Sitting apparatus

Abstract

A sitting apparatus having a frame configured to be situated at a sitting location. A seat assembly on the frame defines a support for a user in a sitting position. At least one armrest assembly has at least one surface to support an arm of a user in a sitting position on the seat assembly. The at least one armrest assembly is configured to be changed between first and second states. The at least one surface changes in angular relationship to a horizontal reference plane as an incident of the at least one armrest assembly changing between the first and second states.

Claims

1. A sitting apparatus comprising: a frame configured to be situated at a sitting location; a seat assembly on the frame defining a support for a user in a sitting position; and at least one armrest assembly having at least one surface to support an arm of a user in a sitting position on the seat assembly, the at least one armrest assembly configured to be changed between first and second states, the at least one surface changing in angular relationship to a horizontal reference plane as an incident of the at least one armrest assembly changing between the first and second states, wherein the at least one surface moves in an arc centered above the at least one surface as the at least one armrest assembly changes between the first and second states.

2. The sitting apparatus according to claim wherein the sitting apparatus has a front and rear and laterally spaced sides and the sitting apparatus is configured so that a lateral inclination of the at least one surface can be changed.

3. The sitting apparatus according to claim 1 wherein the sitting apparatus has a front and rear and laterally spaced sides and a front-to-rear inclination of the at least one surface changes as the at least one armrest assembly changes between the first and second states.

4. The sitting apparatus according to claim 3 wherein the armrest assembly is configured so that the at least one surface follows movement of a part of the at least one armrest assembly that pivots around a laterally extending axis at which the arc is centered as the at least one armrest assembly is changed between the first and second states.

5. The sitting apparatus according to claim 4 wherein the laterally extending axis is located at least approximately where a shoulder joint of a user in the sitting position is located.

6. The sitting apparatus according to claim 4 wherein the laterally extending axis is adjacent to the part of the at least one armrest assembly.

7. The sitting apparatus according to claim 4 wherein the part of the at least one armrest assembly is connected to the frame through a mechanical linkage comprising first and second relatively movable components.

8. The sitting apparatus according to claim 7 wherein the part of the at least one armrest assembly defines a link member in the mechanical linkage.

9. The sitting apparatus according to claim 7 wherein the mechanical linkage has a projected pivot located at least approximately where one of: a) a shoulder joint; and b) an elbow joint of a user in the sitting position is located.

10. The sitting apparatus according to claim 1 wherein the sitting apparatus further comprises a locking assembly that is operable to selectively maintain the at least one armrest assembly in at least one of the first and second states.

11. The sitting apparatus according to claim 10 wherein the locking assembly comprises an actuator that is configured to be moved by a user, the actuator comprising at least one of: a) a component that is movable independently of the at least one surface on the at least one armrest assembly; and b) a part of the at least one armrest assembly that moves with the at least one surface as the at least one armrest assembly is changed between the first and second states.

12. The sitting apparatus according to claim 1 wherein the at least one armrest assembly comprises first and second laterally spaced armrest assemblies.

13. The sitting apparatus according to claim 12 wherein the first and second armrest assemblies are configured so that the at least one surface on the first and second armrest assemblies can be relatively moved to change a lateral spacing between the at least one surface on the first and second armrest assemblies.

14. The sitting apparatus according to claim 12 wherein the first and second armrest assemblies are configured so that the at least one surface on each of the first and second armrest assemblies can be selectively raised and lowered relative to the frame.

15. The sitting apparatus according to claim 12 wherein the first and second armrest assemblies are configured so that the at least one surface on each of the first and second armrest assemblies can be selectively moved around a respective vertically extending axis.

16. The sitting apparatus according to claim 1 wherein the sitting apparatus further comprises a backrest that is configured to be moved relative to the frame so as to thereby change an angular orientation of the backrest relative to the frame.

17. The sitting apparatus according to claim 1 wherein the sitting apparatus further comprises a wheeled support for the frame.

18. The sitting apparatus according to claim 4 wherein the laterally extending axis is located at least approximately where an elbow joint of a user in the sitting position is located.

19. A sitting apparatus comprising: a frame configured to be situated at a sitting location; a seat assembly on the frame defining a support for a user in a sitting position; and at least one armrest assembly having at least one surface to support an arm of a user in a sitting position on the seat assembly, the at least one armrest assembly configured to be changed between first and second states, the at least one surface changing in angular relationship to a horizontal reference plane as an incident of the at least one armrest assembly changing between the first and second states, wherein the at least one surface moves in an arc centered approximately at a height of the one surface.

20. A sitting apparatus comprising: a frame configured to be situated at a sitting location; a seat assembly on the frame defining a support for a user in a sitting position; and at least one armrest assembly having at least one surface to support an arm of a user in a sitting position on the seat assembly, the at least one armrest assembly configured to be changed between first and second states, the at least one surface changing in angular relationship to a horizontal reference plane as an incident of the at least one armrest assembly changing between the first and second states, the armrest assembly comprising a linkage with relatively movable link members that connect to each other and a part of the at least one armrest assembly that moves as one piece with the at least one surface for relative movement around four substantially parallel axes so that the linkage has a projecting pivot location around which the at least one surface moves in an arcuate path as the at least one armrest assembly is changed between the first and second states.

