat and ~ack are shown in broken lines.

l9 Fig. 2 is a view in front elevation of the seat assembly of Fig. l.

22 Fig. 3 is a view in horizontal section ~aken along 23 the line 3-3 in Fig. 2.

Fig. 4 is a view in side elevation viewed along the 26 lin~ 4-4 in Fig. 3 but with portions broken away and shown in 27 section, .~ . , ' . ' ` , ~ .
~ ~ - 7 -~ , ' ''" ' ~0553~10 1 Fig. 5 is a partially exploded isometric view of the ,. . .
base assembly, the upper and lower link assemblies and the lever 3 assembly~ together with some related parts, all for the lower 4 part of the seat assembly of Figs. 1-4.

6 Fig. 6 is an exploded isometric view of the lever 7 assembly and seat support assembly and the pitch-responsive 8 springs of the seat assembly o~ Figs. 1-4.

Fig. 7 is a view in side elevation of a sub-assembly 11 controlling the seat height adjustment. Various positions of 12 key parts are shown in broken lines.

1~ Fig. 8 is a view in section of a control valve in the 15 sub-assembly of Fig. 7.

17 Fig. 9 is an exploded isometric view of the sub-assembly 18 of Fig. 7.

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Fig. 10 is a par~ially exploded isometric view of the 21 fore-and-aft-adjustment sub-assembly of the seat assembly of 22 Figs. 1 and 2.

24 Fig. 11 is an exploded isometric view of the seat 25 frame and back frame members and the gear setors, etc., enabling 26 the inclination of the back.

28 Fig. 12 is an exploded isometric view of the adjustment . .
~9 control mechanism for the sub-assembly of Fig. 11.
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1 ~ 5 53 1 ~ Fig. 13 is an enlarged fragmentary view in side 2 elevation of one of the back-inclination-adjustment sub-assemblies 3 of Fig. 11. The sub-assembly is shown engaged in solid lines 4 and disengaged in broken lines.

6 Fig. 14 is an enlarged fragmentary view in front 7 elevation of the sub-assembly of Fig. 13.

9 Fig. 15 is a diagrammatic view in side elevation illus~rating how cab pitch is induced by frame flexure in 11 response to road roug~ness.

13 Fig. 16 is a bottom view o the fore-and-aft 1~ sIide adjustment mechanism of Fig. 10.
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Descrietion of a Preferred_~mbodiment Figs. 1 and 2 show a vehicle seat assembly 20 embodying the invention~ comprising a seat 21 and a back 22. The cushioned seat 21 is mounted on a seat frame 23 (see Fig. 11), which is supported by a fore-and-aft-ad~ustment sub-assembly 24 (See Fig. lO)o The sub-assembly 24 itself rests on a lower seat asse~bly 25, which comprises a number of elements and~sub-assemblies and which is shown as a whole in Figs. 3 and 4. The seat back 22 is supported by a pair of upstanding frame members 26 and 27 and a back pan 28, all shown in Fig. 11.

The lower seat assembly 25 (Figs. 1-4-) The lower seat assembly includes a base assembly 30 and an upper frame assembly 50 which are connected to each other~ not only through an air spring 45 and a shock absorber 49 but also ~ `
through a pitch-isolating system which includes three pivoting assemblies 70~ 80~ and 90. The lower seat assembly 25 also include a valve 110 and a lever 120 for adjusting the seat height through the pressure in the air spring 45 and meehanism for controlling . 20 the valve 110 to maintain the desired seat adjustment when the i driver gets into and out from the seat 21.
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~ The base assembly 30 and related parts (Fi~s. 1-5) .~ .
The base assembly 30 is secured firmly and immovably i to the floor of the truck cab, which is not shown here. The base assembly 30 includes a base plate 31 with upstanding side , edges 32 and 33 and a generally channel-shaped, vertical rear standard 34 rigidly secured to the rear of the plate 31.

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1 The rear standard 34 has a vertical rear wall 35 and two parallel ~ trapezoidal side walls 36 and 37. Thes~ side walls 36 and 37 3 are each provided with two openings 38 and 39 in which are 4 secured a lower annular bearing 40 and an upper annular bearing 41. The rear wall 35 may contain suitable openings 42 to receive ; 6 compressed air conduits 43 from the truck's ~ir compressor f 7 (not shown). The baise plate 31 may fixedly support an air spring 8 pedestal 44 to which is secured the lower end of an air spring 9 45. The base plate 31 may also support a bracket 46 with openings :
~7 to receive a pivoting shaft 48 for a shock absorber 4g.

12 The upper frame assembly 50 (Figs. 1,_2, 4, and 6) 14 The upper frame assembly 50 has an upper pan 51 , 15 provided with a horizontal forward portion 52, a rear horizontal 16 portion 54 at the same level as the portion 52, and a somewhat .
17 lower intermediate horizontal portion 53 joined to the portions 18 52 and 54 by vertical portions 55 and 56. The internediate 19 portion .53 is secured, as by a bolt 57 extending through an open-ing 58 to the upper end 59 of the air spring 45. Secured to the ~1 upper pan 51 and extending down from it is a~generally channel-22 shaped frame member 60 having a forward wall 61 and two parallel, 23 trapezoidal sidewalls 62 and 63. The sidewalls 62 and 63 are 24 bent over at 6~a and 63a at their upper ends for attachment, as by welding, to the pan 51. The sidewalls 62 and 63 each .
26 have openings 64 seating lower bearings 65 and openings 66 27 i~eating uppe~ bearings 67. The sidewall 62 also has an opening 28 68 used in mounting the height-adjusting levqr 120 (deiscribed 29 below) and an arcuate slot 69 through which ~he lever 120 e~tends. ' . ' - 11 - . . :
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,The pitch i.solation system ~ gs.~ 6 and 15 - ' I
2 especlallY I~ s. ~ and 6) I

