US3495870A

US3495870A - Reclining chair mechanism

Info

Publication number: US3495870A
Application number: US722423A
Authority: US
Inventors: Ned W Mizelle
Original assignee: General Steel Products Co Inc Co
Current assignee: General Steel Products Co Inc Co
Priority date: 1968-04-18
Filing date: 1968-04-18
Publication date: 1970-02-17
Anticipated expiration: 1987-02-17
Also published as: FR2006404A1; DE1916781A1; GB1209571A

Description

Filed April 1 8; 196e A umm mmm Feb. l17, 1970 N. w. M|zELLE REGLINING CHAIR MEcHANIsM v :sp1-11.18. v196:3

6 sheets-sheet 2 Filed Feb. 17, 1970 N. w. MIZELLE REGLINING CHAIR MECHANISM s sheets-sheet a Filed April 1s, 196s Feb. 17, 1970 N. w. MIZELLEl 3,495,870

v RECLINING CHAIR MECHANISM l 'Filed April 18, 196s e sheets-sheet 4 17o 175 '|90 19 f x f f 2 FlEl- El N. w.V MlzELLE r 3,495,870A

RECLINING CHAIR ECHANISI v y Feb.' 17,- 19,70

s sheen-sunt 5 Filed April 1s, l196s United States Patent O 3,495,870 RECLINING CHAIR MECHANISM Ned W. Mzelle, High Point, N.C., assignor to General Steel Products, Inc., a corporation of North Carolina Filed Apr. 18, 1968, Ser. No. 722,423 Int. Cl. A47c 1/034 U.S. Cl. 297-84 14 Claims ABSTRACT OF THE DISCLOSURE A three position reclining chair mechanism in which the seat and back move as a unit from upright position to an intermediate position while a retracted leg rest is extended, and in which a parallel linkage system elevates the rear of the seat and reclines the back during further movement to a reclining position while the extended leg rest remains substantially fixed relative to the seat.

Background of the invention Three position reclining chair mechanisms are those in which the seat and back are movable between an upright position, an intermediate position which is still sufciently upright for reading or television viewing, and a reclining position in which the occupant of the chair is more or less recumbent. Desirably such chairs are provided with a retractable and extendable leg rest which is substantially completely extended during a lirst movement of the seat and back from upright position to intermediate position, and which remains in a substantially xed position.

Prior art three position reclining chairs have had a number of undesirable characteristics, among which are the fact that there is a definite stopping of movement between the lirst movement and the further movement, with relative difficulty of initiating the further movement; that once further movement is started the chair cannot be readily balanced in a position between the intermediate and full reclining position; that the leg rest is unduly elevated between the intermediate position and full reclining position; that the front of the seat moves upwardly an excessive distance during movement from upright position to full reclining position; and that the angle between the seat and the back cannot open enough for the occupant to assume a substantially recumbent position.

The structure of the present invention eliminates all the above enumerated disadvantages of the prior art reclining chair mechanisms, and in addition is readily adaptable to use in combined rocking and reclining chair mechanisms, and affords extremely versatile styling possibilities for chair manufacturers using the mechanism.

Summary of the invention In accordance with the present invention, a reclining chair mechanism is of the common type in which two identical sets of hardware are mounted on opposite sides of a chair base, and the chair seat and back are secured to the two sets of hardware. Leg rest brackets are adapted to receive upholstered leg rest members. Each set of hardware includes a base plate on which the entire mechanism is pivotally supported.

The present mechanism has a seat member, and a back bracket is pivoted at the rear end of the seat member and extended rearwardly therefrom. A front seat support arm pivotally mounts the seat member relative to the base, and a back support arm pivotally mounts the 3,495,870 Patented Feb. 17, 1970 ICC pivoted to the forward of the two parallel links, which has an intermediate pivotal connection to the rearward of the two parallel links, and which has its upper end pivotally connected to the rear of the seat member. A retractable and extendable leg rest mechanism is pivotally mounted near the front of the seat, and one part of the pivotal mounting for the leg rest mechanism is an extension of the front seat support arm, so that as the seat swings rearwardly on the front support arm from upright position to intermediate position the leg rest is fully extended.

During the first -movement of the chair mechanism from upright position to intermediate position the rear seat support link swings rearwardly and downwardly about its intermediate pivot on the rear parallel link, while at the same time the front seat support arm and the back support arm move in parallel with the rear seat support link so that the seat and back swing rearwardly as a unit. During this rst movement the front parallel link of the rear seat support linkage idles upwardly and forwardly with the lower portion of the rear seat support link to a dead center position.