21. The sitting apparatus of claim 20 wherein the projecting pivot location is generally at or below a shoulder joint of a user in a sitting position on the sitting apparatus as the at least one armrest assembly changes between the first and second states.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic representation of one form of sitting apparatus, according to the present invention, and including at least one armrest assembly with at least one arm supporting surface thereon for a user in a sitting position;

(2) FIG. 2 is a schematic representation showing additional details for the inventive sitting apparatus in FIG. 1;

(3) FIG. 3 is a partially schematic, side elevation view of a user in a sitting position on the inventive sitting apparatus and with the user's forearm supported on the surface of the armrest assembly with the armrest assembly in a first state;

(4) FIG. 4 is a view corresponding to that in FIG. 3 with the armrest assembly changed to a second state;

(5) FIG. 5 is a schematic representation of a 3-axis reference system for describing the inventive structure;

(6) FIG. 6 is a side elevation view of one exemplary form of sitting apparatus with one exemplary form of armrest assembly incorporated therein;

(7) FIG. 7 is an enlarged, side elevation view of the armrest assembly in FIG. 6 in its first state;

(8) FIG. 8 is a view as in FIG. 7 with the armrest assembly in its second state;

(9) FIG. 9 is a view as in FIG. 8 with the surface on the armrest assembly lowered;

(10) FIG. 10 is a schematic representation of a drive for changing the state of the inventive armrest assembly;

(11) FIG. 11 is a schematic representation of an armrest assembly as in FIG. 10 with a locking assembly thereon and an associated actuator therefor;

(12) FIGS. 12 and 13 are side elevation views of a modified form of armrest assembly in first and second states, respectively;

(13) FIGS. 14 and 15 are side elevation views of another modified form of armrest assembly in first and second states, respectively;

(14) FIGS. 16 and 17 are side elevations views of a further modified form of armrest assembly in first and second states, respectively;

(15) FIG. 18 is side elevation view of an armrest assembly and schematically showing a mechanism for effecting repositioning of the arm supporting surface thereon;

(16) FIGS. 19 and 20 are side elevation views of a modified form of armrest assembly in first and second states, respectively;

(17) FIGS. 21 and 22 are side elevation views of a further modified form of armrest assembly in first and second states, respectively;

(18) FIGS. 23 and 24 are side elevation views of a still further modified form of armrest assembly in first and second states, respectively;

(19) FIG. 25 is a schematic representation of a mechanical linkage connecting between an armrest assembly part, defining an arm resting surface, and a frame;

(20) FIGS. 26 and 27 are schematic representations of a further modified form of armrest assembly incorporating one form of mechanical linkage, as in FIG. 25, and in first and second states, respectively;

(21) FIGS. 28 and 29 show a modified form of linkage similar to that in FIGS. 26 and 27 and in corresponding first and second states, respectively;

(22) FIG. 30 is a further modified form of armrest assembly with a linkage as in FIGS. 26-29 in a first state and with a projected pivot coinciding with a sitting user's elbow;

(23) FIG. 31 is a view as in FIG. 30 wherein the armrest assembly has a projected pivot coinciding with a sitting user's shoulder;

(24) FIG. 32 is a side elevation view of a further modified form of armrest assembly incorporating a mechanical linkage;

(25) FIG. 33 is a side elevation view of a further modified form of armrest assembly including a modified form of mechanical linkage;

(26) FIG. 34 is a side elevation view of a further modified form of armrest assembly with a spring assist;

(27) FIGS. 35 and 36 are schematic representations of a further modified form of armrest assembly in first and second states, respectively;

(28) FIGS. 37 and 38 are schematic representations of a further modified form of armrest assembly, similar to that in FIGS. 35 and 36, in first and second states, respectively;

(29) FIG. 39 is a side elevation view of an armrest assembly with a generic form of locking assembly to fix a desired position of the armrest support surface;

(30) FIG. 40 is a side elevation view of another form of armrest assembly with a specific form of locking assembly incorporated;

(31) FIGS. 41-43 are underside schematic representations of riser components in FIG. 40 in different positions relative to a part on which the armrest surface is defined to place the arm support surface in different positions;

(32) FIG. 44 is a partially schematic, perspective view of a modified form of armrest assembly with a locking assembly thereon; and

(33) FIG. 45 is an enlarged, perspective view of a mounting system, for the part of the armrest assembly in FIG. 44 defining the arm support surface, that allows repositioning of the part of the armrest assembly to operate a locking assembly thereon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(34) In FIG. 1, a sitting apparatus, according to the present invention, is shown in schematic form at 10. The sitting apparatus 10 consists of a frame 12 configured to be situated relative to a support 14 at a sitting location. The support 14 may be any type of support commonly used for sitting apparatus—including a subjacent surface upon which the frame 12 can be placed, a vertically extending structure upon which the frame 12 is mounted, an overhead structure from which the frame 12 is suspended, etc.

(35) A seat assembly 16 is situated on the frame 12 and defines a support 18 for a user in a sitting position.