3 Fig. 15 sho~s how pltch is generated. In response to 4 road roughness, a truck ram~ A flexes up and do~, due to sus~
pension inputs to the rame A. The truck has a cab B ~7ith lront 6 and rear mounts C and D that then tend to vibrate up ancl do~m 7 out of phase, A5 a result the cab B tends to oscillate in ~Jhat 8 may be called a pitch mode.
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The system which supplies pitch isolation to the lower 11 sea~ assembl~, ~5, and which comprises the pitch-res1sting means, , 12 includes thr~e pivo~ing assemblies 70, ~0, and 90, and the adjust-13 able spring connection be~een the frame member 60 and the as-14 sembly 90 ~et orth below.
A lower rectangular pivoting assembly 70 comprises 16 two hollow shafts 71 and 72, one at each end,, joined by a pair 17 of rigid bar links 73 and 74. The rear shaft 71 is pivotally 18 supported around a solid shaft 75, whlch is itself suppoxted by 19 the lower bearings 40 of the sidewalls 36 and 37. ~he forward shaft 72 is pivotally supported around a solid shaft 76, which is 21 itself supported by the lower bearings 64 of,the sidewalls 62 22- and 63. The shafts 75 and 76 may be secured in place by lock rings 23 or other suitable means. The sha~ts 75 and'76 remain stationary .~, i .
~ 24 relative ~o the rear s~andard 34 and the frame member 60, ', 25 respectively, and the respective hollow shats 71 and 72 rotate 26 pi~otally around tkem. , 28 The upper rectangular pivoting assembly 80 comprises i 29 a hollow rear pivot shaft 81, a hollow front,pivot shaft 82, and a pair of forwardly extending bar links 83 ahd 84. ~e shaft , , 31 ~l pivots around a ~olid shàft 85, which is supported by the - 12 - , .~, 1()553~0 1 upper bearings 41 of the sidewalls 3G and 37. Openings 86 in the 2 links 83 and 84 receive a solid shaft 77 about which pivots a 3 hollow shaft 78 of the upper end 79 of the s~ock absorber 49.
4 The hollow front shaft 82 rotates around a solid sha.Et 87, but the shaft 87 is not supported by the walls 6~ and 63 but instead 6 is supported by a pitch-transmitting and snu~bing asse~bly 90.
8 The assembly ~0, which may be called a lever assembly~ `
9 comprises a hollow shaft 91 joining a pair of bars 92 and 93. ;. .
~0 The shaft 91 pivots around a solid shaft 89 that is supported 11 by the upper bearings 67 in the sidewalls 62 and 63 o~ the upper ~2 frame assembly 50. Each bar.92, 93 has an upper vertical portion 13 94 and a lower downwardly and inwardly extending portion 95.
~4 The portions 95 are joined together by a plàte member 96 having a central opening 97. The upper po~tions 94! include bearing 16 openings 98 into which fit the ends of the shaft 87! that pivotally ..
17 supports the hollow shaft 82 of the assembly 80.

19 The forward wall 61 of the frame member ~0 is provided with a boss 99 having a central opening through which extends 21 an adjusting shaft 100 having a threaded inner or rear end lOl.and 2~ . a keyed forward end 102, to which is attache~ a handle ~03~ lying 23 forward of the boss 99. The shaft 100 also extends through the 24 opening 97 in the lever assembly 90, and a frustoconical sprlng 104 is positioned between and bears on the plate 96 and the ~6 forward wall 61. A second frustoconical spring 105 bears against 27 the opposite side of the plate 96, while itslsmaller end bears 28 against a bearing washer 106, which is threa~ed to the threaded ~9 end 101 of the shaft 100. An antirotation wire 107 extends from two openings 108 in the washer 106 to a bracket 109 secured to . j.

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~ ~' ' ' , , 1~553~ 1 1 the wall 63, ~o hold the washer 106 against rotation and thereby 2 enable a~justmcnt of the prPssure of both springs 104 and lO5 3 on the plates 96 and washer 106 and on the wall 61 by rotation of 4 the handle 103. This preloading adjustment is quite important since individuals vary widely as to how much firmness in response 6 they want. , ~ -8 Operation of the pitch isolation system 9 The elements so far described serve to isolate to some extent the pitch of the seat 20 and also to limi~ the amount of 11 pitch. The conical springs 104 and 105 assure the greatest reedom 12 of horizontal movement (i.e., pitch) at the locations closest to 13 the center position of the seat 20 and the greatest resistance to 14 pitch at the two extreme ends of the pitch movement.
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16 Thus, the upper frame assembly 50 is pivotally mounted 17 with respect to the forward shaft 72 of the lower rectangular 18 assembly 70 and also is pivotally mounted with respect to the 19 shaft 91 of the lever assembly 90. As a result, pitch tends to cause the upper seat assembly 50 ~o rotate relatively to the ~1 shaft 72, while the links 83 and 84 of the upper assembly 80 22 resist this rotation of the assembly 50, the forward shaft 82 23 pivoting relatively to the lever assembly 90. This causes 2~ rotation of the lever assembly 90 about the shaft 89, thereby resulting in compression of o~e of the two springs 104 or 105 26 and a restoring moment about the shaft 91. The handle 103 27 en~bles adjustment of the springs 104 and 105 to provide any 28 desired degree of softness or firmness in thè response to pitch, 29 a~d the driver can select what he wants.
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1 Height adjustment (Figs. 1-4 and 7-9) 2 Another important function of the seat-supporting 3 structure is to enable height adjustment and to retain that 4 adjustment once it is set, so that the seat 21 does not change height when the driver gets in or out of the seat 21.
7 A valve 110 (See Figs. 7-9) is com ected by the air 8 conduit 43 to the vehicle's compressor (not shown) and is 9 connected by a conduit 111 to the air spring 45 at a suitable ~ -fitting 112. The valve 110 makes it possible to add further air 11 to the air spring 45 to raise the height o~ the seat assembly 20 12 or to bleed air from the air spring 45 to lower the height o the 13 seat assembly 20. A novel structure holds the alr system sealed 14 for small excursions and adds or bleeds out air for larger ~S excursions. The large excu~sions, however, do not need to change 16 the preset adjustments, so that a large overtravel can be accom-17 modated. The same structure has, as perhaps its most important 18 function, that of preventing the seat 21 from following the ¦
19 driver up during exit but instead causing it to remain during the no-load conditions at the height to which the driver has set 21 it. Furthermore, it is important that there be no moving air 22 lines, so that all the vaLving can remain stationary, since air 23 lines, that move tend to get pinched.

