Armrest assembly for a chair

An armrest assembly includes a mounting plate disposed on a support column and having an elongated moving slot for a first pivot shaft to movably extend therethrough, an armrest plate having a sliding slot elongated transverse to the moving slot such that the first and second pivot shafts extend through and are slidable along the sliding slot to allow the armrest plate to be horizontally movable and turnable relative to the mounting plate, and a retaining unit disposed to produce a magnetically attractive force that generates resistance against a relative movement of the armrest plate to the mounting plate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Patent Application No. 105123138, filed on Jul. 22, 2016.

FIELD

The disclosure relates to an armrest assembly for a chair, and more particularly to an adjustable armrest assembly mounted on a side of a chair.

BACKGROUND

Conventional armrests are generally mounted on two opposite sides of a chair. It is desirable that the armrests are adjustable to be positioned to suit an individual user. An adjustable armrest is disclosed in U.S. Publication No. 2003/0030317 A1 and allows a user to adjust the horizontal position and orientation thereof. With a horizontally slidable seat and a linkage pivotally connected to the slidable seat, and with engagement between a protrusion which is mounted on the slidable seat and a selected one of cavities formed in the linkage, a rest surface of the armrest is retained at a desired position and orientation. However, since the position and orientation of the rest surface depend on the engagement of the protrusion with the selected cavity, the selections available to a user are limited, and the armrest cannot be freely adjusted for meeting the requirements of different users.

SUMMARY

Therefore, an object of the disclosure is to provide an armrest assembly that can alleviate at least one of the drawbacks of the prior art.

According to the disclosure, the armrest assembly includes a support column, a mounting plate disposed on the support column, and having a first moving slot which is elongated in a first direction, and a pivotal unit including first and second pivot shafts which are aligned with each other in a second direction that is transverse to the first direction. The first pivot shaft extends through the first moving slot and is movable relative to the mounting plate in the first direction. The second pivot shaft is disposed on the mounting plate. An armrest plate has a sliding slot which is elongated in the second direction and through which the first and second pivot shafts extend to be slidable in the second direction so as to permit the armrest plate to be movable relative to the mounting plate in the second direction and to be turnable about the second pivot shaft. A retaining unit includes at least one retaining module which is mounted on the pivotal unit, and a retaining plate which is disposed adjacent to the retaining module and which is configured to cooperate with the retaining module to produce a magnetically attractive force that generates resistance against a relative movement between the retaining module and the retaining plate to resist a movement of the armrest plate relative to the mounting plate.

DETAILED DESCRIPTION

Referring toFIGS. 1 to 3, an embodiment of an armrest assembly according to this disclosure is adapted to be mounted on either side of a chair (not shown), and includes a support column2, a mounting plate3, a pivotal unit4, an armrest plate5, a retaining unit6and a resting cushion7.

The support column2is adapted to be secured at either side of a chair to have a predetermined height for supporting an arm of a user. The support column2has a recessed upper portion20facing upwardly.

The mounting plate3is disposed on the support column2, and is fixedly fitted to the recessed upper portion20in this embodiment. The mounting plate3has first and second moving slots31,32which are elongated in a first direction (L1). Alternatively, the first and second moving slots31,32may be curved about an upright axis and face each other in a second direction (L2) that is transverse to the first direction (L1). In this embodiment, the first direction (L1) may be a left-right direction of the chair, while the second direction (L2) may be a fore-aft direction of the chair.

With reference toFIGS. 1, 3 and 4, the pivotal unit4includes first and second pivot shafts41,42which are aligned with each other in the second direction (L2). The first pivot shaft41extends through the first moving slot31and is movable relative to the mounting plate3in the first direction (L1). The second pivot shaft42extends through the second moving slot32and is movable relative to the mounting plate3in the first direction (L1).

Referring toFIGS. 3 to 5, the first pivot shaft41has a first toothed portion411surrounding an upright axis thereof, and the second pivot shaft42having a second toothed portion421surrounding an upright axis thereof.

The armrest plate5has a sliding slot51which is elongated in the second direction (L2) and through which the first and second pivot shafts41,42extend to be slidable in the second direction (L2) so as to permit the armrest plate5to be movable relative to the mounting plate3in the second direction (L2). The sliding slot51has a length that is larger than the distance between the first and second pivot shafts41,42so as to permit movement of the armrest plate5in the second direction (L2). Additionally, the armrest plate5is turnable about the first pivot shaft41or the second pivot shaft42, and is movable in the first direction (L1) relative to the mounting plate3along with the movement of the first and second pivot shafts41,42in the first direction (L1).

