Hub for a rotatable chair

Abstract

According to an example aspect of the present invention, there is provided a hub for a rotatable chair, comprising a swivel shaft, a swivel shell arranged rotatably around the swivel shaft and a locking piston placed axially movably within the swivel shaft. There is a hole in the swivel shaft and a ball is placed movably in the hole. The ball is movable to a pocket in the swivel shell and an actuating mechanism is arranged for moving the locking piston in longitudinal direction of the swivel shaft for pushing the ball to the pocket and releasing it therefrom through the hole.

Claims

1. A hub for a rotatable chair, comprising: a swivel shaft; a swivel shell arranged rotatably around the swivel shaft; a locking piston placed axially movably within the swivel shaft; a hole in the swivel shaft; a ball placed movably in the hole; a pocket in the swivel shell; and an actuating mechanism for moving the locking piston in a longitudinal direction of the swivel shaft for pushing the ball to the pocket and releasing it therefrom through the hole.

2. The hub according to claim 1, wherein the hub comprises a plurality of the holes, balls, and pockets, and wherein the number of the holes and the balls is greater than one and the number of the pockets is a multiple of the number of balls.

3. The hub according to claim 1, wherein the hub comprises a plurality of the holes and a plurality of the pockets, and wherein the angle between the holes is dividable with the number of pockets.

4. The hub according to claim 1, wherein the hub comprises a plurality of the pockets, and wherein the pockets are disposed in a star pattern.

5. The hub according to claim 1, wherein the actuating mechanism comprises an activating pin and a spring.

6. The hub according to claim 5, wherein the spring is one of the group: coil spring, gas spring, elastic cushion spring, leaf spring or magnetic spring.

7. The hub according to claim 1, wherein the hub comprises a plurality of the balls, holes, and pockets, and wherein the number of the balls and the holes is four and the angle between the pockets is 45.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 illustrates a locking position of hub for a rotatable chair in accordance with at least some embodiments of the present invention;

[0013] FIG. 2 illustrates a rotating position of hub for a rotatable chair in accordance with at least some embodiments of the present invention;

[0014] FIG. 3 is cross section of FIG. 1;

[0015] FIG. 4 is a cross section of FIG. 2.

EMBODIMENTS

[0016] The aim of the invention is to enable locking of a rotatable chair so that sitting down on the chair and rising from the chair can be done more safely. When the rotation of the chair is locked, the chair can't turn away by mistake when a person is sitting on the chair or standing up. The locking mechanism is based on locking balls that can be pushed into locking pockets for locking the rotation movement and released from them to enable rotation.

[0017] FIG. 1 illustrates a hub for a in accordance with at least some embodiments of the present invention. The main body of the hub is a swivel shaft 1. The swivel shaft 1 has a conical part around which is mounted a swivel shell 4. The swivel shell 4 is connected to the swivel shaft 1 by two bearings 3 to allow rotation of the swivel shaft 1 in relation to the swivel shell 4. In this example the bearings 3 are roller bearings, but any type of bearings can be used. The swivel shaft 1 or the swivel shell 4 is mounted on the base or stand of the chair and the seat part of the chair is mounted on the other part. An activating pin 6 is set in a boring in the swivel shaft 1 and it extends from the end of the swivel shaft 1. In this example, a spring 7 is arranged between the end of the activating pin 7 and the swivel shaft 1. The spring 7 pushes the activating pin 7 towards a locking position.

[0018] On the opposite end of the activating pin 7 in relation to the spring is a locking piston 5. The locking piston 7 has a first cylindrical part on which the activating pin 7 is attached and a second cylindrical part having a larger diameter and conical part connecting the cylindrical parts. The locking piston 5 is seated on a recess 10 at the end of the swivel shaft 1. The recess 10 is longer than the locking piston 5 so that the locking piston 5 can move in the recess. At the side wall of the recess 10 are four holes 8 extending through the side of the swivel shaft 1. In the holes are mounted four balls 2. The balls 2 are made of steel, for example, but other construction materials like plastics, ceramics or other metals or metal alloys can be used. However, steel balls are readily available in various sizes at a reasonable cost. The swivel shell has a plurality of pockets 9 placed at the same plane in the cross section as the holes 8. The holes 8, and the balls 2 can be aligned with the pockets 9 by rotating the swivel shaft 1 in relation to the swivel shell 4.