The valve 110 (See Fig. 83 has an inlet 113 connected 26 to the conduit 43, an outlet 114 connected to the conduit 111, ~7 and a bleed opening 115. A spool assembly 116 is mounted on a 28 plunger 117, and the valve's housing 118 is so oriented that -29 when the plunger 117 is moved downwardly, compressed air from ~he conduit 43 is supplied to the air spring 45 via the conduit 111;
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1 ~nd when ~he plung~r 117 is moved upwardly, air is bled from ' ':
the air spring 4S via the conduit lll and the bl~'ed opening 115.
3 ~ , 4 A height-adjusting leve~ 120 has a handle 121 conveni-5, ently located for the driver to operate the device while he is '~
, 6 in the seat 21. From the handle 121, a transverse portion 122 7 of the lever 120 passes tnrough the slot 69 of the wall 62 and 8 leads to a fore-and-aft exte~ding portion :L23 having an opening 9 124.' A bolt-like stu~ shaft 125 extends through this opening 124 and through the opening 68 and is'used to mount the lever 120 ~ 11 pivotally to the wall 62. The slot 69 in the plate 62 serves to . ~ :
' 12 limit the amount of travel of the lever 120. A friction detent ~3 i9 provided to hold the lever 120, in a position to which it is 1~ set, as by a stack of Belleville washers 126 surrounding the stub ~ , 15 shaft 125 and bearing against the wall 62 and against the lever ~, ! 16 portion 123.
17 . ' : ' 18 The lever 120 also has a second transverse portion 127 '~ 19 leading to a long fore-and-aft portion 128 that terminates in ' 20 a lever pin 129. The lever pin 129 rides slidably atop a ' ~ 21 channel-snaped control arm 130, which is spring-mounted so that, ', 22 its upper wall 131 follows the lever pin 129 upwardly and also ~;,, 23 yields so that the control arm 130 can be forced downwardly 24 by the lever pin 129. The'control arm 130 is provided with side . 25 walls 132 and 133 each of which has an arcuate slot 134 and two :I 26 pivot openings 135 and 136.
27 - -, - , : '28 A pin 137 extends across through the two openings 135 29 and also extends through an opening 138 in the hea~ 139 of 30 the plunger 117 for the valve 110. Another pin 140 extends . ' 31 through openings 141 in a clevised end 142 o~ the body 118 of ' ,.................. .

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~ ~ S 5 3 80 1 the valve 110 ~nd cxtends out throu~h the two slots 134. A third 2 pin 143 extends through the openings 136 of the control arm L30 3 and is hooked to one end of each of a pair of springs 14l~ and 145, 4 the other end of each sprin~ 144 and 145 being anchored to a bracket 146 on the base plate 31. The valve body 118 is anchored 6 to the base assembly 30, as to the bracket 14 9 Operation of the height adjusting and maintaining su~-assembly 11 The control anm 130 (as shown in Fig. 7) pivots clockwise 12 (downwardly) when the handle 121 is manually lifted, so that the 13 lever 120 is moved counterclockwise, the springs 144 and 145 14 resist-Lng this movement and being ready to restore the control arm 130 toward its original position when the lever handle 121 is 16 released. Similarly, the springs 144 and 145 cause the control 17 arm 130 to swing counterclockwise (upwardly) when the lever 120 ;
18- is manually moved clockwise as the lever handle 121 is depressed.
g These movements enable manual adjustment of the seat height, as will be seen.

2~' Since the lever 120 is secured by the stub shaft 125 23 to the wall 62 of the upper frame assembly 50, the lever 120 24 also moves up and down with the seat 21. Downward movement of the seat 21 and the lever 120 depresses the control arm 130 26 (clockwise movement); upward movement of the seat 21 and the 27 lever 120 enables the contxol arm 130 to rise, (counterclockwise .
28 movement).

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The control arm 130, when swung, piVQtS first about the pin 140 and raises or depresses the plunger 117; when the plunger 117 reaches an extreme downward position, the control arm 130 then pivots about the pin 137.
With the control arm 130 in its equllibrium position and the lever arm 120 not being dlsturbed manually9 substantial downward movement of the upper frame as6embly 50 carries the whole lever arm 120 down and causes the pin 129 to depress the control arm 130. The springs 144 and 145 then exert sufficient force to cause the control arm 130 to pivot about the pin 140 and also to depress the plunger 117. As the plunger 117 is depressed, the valve 110 supplies air to the air spring 45 via the conduit 111. Further downward motion of the seat assembly 50 causes the plunger 117 to~bottom, with the control arm 130 at the position 130a~ shown in broken lines in Fig. 7. Once the plunger 117 has bottomed~ further rotation of the control arm 130 takes place about the pin 137, and the control arm 130 is then lifted off from the pin 140. The maximum downward travel of the control arm 130 is 1 ~
; 20 indicated by a position 130b, shown in broken lines in Fig. 7.
; The air being supplied to the air sprin~ 45 causes the seat assembly 20 and therefore the lever 120 to return t~ its initial equilibrium position. If the seat assembly 20 should attempt to rise further~ the springs 144 and 145 rotate the control arm 130 about the pivot pin 140, lifting the plunger 117 and keeping the control arm 130 in contact with the pinnl29 on l the lever 120, thereby bleeding air from the air spring 45. Posi-J tion 130c corresponds to the end of the plunger travelO If there 30 is further upward travel~ the pin 129 is!~lifted off the control :'.

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1 arm 130. When sufficicnt ~ir has been bled from the air spring 45 ~ the sPat assembly 20 again returns to its equilibrium position.
4 When it is desired to adjust the seat height, the S, driver either depresses or raises the handle 121, and the sea~
6 assem~ly 20 moves to its desired level. The handle 121 remains 7 in any position to which it is set, by virtue of the washers 126.
8 The operation is substantially the same as that which has been 9 described already in regard to the admission or release of air.

12 The fore-and-at adjustment assembly 24 ~Fies. 1, 2, 10, and 16) 13 - _ 14 To the upper pan 51 are secured two lower channel guide .~ 15 members 150, one on each side. An upper channel guide member 1~1 16 is interlocked with the lower channel guide member lS0 and enables 17 fore-and-aft ~ovement. Thus, screws or studs 152 may secure the 18 lower member-150 to the pan 51, extending through the openings 19 153, while upwardly extending studs or bolts 154 may secure the upper channel guide members lSl to the upper seat ~rame 23, extend-21 ing through the openings 155 in side frame members 156 and 157 of 22 the ~rame 23 and also, at the rear through a channeled cross ~3 frame member 158.
~4 A ~ever arm 160 having a handle 161 is attached to a 26 crank 162, which is connected to an identical crank 163 by a 27 connecting rod 164.The cranks 162 and 163 are pivotally attached 28 to the bottoms o the lower channels 150 and carry a pawl 165 ~9 having an opening 166 which normally engages some detents 167 ? 30 in a rack 168 secured to the upper channels 151, so that the ~' ' ' , . '"' ~, ^ - 19 : . .