(36) At least one armrest assembly 20 has at least one surface 22 to support an arm of a user in a sitting position on the seat assembly 16. While typically two such armrest assemblies 20 are incorporated, it is possible that a single armrest assembly 20 might be provided on one side of the seat assembly 16 or in a more laterally centered position.

(37) The at least one armrest assembly 20 is configured to be changed between first and second states. The at least one surface 22 is changed in angular relationship to a horizontal reference plane as an incident of the at least one armrest assembly changing between the first and second states.

(38) The sitting apparatus 10 may further include a backrest 24 that is configured to be moved relative to the frame 12 so as to thereby change an angular orientation of the backrest 24 relative to the frame 12.

(39) The seat assembly 16 may have a fixed orientation or may be adjustable relative to the frame 12. The backrest 24 may be mounted to the frame 12 independently of the seat assembly 16. Alternatively, as shown in dotted lines in FIG. 1, the backrest 24 and seat assembly 16 may be interconnected so that the seat assembly 16 and backrest 24 move in a coordinated manner.

(40) As also shown in dotted lines in FIG. 1, the backrest 24 may be interconnected to the at least one armrest assembly 20 so that changing of the angular position of the backrest 24 effects a predetermined movement of the at least one armrest assembly 20 to thereby reorient the surface(s) 22 thereon.

(41) The schematic showing of the components in FIG. 1 is intended to encompass specific components as described in exemplary embodiments hereinbelow, and virtually an unlimited number of variations in those components and their interaction that would be obvious to one skilled in the art with the teachings herein in hand.

(42) Generally, as shown also in schematic form in FIG. 2, the sitting apparatus 10, in a form with separate and laterally spaced armrest assemblies 20 on the frame 12, utilizes an armrest assembly construction and connecting structure 26 between each armrest assembly 20 and frame 12 that allows each of the surfaces 22 to be moved relative to each other and the frame 12 in multiple dimensions. While in its most basic form, only a single change in angular orientation of the surfaces 22 relative to a horizontal reference plane might be allowed, as through a front-to-rear change in inclination, in other preferred forms, the surfaces 22 thereon are at least one of: a) movable towards and away from each other in a lateral direction; b) movable vertically relative to the frame 12; c) angularly repositioned around a fore-and-aft axis; and d) movable around a vertically extending axis. The primary movement of the armrest assembly surfaces 22 that is desired is relative to the frame 12 in a manner that front-to-rear inclination of the surfaces 22 changes as the armrest assemblies are changed between the aforementioned first and second states.

(43) As seen in FIGS. 3 and 4, this primary desired movement of the surfaces 22 on the armrest assemblies 20 involves repositioning at least a part 28 of each armrest assembly 20, that defines its respective surface(s) 22. For simplicity, each armrest assembly 20 will be described with a single surface 22. In the first state for the representative armrest assembly 20, as shown in FIG. 3, the surface 22, while potentially contoured, approximates a flat support surface that is substantially parallel to a horizontal reference plane HP. As shown in FIG. 4, in the second state for the armrest assembly 20, the surface 22 is at an angle α to the horizontal plane HP with the front of the surface 22 inclined relative to the rear thereof.

(44) Different angles α may be selectively settable. It is conceivable that the angle α may be as great as 75° or more.

(45) As can be seen in FIGS. 3 and 4, the surface 22 will generally support primarily forearm and elbow regions FA, E on a user U with the user U in a sitting position on the seat assembly 16/support 18.

(46) The schematic showing of the inventive structure is intended to encompass a wide range of different capabilities. For example, in one form, the armrest assembly surfaces 22 are movable only as in FIGS. 3 and 4. This movement may be effected either by manually grasping the parts 28 to effect movement thereof or, more preferably, simply by causing movement in response to movement of the user's forearm region and/or in response to other weight shift and/or force application by the user. The position of the armrest assembly surfaces may be maintained by forces applied by the user or may be mechanically fixed by appropriate structure, as described below.

(47) In one preferred form, the various dimensions of movement of the surfaces 22—lateral and front-to-rear inclination around front-to-rear and laterally extending axes respectively, movement towards and away from each other, vertical movement, etc.—may be effected in one fluid motion by reason of the adjustment of the user's body to which the sitting apparatus 10 automatically responds. The various dimensions of movement may alternatively be effected through automated mechanisms or manually by separate manipulation of the parts, with the different configurations maintained automatically, or through one or more separate locking assemblies as shown generically at 30 in FIG. 2. Each locking assembly 30 may be operable through one or more actuators 32. The locking assemblies 30 can be used to maintain one or both of the aforementioned first and second states or other states resulting from repositioning of the surfaces 22 relative to the frame 12.

(48) For purposes of the description hereinbelow, a reference system as shown in FIG. 5 will be utilized. A three axis reference arrangement is shown with the X axis extending laterally in the direction of the double-headed arrow 34, the Y axis extending in a front-to-rear direction, as indicated by the double-headed arrow 36, and a Z axis extending in the vertical direction, as indicated by the double-headed arrow 38.

