US 3883173 A
A seat has individual supports for the lower thigh of the user which are pivotally mounted at the front of the seat portion of the seat (i.e., the portion on which the user sits and which bears his weight). They are able to be individually depressed against a spring-loading by the user applying weight to them. The depression occurs in a pivoting motion about a pivot axis adjacent the upper surface of the seat portion but the path of this motion is defined by a linkage beneath the thigh supports and the seat portion, and there is no hinge at the pivot axis. The limit uppermost position of the supports, to which they are urged by the spring-loading, is controllable and two mechanisms are shown for this.
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Description (OCR text may contain errors)
United States Patent Shephard et al.
[ SEAT WITH THIGH SUPPORT  Inventors: Bernard William Shephard,
Basildon; Kenneth George Draper, Burnham-on-Crouch, both of England  Assignee: Ipeco Europe Limited, Essex,
England 22 Filed: Jan. 26, 1973 21 Appl. No.: 327,144
 Foreign Application Priority Data  Field of Search 297/422-427, 297/428-437, 68, 312, 201, 338, 284; 108/145, 147; 248/421  References Cited UNITED STATES PATENTS 2,569,310 9/1951 Hitt 108/147 X 3,405,900 Robinson 108/147 X [451 May 13,1975
3,443,850 5/1969 Scime et al. 108/147 X 3,472,488 10/1969 Naughton 108/147 X 3,550,953 12/1970 Neale 297/312  ABSTRACT A seat has individual supports for the lower thigh of the user which are pivotally mounted at the front of the seat portion of the seat (i.e., the portion on which the user sits and which bears his weight). They are able to be individually depressed against a springloading by the user applying weight to them. The depression occurs in a pivoting motion about a pivot axis adjacent the upper surface of the seat portion but the path of this motion is defined by a linkage beneath the thigh supports and the seat portion, and there is no hinge at the pivot axis. The limit uppermost position of the supports, to which they are urged by the springloading, is controllable and two mechanisms are shown for this.
9 Claims, 7 Drawing Figures F" TENTH] HAY I 31975 SHEET 3 BF 6 SEAT WITH THIGH SUPPORT FIELD OF THE INVENTION This invention relates to seats with thigh supports, for use in vehicles, particularly in aeroplanes.
BACKGROUND OF THE INVENTION For maximum comfort and efficiency it is desired to give the most support to the body of the user of the seat as he sits at the controls during routine driving or flying or during rest periods. However, giving maximum support may be incompatible at first sight with allowing him maximum freedom of movement during manoeuvres of a violent or emergency nature.
In particular, there are problems in adequately supporting the lower thigh of a user of a seat. This is a part which needs support if the person is to be given maximum comfort and yet it is a part which has to perform quite wide ranges of motion if there is a need for violent evolutions using foot controls, in particular the rudder bar of an aeroplane. The pilot of an aeroplane must be completely free to use the full extension of his legs.
Various forms of adjustable leg supports have previously been proposed, in U.K. Pat. Specifications Nos. 1,168,927 and 1,199,756. In both of these the axis about which the support pivots is defined by a hinge arrangement and is at the base of the seat portion. This means that for different positions of the support the seat portion as a whole has different apparent lengths from where it meets the back of the seat to the front of the thigh support and there either has to be a gap between the front of the fixed part of the seat portion and thigh support; and in U.l(. Pat. Specification No. 1,168,927 the movable part is made L-shaped and carried all along the sides of the seat portion.
The support in U.K. Pat. Specification No. 1,168,927 is also depressible by the user against spring-loading and adjustable as to the limit position to which the spring-loading urges the support: but the arrangement is such that all the motion is about an axis behind the front of the seat portion and below it. The effect in this construction is that there are upholstered support pads which are movable up and down in front of the fixed seat portion and, when raised, there is a sudden step between the support and the front of the fixed seat portion.
SUMMARY OF THE INVENTION An object of the invention is to provide an aircrew seat where movable support is given to the lower part of the thigh of a crew member using the seat without discomfort to the user, without need to adjust his sitting position as the support means and without substantial sacrifice of his freedom of movement.
