Stackable chair and a method of adjusting a stackable chair

Abstract

Storage of chairs when not in use, for instance in halls used by various groups, is a common problem which has been addressed by providing chairs that are stackable upon one another. Usually, this requires the chair to be composed of sloping legs and a sloping backrest, such that the seat of a lower chair can fit between the legs of an upper chair, and the backrest of the upper chair can rest on the backrest of the lower chair. It is desirable to be able to stack chairs with as small a vertical displacement as possible, usually limited by the depth of the seat, which is typically substantially horizontal. For instance, the base of an upper seat may sit (when stacked) on the upper portion of a lower seat. However, these chairs are usually mass produced and so designed to fit the average shape, which is not accommodating for a lot of people. The present invention provides a chair where seat 13 height, back 3 angle, seat 13 tilt and seat 13 roll are adjustable.

Claims

1. A stackable chair configured to be mounted upon an identical stackable chair to form a secure arrangement, the stackable chair comprising: independently extendable legs; a pivotable seat, wherein the pivotable seat is pivotable independently of extension of the legs; at least one actuator to control movement of the legs; a leg extension sensor measuring displacement of the legs relative to the seat; and a processor configured to determine an absolute displacement of at least one of the legs or seat, wherein the determination of the absolute displacement is based on, a number of revolutions of a motor moving the at least one of the legs or seat, and a datum reflecting a relative position of the at least one of the legs or seat.

2. The chair of claim 1, further comprising: substantially round feet on the extendable legs.

3. The chair of claim 1, further comprising: a back support.

4. The chair of claim 1, wherein the at least one actuator is configured to control movement of the seat.

5. The chair of claim 4, further comprising: at least one user interface device to activate the at least one actuator.

6. The chair of claim 5, further comprising: a controller configured to receive an input signal indicative of a user-selected orientation of the chair from the user interface device and, in response thereto, sending a control signal to the at least one actuator to control movement of the legs and/or seat.

7. The chair of claim 1, further comprising: a display configured to present an indication of the chair orientation.

8. The chair of claim 1, further comprising: an internal memory to store data on the orientation of the chair.

9. The stackable chair of claim 1, wherein each of the independently extendable legs slope vertically from the seat so as to fit laterally around the seat of the identical stackable chair and secure to the identical stackable chair without lateral movement.

10. A method of adjusting a stackable chair, the method comprising the steps of: providing a chair according to claim 1; extending a first leg of the chair by a first amount; and extending a second leg of the chair by a second amount different to the first amount.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

(2) FIG. 1 shows a chair in four different configurations.

(3) FIG. 2 is a perspective view of a leg of the chair of FIG. 1.

(4) FIG. 3 shows the internal structure of the leg of FIG. 2.

DETAILED DESCRIPTION

(5) The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily be considered to be an embodiment of the invention. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

(6) Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein.

(7) Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein.

(8) It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

(9) Similarly, it is to be noticed that the term “connected”, used in the description, should not be interpreted as being restricted to direct connections only. Thus, the scope of the expression “a device A connected to a device B” should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means. “Connected” may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other. For instance, wireless connectivity is contemplated.

(10) Reference throughout this specification to “an embodiment” or “an aspect” means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, or “in an aspect” in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may refer to different embodiments or aspects. Furthermore, the particular features, structures or characteristics of any embodiment or aspect of the invention may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or aspects.

(11) Similarly, it should be appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of the invention. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

(12) Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

(13) In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures, and techniques have not been shown in detail in order not to obscure an understanding of this description.

(14) In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

(15) The use of the term “at least one” may mean only one in certain circumstances. The use of the term “any” may mean “all” and/or “each” in certain circumstances.

(16) The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features. It is clear that other arrangements can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching, the invention being limited only by the terms of the appended claims.

(17) FIG. 1 shows a chair in four different configurations. In (a), the legs 5 of the chair are at their minimum (shortest) extension, and the back rest 3 and the seat 13 are both in a neutral position. A user interface 15 is provided to allow a user to independently adjust the extension of the legs 5 and the pitch of the seat pad 13, thereby adjusting the height, pitch and roll of the seat pad 13 and the height an angle of the back rest 3 relative to the frame.

(18) In (b), the legs 5 are at their maximum (longest) extension, and the back rest 3 and seat pad 13 are both in a neutral position. The legs 5 are formed of upper (outer) 7 and lower (inner) 9 telescopic portions.

(19) In (c), the rear legs 5 are extended more than the front legs 5 such that the chair is pitched forward. This has the effect of increasing the slope of the back rest 3. However, the seat pad 13 is independently rotated about a horizontal lateral axis (extending out of the page) such that the rear portion thereof is lowered and the front portion is raised. In this way, the seat pad may be maintained in a substantially neutral position.

(20) In (d), the front legs 5 are extended more than the rear legs 5 such that the chair is pitched backwards. This has the effect of decreasing the slope of the back rest 3. However, the seat pad 13 is independently rotated about the same axis, but this time such that the rear portion is raised and the front portion is lowered. Again, the seat pad 13 may be maintained in a substantially neutral position.

(21) Of course it is also possible to adjust the chair such that the seat pad 13 is not in a neutral position; that is, it could be tipped either forward, backward, left or right, depending on the adjustment of the legs 5.

(22) FIG. 2 is a perspective view of a leg of the chair of FIG. 1. The leg comprises an upper portion 7 insertable within it (shown partially inserted) is a lower portion 9. Lower portion 9 has a foot 23 at a lower end thereof. Upper portion 7 has a bracket 21 at an upper end thereof for attaching to a frame around the seat pad.

(23) FIG. 3 shows the internal structure of the leg of FIG. 2; specifically the mechanism within the upper portion and its interaction with the lower portion 9. At an upper end of the lower portion 9 is a slidable bearing 39 arranged to slide against an interior surface of the upper portion. Similarly disposed within a lower end of the upper portion (not shown) is a slidable bearing 41 arranged to slide against an outer surface of the lower portion 9. In this way, movement of the lower portion 9 relative to the upper portion may be smooth and secure.

(24) The slidable bearings 39 and 41 may incorporate leaf springs (not shown) such that they are biased between the inner and outer leg portions, thereby preventing wobbling/rattling of the legs in use.

(25) The slidable bearings 39 and 41 may be mutually arranged to act as ‘stops’ such that over-extension of the leg is prevented.

(26) Secured to an upper end of the upper portion (not shown) is an actuator 31 comprising an electric motor configured to rotate a shaft 37 having a helical thread disposed thereon. A corresponding threaded hole is provided in the top of the lower portion 9 such that, when the actuator 31 rotates the shaft 37, the lower portion 9 is either drawn toward or pushed away from the actuator 31, depending on the direction of rotation.

(27) A sensor 35 is provided within the leg that is configured to send a signal to a controller in response to the leg reaching a predetermined extension. Various alternative arrangements of sensor are envisaged and have been described hereinbefore.