AU564548B2

AU564548B2 - Seat tilting mechanism

Info

Publication number: AU564548B2
Application number: AU30698/84A
Authority: AU
Inventors: Paul Andrew Boardman
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-06-18
Filing date: 1984-06-18
Publication date: 1987-08-13
Anticipated expiration: 2004-06-18
Also published as: EP0151141B1; DK74285A; WO1985000006A1; JPS60501589A; DE3480166D1; NO850578L; FI850635L; DK74285D0; EP0151141A1; FI850635A0; AU3069884A; GB8316651D0

Description

-J-

ARMCHAIR WITH TILTABLE SEAT

TECHNICAL FIELD

This invention relates to an armchair having a tiltable seat to provide aid to an occupant in rising from the seat.

BACKGROUND ART Chairs having tiltable seats are known in the art. For example, a chair having a seat in which the tilting move¬ ment is actuated by spring-loading designed specifically for a particular user is known. It is also known to pro¬ vide a chair with a tiltable seat in which the tilting movement is pneumatically or electrically controlled.

However, these seats tend to be expensive, bulky and difficult to operate by infirm or elderly persons.

DISCLOSURE OF THE INVENTION The present invention seeks to overcome the disadvantages of prior constructions by providing a chair with a tiltable seat which is actuated by a relatively simple mechanism and which utilizes the normal force which an occupant exerts in rising from the seat.

To this end, the invention provides an armchair having a seat tiltable relative to a fixed frame of the chair to provide aid to an occupant in rising from the chair, the seat being tiltable from a lowered position to a raised position by a lever mechanism provided beneath the seat,

-^{* E}

O PI characterised in that the lever mechanism is operatively connected to at least one pivotal arm assembly of the chair and is actuated by downward movement of that arm by force exerted thereon by the occupant in rising from the chair.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings .

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective view of an armchair according to the invention;

FIGURE 1A is an exploded view of the main structural com¬ ponents of the chair;

FIGURE 2 is a side view of one side frame member of the chair showing the seat in a til ted and raised posi tion;

FIGURE J is a side view similar to FIGURE 2 but showing the seat in a lowered posi tion as normally occupied.

FIGURE 4 is a part-sectional perspecti ve view of a pivotal arm assembly incorporating locking means by which the til t¬ ing mechanism is held locked relati ve to the fixed frame of the chair;

FIGURE 5 is a detailed cross-sectional view of the locking means shown in locked condition; and

FIGURE 6 is a view similar to FIGURE 5 but showing the locking means in a released condi tion .

/ j O tvlϊ . BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the drawings, the armchair 10 is of modular con truction of which the main structural components comprise a pair of similar side frames 12, 14 respecti vely, inter¬ connected and spaced apart by a til table sea t pan 16 and a back frame 18, and a pair of pi votal arm assemblies 20, 22 respecti vely, each of which actuates a seat til ting mechanism such as mechanism 24.

Side frame 14 comprises a main upright strut 26, a foot 28 integral wi th upright strut 26 and a forwardly projecting support member 30 also integral wi th the upright strut intermediate i ts ends. Side frame 12 is of similar cons¬ truction.

The back frame 18 is a simple rectangular frame comprising longi tudinal and transverse frame elements 32, 34 and 36, 38 respecti vely. The longi tudinal frame elements are formed wi th fastening locations '1 ' at which the side frames are connected to the back frame by sui table fasteners at fixing locations ' f . The transverse frame element 38 is displac- ed forwardly of the plane containing the other frame elements and thereby provides a step 's ' on which the rear¬ most part of the seat pan is supported when the seat is in i ts lowered (substantially horizontal ) posi tion . The back frame is in-filled by a sui table material , which may be at tached to the longi tudinal frame elements as shown in order to provide the chair back 40.

The seat pan 16 also comprises a generally rectangular frame comprising longi tudinal and transverse frame elements 42, 44 and 46, 48, respecti vely. The forward transverse frame element 48 is displaced rearwardly and below the longi tudinal frame elements so that the frame in-fill mat¬ erial 50 is wrapped over the leading edge of the seat to aid comfort of the user. The forward end of each of the longi tudinal frame elements is furnished wi th a journal bush 52 and 54, respecti vely, by which the leading edge of -4-

of the seat is pivotally connected to the tilting mechanism 24.

The seat tilting mechanism will now be described with 5 reference to mechanism 24 associated with side frame 14, it being understood that a similar mechanism is associated with the other side frame 12.