With the chair in intermediate position, all the occupant of the chair need do to move it to full reclining position is to shift his weight slightly against the back of the chair which swings the front parallel link above its dead center position and permits the two parallel links to swing upwardly and elevate the rear seat support link and the rear of the seat with respect to the base. During this movement the back bracket, because it is directly connected to the base by the back support arm, is caused to swing downwardly about its pivotal connection with the rear of the seat member so that in reclining position the back of the chair occupies a very wide angle with reference to the seat. During such further movement the upward pivoting of the seat member is about its pivotal connection with the front seat support arm. Thus, there is little relative movement between the seat and the leg rest, and no movement of the leg rest during such further movement of the chair.

In a preferred embodiment of the invention the seat member is not mounted directly upon the base at the front, but instead there is a long mounting link which is pivoted toward the rear of the base and extends forwardly with the front seat support arm pivoted at its forward end. Forward of its pivotal connection with the base the long mounting arm is linked to the base through a short forward link and one arm of a bell crank which has its other arm connected by a long coordinating link with the back parallel link of the rear seat support linkage. Accordingly, in this form of the invention the front of the seat moves up about one third as far as does the back of the seat during the further movement from intermediate position to reclining position.

The reclining chair mechanism of the present invention lends itself to incorporation into a variety of reclining chair structures, either low leg or high leg, and by merely changing the shape of the seat member the same mechanism is adapted for use either with an inner spring seat cushion or with horizontally sinusoidal seat springs.

In a simplified and somewhat less complex and costly modification of the mechanism, the long support link and associated bell crank, etc. are eliminated, and the front seat support arm is pivoted directly on the base. In this simplied form, of course, the front of the seat is not elevated with the rear of the seat during 'further movement from intermediate position to full reclining position.

The principal object of the present invention, therefore, is to provide a reclining chair mechanism which may be used in a wide variety of reclining chair constructions of various styles and types.

A further object of the invention is to provide a reclining chair mechanism of the three position type in which the chair may be moved from upright position to intermediate position and on to fully reclining position with ease, and with the ability to balance the occupant in any position between intermediate position and fully reclined position by slight body movement.

Yet another obiect of the invention is to provide a three position reclining chair mechanism in which relative movement between the seat and the leg rest during travel of the chair from intermediate position to reclining position is very slight.

Yet another object of the invention is to provide a reclining chair mechanism in which the rear of the seat is elevated as the back is reclined during movement from intermediate position to reclining position, so as to afford a maximum angle of inclination between the seat and the back when the chair is fully reclined and there-by permit the occupant to assume a nearly recumbent position.

Description of the drawings FIG. 1 is a longitudinal sectional view of the high leg reclining chair embodying a iirst form of the reclining chair mechanism of the invention with the mechanism and the chair parts in upright position;

FIG. 2 is a fragmentary view similar to FIG. 1 illustrating the first embodiment of the mechanism in intermediate, or television viewing position;

FIG. 3 is a view like FIG. 2 illustrating the mechanism in reclining position;

FIG. 4 is a sectional View taken substantially as illustrated along the line 4-4 of FIG. 2;

FIG. 5 illustrates the mechanism of a second .form of the invention with the mechanism in upright position;

FIG. 6 illustrates the second form of the invention in intermediate position;

FIG. 7 illustrates the second form of the invention in reclining position;

FIG. 8 is a sectional view taken substantially as illustrated along the line 8-8 of FIG. 6;

FIG. 9 is a side elevational view of the mechanism of a third form of the invention illustrated in upright position;

FIG. 10 is a view showing the third form of the mechanism in intermediate position; and

FIG. 11 is a view illustrating the mechanism of the third form of the invention in reclining position.

Detailed description of the invention Referring to the drawings in greater detail, and referring first to FIGS. 1 to 4, a reclining chair has a rectangular wooden base, indicated generally at 20, which includes side rails 21, back bars 22 and 23, and a forward cross member 24, together with front legs 25 and rear legs 26. Arm frames 27 surmount the side rails 21 and are adapted to be upholstered in any desired manner.