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1 handle 161 can be swung to release the pawl 165 from the rack 168.
~ 2 Then the upper channels 151 can move fore and aft relative to the ; 3 lower channels 150. Rollers and bearings in ~he channels reduce 4 the friction of such relative movement. The driver can thus move the seat 21 fore and aft relative to the lower seat assembly 6 25. Springs 169, secured between the cranks 162, 163 and the 7 respective lower channels 150, act to urge the pawls 165 to their 8 locked position when the handle 161 is released, thereby engaging 9 the rack 168 and holding the seat rame 23 in the position ; 10 to which it has been adjusted.

13 Seat back inclination (Figs. 1, 2, and 11-14) ' ~ Ad~ustment of the reclining back 22'is rapid, and the 16 locklng in place is automatic and sure.
`~ 17 , 18 The back 22 is supported by the two frame n;embers 26 19 and 27 and by a light sheet-metal pan 28. It is impractical to rely upon the pan 28 to hold the back 22 rigid, and prior art 21. devices, in requiring a torsionally rigid seat back frame have ~2 required a heavy, thick frame. In today's trhcks, where space 23 is at a premium, a thin back is needed, and bulky supports are 24 out of the ques~ion.

~6 In order to solve the problems encountered, the back 27 frame side members 26 and 27 double as indexing sectors (See 28 Fi8. 11~, each having an arcuate ge~r sector il70 along their 29 lower edges, and the members 26 and 27 are both ratatably mounted on a large rigid torsion bar 171 by bearings '172. The torsion , - 2~ -.. . . . .

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S53~
bar 171 extends through and is ~ournaled in bearings 173 ln~
upright flanges 174 of the seat fr~me ~ide members lS6 and 157 Secured to the torsion bar 1.71 are a pair of lockup fingers 17.5 (Fig. 12) having keying openings 176 for securing the~l to non round portions 177 of the torsion bar 171. Each lockup finger 175 has a flange 178 with an opening 179 there-- through.

A pair of lockup sectors 180 having an arcuate toothed :
edge 181 adapted for engagement with the gear sectors 170 have bearings 18~ that aretmounted rotatably on respective stub shafts 183 that are secured to the frame flanges 17~l. Return springs 184 are each secured at one end to a stub shaft 183 and at the other end to the opening 179. Each lockup sector 180 has an arcuate slot 185 which is progressively eccentric relative to the ;~ :~
torsion bar 171 and which receives a pin 186 that is secured to the lockup finger 175. Thus, the effective ramp angle of the ` slot 185 varies with the position of the lockup finger 175. ~ -~
;
:~ On one end of the torsion bar 171, a crank 187 is secured, and a handle 188 is secured to the crank 187. By lifting on the ~ -handle 188, the driver ro~ates the crank 187 and therefore the torsion bar 171 and the lockup fingers 175. Rotation of the lockup fingers 175 toward~and end 190 of the slot 185 nearer the stub shaft 183 causes the lockup sector 180 to be moved away from the .indexing sector, disengaging the teeth 181 from the teeth 170.
~:~ While the teeth are so disengaged, the driver adjusts the back ~ 22 to the desired inclination, and then he releases the handle s 30 188. This release enables the return spring 184 to rotate the lockup fingers 175 and torsion bar 171 and to pull the lockup sector 180 into engagement with the teeth 170. Ad~ustment is helped by ` -21-' :'` .

1~5531~V l 1 a pair of springs 191, which are secured at one end to th~ cross 2 frame member 158 and at the other end to a brack~t 192 on thé
3 back frame members 26 and 27; these springs 1~1 preload the 4 seat back forwardly, so that the operator does not have to pull it up fro~ a reclined position.
7 Incipient lockup occurs when the lockup finger pin 186 8 is at a position in the slot 185 such that the effective ramp 9 angle is so small that it would require an unattainably small coefficient of friction between the pin 186 and the slot 185 for 11 "camout" to occur, and therefore there is no camout.

13 This adjustment is rapid and sure, with positive 14 detent locking on both sides and a positive locking for both fore-and-aft back loading.

17 ' !
18 Other adjustmentsand features 19 A handle 200 (See Figs. 1, 2, and 11) is used to adjust the angle of the seat cushion 21 relative to the floor 21 plane. The seat cushion 21 is attached to the seat frame 23 by 22 a pair o bolts 201 near the rear of the cush~on 21, and two 23 rubber washers 202 and 203 at each bolt 201 isolate the cushion 24 21 ~rom the frame 23 and enable the cushion 21 to pivot there slightly relative to the frame 23. Forward of this is a trans-26 verse shaft 204 that rests in slots 205 in the seat frame 23 ~7 and to which two roughly triangular cams 206 and the handle 200 28 are attached. Turning the handle 200 rotates,the cams 206 ~9 thereby elevating ~he front of the cushion 21lto the operators' choice of positions;
. ~, .
~, i ~ - 22 -'.

., , . . ....... ... ....... .. . .... .

lOS5380 1 Figs. 4 and 6~ especially, show a ormed hollow tube 210 2 that is welded to the upper pan 51. The open ends 211 and 21~
3 of the tube 210 are threaded to accommodate a bolt in each end.
4 The tube 210 serves as the intermediate connecting point for the seat belt installation. All suspension seats require two sets of 6 seat belts: one conventional set of belts to restrain the -7 occupant in the seat, and another set of "tether belts" that run 8 from the seat to the floor anchorages. The lap belt is adjusted 9 snugly around the occupant, while the tether belts are left suffi-ciently loose to permit the seat to move up and down through 11 its normal range of motion. The intermediate connecting point `~
12 is the point where these two sets of belts are joined together.
This arrangement avoids the constant loosening and ~ightening 1~ problem one would have if the lap belt went aLl the way to the floor.

17 To those skilled in the art to which this invention 18 relates, many changes in co~.struction and widel~ differing 19 embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the 21 invention. The disclosures and the description herein are 22- purely illu5trative and are not intended to be in any sense 23 limiting.
2~ . -I clairn:

, . . . ..