Clearly these considerations are most important for members of aircrew, but apply also, though less forcibly, to drivers, particularly, of heavy commercial vehicles or heavy passenger vehicles.
We provide, in this invention, a seat having separate upholstered thigh support portions on each side of the front of the seat portion of the seat, each of which is individually resiliently loaded upwardly towards a support portion but is individually movable downwardly in an arcuate motion on pressure applied to it from above, being constrained to execute that arcuate motion about a pivot axis lying adjacent to the upper surface of the seat portion, without a pivotal hinge being provided at that axis.
In this specification seat portion refers to the essentially horizontal part on which the user sits and by which he is vertically supported.
Embodiments of seat according to the invention will now be described with reference to the accompanying drawings wherein:
FIG. 1 is a perspective view of an embodiment as an aircrew seat,
FIG. 2 is a plan view of the mechanism of the thigh support portion of the embodiment,
FIG. 3 is a sectional view on the line III-III of FIG. 2 with the thigh support of the embodiment in an uppermost position,
FIG. 4 is a sectional view similar to that of FIG. 3 but with the thigh support portion of the embodiment in a lowermost position,
FIG. 5 is a sectional view on the lines VV of FIG.
FIG. 6 is a view similar to that in FIG. 3 but showing a modified embodiment, and
FIG. 7 is an underneath plan of the modified embodiment, certain parts being removed for clarity.
In FIG. 1 there is generally indicated an aircrew seat 1 having a seat portion 2 with at each side of its front end, thigh support portions 4. These are separated so as to offer a channel 5 between them to receive the control column of the aircraft.
To allow the aircrew member maximum freedom of movement during evolutions each thigh support portion 4 is separately depressible when pressure is exerted on it from above, in an arcuate movement of which the axis is at the front of and adjacent the upper surface of the seat portion.
The mechanism by which this is achieved without however providing a load bearing hinge adjacent the upper surface of the seat portion will now be described with reference to the remaining FIGURES.
The two thigh support portions 4 are mirror images of each other and only one will be described. Each side frame 6 of the seat portion is of box section and on the mutually outermost faces of the extreme front portion have secured to them slideways 7. Studs 8 at the ends of struts 9 which are fixedly secured to a tray under the upholstery 10 of the thigh support portion 4, are slidable along the slideways. At its front end each slideway is closed by a bridge 11 so as to provide a stop against movement of the studs 8 in that direction.
Pivoted to each strut 9 is an arm 12 which is fixed at its lower end to a shaft 13 common to both arms 12 of the one thigh support portion 4. The shaft 13 is journalled in the side frame 6. The effect of the constraint imposed on the thigh support portion 4 by the arm 12 moving on the axis of the shaft 13 and by the studs 8 sliding in the slideway 7 is to constrain the thigh support 4 to move, when appropriate pressures are applied to it, in an arcuate movement centred on an axis at the position 14 adjacent to the top surface of the front of the seat portion 2. To accommodate the movement which the thigh portion may make, the upholstery of the seat portion is brought to a shallow neck where the axis 14 is positioned and a void is left beneath that neck, which void defines a reentrant which in the illustrated embodiment is essentially prism-shaped as seen at 15 in FIG. 3, when the thigh support is in its upward position. This void is thus of a shape that its sides are substantially closed together, as shown in FIG. 4, when the thigh support is lowered.
It can be seen that a pivot axis has been provided adjacent the top surface of the upholstery of the seat portion without however any load-bearing hinge being provided there, so that there is no obstruction to the depression of the upholstery in that region.
In one mechanism for providing resilient loading upwardly of the thigh support portion 4, lever arms are fast with the shaft 13 and are joined by connecting rods 21 pivotally to essentially triangular double members 22 which are pivoted at 23 to the respective members of the side frame 6. The point of attachment to the rod 21 is remote from the pivot axis 23 as is also an anchor shaft 24, common between the plates 22 (and not shown in FIG. 2), to which is hooked a rubber band tension spring 25 which passes round a pulley 26 in a trunnion 27 attached to a cross member between the side members of the frame 6. The shaft 24 has a spacer sleeve to keep the hooks 37 of the tension spring spaced axially apart as is best seen in FIG. 5. The action of the spring 25 is to urge the members 22 rearwardly (to the right as seen in the FIGURES) hence to tend to rotate the shaft 13 and the arms 12 counter-clockwise thereby to restore the thigh support to its uppermost position.