The reclining chair mechanism of the first form of the present invention includes a base plate 30 which is screwed to one of the side rails 21 of the chair frame, and the entire mechanism is mounted upon the base plate 30 so that a furniture manufacturer need only mount a pair of such base plates on the opposite side rails 21 of a chair frame, mount an upholstered seat (not shown) on seat members 31 of the two mechanisms, mount a back frame suitable for upholstering on back brackets 32 of the two mechanisms, and mount

leg rests boards

29a and 29b, suitable for upholstering, upon

leg rest brackets

33a and 33b,` respectively of the two mechanisms. The leg rest brackets are pivotally connected at 33C.

In the first form of the invention the seat member 31 is supported upon a front support linkage, indicated generally at 34, and upon a rear support linkage, indicated generally at 35. The seat member 31 has a central portion 36 which is adapted to receive a drop-in coil spring base, and at the front of the central portion 36 the seat member has an upwardly and forwardly extending p0rtion 37 which terminates in a mounting arm portion 38, while at the rear of the central portion 36 there is an upwardly extending arm portion 39 which forms the back of the seat member. The back bracket 32 is pivoted at 40 on the upper end of the seat arm 39.

The front seat support linkage 34 includes a long support arm 41 which is pivotally mounted at 42 toward the rear of the base plate 30, and a front seat support arm 43 is pivoted at 44 on the front of the long support arm 41 and at 45 has a pivotal connection with the mounting arm portion 38 of the seat member 31. The front seat support linkage 34 also includes a bell crank 46 which is pivoted at `47 on the base and has a first arm 48 and a second arm 49. A short link 50 is pivotally mounted at 51 on the first arm 48 of the bell crank and is pivotally connected at 52 to the long support arm 41. A long coordinating link 53 is pivoted at 54 to the second arm 49 of the bell crank, and at 55 to a rear parallel link 56 of the rear seat support linkage means 35.

As best seen in FIG. 3, the rear seat support linkage means 35 includes the rear parallel link 56 which is pivotally mounted on the base 30 at 57, a front parallel link 58 which has a longitudinal slot 59 by means of which it makes a lost motion connection with a rivet 60 on which it is pivotally supported on the base 30, and a rear support link 61 which has a lower pivotal connection 62 with the front parallel link 58, an intermediate pivotal connection 63 with the rear parallel links 56, and an upper pivotal connection 64 with the rear arm portion 39 of the seat member 31. Thus, the rear support link 61 supports the rear of the seat member 31 and is operatively mounted upon the rear parallel link 56 and the front parallel link 58. Movement of the rear parallel link 56 is limited by a slot 56a| which is impaled by a stud. The back bracket 32 is supported by a back bracket support arm 65 to which it is pivotally connected at 66, and the support arm 65 is pivotally mounted upon the base 30 on the same pivot 57 which carries the rear parallel link 56.

The

leg rest brackets

33a and 33b are mounted on a retractable and extensible leg rest linkage which is best seen in FIGS. 2 and 3. It includes a hanger link 67 which is pivoted at 68 on the forward portion of the long support arm, and an arm 69 which is an extension of the front seat support arm 43 below the pivot 44. A link 70 is pivoted on the link 67 at 71, on the arm 69 at 72, and on the bracket 33a at 73. A link 74 is pivoted intermediate its ends at 75 on the link 70, and a link 76 connects the arm 69 to the link 74 through a pivot 77 on the arm and a pivot 78 on the link 74. A bell crank 79 is pivoted at 80 on the bracket 33a and has one arm pivotally connected at 81 to the link 74. A link 82 connects the other arm of the bell crank to the bracket 33b by a pivot S3 on the bell crank and a pivot 84 on the bracket.

Thus, the

links

67, 70, 74, 76 and 79, together with the arm extension 69, act as a lazy tongs linkage to extend the leg rest as the front seat support arm 43 moves from the upright position of FIG. l to the intermediate position of FIG. 2. The bell crank 79 and the link 82 cooperate with the pivotally connected

leg rest brackets

33a and 33b to unfold the bracket 33b with respect to the bracket 33a during said movement of the leg rest linkage.

The link 67 has a flat surface 67a which cooperates with a surface 69a on the support arm extension 69 to stop the unfolding movement of the leg rest.