[0019] The mechanism operates as follows:

[0020] In the locking position depicted in FIGS. 1 and 3. Now, the spring 7 pushes the activating pin 6 so that the locking piston 5 is seated against the end of the recess 10. The larger, second cylindrical part is located at the level of the holes 8 and pushes the balls 2 in the holes 8 so that they partially extend to the pockets 9 in the swivel shell 4. Now the relative rotation of the swivel shaft 1 and the swivel shell 4 is locked. In an embodiment, eight pockets 9 are set in the swivel shell 4 in a star pattern so that the pockets are placed at 45 intervals. This allows locking of the mechanism in corresponding angular positions.

[0021] The rotating, unlocked position is depicted in FIGS. 2 and 4. The activating pin 6 is activated by pushing it against the spring 7. An activating mechanism is not depicted here as many types of mechanisms can be used. The type of activating mechanism is defined by design and construction of the chair. For example, a lever or push button at the side of the chair can be utilized. As the activating pin 6 is pushed, the locking piston 5 moves within the recess 10 away from the end of the recess so that the conical part of the locking piston 5 is set at the level of the holes 8. The balls rest now on the conical part and the smaller first cylindrical part of the locking piston 5, allowing the balls to retreat from the holes 8 towards the recess 10 and the locking piston 5. This allows the ridges between the pockets 9 in the swivel shell 4 to travel over the balls 2 so that the relative rotation of the swivel shell 4 and the swivel axle is allowed. Releasing the activating pin 6 pushes the balls 2 back to the pockets 9. The conical part of the locking piston 5 facilitates movement of the locking piston 5 and the balls 2. The use of balls 2 as locking elements allows rotating the parts of the mechanism in relation to each other and movement of the balls 2 in the holes 8 without any other activating or returning mechanism than the locking piston 5. Thus, the mechanism is simple and reliable yet provides smooth rotating movement without jarring.

[0022] The number of the balls 2 can be anything between 1-10. At least one is needed for locking and the highest number is limited by space requirements for constructional reasons. The angle between the holes 8 through the swivel shaft 1 has to be dividable with the number of the pockets 9 in the star pattern of the swivel shell 4 to allow locking. The pushing function between the activating pin 6 and the spring 7 can be opposite, i.e., the activating rod can be in upside-down position in relation to the position in the FIGS. 1 and 2 and a mechanism can be used to pull locking piston upwards instead of pushing the activating pin 6 downwards. The placement of the spring can be varied and different kinds of springs can be used, for example types from a group comprising coil spring, gas spring, elastic cushion spring, leaf spring or magnetic spring.

[0023] It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

[0024] Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases in one embodiment or in an embodiment in various places throughout this specification are not necessarily all referring to the same embodiment.

[0025] As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention.

[0026] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0027] While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

[0028] The verbs to comprise and to include are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of a or an, i.e. a singular form, throughout this document does not exclude a plurality.

INDUSTRIAL APPLICABILITY

[0029] The invention can be utilized for manufacturing chairs.

REFERENCE SIGNS LIST

[0030] 1 swivel shaft [0031] 2 ball [0032] 3 ball bearing [0033] 4 swivel shell [0034] 5 locking piston [0035] 6 activating pin [0036] 7 spring [0037] 8 hole [0038] 9 pocket [0039] 10 recess

CITATION LIST

Patent Literature

[0040] U.S. Pat. No. 10,080,439, JP H07222637, KR 20100106833, FI 83590