Means are provided to limit and adjustably control the uppermost position. A shaft 30 is fast between the double members 22, approximately half way between the pivot point 23 and the shaft 24. A scissor linkage 31 of which each element is a pair of parallel fingers is controlled by left and right hand threaded nuts 32 running on oppositely threaded sleeves 36 rotated by a control shaft 33. The control shaft 33 is common to both thigh supports and has at one end a control wheel 35. The parallel fingers fit one above and one below the shaft 30.
It can be seen that by adjusting the position of the control wheel the nuts 32 can be made to move towards one another causing rollers 34 on the scissor linkage 31 to thrust the shaft 30 away from the control shaft 33 thus adjusting the rightmost position that the members 22 may adopt and hence the uppermost position of the thigh support portions 4.
In any intermediate adjusted position of the control wheel 35 the thigh support portion 4 can still be depressed by pressure from above causing the shaft 30 to move away from the stop face provided by rollers 34 in the scissor linkage 31.
A modified mechanism for spring-loading the thigh support portions and controlling their uppermost positions is shown in FIGS. 6 and 7.
Upward spring-loading is applied to the thigh support portion (only its base tray is shown in these FIGURES the upholstery is exactly as in the earlier FIGURES) by keying a single lever arm 20 to the shaft 13 which is in turn fixed to the arms 12 pivoted to the struts 9. This lever arm 20' is biassed upwardly by a rubber band spring 25 anchored by its hooks 37' to the respective side walls of the side frame 6, and passing round a trunnion pulley 27'. This has a stern which passes through a short shaft 38 housed rotatably in a split in the free end of the lever arm 20'. This bias urges the arms 12 forward, having the effect of biassing the thigh support portion upwardly.
To control the limit upward position, a control shaft 33' having a control knob as in the first-described mechanism, is fitted with a bevel gear 40 which drives a smaller such gear 41 which is fixed to a shaft journalled in a pivotable cross-member 39 of the side frame 6, and having a screw-threaded portion 42.
A nut 43 screw-threadedly engages that portion and is housed within and is slidable along a tubular part having a parallel, opposed, guide slots 45 in its opposite walls. This tubular part is mounted pivotally at 47 between a pair of lugs 48 on the undersurface of the base tray of the thigh support portion. A pin 44 projects from the nut 43 on two sides and engages in the opposed guide slots 45.
As the control knob is rotated in the appropriate sense the nut 43 is drawn towards the cross-member 39 and the pins 44 engage the ends of the guide slots so that the lugs 48 are also so drawn. This has the effect of lowering the uppermost position of the thigh support portions together.
However, if the user wishes to depress either of the thigh support portions against its spring-loading, the effect is to press the lugs 48 towards the crossmember 39, and it is free to undergo this movement because the pins 44 will travel freely along the guide slots 45.
1. An upholstered seat comprising: a main seat portion having upper and lower surfaces, a forward end and individual thigh support portions each of which includes an upper and lower surface, biasing means individually and resiliently urging each of said thigh support portions upwardly into an upper support position, each of said thigh support portions being independently movable with respect to the other, said individual thigh support portions being located in juxtaposition with the forward end of said main seat portion at opposite sides thereof, individual strut means in fixed relation with each of said thigh support portions and extending downwardly therefrom and including guide pins, 21 frame member in fixed relation with said main seat portion, said frame member including a pair of elongate slots in which said guide pins are slidably received, a linkage assembly operatively connecting said biasing means to the thigh support portion associated therewith, said linkage assembly including a pivotally mounted lever means having one end mounted to one of said strut means and another end to a connecting link which is in turn operatively connected to said biasing means, said linkage assembly being disposed below the lower surface of said thigh and main seat portions, said guide pins, elongate slots and linkage assembly cooperating to direct the movement of said thigh support portions along an arcuate path about a pivot axis located adjacent the upper surface thereof at said upper surface of said main seat portion, each of said thigh support portions being movable downwardly along said arcuate path upon the application of a load to it from above, whereby said individual thigh support portions are individually resiliently loaded upwardly and individually movable with respect to each other about said pivot axis adjacent the upper surfaces thereof without the presence of a pivotal hinge at said pivot axis.