^ - 23 : . - '

Claims (20)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A vehicle seat, including in combination:
a base assembly secured to the floor of the vehicle and having a horizontal portion and an upwardly extending supporting portion, a seat assembly spaced from said base assembly and including a seat frame having a horizontal portion and a down-wardly extending portion, a seat supported by said frame, and a rigid torsion rod extending through and journaled on said frame, an air spring resting on said horizontal portion of said base assembly and secured to said horizontal portion of said seat assembly and supporting said seat assembly and seat, manually operated means for adjusting the amount of air in said air spring to place said seat at a desired elevation, weight-actuated means responsive to a change in the weight bearing on said seat for changing the amount of air in said air spring by an amount sufficient to retain said air spring in the position to which it had last been set by said manually operated means, two back frame uprights, one at each side, rotatably supported on said rod, each having a lower arcuate gear-toothed edge, a thin sheet metal pan secured to and between said uprights, a pair of lockup sectors pivotally mounted to said seat frame, each having an arcuate gear sector for engagement with a said gear-toothed edge, engagement means urging each said gear sector into engagement with its associated said gear-toothed edge, manually operated disengagement means secured to said rod for disengaging said gear sector from said gear-toothed edge to enable adjustment of the inclination of said back, and yieldable pitch-resisting means operably interconnecting said upwardly extending portion of said base assembly with said downwardly extending portion of said seat assembly, enabling limited and dampened fore-and-aft movement of said scat assembly, substantially independent of vertical movement of said seat assembly, comprising a lower pivoting assembly with its rear end pivotally supported by said upwardly extending supporting portion and its forward end pivotally supporting said downwardly extending portion, said downwardly extending portion having a transverse generally vertical wall with a central opening therethrough, an upper pivoting assembly with its rear end pivotally supported by said upwardly extending supporting portion and having a forward end, a lever assembly comprising a pair of lever arms with their upper ends pivotally supported by said downwardly extending portion, the forward end of said upper pivoting assembly being pivoted to said lever arms therebelow, and a transverse plate joining still lower portions of said lever arms, said plate having a central opening aligned with the central opening of said transverse wall, a spring mounting shaft having an adjustment handle at its forward end and extending rearwardly through said central opening of said transverse wall and then through and beyond said central opening of said plate, a bearing washer adjustably threaded to the rear end of said spring mounting shaft, means securing said bearing washer against rotation, and a pair of spring means around said spring mounting shaft, namely forward spring means between and bearing on said transverse wall and said plate, and rear spring means between and bearing on said plate and said bearing washer.

2. The vehicle seat of claim 1 wherein each of said pair of spring means is a frustoconical metal spring.

3. The vehicle seat of claim 1 wherein a telescoping shock absorber is pivotally connected at a lower end to said base assembly and is pivotally connected at an upper end to said upper pivoting assembly.

4. A vehicle seat, including in combination:
a base assembly secured to the floor of the vehicle and having a vertical supporting portion, a seat assembly spaced from said base assembly and including a seat frame having a vertical depending portion with a transverse wall having a central opening and a side wall having an arcuate slot therethrough, and two back frame uprights, one at each side, each having a lower arcuate gear-toothed edge with a thin sheet metal pan secured to and between said uprights, an air spring interposed between said base plate and said seat frame, said air spring having a pneumatic conduit connected therethrough, a lower pivoting assembly with its rear end pivotally supported by said vertical supporting portion and its forward end pivotally supporting said vertical depending portion, an upper pivoting assembly with its rear end pivotally supported by said vertical supporting portion and having a forward end, a lever assembly comprising a pair of lever arms with their upper ends pivotally supported by said depending portion, the forward end of said upper pivoting assembly being pivoted to said lever arms therebelow, and a transverse plate joining still lower portions of said lever arms, said plate having a central opening aligned with the central opening of said transverse wall, a spring mounting shaft having an adjustment handle at its forward end and extending rearwardly through said central opening of said transverse wall and then through and beyond said central opening of said plate, a bearing washer adjustably threaded to the rear end of said spring mounting shaft, means securing said bearing washer against rotation, a pair of springs around said spring mounting shaft, namely a forward spring between and bearing on said transverse wall and said plate, and a rear spring between and bearing on said plate and said bearing washer, a valve having a housing supported by said base assembly and connected to said pneumatic conduit and also to a supply of compressed air and having a bleed opening and a plunger controlling a valve member having a neutral position sealing off said conduit, a lower position connecting said conduit to said supply, and an upper position connecting said conduit to said bleed opening, said plunger having extreme upper and lower positions, a channel-shaped control arm having an upper surface and two depending flanges and carrying a first pin, a second pin pivotally secured to said plunger at its upper end, and an arcuate slot in between them, said valve housing having a third pin extending across said slot, spring means connecting said first pin to said base assembly, a lever arm pivotally secured to said vertical side wall, having at its rear end a pin engaging said upper surface of said control arm, and extending through said slot in said vertical side wall and having a forward end for manipulation by a person in said seat, and brake means normally holding said lever arm in the posi-tion in which it was last manually set, regardless of vertical movement of said seat assembly, a rigid torsion rod extending through and journaled on said seat frame and rotatably supporting said back frame upright thereon, a pair of lockup fingers secured to said rod, one adjacent each said upright and carrying a fourth pin, a pair of sectors, each having an arcuate gear sector for engagement with a said gear-toothed edge, and having an arcuate slot through which said fourth pin extends, a pair of stub shafts each secured to said seat frame and pivotally supporting a said lockup sector, spring means joining each said stub shaft to a said lockup finger and urging said gear sector into engagement with its associated said gear-toothed edge, and crank means secured to said rod for rotating of said rod to disengage said gear sector from said gear-toothed edge and enable adjustment of the inclination of said back.

5. The vehicle seat of claim 4 wherein said seat frame comprises a lower frame assembly having said vertical de-pending portion and bearing on said-air spring, an upper frame assembly supporting said torsion rod, and a fore-and-aft adjust-ment assembly joining said lower frame assembly to said upper frame assembly and having means for releasably locking them to-gether at various fore-and-aft relationships relative to each other.

6. A vehicle seat, including in combination:
a base assembly secured to the floor of the vehicle and having a horizontal portion and an upwardly extending sup-porting portion, a seat assembly spaced from said base assembly and including a seat frame having a horizontal portion and a down-wardly extending portion, and a seat supported by said frame, an air spring resting on said horizontal portion of said base assembly and secured to said horizontal portion of said seat assembly and supporting said seat assembly, and yieldable pitch-resisting means operably interconnecting said upwardly extending portion of said base assembly with said downwardly extending portion of said seat assembly, comprising at least one lever pivoted to and depending from said horizon-tal seat frame portion between said downwardly extending seat frame portion and said upwardly extending supporting portion of the base assembly, means pivotally connected to said lever at a point spaced from said horizontal seat frame portion for restraining fore-and-aft movement of the lever at said point, and spring means connected to the lever and to said downwardly extending portion for yieldably resisting pivoting of the lever about said point and thereby yieldably resisting fore-and-aft movement of the seat assembly, substantially independent of verti-cal movement of said seat assembly, manually operated means for adjusting the amount of air in said air spring to place said seat at a desired elevation, and weight-actuated means responsive to a change in the weight bearing on said seat for changing the amount of air in said air spring by an amount sufficient to retain said air spring in the position to which it had last been set by said manually operated means.