(49) Referring to FIG. 6, one more specific exemplary form of sitting apparatus 10 is shown. The support 14 is in the form of a pedestal 40 projecting upwardly from a wheeled carriage 42. The seat assembly support 18 is located at the top of the support 14. The support 18 may be at a fixed vertical height or may be vertically adjustable relative to the support 14.

(50) A backrest 24 is connected to the support 18.

(51) The frame 12 includes a fixed base 44 at one side of the frame 12 through which the exemplary armrest assembly 20 is operatively mounted. In this embodiment, like armrest assemblies 20 are provided at each side of the sitting apparatus 10.

(52) Details of one exemplary armrest assembly 20 are shown in FIGS. 7-9. In this embodiment, the armrest assembly 20 has first and second riser components 46, 48 that are configured to be placed in different vertical relationships to thereby change the armrest assembly 20 between its first state, as shown in FIG. 7, and its second state, as shown in FIG. 8. As noted above, in the first state, the surface 22, approximated as a generally flat surface, resides in a plane that is substantially parallel to the horizontal reference plane HP. In the second state, as shown in FIG. 8, the surface 22 is angled in relationship to the horizontal reference plane HP. In this case, the surface 22 makes an angle α with respect to the horizontal reference plane HP.

(53) The riser components 46, 48 are substantially straight and may be abutted to each other, in which relationship they can slide vertically together guidingly within the frame base 44 and relative to each other in the vertical direction—along the Z axis.

(54) The upper ends of the riser components 46, 48 are respectively joined to a part 50 of the armrest assembly 20, defining the surface 22, for pivoting movement about axes 52, 54, respectively. The axes 52, 54 extend laterally parallel to the X axis.

(55) With the armrest assembly 20 in its first state, the axes 52, 54 are at the same height, as seen in FIG. 7. By advancing the first riser component 46 upwardly relative to the second riser component 48 and/or the second riser component 48 downwardly relative to the first riser component 46, the relationship in FIG. 8 is realized wherein the riser components 46, 48 and part 50 cooperate to incline the surface 22 from rear to front.

(56) The riser components 46, 48 are also movable together guidingly within the base 44 in a vertical direction to change the height of the surface 22 relative to the frame 12 with the armrest assembly 20 in either its first or second states, as shown in FIG. 9.

(57) The riser components 46, 48 also cooperate with the frame base 44 to be guided together in movement around a vertical axis 56. This allows the fore-and-aft length of the part 50 to be selectively either aligned with the Y axis or angled with respect thereto.

(58) FIG. 8 discloses a generic form of a drive or drives 58 that are configured to effect relative movement between the riser components 46, 48 and base 44 to allow the armrest assembly 20 to be moved relative to the frame 12 in the various manners described above. The drive(s) 58 could be automated or simply respond to different weight shifting and movements of the user's limbs.

(59) In one exemplary form, as shown additionally in schematic form in FIG. 10, the drive 58 consists of one or more toothed members 60 that cooperate with one or more drive gears 62. One or more toothed members 60 can be associated with the frame 12 and/or components making up the armrest assembly 20. One or more drive gears 62 effect appropriate movement of the toothed member(s) 60 to change the state of the armrest assembly 20 and cause the other movements of the surface 22, as described above.

(60) The drive gear(s) 62 can be moved through an appropriate actuator 64. The change of state may be accomplished automatically in response to operation of the actuator 64 and/or may result from a shifting of the user's limbs and weight.

(61) In the embodiment shown in FIGS. 7-9, one toothed member is shown on the riser component 48 which cooperates with a drive gear 62 that is on the riser component 46 and turned to effect relative vertical movement between the riser components 46, 48.

(62) The generic showing of the drive 58 in FIG. 8 is intended to encompass virtually an unlimited number of other drive transmission structures/mechanisms, including crank-and-slot arrangements, screw gear arrangements, rack-and-pinion arrangements, etc.

(63) As noted above, a particular configuration of the sitting apparatus 10, including the armrest assemblies 20, can be maintained by forces applied by a user. The aforementioned locking assemblies 30 can be utilized to maintain any desired state of the armrest assemblies 20, including the first and second states described above.

(64) In one exemplary form, shown schematically in FIG. 11 with a part 66 of the armrest assembly having teeth 68, as on the member 60 in FIG. 10, the locking assembly 30 may have a component 70 that is moved between adjacent teeth 68 with the locking assembly in a locked state. Disengagement of the components 70 from between the teeth 68 places the locking assembly in an unlocked state. Repositioning of the components 70 can be effected directly or indirectly through the aforementioned actuator 32, that may be a dedicated component. Alternatively, movement of another component, such as the part 50, as described below, may effect changing of the locking assembly 30 between locked and unlocked states. In that event, the part 50 serves as the actuator 32.

(65) The component 70 may be movable through a pivoting action, through translation, or in another manner to effect changing of the state of the locking assembly 30.

(66) It is not necessary that the component 70 interact with existing components, as a dedicated locking structure might be incorporated as an alternative.

(67) A number of different embodiments are described below. Corresponding parts on the various embodiments will be identified with the same reference numerals and differentiated with different “′” designations.

(68) In FIGS. 12 and 13, one modified form of armrest assembly is shown at 20′. The armrest assembly 20′ has riser components 46′, 48′ that cooperate with a fixed frame base 44′.

