REMOVAL MECHANISM

Abstract

A chair component (200, 102) for a chair (100) is provided with a gas spring receiving hole (202) into which an end of a gas spring (104) of the chair (100) is insertable, and a removal mechanism (220) for removing the gas spring (104) from the chair component (200, 102). The removal mechanism (220) comprises a threaded bolt (222) arranged in a threaded hole (204) in the chair component (200, 102). The threaded hole (204) is arranged adjacent to the gas spring receiving hole (202). A longitudinal axis of the threaded hole (204) is essentially parallel to a longitudinal axis of the gas spring receiving hole (202). A screw drive (226) is provided at a first end of the threaded bolt (222) for turning the threaded bolt (222) in the threaded hole (204). An overlap element (228) is provided at a second end of the threaded bolt (222). The overlap element (228) extends in a radial direction beyond an outer circumference of the thread of the threaded bolt (222) to such an extent that the overlap element (228) at least partially overlaps the gas spring receiving hole (202).

Claims

1. A chair component for a chair, wherein the chair component is provided with a gas spring receiving hole into which an end of a gas spring of the chair is insertable, and a removal mechanism for removing the gas spring from the chair component, wherein the removal mechanism comprises a threaded bolt arranged in a threaded hole in the chair component, wherein the threaded hole is arranged adjacent to the gas spring receiving hole, wherein a longitudinal axis of the threaded hole is essentially parallel to a longitudinal axis of the gas spring receiving hole, wherein a screw drive is provided at a first end of the threaded bolt for turning the threaded bolt in the threaded hole, and wherein an overlap element is provided at a second end of the threaded bolt, the overlap element extending in a radial direction beyond an outer circumference of the thread of the threaded bolt to such an extent that the overlap element at least partially overlaps the gas spring receiving hole.

2. The chair component of claim 1, wherein the overlap element has a circular outer shape coaxial with a longitudinal axis of the threaded bolt.

3. The chair component of claim 1, wherein the overlap element comprises a screw head and a washer.

4. The chair component of claim 1, wherein an outer diameter of the screw drive at the first end of the threaded bolt is smaller than an outer diameter of the thread of the threaded bolt.

5. The chair component of claim 1, wherein the screw drive at the first end of the threaded bolt comprises at least one of a hex key and a hexalobular internal.

6. The chair component of claim 1, wherein the threaded hole and the gas spring receiving hole each extend from a first surface of the chair component to an opposing second surface of the chair component, wherein the threaded bolt is screwed into the threaded hole from the second surface, wherein the gas spring receiving hole has a conical shape with a first diameter at the first surface and a second diameter smaller than the first diameter at the second surface.

7. The chair component of claim 6, wherein the threaded bolt is adjustable by turning the threaded bolt within the threaded hole between a mounting position in which the gas spring can be mounted at the chair component and a removal position in which the gas spring is removed from the chair component, wherein a distance between the overlap element and the second surface in the mounting position is larger than a distance between the overlap element and the second surface in the removal position.

8. The chair component of claim 7, wherein the chair component is configured such that, when the gas spring is mounted to the chair component, an end of the gas spring protrudes from the second surface of the chair component, wherein the overlap element is configured such that, when the gas spring is mounted to the chair component, the overlap element urges the end of the gas spring to reduce an amount by which the end of the gas spring protrudes beyond the second surface of the chair component as the overlap element transitions from the mounting position to the removal position.

9. The chair component of claim 1, wherein the chair component comprises a base support of the chair configured to support a chair seat.

10. The chair component of claim 1, wherein the chair component comprises a pedestal of the chair.

11. A chair, comprising a pedestal, a gas spring, a base support, and a chair seat, wherein at least one of the pedestal and the base support comprises a chair component, provided with a gas spring receiving hole into which an end of a gas spring of the chair is insertable, and a removal mechanism for removing the gas spring from the chair component, wherein the removal mechanism comprises a threaded bolt arranged in a threaded hole in the chair component, wherein the threaded hole is arranged adjacent to the gas spring receiving hole, wherein a longitudinal axis of the threaded hole is essentially parallel to a longitudinal axis of the gas spring receiving hole, wherein a screw drive is provided at a first end of the threaded bolt for turning the threaded bolt in the threaded hole, and wherein an overlap element is provided at a second end of the threaded bolt, the overlap element extending in a radial direction beyond an outer circumference of the thread of the threaded bolt to such an extent that the overlap element at least partially overlaps the gas spring receiving hole.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Embodiments of the invention will be described with reference to the accompanying drawings.

[0020] FIG. 1 is a schematic isometric view of a chair comprising a chair component according to an embodiment.

[0021] FIG. 2 is an isometric view from below of the chair of FIG. 1.

[0022] FIG. 3 is a schematic isometric view of a base support according to an embodiment with a removal mechanism in a mounting position.

[0023] FIG. 4 is a schematic isometric cross-sectional view of the base support of FIG. 3.

[0024] FIG. 5 is a schematic cross-sectional side view of the base support of FIG. 3.

[0025] FIG. 6 is an isometric view from below of the base support of FIG. 3.