A comparison of FIGS. 1, 2 and 3 shows that as the reclining chair mechanism moves from the upright position of FIG. 1 to the intermediate position of FIG. 2 the front seat support arm 43, the rear support link 61 and the back bracket support arm 65 swing rearwardly in parallel about their

respective pivots

44, 63 and 57 so that the front of the seat member 31 swings upwardly on a short are and then slightly downwardly, while the rear of the seat member and the back bracket swing rearwardly and downwardly as a unit without relative motion between them. At the same time, the leg rest operating arm 69, the extension of the front seat support arm 43, extends the leg rest linkage and pivots the leg rest bracket 33b into alignment with the leg rest bracket 33a.

During the further movement from the intermediate position of FIG. 2. to the reclining position of FIG. 3, the front seat support linkage and the rear seat support linkage cooperate to elevate the entire Seat member 31 a short distance at the front and a considerably greater distance at the rear while the 4back bracket 32 pivots downwardly with respect to the seat member about the pivot 40. The elevating of the seat member 31 is produced by rotation of the bell crank 46 and of the two

parallel links

56 and 58 of the rear seat support linkage, coordinated through the coordinating link 53. Rotation of the bell crank 46 about its pivot 47 acts through the short link 50 to pivot the long support arm 41 about its pivotal connection 42 to the base 30, and thus elevate the front of the seat. At the same time, the rear parallel link 56 and the front parallel link 58 pivot about their respective pivotal connections 57 and 60 with the frame to elevate the supporting link 61 and thus elevate the rear of the seat member. Since the back bracket 32 is linked to the base 30 by the back support arm 65, it is forced to pivot downwardly about the pivot 40 as the rear of the seat is elevated.

It will be observed that in the upright position of FIG. l and the intermediate position of FIG. 2 the pivotal connection 63 between the rear support link 61 and they rear parallel link 56 is coaxial with the pivotal connection 60 between the front parallel link 58 and the base 30, so that during the first movement of the chair, from upright position to intermediate position, the front parallel link idles upwardly and forwardly about the pivot 60 with the lower portion of the rear support link 61, and that in the intermediate position of FIG. 2 the front parallel link has reached a dead center position in which the pivot 62 which connects it with the rear support link 61 is aligned with the pivot 57 of the rear parallel link and the pivotal connection 63 of the support link 61 and the rear parallel link. Accordingly, the front parallel link 58 serves, during the rst movement of the seat and back, to lock the parallel linkage against rotation, whereas when the link 58 reaches the dead center position the parallel links are free to move in unison. The slotted connection 59-60 for the front parallel link 58 provides a lost motion connection between that link and the base 30 without which the link could not idle upwardly and forwardly about the pivot 60 from the position of FIG. l to the position of FIG. 2.

Referring now to the second form of the invention illustrated in FIGS. 5 to 8, the mechanism is similar to that of the first form of the invention except that the front support linkage means is eliminated, and the leg rest is of the one piece type `which has an operating linkage that extends a substantial distance below the chair seat and thus is not adaptable to a high leg chair style as is the rst form of the invention. However, it is apparent to those skilled in the art that either type of leg rest may be used with the rst form of the invention or with the second form of the invention.

The second mechanism includes a base plate 130', a seat member 131 which is identical with the seat member 31, and a back bracket 132 which is pivoted to the rear of the seat member 131 at 140. A front seat support arm 143 is pivoted on the base 130 at 144, and is pivotally connected to the front of the seat member 131 at 145.

A rear seat support linkage 135 is identical to the rear support linkage 35 of the first form of the invention, and includes a rear parallel link 156y pivoted on the base 130 and 1-57, and a front parallel link 158 having a longitudinal slot 159 by means of which it makes a lost motion connection with a pin 160 on the base 130. A rear support link 161 is pivotally connected at its lower end to a pivot 162 on the front parallel link 158, has an intermediate pivotal connection 163 with the rear parallel link 156, and has an upper pivotal connection 164 with the rear of the seat member 131. A back bracket support arm 165 is pivoted at 166 to the -back bracket 132 and is connected to the base 130 at the pivot 157 of the rear parallel link 156. A downward extension 165:1 of the back bracket support arm 165 is provided with an aperture, and an integral bracket portion 158a on the front parallel link 158 is provided with a slot so that a tension spring may be interposed between the extension 165a and the bracket portion 158a to urge the mechanism toward the upright position of FIG. 5.