(69) The part 50′, defining the surface 22′, is connected to the riser component 48′ for pivoting movement relative thereto around a laterally extending axis 54′.

(70) A cam component 72 is mounted to the riser component 48′ for pivoting movement around a laterally extending axis 74. The cam component 72 is also connected to the riser component 46′ for pivoting movement about a laterally extending axis 76 that is offset from the axis 74.

(71) Upward movement of the riser component 46′ within the frame base 44′ and relative to the riser component 48′ causes the cam component 72 to act against an underside surface 78 of the part 50′ forwardly of the axis 54′, thereby causing pivoting of the part 50′ around the axis 54′ between the position shown in FIG. 12 and that in FIG. 13. This corresponds to a change between first and second states for the previously described armrest assembly 20.

(72) In FIGS. 14 and 15, a further variation of the inventive armrest assembly is shown at 20″ with riser components 46″, 48″ between which a third riser component 80 is provided that is in a fixed position relative to the frame 12″. The riser components 46″, 48″, 80 cooperate with a fixed frame base 44″.

(73) The upper ends of the riser components 46″, 48″ each is pivotally connected to the part 50″ for relative movement around laterally extending axes 52″, 54″, respectively. The upper end of the riser component 80 is connected to the part 50″ for pivoting movement around a laterally extending axis 82, that is between the axes 52″, 54″. As depicted, the axes 52″, 54″, 80 reside in a common plane.

(74) The lower region of the riser component 80 is fixed to the frame base 44″. As the riser components 46″, 48″ are moved up and down relative to each other and the riser component 80, the part 50″ pivots about the axis 82 whereby the part 50″ is changed between the positions shown in FIG. 14 and FIG. 15. The FIG. 14 state for the armrest assembly 20″ corresponds to the first state for the armrest assemblies 20, 20′, previously described, with the state of the armrest assembly 20″ in FIG. 15 corresponding to the second state for the armrest assemblies 20, 20′.

(75) In FIGS. 16 and 17, a further modified form of armrest assembly is shown at 20′″. The primary difference between the armrest assemblies 20, 20′″ is that the riser component 46′″ is made from two pieces 84, 86 with adjacent ends joined for pivoting movement around a laterally extending axis 88.

(76) As the armrest assembly 20′″ is changed from a first state into a second state, corresponding to those shown for the armrest assembly 20, by upward movement of the riser component 46′″ relative to the riser component 48′″, the riser component pieces 84, 86 pivot, as shown in FIG. 17, thereby avoiding any friction or binding that might interfere with the transition of states. The operation of the armrest assembly 20′″ is otherwise the same as that for the armrest assembly 20.

(77) In FIG. 18, a further modified form of armrest assembly is shown at 20.sup.4′. The armrest 20.sup.4′ has a single riser component 90 that cooperates with a fixed frame base 44.sup.4′. An upper region of the riser component 90 is connected to the part 50.sup.4′ so that the part 50.sup.4′ moves relative thereto around a laterally extending axis 82.sup.4′, which allows the part 50.sup.4′ to pivot between the solid lines and dotted line positions, respectively representing first and second states for the armrest assembly 20.sup.4′.

(78) An appropriate mechanism 92 connects between the part 50.sup.4′ and at least one of the riser component 90 and fixed frame base 44.sup.4′ to allow automated changing of the state of the armrest assembly, permit user limb movement to effect this reconfiguration, effect locking, etc.

(79) In FIGS. 19 and 20, a further modified form of armrest assembly, according to the present invention, is shown at 20.sup.5′. The armrest assembly 20.sup.5 has a part 50.sup.5′, which defines the surface 22.sup.5′, that is fixed to a guide piece 94. The guide piece 94 has a curved length, with the curvature thereof matched to the curvature of a passage 96 for the guide piece 94 defined by a support 98.

(80) The support 98 has a bent shape with a lower portion 100 that cooperates with a fixed frame base 44.sup.5′ to allow the support 98 to be moved guidingly upwardly and downwardly relative to the frame base 44.sup.5′. As depicted, the lower part 100 and frame base 44.sup.5′ make a telescoping connection. As with all such connections incorporated in any embodiments, the invention contemplates that the inside/outside relationship of telescoped components can be reversed.

(81) In FIG. 19, the guide portion 94 is shown extended a predetermined amount into the passage 96, which represents a first state for the armrest assembly 20.sup.5′. Because of the complementary curvatures of the guide portion 94 and passage 96, upward movement of the guide portion 94 relative to the support 98 causes the part 50.sup.5′ to incline from rear to front until the corresponding second state for the armrest assembly 20.sup.5′, as shown in FIG. 20, is achieved.

(82) FIGS. 21 and 22 show an armrest assembly at 20.sup.6′ that is a refinement of the more generic version shown in FIGS. 19 and 20 for the armrest assembly 20.sup.5′ therein. The armrest assembly 20.sup.6′ utilizes the same type of support 98.sup.6′ that cooperates with a fixed frame base 44.sup.6 and guide piece 94.sup.6′ on a part 50.sup.6′ that defines the armrest surface 22.sup.6′.