[0026] FIG. 7 is a schematic isometric view of a base support according to an embodiment with a removal mechanism in a removal position.

[0027] FIG. 8 is a schematic isometric cross-sectional view of the base support of FIG. 7.

[0028] FIG. 9 is a schematic cross-sectional side view of the base support of FIG. 7.

DETAILED DESCRIPTION OF EMBODIMENTS

[0029] Exemplary embodiments of the invention will be described with reference to the drawings. While some embodiments will be described in the context of specific fields of application, such as in the context of an office type chair, home chair or industrial chair, the embodiments are not limited to this field of application. The features of the various embodiments may be combined with each other unless specifically noted otherwise. Same reference signs in the various drawings refer to similar or identical components.

[0030] FIG. 1 shows a chair 100 which includes a pedestal 102, a gas spring 104, a base support 200, a chair seat 106 and a chair back 108. As an example, the chair 100 is illustrated to be a height adjustable chair. The base support 200 may comprise a motion mechanism. The base support 200 may connect the chair seat 106, the chair back 108 and the gas spring 104. The motion mechanism may effect a coordinated motion of the chair back 108 and the chair seat 106. The pedestal 102 includes a number of support feet extending radially from a center of the pedestal 102 and a corresponding number of casters supported on the outer ends of the support feet. The gas spring 104, also known as gas cylinder or lifting mechanism, may be mounted at the center of the pedestal 102 to enable the height of the chair seat 106 to be adjusted by an occupant.

[0031] The gas spring 104 comprises a cylinder 110, a piston within the cylinder 110, and a piston rod 112. The gas spring 104 may comprise further components, for example a piston rod guide bushing, a piston rod seal, one or more valves and a coil spring. The piston is movable in the up and down directions. A lower end of the piston rod 112 is coupled to the piston within the cylinder 110 and an upper end of the piston rod 112 is coupled to the base support 200. For coupling the piston rod 112 to the base support 200, the base support may provide a gas spring receiving hole into which the upper end of the piston rod 112 is inserted. The upper end of the piston rod 112 may have a conical shape that tapers further upward. The gas spring receiving hole may have a matching conical shape that tapers further upward also.

[0032] The lower end of the cylinder 110 is coupled to the pedestal 102. The pedestal 102 may have a central hole into which the lower end of the cylinder 110 may be inserted. The lower end of the cylinder 110 may have a conical shape that tapers further downward. The central hole may have a matching conical shape that tapers further downward also.

[0033] In this way, a strong and reliable connection is made between the upper end of the piston rod 112 and the base support 200, and between the lower end of the cylinder 110 and pedestal 102. The connection may strengthen when a user sits on the chair and presses the conical surfaces against each other. However, separating the gas spring from the base support 200 or pedestal 102 may be difficult and may require large forces.

[0034] Separating the gas spring from the base support 200 or the pedestal 102 may be necessary for replacement of the gas spring or for stowing the chair in a space-saving manner. In order to achieve this without requiring large forces to be applied by an operator, a removal mechanism can be provided, which will be described below using the base support 200 as an example. FIG. 2 is an isometric view from below of the chair of FIG. 1 and indicates a suitable position of the removal mechanism 220 at the base support 200. It is obvious for a person skilled in the art that is such a removal mechanism can be provided in the same way at the pedestal 102.

[0035] FIG. 3 is a schematic isometric view of the base support 200 in connection with the gas spring 104. The base support 200 includes a removal mechanism 220. In FIG. 3, the pedestal 102, the chair seat 106 and a chair back 108 are not shown for clarity reasons. FIG. 4 show a schematic isometric cross-sectional view of the base support 200 of FIG. 3, and FIG. 5 shows a schematic cross-sectional side view of the base support 200 of FIG. 3.

[0036] As illustrated in FIG. 3 to FIG. 5, the conical upper end of the piston rod 112 is inserted in a matching conical gas spring receiving hole 202 of the base support 200. The conical shapes of the upper end of the piston rod 112 and the matching hole 202 have a decreasing diameter in the upward direction. The upper end of the piston rod 112 protrudes slightly beyond the upper edge of the hole 202, for example by a few millimeters, for example 3 to 5 mm. In other words, when the piston rod 112 is inserted at a first lower surface 208 of the base support 200 in the upwards direction, the upwards movement of the piston rod 112 is limited by the engagement of the conical shape of the piston rod 112 with the matching conical shape of the hole 202. In the engaged position, the upper end of the piston rod 112 protrudes slightly beyond a second upper surface 210 of the base support 200 in the upwards direction.

[0037] The removal mechanism 220 comprises a threaded bolt 222 which is arranged in a matching threaded hole 204 in the base support 200. The threaded hole 204 is arranged adjacent to the gas spring receiving hole 202. Preferably, a longitudinal axis of the threaded hole 204 and a longitudinal axis of the gas spring receiving hole 202 are parallel. A distance 206 between the threaded hole 204 and the gas spring receiving hole 202 may be small, for example a few millimeters, for example 3 to 5 mm. A diameter of the threaded hole 204 may be a few millimeters. For example, the threaded bolt 222 and the threaded hole 204 may have matching metric threads, such as in the range of M4 to M10, preferably M6. In other examples the threaded bolt 222 and the threaded hole 204 may have matching imperial threads.