2. A seat as defined in claim 1 wherein the thigh support portions are upholstered continuously with the mam seat portion.
3. A seat as defined in claim 2 wherein the upper surface of the upholstery is smooth and uninterrupted adjacent the pivot axis, and the lower surface of the upholstery is interrupted by a reentrant when the thigh support portion is upward, the pivot axis being in a narrow neck of upholstery between the front of the seat portion and the thigh support portion.
4. A seat as defined in claim 1 wherein an adjustable limit means is operatively connected to said individual thigh support positions for selectively and individually regulating the upper support positions thereof.
5. A seat as defined in claim 4 wherein said linkage assembly includes a pivotally mounted connecting member to which said connecting link and biasing means are respectively connected and said adjustable limit means is connected to said pivotally mounted connecting member, said adjustable limit means acting to limit the forward arcuate travel of said pivotally mounted connecting member, thereby enabling the selective and individual regulation of the upper support position of each of said individual thigh support members.
6. A seat as defined in claim 5 wherein said adjustable limit means comprises a scissors linkage movable into respective open and closed positions, one pair of arms of said scissors linkage being operatively interconnected with said pivotally mounted connecting member to provide a stop means for said linkage assembly in one of said open or closed positions, and the opposed pairs of arms of said scissors linkage being screwthreadedly engaged in an oppositely screw-threaded fixed control axis, whereby rotation ofa control rod operates to regulate the extent to which said scissors linkage can travel in the fully open and fully closed positions associated with the particular setting of the control rod to thereby selectively control the action of said stop means on the linkage assembly.
7. The seat as defined in claim 4 wherein said adjustable limit means comprises a freely movable link, one end of which is mounted to one of said individual thigh support portions and the other end of which is con nected to said main seat portion, downward depression of the thigh support portion associated therewith being in opposition to the resilient loading provided by said biasing means and being in the direction of free move ment of said movable link, said link including an adjustable stop means for selectively determining the position from which said movement starts, whereby the uppermost position of the thigh support portion associated therewith can be selectively regulated.
8. A seat as defined in claim 7 wherein said freely movable link is separate from said linkage assembly.
9. In a seat having a main seat portion fixed relative to pivotally adjustable and depressible individual thigh support portions and having an upper surface for receiving and supporting vertically a user of the seat, the improvement comprising biasing means urging each of said thigh support portions into an upper support position, said thigh support portions including individual strut means in fixed relationship therewith and extend ing downwardly therefrom, said main seat portion including a frame member in fixed relationship therewith, and constraining means associated with each of said strut means and frame member, said constraining means including a guide pin which is slidably received within an elongate slot, one of said guide pin and elongate slot being in fixed relationship to said strut means and the other being in fixed relationship to said frame, a linkage assembly operatively connecting said biasing means to the thigh support portions associated therewith, said linkage assembly being disposed below said main seat and thigh support portions and including a pivotally mounted lever means having one end mounted to one of said strut means and another end fixed to a connecting link which in turn is operatively connected to said biasing means, whereby travel of said guide pin along said elongate slot in cooperation with the linkage assembly provides constrained movement of said thigh support portion associated therewith for limiting movement of said thigh support portion along an arcuate path about a pivot axis located adjacent the upper surface thereof at a forward end of said main seat portion and said individual thigh support portions are individually resiliently loaded upwardly and individually movable with respect to each other about said pivot axis adjacent the upper surfaces thereof without the presence of a pivotal hinge at said pivot axis.
UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION C PATENT NO. 1 3,883,173
DATED May 13, 1975 INV ENTOR(S) Bernard William Shephard et al.
It is certified that error appears in the above-identified patent and that said Letters Patent 9 are hereby corrected as shown below:
Column 1, line 54, "means" should read moves- Q Column 5, line 6, "positions" should read -portions- Signed and Sealed this second Day Of September 1975 [SEAL] Arrest:
RUTH C. MASON C. MARSHALL DANN Alrestr'ng Officer (mnmrssrrmer uflarenrs and Trademarks