(83) In this embodiment, the curvatures of the passage 96.sup.6′ and guide piece 94.sup.6′ are approximated by an arc with a radius R that is centered at approximately the location of a user's elbow, indicated at 102, with the user in a sitting position. Thus, as a user, in a sitting position with his/her forearms resting on the surface 22.sup.6′, bends his/her arm at the elbow, the part 50.sup.6′ of the armrest assembly 20.sup.6′ comfortably follows that path. That is, the surface 22.sup.6′ follows the natural pivot path of a user's forearm as it hinges at the user's elbow.

(84) FIGS. 23 and 24 show a further modified form of armrest assembly at 20.sup.7′ that has the same basic components as the armrest assembly 20.sup.6′—notably, a support 98.sup.7′ defining a curved passage 96.sup.7′ that cooperates with both a fixed frame base 44.sup.7′ and a guide piece 94.sup.7′ with a part 104 having a curvature matched to that of the passage 96.sup.7′.

(85) The primary difference between the armrest assemblies 20.sup.6′ and 20.sup.7′ is that the curvature of the guide piece 94.sup.7′ and that of the passage 96.sup.7′ is greater than that for the corresponding parts on the armrest assembly 20.sup.6′.

(86) In a preferred form, the curvature of each of these components is approximated by an arc with a radius R2 centered approximately where a user's shoulder pivots with the user U in a sitting position, as shown in FIG. 23. This arc center location is indicated at 106. Accordingly, movement of the part 50.sup.7′ defining the surface 22.sup.7′ comfortably follows the pivoting movement of the entire arm of the user as it is repositioned while generally maintaining the bent shape shown in FIG. 23.

(87) Essentially, for the armrest assemblies 20.sup.6′ and 20.sup.7′, the pivot axes for the parts 50.sup.6′ and 50.sup.7′ are moved from a location adjacent to the parts 50.sup.6′ and 50.sup.7′ to be at or adjacent elbow and shoulder joints for a user.

(88) In FIG. 25, another generic type structure for connecting the exemplary arm assembly part 50, with the surface 22 thereon, to the fixed frame 12, is shown. The connecting structure is a mechanical linkage 108. This mechanical linkage 108 is part of the generic connecting structure 26 identified in FIG. 2. Specific exemplary forms of the mechanical linkage 108 will now be described, with it being understood that these are exemplary in nature only as virtually an unlimited number of different mechanical linkages might be devised that facilitate movement of the arm rest assembly part 50 relative to the frame 12 to change the associated armrest assembly between first and second states therefor.

(89) In FIGS. 26 and 27, an armrest assembly according to the present invention is shown at 20.sup.8′ with one form of the mechanical linkage 108.sup.8′ incorporated. While not required, this mechanical linkage uses four link members L1, L2, L3, L4, with the front and rear of the armrest assembly 20.sup.8′ identified at F and R, respectively. The link members L1, L2, L3, L4 pivot where connected to each other about parallel axes extending into the page. The link member L1 is the part 50.sup.8′ that defines the arm support surface 22.sup.8′. The link member L3 is fixed to, or part of, the frame 12.sup.8′.

(90) Through this linkage arrangement, the link member L1 can be controllably repositioned to change the armrest assembly 20.sup.8′ between the FIG. 26 and FIG. 27 states, corresponding to the aforementioned first and second states therefor.

(91) Changing of the states of the armrest assembly 20.sup.8′ can be effected by any means or mechanism herein described or mentioned.

(92) FIGS. 28 and 29 show a modified form of mechanical linkage 108.sup.9′ on an armrest assembly 20.sup.9′ with four link members L1.sup.9′, L2.sup.9′, L3.sup.9′, L4.sup.9′ corresponding to the link members L1, L2, L3, L4, successively on the armrest 108.sup.8′. The armrest assembly 20.sup.9′ has a front F and rear R.

(93) The transverse orientation of the fixed link member L3.sup.9′, compared to the corresponding link member L3, and the L-shaped configuration of the link member L1.sup.9′, allow an inverted configuration for the link L1.sup.9′ having the associated armrest surface 22.sup.9′.

(94) Again, the linkage 108.sup.9′ allows changing of the armrest assembly 20.sup.9′ between first and second states as shown respectively in FIGS. 28 and 29.

(95) FIG. 30 shows another modified form of armrest assembly 20.sup.10′ with a mechanical linkage 108.sup.11′ with four link members L1.sup.10′, L2.sup.10′, L3.sup.10′, and L4.sup.10′, with the operative orientation of the mechanical linkage 108.sup.10′ having a front and rear as identified at F and R.

(96) The mechanical linkage 108.sup.10′ has a projected pivot location at 110 that corresponds to a user's elbow joint location with the user's arm resting on the surface 22.sup.10′.

(97) FIG. 31 depicts a further modified form of armrest assembly 20.sup.11′ with a front F and rear R and corresponding link members L1.sup.11′, L2.sup.11′, L3.sup.11′, and L4.sup.11′ which cause the projected pivot location at 112 to reside at a user's shoulder joint with the user in a sitting position and having his/her arm resting on the surface 22.sup.11′.