[0038] At a first end at the lower side of the threaded bolt 222 a screw drive 226 is provided for turning the threaded bolt 222 in the threaded hole 204. The screw drive 226 may be a set of shaped cavities and protrusions on first end at the lower side of the threaded bolt 222 that allows torque to be applied to the threaded bolt 222. The screw drive 226 may comprise for example a hex key, also known as Allen key, or a hexalobular internal, also known as star drive or Torx. For example the screw drive 226 may comprise a hex key with a size in the range of 3 to 8, or a hexalobular internal with a size in the range of T10 to T40. In particular, the first end of the threaded bolt 222 is headless such that the first end of the threaded bolt 222 may be completely screwed in and through the threaded hole 204. In other words, the screw drive at the first end may be smaller than an outer diameter of the thread of the threaded bolt 222.

[0039] FIG. 6 shows the screw drive 226 within the threaded hole 204 in an isometric view from below the base support 200.

[0040] At a second end at the upper side of the threaded bolt 222 an overlap element 228 is provided. The overlap element 228 may comprise for example a screw head 230 in combination with a washer 232. The overlap element 228 may extend in a radial direction from a longitudinal axis of the threaded bolt 222 beyond an outer circumference of the threaded hole 204 to such an extent that the overlap element 228 at least partially overlaps the gas spring hole 202. As a result, the overlap element 228 also at least partially overlaps the upper and of the piston rod 212.

[0041] The overlap element 228 may have a circular outer shape. For example, the outer shape of the screw head 230 and/or the outer shape of the washer 232 may be circular. In other examples, the screw head 230 may have a non-circular out shape, e.g. a hexagonal shape as shown in FIG. 3, and the washer 232 may have a circular outer shape.

[0042] A position of the threaded bolt 222 in the up/down and direction is adjustable by turning the threaded bolt 222 within the threaded hole with 204.

[0043] In FIG. 3 to FIG. 5, the threaded bolt 222 is in a position in which the piston rod 112 can extend beyond the upper edge of the gas spring receiving hole 202, i.e. the upper end of the piston rod 112 can extend beyond the upper surface 210. In this position, the gas spring 104 can be mounted at the base support 200. Therefore, this position is called the mounting position. In the mounting position, a distance between the lower side of the overlap element 228, for example the lower side of the washer 232, and the upper edge of the spring receiving hole 202 is at least the amount by which the upper end of the piston rod 112 protrudes beyond the upper edge of the gas spring receiving hole 202. The distance in the mounting position may be in the range of a few millimeters, for example 3 to 5 mm.

[0044] By turning the threaded bolt 222 in the threaded hole 204, the threaded bolt 222 can be moved in the downward direction. For example, the threaded bolt 222 can be turned in the threaded hole 204 by applying a corresponding Allen key or Torx wrench to the screw drive 226. The screw drive 226 may be accessible even in an assembled state of the chair 100, i.e. the screw drive 226 is accessible without removing the chair seat 106 from the base support 200.

[0045] The rotation of the threaded bolt 222 causes a downward movement of the threaded bolt 222 such that a large force can be generated by applying a small torque on the screw drive 226. The small torque can be easily applied by an operator using a corresponding simple and inexpensive tool, for example an Allen key or Torx tool. The resulting large force presses the piston rod 112 out of the gas spring receiving hole 202. No complex special tools are required to press out the piston rod 112. Hammering out the piston rod 112 can be avoided, preventing damage to the piston rod 112 and base support 200.

[0046] FIG. 7 to FIG. 9 show the threaded bolt 222 in a position in which the piston rod 112 has been urged in the downward direction such that engagement between the conical shape of the upper end of the piston rod 112 and the conical shape of the gas spring receiving hole 202 is released. In this position, the gas spring 104 can be removed from the base support 200. Therefore, this position is called the removal position. As can be seen in particular in FIG. 9, in the removal position, the distance between the lower side of the overlap element 228, in particular the lower side of the washer 232, and the upper edge of the spring receiving hole 202 has been reduced compared to the corresponding distance in the above described mounting position. The distance in the removal position may be close to zero, for example less than 3 mm, in particular less than 1 mm.

[0047] As discussed above, a similar removal mechanism may be provided at pedestal 102 for removing the cylinder 110 from a corresponding cylinder receiving hole in the pedestal 102. A threaded hole may be provided in the pedestal 102 parallel to and close by the cylinder receiving hole. The overlap element of a corresponding threaded bolt may be provided at the lower side whereas the drive screw of the threaded bolt is at an upper side of the pedestal 102 and accessible from the upper side.

[0048] While exemplary embodiments have been described in the context of office-type chairs, the removal mechanism 220 and the chair 100 according to embodiments of the invention are not limited to this particular application. Rather, embodiments of the invention may be employed in a wide variety of chairs comprising gas springs. For example, the removal mechanism 220 can be applied to any chair mechanism, for example to structures that fit a gas cylinder or gas spring.