7. A vehicle seat, including in combination:
a base assembly secured to the floor of the vehicle and having a verticle supporting portion, a seat frame assembly spaced from said base assembly and having a vertical depending portion with a transverse wall having a central opening and a side wall having an arcuate slot therethrough, an air spring interposed between said base plate and said seat frame assembly, said air spring having a pneumatic conduit connected thereto.
a lower pivoting assembly with its rear end pivotally supported by said vertical supporting portion and its forward end pivotally supporting said vertical depending portion, an upper pivoting assembly with its rear end pivotally supported by said vertical supporting portion and having a forward end, a lever assembly comprising a pair of lever arms with their upper ends pivotally supported by said depending portion, the forward end of said upper pivoting assembly being pivoted to said lever arms therebelow, and a transverse plate joining still lower portions of said lever arms, said plate having a central opening aligned with the central opening of said transverse wall, a spring mounting shaft having an adjustment handle at its forward end and extending rearwardly through said central opening of said transverse wall and then through and beyond said central opening of said plate, a bearing washer adjustably threaded to the rear end of said spring mounting shaft, means securing said bearing washer against rotation, a pair of frustoconical springs around said spring mounting shaft, namely a forward spring between and bearing on said transverse wall and said plate, and El rear spring between and bearing on said plate and said bearing washer, a valve having a housing supported by said base as-sembly and connected to said pneumatic conduit and also to a supply of compressed air and having a bleed opening and a plunger controlling a valve member having a neutral position sealing of said conduit, a lower position connecting said conduit to said supply, and an upper position connecting said conduit to said bleed opening, said plunger having extreme upper and lower positions, a channel-shaped control arm having an upper surface and two depending flanges and carrying a first pin and a second pin pivotally secured to said plunger at its upper end, and an arcuate slot in between them, said valve housing having a third pin extending across said slot, spring means connecting said first pin to said base assembly, a lever arm pivotally secured to said vertical side wall, having at its rear end a pin engaging said upper surface of said control arm, and extending through said slot in said vertical side wall and having a forward end for manipulation by a person in said seat, and brake means normally holding said lever arm in the position in which it was last manually set, regardless of vertical movement of said frame assembly.

8. The vehicle seat of claim 7 having a shock absorber pivotally connected at a lower end to said base assembly and pivotally connected at an upper end to said upper pivoting as-sembly, in between its rear end and its forward end.

9. A vehicle seat, including in combination:
a base assembly secured to the floor of the vehicle and having a vertical supporting portion, a seat frame spaced from said base assembly and having a vertical depending portion with a transverse wall having a central opening, seat supporting spring means interposed between said base plate and said seat frame, a lower pivoting assembly with its rear end pivotally supported by said vertical supporting portion and its forward end pivotally supporting said vertical depending portion, an upper pivoting assembly with its rear end pivotally supported by said vertical supporting portion and having a forward end, a lever assembly comprising a pair of lever arms with their upper ends pivotally supported by said depending portion, the forward end of said upper pivoting assembly being pivoted to said lever arms therebelow, and a transverse plate joining still lower portions of said lever arms, said plate having a central opening aligned with the central opening of said transverse wall, a spring mounting shaft having an adjustment handle at its forward end and extending rearwardly through said central opening of said transverse wall and then through and beyond said central opening of said plate, a bearing washer adjustably threaded to the rear end of said spring mounting shaft, means securing said bearing washer against rotation, and a pair of springs around said spring mounting shaft, namely a forward spring between and bearing on said transverse wall and said plate, and a rear spring between and bearing on said plate and said bearing washer.

10. The vehicle seat of claim 9 wherein a telescoping shock absorber is pivotally connected at a lower end to said base assembly and is pivotally connected at an upper end to said upper pivoting assembly,

11. A vehicle seat, including in combination:
a base assembly secured to the floor of the vehicle and including a base plate and vertical rear standard including a pair of side walls supporting a rear upper horizontal shaft and a rear lower horizontal shaft thereacross, a seat assembly spaced from said base assembly and including a seat frame having a channel-shaped forward member having a front wall and two rearwardly extending side walls, said front wall having a central opening, said side walls supporting a forward upper horizontal shaft and a forward lower horizontal shaft thereacross, an air spring vertically disposed between said base plate and said seat frame, a lower pivoting assembly pivoted at its rear end to said rear lower shaft and pivoted at its forward end to said forward lower shaft, an upper pivoting assembly pivoted at its rear end to.
said rear upper shaft and having a forward end, a lever assembly comprising a pair of lever arms pivoted at their upper ends to said forward upper shaft, the forward end of said upper pivoting assembly being pivoted to said lever arms therebelow, and a plate joining still lower portions of said lever arms, said plate having a central opening aligned with the central opening of said front wall, a spring mounting shaft having an adjustment handle at its forward end and extending rearwardly through said central opening of said front wall and then through and beyond said central opening of said plate, a bearing washer adjustably threaded to the rear end of said spring mounting shaft, means securing said bearing washer against rotation when said shaft is rotated by said adjustment handle, and a pair of frustoconical springs around said spring mounting shaft, namely a forward spring between and bearing on said front wall and said plate, and a rear spring between and bearing on said plate and said bearing washer.

12. A vehicle seat, including in combination:
a base assembly secured to the floor of the vehicle and including a pair of vertical side walls, each side wall support-ing an upper rear bearing and a lower rear bearing, a seat assembly spaced from said base assembly and including a seat frame having a channel-shaped forward member having a front wall and two rearwardly extending side walls said front wall having a central opening, said side walls each supporting an upper forward bearing and a lower forward bearing, an air spring resting on said base assembly and secured to and supporting said seat assembly, a lower generally rectangular pivoting assembly comprising a rear shaft and a forward shaft rigidly connected together, means for rotatably supporting said rear shaft with respect to said lower rear bearings>
means for rotatably supporting said forward shaft with respect to said lower forward bearings, an upper generally rectangular pivoting assembly comprising a back shaft and a front shaft rigidly connected together, means for rotatably supporting said back shaft with respect to said upper rear bearings, a lever assembly comprising a lever shaft, a pair of lever arms joined at their upper ends by said lever shaft and each having below said shaft a lever bearing, and a plate joining the lower portions of said lever arms, and having a central opening therethrough aligned with the central opening of said front wall, means for rotatably supporting said lever shaft, with respect to said upper forward bearings, means for rotatably supporting said front shaft with respect to said lever bearings, a spring mounting shaft having a handle at its forward end and extending rearwardly through said central opening of said front wall and then through and beyond said central opening of said plate, a bearing washer adjustably threaded to the rear end of said spring mounting shaft, means securing said bearing washer against rotation, and a pair of frustoconical springs around said spring mounting shaft, namely, a forward spring between and bearing on.
said front wall and said plate, and a rear spring between and bearing on said plate and said bearing washer.