(98) In each of the embodiments in FIGS. 26-31, the part of the armrest assembly that defines each surface 22.sup.8′, 22.sup.9′, 22.sup.10′, 22.sup.11′ defines one of the link members. However, this is not a requirement.

(99) FIG. 32 discloses a further modified form of armrest assembly at 20.sup.12′ with a part 50.sup.12′ defining a support surface 22.sup.12′. The part 50.sup.12′ is part of a mechanical linkage at 108.sup.12′ that is mounted on a support 114 that moves guidingly in a vertical direction relative to a fixed frame base 44.sup.12′.

(100) The mechanical linkage 108.sup.12′ has three link members L5, L6, L7 with the link member L5 being the part 50.sup.12′ defining the surface 22.sup.12′. The link members L6, L7 each has an end connected to the support 114 for pivoting movement about laterally extending axes 116, 118, respectively. The opposite ends of the links L6, L7 move within horizontally elongate slots 120, 122, respectively on the part 50.sup.12′. The links L6, L7 are thus allowed to pivot and translate within the slots 120, 122, which thereby allows the surface 22.sup.12′ to be inclined from rear to front as in earlier embodiments. By this reconfiguration, the armrest assembly 20.sup.12′ is changed between corresponding first and second states. The part 50.sup.12′ moves without a fixed pivot axis. Essentially, it pivots and translates simultaneously as the armrest assembly 20.sup.12′ changes states. The armrest assembly 20.sup.12′ is front/rear neutral.

(101) FIG. 33 shows an armrest assembly 20.sup.13′ with a front F and rear R and a mechanical linkage 108.sup.13′ with similarities to the mechanical linkage 108.sup.12′ in FIG. 31.

(102) The mechanical linkage 108.sup.13′ has three link members L5.sup.13′, L6.sup.13′ and L7.sup.13′.

(103) In place of the slot 122, the part 50.sup.13′ has a pivot connection to the link member L7.sup.13′ which allows the link members L5.sup.13′, L7.sup.13′ to move relative to each other around a fixed, laterally extending axis 124. This linkage arrangement allows reorientation of the part 50.sup.13′ to change the armrest assembly 20.sup.13′ between corresponding first and second states.

(104) Both armrest assemblies 20.sup.12′ and 20.sup.13′ can be automatically or manually reconfigured by incorporating an appropriate mechanism and potentially separate actuating structure therefor.

(105) In FIG. 34, a further modified form of armrest assembly is shown at 20.sup.14′. The armrest assembly 20.sup.14′ has riser components 46.sup.14′, 48.sup.14′ that move vertically relative to each other to effect a change of state of the armrest assembly 20.sup.14′, as a result of a front inclination of the part 50.sup.14′ defining the armrest surface 22.sup.14′.

(106) Rather than providing fixed pivot locations for the upper regions of the riser components 46.sup.14′, 48.sup.14′, the riser 46.sup.14′ has a component 126 that moves in an elongate slot 120.sup.14′. Thus, the upper end of the riser component 46.sup.14′ translates and pivots relative to the part 50.sup.14′ as the state of the armrest assembly 20.sup.14′ is changed.

(107) In this embodiment, the riser component 48.sup.14′ is normally urged upwardly relative to a fixed frame base 44.sup.14′ by a biasing assembly shown schematically at 130. An additional biasing assembly 132 urges the riser component 46.sup.14′ upwardly relative to the riser component 48.sup.14′ so that the biasing forces provide a “spring assist” as the armrest assembly 20.sup.14′ is being changed into its second state, as depicted in FIG. 34.

(108) This structure, among other things, potentially allows for a more comfortable transition between first and second states, regardless of how the transition is effected.

(109) In FIGS. 35 and 36, a further modified form of armrest assembly is shown at 20.sup.15′. In this embodiment, a part 50.sup.15′, upon which the surface 22.sup.15′ is defined, has a guide portion 134 that moves in a track 136 that is on or part of the frame 12.sup.15. The guide portion 134 and track 136 have a complementary curved shape so that the part 50.sup.15′ is guided around a laterally extending axis 138. This movement allows the armrest assembly 20.sup.15′ to be changed between the first state in FIG. 35 and the second state in FIG. 36, corresponding to those same states for the various armrest assemblies discussed above.

(110) The axis 138 may be located at, or adjacent, a user's elbow joint with the user in a sitting position.

(111) FIGS. 37 and 38 show a further alternative form of armrest assembly at 20.sup.16′, which utilizes the same basic structure, shown in FIGS. 35 and 36, to guide the part 50.sup.16′ with the surface 22.sup.16′ about an axis 138.sup.16′ to place the armrest assembly 20.sup.16′ in first and second states, respectively in FIGS. 37 and 38.

(112) The armrest assembly 20.sup.16′ is preferably configured so that the axis 138.sup.16′ coincides with, or is adjacent to, a user's shoulder joint with the user in a sitting position.

(113) This basic concept can be utilized with a number of different interacting components. For example, bearings might be utilized to guide relative movement between the components. Wheels could move in a track. A ball and socket, universal joint, or gimbal arrangement could be utilized. Virtually any type of structure that allows this guided movement of the parts 50.sup.15′, 50.sup.16′ is contemplated.