Mechanism 24 comprises a main tilting lever 56 which is 10 pivotally mounted at 'P* intermediate its ends to support member 30 of side frame 14. One end of lever 56 carries a stub shaft 58 which engages beneath seat pan longitudinal frame element 44.

15 The stub shaft 58 may be replaced by a rod which connects together the main lifting le ers of both tilting mechanisms and which extends across the seat par 16. The opposite end of main tilting lever 56 is pivotally mounted at 60 to the lower end of a connecting strut 62 of pivotal arm assembly

20 22. The upper end of strut 62 is hinged to the forward end of pivotal arm 64 of the assembly 22 by means of a hinged connection 66. The rearward end of pivotal arm 64 is pivotally mounted to the side frame 14 by pivotal connection 68.

25

In order to provide simultaneous lifting and forward movement of the seat pan 16, a main lifting lever 70 has one of its ends pivotally journalled to the leading edge of the seat frame by means of a pivotal connection to journal

30 bush 54 and has its opposite end pivotally and slidably mounted to the support member 30 adjacent upright strut 26 by means of pivot 72 mounted within slider 74, The main lifting lever 70 is interconnected with the main tilting lever 56 intermediate their ends by means of pivotal

35 connection 76.

The seat tilting mechanism 24 is actuated by pivotal move¬ ment of the arm assembly 22 as will now be described.

-^T-ΪE

OMPI The connecting strut 62 of the arm assembly 22 is of hollo construction and houses a reciprocal actuator push rod 7 which slides in a through bore 80 of the strut 62. Th upper end of push rod 78 abuts the undersurface of a actuating but ton 82 wi thin button recess 84. The lower en of the push rod is formed to provide an inclined face 8 which cooperates wi th detent 88 ha ving a cunieform reces 90 in i ts mid-section . Detent 88 is slidably accommodate wi thin a blind bore 92 extending trans versely o f the s tru adjacent i ts lower end. The detent has a locking nos portion 94 which normally protrudes proud of the mouth o blind bore 92 and engages in a recessed step 96 provided a the forward end of support member 30 thereby to hold th pi votal arm assembly locked to the support member agains pi votal movement .

In order to release strut 62 to permi t pi votal movemen o f the arm assembly 22 the push rod is caused to mo ve down wardly whereby the inclined surface 86 acts on the opposi t ely inclined surface 98 of the detent mid-section an forced the detent to slide inwardly of blind recess 9 against the force of compression spring 100. Thus, th nose portion 94 is retracted out of engagemen t wi th the recess step 96 to unlock the pi votal arm assembly .

The actuating but ton extends through an aperture 102 pro vi¬ ded a t the forward end o f pi votal arm 64 so tha t an exposed portion of the button stands proud of the pi votal arm 64 and is depressed to cause a downward movement of the push rod.

The lower end of strut 62 is formed wi th a stepped portion 104 which seats in an opposi tely stepped portion provided in the lower forward end of support member 30 when the arm assembly is in i ts locked condi tion .

The other arm assembly 20 is similarly constructed.

OMPI When both arm assemblies are in their locked positions, the pivotal arms thereof are in a substantially horizontal position and the connecting struts are in an upright posi¬ tion as shown in solid lines in FIGURE 2. Moreover, in this condition the seat pan 16 is in its lowered position i.e substantially horizontal and the main levers of the tilting mechanism 56 and 70 are in folded condition adjacent the inner faces of the support members of their respective side frames. Hence, the chair may be used as a normal arm chair.

In order to benefit from the aid a user derives in rising from the chair by the tiltable seat, the occupant first depresses the actuating buttons of each arm assembly simultaneously so as to unlock those assemblies. The occupant thereafter actuates the seat tilting mechanism by pushing downwardly on the forward ends of the pivotal arms during rising and also shifts forwardly in the seat. This is a quite natural movement normally affected in rising from an armchair.

However, in the chair according to this invention, such rising movement by the occupant operates the tilting mechanism again referred to in relation to mechanism 24. As the pivotal arm 64 moves downwardly about pivot 68, connecting strut 62 pivots anti-clockwise about hinge 66 thereby causing the main tilting lever 56 to rotate clock¬ wise about pivots 60 and 'P'. Thus, stub shaft 58 pushes upwardly against the seat frame and in so doing executes a relative sliding movement with respect thereto travelling forwardly of the seat frame. Thus, the seat is caused to pivot about its journalled forward end e.g jounal bush 54 in a clockwise direction whereby the rear of the seat frame is raised relative to its front end.