The extensible and retractable leg rest mechanism includes a leg rest bracket 133 which is moved by a linkage that includes a link 167 pivoted at 168 on the base 130, an extension arm 169 of the front seat support arm 143, a long link 170 which is pivoted at 171 to the link 167, at 172 to the arm 169, and at 173 to the leg rest bracket 133. A link is pivoted at 191 to the arm 169 and at 192 to the leg rest bracket 133. Thus, the

links

167, 170, 190 and the arm 169 function as a lazy tongs linkage so that, when the chair mechanism is moved from the upright position of FIG. 5 to the intermediate position of FIG. 6 the rearward swinging movement of the front seat support arm 143 and the corresponding forward swinging movemnt of the leg rest arm 169 extend the leg rest as seen in FIG. 6.

In operation the second form of the mechanism functions much as does the first form, except that since there is no front support linkage the front of the seat member 131 is not elevated during movement from the intermediate position of FIG. 6 to the reclining position of FIG. 7. Otherwise the operation is the same,V with the seat member swinging rearwardly and downwardly during the first movement about the front seat support arm 143, the back bracket support arm 165 and the rear support link 161, said arms and said link moving in parallel so that there is no relative motion beteen the back bracket 132 and the seat member 131. During the second movement from the position of FIG. 6 to the position of FIG. 7 the

parallel links

156 and 158 of the rear seat support linkage swing in parallel about their

respective pivots

157 and 160 so as to elevate the rear support link 161 and thus swing the seat member 131 upwardly about its pivotal connection 145 with the front seat support arm 143. During this movement the link 165 causes the back support bracket 132 to swing downwardly about the pivot '.140 on the back of the seat member 131.

As in the first form of the invention, the front parallel link 158 idles upwardly and forwardly about the pivot 160 during the rst movement, and unitl it reaches the dead center position the

parallel links

156 and 158 are locked against parallel movement. The lost motion connection between the link 158 and the base 130 permits the idling movement of the link 158 during the travel of the mechanism between the upright position of FIG. 5 and the intermediated position of FIG. 6.

Referring now to FIGS. 9, l0 and 11, which illustrate the third form of the invention, the mechanism is seen to be exactly like that of the first form except that the unit has a seat member, indicated generally at 231, the structure of which is different from that of the seat -member 31. As indicated `in the detailed description of the first form, the drop center portion 36 of the seat member 31 adapts it to support a drop-in coil spring base. In contrast, the seat member 231 extends straight from front to rear, and thus is particularly adapted to receive a seat structure consisting of horizontally oriented serpentine spring members of the type commonly used in upholstered furniture.

The dimensions of the seat member 231 from its front pivot 245 to its rear upright arm 239 are identical with those of the seat member 31, so that a manufacturer of reclining chair mechanisms may supply a customer either with a mechanism to receive a drop-in coii spring base or with a mehanism to receive a serpentine spring seat cushion merely by using either the seat member 31 or the seat member 231. All other parts in the two units are identical, and thus no further detailed description of the third form of the invention is given herein although the drawings are numbered with reference numerals corresponding to those of the rst form of the invention but 200 numbers higher in each case.

As is well known in the art, and as previously suggested herein, various substitutions of parts may be made as, for example, using a .leg rest and leg rest linkage like that of the second orrn of the invention on the structure of the iirst or third lform of the invention, or by using the leg rest and leg rest operating mechanism of the iirst and third forms of the invention, with the second form of the invention. Similarly, the seat member 231 of the rst form of the invention may be substituted for the seat member 131 in the second form of the invention if a customer desires the combination of the lower priced linkage with the seat member designed to receive the lower cost type of upholstered seat.

In view of the fact that each of the last above mentioned modifications would be obvious to one skilled in the art in View of the structure illustrated and described for the rst three forms, no more detail of such modications is given herein.

The foregoing detailed description is given for clearness of understanding only, and no unnecessary limitations are to be understood therefrom, as modifications will be obvious to those skilled in the art.

I claim:

1. In a three position reclining chair mechanism, combination: a base; a seat member; a back bracket member pivoted on the rear of the seat member and extending rearwardly therefrom; a front seat support arm pivotally mounting the front of the seat member relative to the base; a back support arm pivotally mounting the back bracket on the base behind the seat member, said support arms swinging rearwardly substantially in parallel as the seat member and back bracket perform a rst movement from an upright position to an intermediate position so that said member and said bracket move between said positions substantially without relaitve movement; and linkage means supporting the rear of the seat member on the base, said linkage means including front and rear parallel links pivoted on the base and a support link pivoted on said links and pivotally connected at its upper end to the rear of the seat member, the upper end of said support link swinging rearwardly and downwardly about its connection to the rear parallel link during rst movement of the seat member and back bracket, and said parallel links cooperating to elevate said support link and the rear of the seat member during a further movement from intermediate position to reclining position, said support link and said back support arm cooperating to pivot the back bracket downwardly about its pivotal connection to the seat member during said further movement.