(114) The invention contemplates variations of the above structures within the schematic showings thereof. For example, as shown in FIG. 23, the base 44.sup.7′, that is normally a fixed part of the frame, might be movable independently around a laterally extending axis 140 to provide, or augment, the inclination of the surface 22.sup.7′.

(115) With the various embodiments described above, an adjusted position of the armrest surfaces may be maintained either by forces imparted by a user or through mechanical structure that may be operated by the user. The locking assembly/locking assemblies 30 that accomplish this, if manually operated, may utilize a dedicated actuator 32 or may be operated through manipulation of one or more basic components of the particular sitting apparatus that perform the function of a separate actuator.

(116) As one example, as shown schematically in FIG. 39, the locking assembly 30 on the generically depicted armrest assembly 20.sup.17′ may be actuated by the part 50.sup.17′, as by turning the part 50.sup.17′ around its fore-and-aft/Y axis 142. The schematic showing is intended to encompass a locking assembly 30 that might be so actuated to fix the part 50.sup.17′ against some or all of the potential movements permitted by the constructions described above—including front-to-rear/rear-to-front inclination, vertical shifting, pivoting about the vertical/Z axis 144, etc. This allows a user to effect locking of the part 50.sup.17′ against one or more of the noted movements through the convenient manipulation of the part 50.sup.17′. The turning of the part 50.sup.17′ around the axis 142 is only one exemplary actuating movement.

(117) Turning of the part 50.sup.17′ around the axis 142 introduces the aspect that the part 50.sup.17′ may have an additional degree of adjustment permissible through which the surface 22.sup.17′ may be tipped from side to side.

(118) Myriad different structures can be devised to effect locking of the surfaces 22 through the connecting structure 26, as shown schematically in FIG. 2.

(119) As noted above, a discrete/dedicated actuator 32 might be provided and accessible to a user to operate the locking assembly 30.

(120) In FIG. 40, an armrest assembly is shown at 20.sup.18′ having an overall construction similar to the armrest assembly 20.sup.14′ in FIG. 33. Grooves (not shown) may be provided on riser components 46.sup.18′, 48.sup.18′ to allow vertical/Z axis turning with respect to a fixed base 44.sup.18′. Separate sprag clutches 146, 148 are provided to make up a locking assembly 30.sup.18′.

(121) The clutch 146 pivots at the riser component 48.sup.18′. The clutch 148 pivots on the fixed base 44.sup.18′.

(122) As shown in FIGS. 41 and 42, the pivoting of riser components 46.sup.18′, 48.sup.18′, as shown in FIG. 40, allows different relationships to be set between the riser components 46.sup.18′, 48.sup.18′ and the part 50.sup.18′ with which they are associated. Two exemplary relationships are shown in FIGS. 41 and 42. The result of changing the relationship of the part 50.sup.18′ and riser components 46.sup.18′, 48.sup.18′ is that the lateral position of the part 50.sup.18′ likewise changes. This function can be used to adjust spacing between the surfaces 22.sup.18′ on the laterally spaced armrest assemblies 20.sup.18′ on the particular sitting apparatus.

(123) As seen in FIG. 43, this same pivoting of the riser components 46.sup.18′, 48.sup.18′ relative to the part 50.sup.18′ may effect reorientation of the part 50.sup.18′ around the vertical/Z axis.

(124) FIGS. 44 and 45 show a still further embodiment of the inventive armrest assembly 20.sup.19′ that is configured to allow the surface 22.sup.19′ on the part 50.sup.19′ to be repositioned relative to the frame 12.sup.19′ by movement: a) selectively around separate Z axes 150, 152; b) along a horizontal axis, as indicated by the double-headed arrow 154; and c) vertically along the axis 152, as indicated by the double-headed arrow 156.

(125) The locking assembly 30.sup.19′ is designed to be operated by turning of the part 50.sup.19′ around the Y axis 158, as indicated by the arrows 160. The locking assembly 30.sup.19′ includes a rod 162 with ends 164, 166 supported for a gimbal-like motion that allows the tilting around the axis 158 through manipulation of the part 50.sup.19′ to thereby actuate the other components making up the locking assembly 30.sup.19′ to fix the surface 22.sup.19′ against movement in one or more manners.

(126) Generally, it should be understood that the various components and functions from the different embodiments described above are contemplated to be interchanged to provide additional versatility.

(127) The invention is also contemplated to be used with sitting apparatus having all known types of structures to change orientations and positions of arm supporting surfaces on armrest assemblies.

(128) The particular mechanisms utilized may be incorporated at least partially within certain components on existing chair technology. Alternatively, the structure can be independently constructed and added to the conventional components.

(129) While the second state for the various surfaces 22 is described as inclined at a forward end thereof, opposite inclination is also contemplated.

(130) If the actuator for the locking assembly is an existing component, it is not limited to the tilting of the part 50 about the Z axis. Any functional component on a sitting apparatus can be adapted to be an “actuator” through potentially relatively simple and convenient manipulation.

(131) The foregoing disclosure of specific embodiments is intended to be illustrative of the broad concepts comprehended by the invention.