Since levers 56 and 70 are interconnected, clockwise rotation of lever 56 also causes pivot 76 to shift relative to fixed pivot 'P' and thus the pivotal movement of lever 56 is accompanied by a generally forward sliding movement of pivot 72 relative to slider 74 during anti-clockwise rotation of lever 70 about pivot 72. Thus, the leading edge of the seat simultaneously is raised and moved forwar- dly relative to the support member 30. Hence, the scissor- like assembly of levers 56 and 70 is 'opened' when the seat is in its raised and tilted condition.

When the occupant returns to the chair and sits upon the seat, the occupants body-weight causes the seat to be lowered thus 'closing' the scissor-like mechanism to its initial position. The connecting strut detents automatica¬ lly lock into the support members due to their spring loaded bias and due to the ramp surface provided at the tip of the detent nose portion.

As shown in FIGURE 1 the feet of the side frames have divergent forward facing portions to provide a stable base for the chair. Further, this arrangement allows a user having a walking aid to approach the chair more easily.

In order to allow the seat to return gradually to its lowere position a one-way damping device 'D', which may be a pneu matic piston and cylinder device is interconnected betwee pivot 54 and 58 thereby to return lowering movement of th seat. It is to be understood that the relative ratios of th lever sizes and their pivotal locations can be adjusted t provide different tilt angles of the seat and to vary th height to which the seat is raised. For example, where th damping device 'D' is a pneumatic piston and cylinder devic the angle of inclination of the raised seat is arranged to b less acute so that end 58 of the main tilting lever travels smaller distance relative to the seat frame.

Claims

1. An armchair having a seat til table relati ve to a fixed frame of the chair to provide aid to an occupant in rising from the chair, the seat being tiltable from a low¬ ered position to a raised posi tion by a lever mechanism provided beneath the seat, characterised in that the lever mechanism is operatively connected to at least one pi votal arm assembly of the chair and is actuated by downward movement of that arm by force exerted thereon by the occupant in rising from the chair.

2. An armchair according to claim 1 , further character¬ ised in that the lever mechanism causes the rear of the seat to til t forwardly relati ve to a forward part of the seat and simul taneously raises and moves the seat forwardly relati ve to the fixed frame.

3. An armchair according to claim 1 or claim 2 further characterised in that the fixed frame of the seat comprises a cantilevered support element about which the lever mech- anism is pivotal and in that locking means is provided to lock said pi votal arm assembly relative to the support element and thereby arrest movement of the lever mechanism when the chair is in use.

CMPΓ

4. An armchair according to claim 3, further charact¬ erised in that the pi votal arm assembly comprises a pi votal arm pi votally mounted to a part of the fixed frame above said cantilevered support element and a connecting strut ha ving one end pi votally connected to the pi votal arm remote from i ts pi votal mounting and an opposite end connected to one end of a main til ting lever of the lever mechanism said opposi te end of the arm also incorporating the locking means by which the pi votal arm assembly is locked relati ve to the fixed frame .

5. An armchair according to claim 4 , further charact¬ erised in that said main til ting lever is pi votally mounted intermediate i ts ends to said cantilever support member and has an opposi te end loca ted for abutment wi th the chair seat such as to til t a rear part of the seat relati ve to a forward end thereof during rotation of the main til ting lever wi th respect to said cantilevered support member .

6. An armchair according to claim 5, further charact¬ erised in that a main li fting lever pi votally is connected to said main li fting lever intermediate the ends of those levers to form a scissor-like assembly, in that one end of the main li fting lever pi votally is mounted to a forward part of the seat and in that the opposi te end of the main li fting lever is pi votally and slidably mounted to said cantilevered support member rearwardly of the pi votal connection between the main til ting lever and the canti¬ levered support member.

7. An armchair according to any of clai ns 4 to 6, furthe characterised in that the locking means comprises a deten housed in said connecting strut of the pi votal arm assembl which detent engages a forward end of said cantilevere support element and in that the detent is movable out o locking engagement wi th said cantilevered support element b a reciprocal rod movable by an actuating button provided a the forward end of the pi votal arm of the arm assembly

8. An armchair according to claim 7, further characteris¬ ed in that the detent is resiliently biased automatically to lock the pi votal arm assembly when the seat is returned to i ts lowered posi tion.

OMPI