13. The vehicle seat of claim 12 having a telescop-ing shock absorber pivotally connected at its lower end to said base assembly and at its upper end to said upper pivoting assembly in between said back shaft and said front shaft.

14. A vehicle seat, including in combination:
a base assembly secured to the floor of the vehicle and including a base plate and vertical rear standard including a pair of side walls, each side wall having a pair of bearing, openings mounting an upper rear bearing and a lower rear bearing, a seat assembly spaced from said base assembly and including a seat frame having a generally horizontal portion and a channel-shaped forward member having a front wall and two rearwardly extending side walls, said front wall having a central opening, said side walls each having a pair of bearing openings mounting an upper forward bearing and a lower forward bearing, a lower generally rectangular pivoting assembly comprising a hollow rear shaft, a hollow forward shaft and a pair of links rigidly connecting said shafts, a first solid shaft supported by said lower rear bearings for rotatably supporting said hollow rear shaft therearound, a second solid shaft supported by said lower forward bearings for rotatably supporting said hollow forward shaft therearound, an upper generally rectangular pivoting assembly com-prising a hollow back shaft, a hollow front shaft, and a pair of links rigidly connecting these said shafts, a third solid shaft inside said hollow back shaft and supported by said upper rear bearings for rotatably supporting said back shaft, a lever assembly comprising a hollow lever shaft, a pair of lever arms joined at their upper ends by said lever shaft and each having below said shaft a lever bearing, and a plate joining the lower portions of said lever arms, and having a central opening therethrough aligned with the central opening of said front wall, a fourth solid shaft supported by said upper forward bearings and surrounded by and rotatably supporting said hollow lever shaft, a fifth solid shaft supported by said lever bearings and surrounded by and rotatably supporting said hollow front shaft, a spring-mounting horizontal shaft having a handle at its forward end and extending rearwardly through said central opening of said front wall and then through and beyond said central opening of said plate, a bearing washer adjustably threaded to the rear end of said spring mounting shaft, means securing said bearing washer against rotation, a pair of frustoconical springs around said spring mounting shaft, namely a forward spring between and bearing on said front wall and said plate, and a rear spring between and bearing on said plate and said bearing washer, and an air spring resting on said base plate and secured to said generally horizontal portion of said seat assembly.

15. The vehicle seat of claim 14 having a telescoping shock absorber pivotally supported at its lower end by said base plate and having a hollow shaft at its upper end, a sixth solid shaft supported by the links of said upper pivoting assembly in between said back shaft and said forward shaft and surrounded by and rotatably supporting the hollow shaft of said shock absorber.

16. A vehicle seat, including in combination: a base assembly secured to the floor of the vehicle and having a horizontal portion and an upwardly extending supporting portion, a seat assembly spaced from said base assembly and including a seat frame having a horizontal portion and a downwardly extending portion and a seat supported by said frame, an air spring resting on said horizontal portion of said base assembly and secured to said hori-zontal portion of said seat assembly and supporting said seat assembly and seat, yieldable pitch-resisting means operably interconnecting said upwardly extending portion of said base assembly with said downwardly extending portion of said seat assembly, comprising at least one lever pivoted to and depending from said horizontal seat frame portion between said downward-ly extending seat frame portion and said upwardly extending supporting portion of the base assembly, means pivotally connected to said lever at a point spaced from said horizontal seat frame portion for restraining fore-and-aft movement of the lever at said point, and spring means connected to the lever and to said downwardly extending portion for yieldably resisting pivoting of the lever about said point and thereby yeildably resisting fore-and-aft movement of the seat assembly, substantially independent of vertical movement of said seat assembly, manually operated means for adjust-ing the amount of air in said air spring to place said seat at a desired elevation, weight-actuated means responsive to a change in the weight bearing on said seat for changing the amount of air in said air spring by an amount sufficient to retain said air spring in the position to which it had last been set by said manually operated means, two back frame uprights, one at each side, rotatably supported by said seat frame each having a lower arcuate gear-toothed edge, a thin sheet metal pan secured to and between said uprights, a pair of lockup sectors pivotally mounted to said seat frame, each having a gear sector for engagement with a said gear-toothed edge, engagement means urging each said gear sector into engagement with its associated said gear-toothed edge, and manually operated disengagement means for disengaging both said gear sectors from said gear-toothed edges to enable adjustment of the inclination of said back.

17. A vehicle seat including in combination:
a base assembly secured to the floor of the vehicle and having a horizontal portion and an upwardly extending sup-porting portion, a seat assembly spaced from said base assembly and including a seat frame having a horizontal portion and a down-wardly extending portion and a seat supported by said frame, an air spring resting on said horizontal portion of said base assembly and secured to said horizontal portion of said seat assembly and supporting said seat assembly and seat, yieldable, adjustable, spring-operated pitch-resisting means operably interconnecting said upwardly extending portion of said base assembly with said downwardly extending portion of said seat assembly, enabling limited and dampened fore-and-aft movement of said seat assembly substantially independent of verti-cal movement of said seat assembly, said pitch-resisting means including at least one lever pivoted to and depending from said horizontal seat frame portion between said downwardly extending seat frame portion and said upwardly extending supporting portion of the base as-sembly, means pivotally connected to the lever at a point spaced from said horizontal seat frame portion for restraining fore-and aft movement of the lever at said point, and spring means connected to the lever and to said downwardly extending portion for yieldably resisting pivoting of the lever about said point and thereby yieldably resisting fore-and-aft movement of the seat assembly, manually opeated means for adjusting the amount of air in said air spring to place said seat at a desired elevation, weight-actuated means responsive to a change in the weight bearing on said seat for changing the amount of air in said air spring by an amount sufficient to retain said air spring in the position to which it had last been set by said manually operated means, two back frame uprights, one at each side, rotatably supported by said seat frame each having a lower arcuate gear-toothed edge, a thin sheet metal pan secured to and between said uprights, a pair of lockup sectors pivotally mounted to said seat frame, each having a gear sector for engagement with a said gear-toothed edge, engagement means urging each said gear sector into engagement with its associated said gear-toothed edge, and manually operated disengagement means for disengaging both said gear sectors from said gear-toothed edges to enable adjustment of the inclination of said back.