2. The mechanism of claim 1 in which the front parallel link has a lost motion connection, the support link is mounted on the front parallel link at its lower end and has an intermediate pivotal connection with the rear parallel link, and in which the front parallel link pivots idly forwardly and upwardly with the lower part oi the support link to a dead center position during the rst movement.

3. The mechanism of claim 1 which includes an extensible and retractable leg rest pivotally mounted adjacent the front of the base, and in which the front seat support arm has an extension which provides part of the pivotal mounting for the leg rest so that the irst movement of the seat member extends the leg rest.

4. The mechanism of claim i in which the seat member pivots about the front seat support arm during said further movement.

5. The mechanism of claim 1 where includes a long support arm pivotally mounted toward the rear of the base and having the front seat support arm pivotally mounted at its front end, a bell crank pivotally mounted on the base below sai-d long suport arm, a short link connecting a i'lrst arm of the bell crank to the long support arm, and a long coordinating link connecting the second arm of the bell crank to the rear parallel link.

5. The mechanism of claim S which includes an extensible and retractable leg rest which is pivotally mounted on the front portion of the long support arm, and in which the front seat support arm has an extension which provides part of the pivotal mounting for the leg rest so that the rst movement of the seat member extends the leg rest.

7. The mechanism of claim 1 in which the seat member is substantially straight from front to rear, and has an upwardly extending portie-n at the rear in which the pivots for the back bracket and the support link are mounted.

Vv8. The mechanism of claim 1 in which the seat member has a central portion adapted to receive a drop-in spring base, the front portion of the seat member extends forwardly and upwardiy from said central portion, and there is an upwardly extending portion at the rear of said central portion in which the pivots for the back bracket and the support link are mounted.

9. In a three position reclining chair mechanism, in combination a base;

a seat member;

a back bracket pivoted on the rear of the seat member and extending rearwardly therefrom;

front linkage means mounting the front of the seat member on the base, said front linkage means including a long support arm pivoted on the base, a plurality of links adapted toraise and lower the front of said support arm, and a front seat support arm pivotally mounting the front of the seat member on the long support arm;

rear linkage means mounting the rear of the seat member on the 1oase, said rear linkage means including a plurality of links pivoted on the base and a support link connecting the rear of the seat member with said plurality of links;

a back support arm pivotally mounting the back bracket on the base behind the seat member;

a coordinating link connecting the front linkage means and the rear linkage means; said front and rear linkage means and said back support arm cooperating to support the seat and back bracket for a rst unitary rearward swinging movement from an upright position to an intermediate position, and said front and rear linkage means cooperating during further movement to elevate the front and rear of the seat member while said back support arm causes the back bracket to tilt downwardly relative to the rear of the seat member;

and extensible and retractable leg rest means swingingly suspended from the front of the front linkage means and operatively connected with the front seat support arm so that the leg rest is substantially fully extended during irst movement.

10. The mechanism of claim 9 in which the plurality of links in the front linkage means comprises a bell crank pivoted on the base and a short link pivoted on one arm of the bell crank and on the long support arm, and in which the coordinating link is pivotally connected to the other arm of the bell crank.

11. The mechanism or" claim 9 in which the plurality of links in the rear linkage means comprises front and rear parallel links pivoted on the base, and in which the rear support link is pivoted at its lower end on the front parallel link, is pivoted intermediate its ends on the rear parallel link, and is pivoted at its upper end on the seat member.

12. The mechanism of claim 11 in which the coordinating link is pivotally connected to the rear parallel link.

13. The mechanism of claim 12 in which the plurality of links in the front linkage means comprises a bell crank pivoted on the base and a short link piv'oted on one arm of the bell crank and on the long support arm, and in which the coordinating link is pivotally connected to the other arm of the bell crank.

14. The mechanism of claim 9 in which the relationship between the front linkage means, the rear linkage means and the coordinating link is such that during said further movement the rear of the seat member elevates more than twice as far as does the front of the seat member.

References Cited UNITED STATES PATENTS JAMES T. McCALL, Primary Examiner