18. A vehicle seat including in combination:
a base assembly secured to the floor of the vehicle and having a horizontal portion and an upwardly extending sup-porting portion, a seat assembly spaced from said base assembly and including a seat frame having a horizontal portion and a down-wardly extending portion and a seat supported by said frame, an air spring resting on said horizontal portion of said base assembly and secured to said horizontal portion of said seat assembly and supporting said seat assembly and seat, yieldable pitch-resisting means operably interconnecting said upwardly extend-ing portion of said base assembly with said downwardly extending portion of said seat assembly, comprising at least one lever pivoted to and depending from said horizontal seat frame portion between said downwardly extending seat frame portion and said upwardly extending supporting portion of the base as-sembly, means pivotally connected to said lever at a point spaced from said horizontal seat frame portion for restraining fore-and-aft movement of the lever at said point, and spring means connected to the lever and to said downwardly extending portion for yieldably resisting pivoting of the lever about said point and thereby yieldably resisting fore-and-aft movement of the seat assembly, substantially independent of vertical movement of said seat assembly, manually operated means for adjusting the amount of air in said air spring to place said seat at a desired elevation, weight-actuated means re-sponsive to a change in the weight bearing on said seat for changing the amount of air in said air spring by an amount sufficient to retain said air spring in the position to which it had last been set by said manually operated means, said manually operated means and said weight-actuated means comprising:
a valve having a housing supported by said base assembly and connected by pneumatic conduit to said air spring and also to a supply of compressed air and having a bleed opening and a plunger controlling a valve member having a neutral position sealing off said conduit, a lower position connecting said conduit to said supply, and an upper position connecting said conduit to said bleed opening, said plunger having extreme upper and lower positions, a con-trol arm connected at a first pivot point to the upper end of said plunger with spring means connected to one end of the control arm and to the base assembly for urging said one end downwardly, and means anchored to the base assembly normally supporting the control arm at a second pivot point between the first pivot point and said one end of the control arm, a lever arm pivot-ally secured to said seat assembly along a generally horizontal axis and having at its rear end a projection engaging the upper surface of said control arm near an end of the control arm opposite said one end, so that downward movement of said projection moves said opposite end of the control arm down-wardly, said lever arm having a forward end for manipulation by a person in said seat, and brake means normally holding said lever arm in the position in which it was last manually set, regardless of vertical movement of said seat assembly, two back frame uprights, one at each side, rotatably supported by said seat frame each having a lower arcuate gear-toothed edge, a thin sheet metal pan secured to and between said uprights, a pair of lockup sectors pivotally mounted to said seat frame, each having a gear sector for engage-ment with a said gear-toothed edge, engagement means urging each said gear sector into engagement with its associated said gear-toothed edge, and manual-ly operated disengagement means for disengaging both said gear sectors from said gear-toothed edges to enable adjustment of the inclination of said back.

19. A vehicle seat, including in combination: a base assembly secured to the floor of the vehicle and having a vertical supporting portion, a seat frame assembly spaced from said base assembly and having a vertical depending portion with a transverse wall having a central opening, air spring inter-posed between said base plate and said seat frame assembly, said air spring having a pneumatic conduit connected thereto, a lower pivoting assembly with its rear end pivotally supported by said vertical supporting portion and its forward end pivotally supporting said vertical depending portion, an upper pivoting assembly with its rear end pivotally supported by said vertical supporting portion and having a forward end, a lever assembly comprising a pair of lever arms with their upper ends pivotally supported by said depending portion, the forward end of said upper pivoting assembly being pivoted to said lever arms therebelow, and a transverse plate joining still lower portions of said lever arms, said plate having a central opening aligned with the central opening of said transverse wall.
a spring mounting shaft having an adjustment handle at its forward end and extending rearwardly through said central opening of said transverse wall and then through and beyond said central opening of said plate.
a bearing washer supported by the rear end of said spring mounting shaft, means associated with said spring mounting shaft, said transverse wall and said bearing washer for axially adjusting the position of the bearing washer in response to rotation of the adjustment handle, a pair of compression springs around said spring mounting shaft, one positioned between and bearing on said transverse wall and said plate, and the other between and bearing on said plate and said bearing washer, a valve having a housing supported by said base assembly and connected to said pneumatic conduit and also to a supply of compressed air and having a bleed opening and a plunger controlling a valve member having a neutral position sealing off said conduit, a lower position connecting said conduit to said supply, and an upper position connecting said conduit to said bleed opening, said plunger having extreme upper and lower positions, a control arm connected at a first pivot point to the upper end of said plunger with spring means connected to one end and to the base assembly for urging said one end downwardly, and means anchored to the base assembly normally supporting the control arm at a second pivot point between the first pivot point and said one end of the control arm, a lever arm pivotally secured to said seat assembly along a generally horizontal axis and having at its rear end a projection engaging the upper surface of said control arm near an end of the control arm opposite said one end, so that downward movement of said projection moves said opposite end of the control arm downwardly, said lever arm having a forward end for manipulation by a person in said seat, and brake means normally holding said lever arm in the position in which it was last manually set, regardless of vertical movement of said seat assembly.

20. A vehicle seat, including in combination:
a base assembly secured to the floor of the vehicle and having a vertical supporting portion, a seat frame spaced from said base assembly and having a vertical depending portion with a transverse wall having a central opening, seat supporting spring means interposed between said base plate and said seat frame, a lower pivoting assembly with its rear end pivotally supported by said vertical supporting portion and its forward end pivotally supporting said vertical depending portion, an upper pivoting assembly with its rear end pivotally supported by said vertical supporting portion and having a forward end, a lever assembly comprising a pair of lever arms with their upper ends pivotally supported by said depending portion, the forward end of said upper pivoting assembly being pivoted to said lever arms therebelow, and a transverse plate joining still lower portions of said lever arms, said plate having a central opening aligned with the central opening of said transverse wall, a spring mounting shaft having an adjustment handle at its forward end and extending rearwardly through said central opening of said transverse wall and then through and beyond said central opening of said plate, a bearing washer supported by the rear end of said spring mounting shaft, means associated with said spring mounting shaft, said bearing washer and said transverse wall for adjusting the axial position of the washer in response to rotation of the adjustment handle, and a pair of springs around said spring mounting shaft, namely a forward spring between and bearing on said transverse wall and said plate, and a rear spring between and bearing on said plate and said bearing washer.