It is noted that, in this embodiment, the mounting plate3has the first and second sliding slots31,32for allowing the first and second pivot shafts41,42to be movable such that the armrest plate5can be moved in the fore-aft direction and the left-right direction, and can be turned about the upright axis of the first pivot shaft41or the upright axis of the second pivot shaft42. In a variation, as shown inFIG. 6, the second pivot shaft42is fixedly mounted on the mounting plate3without forming of a second sliding slot such that the armrest plate5can be turned relative to the mounting plate3about the upright axis of the second pivot shaft42.

Referring back toFIGS. 3 to 5, the retaining unit6includes two retaining modules61respectively disposed on the first and second pivot shafts41,42, a retaining plate62disposed adjacent to the retaining modules61to cooperate with the retaining modules61to produce a magnetically attractive force, and a rack plate63disposed below the mounting plate3. Alternatively, the retaining unit6may include only one retaining module61disposed on either one of the first and second pivot shafts41,42.

When the armrest plate5is moved manually relative to the mounting plate3, the retaining modules61are moved relative to the retaining plate62such that the magnetically attractive force generates resistance against the relative movement therebetween to resist a movement of the armrest plate5relative to the mounting plate3. Hence, once the armrest plate5is moved to a desired position and orientation, the armrest plate5can be retained in place.

Each retaining module61includes a retaining member611which is disposed to produce the magnetically attractive force with the retaining plate62and which has a notch613, and a receiving member612in which the retaining member611is fitted. The retaining member611is annular to be sleeved on a respective one of the first and second pivot shafts41,42. One of the retaining member611and the retaining plate62is made of a permanent magnet, and the other one of the retaining member611and the retaining plate62is made of a magnetically attractive material. In this embodiment, the retaining members611are permanent magnets, and the retaining plate62is a metal plate. The receiving member612is disposed on a respective one of the first and second pivot shafts41,42, is in the form of a tray, and has a protrusion614which is engaged in the notch613of the retaining member611for fittingly receiving the retaining member611such that the receiving members612as well as the retaining members611are turned together with the turning of the first and second pivot shafts41,42about their upright axes.

The retaining plate62is securely mounted on the armrest plate5so as to be moved therewith.

The rack plate63has two rack portions631which are disposed on two sides thereof to respectively mesh with the first and second toothed portions411,421and each of which extends in the first direction (L1).

When the first and second pivot shafts41,42are moved in the first direction (L1), the first and second pivot shafts41,42are rotated about their upright axes with the mesh engagement between the rack portions631and the first and second toothed portions411,421so as to rotate the retaining modules61relative to the retaining plate62, thereby increasing resistance against the movement of the armrest plate5relative to the mounting plate3.

Referring toFIGS. 1 and 2, the resting cushion7is disposed on the armrest plate5for a user to rest his/her arm thereon.

Referring toFIGS. 4, 7 and 8, when it is desired to adjust the armrest plate5in the fore-aft direction, a user can directly move the armrest plate5in the second direction (L2) by means of sliding movement of the first and second pivot shafts41,42along the sliding slot51and against the magnetically attractive force between the retaining modules61and the retaining plate62. Once stopped at a desired position in the fore-aft direction, the armrest plate5can be retained thereat by means of the magnetically attractive force.

Referring toFIGS. 4, 9 and 10, similarly, when it is desired to adjust the armrest plate5in the left-right direction, the user can directly move the armrest plate5in the first direction (L1) so as to move the first and second pivot shafts41,42along the first and second moving slots31,32. Meanwhile, the first and second pivot shafts41,42are rotated about their axes so as to increase the resistance against the movement thereof in the first direction (L1) to thereby keeping movement of the first and second pivot shafts41,42in a synchronous manner. Similarly, once stopped at a desired position in the left-right direction, the armrest plate5can be retained thereat by means of the magnetically attractive force between the retaining modules61and the retaining plate62.

Referring toFIGS. 4, 11 and 12, when it is desired to adjust the orientation of the armrest plate5, the user can directly turn the armrest plate5such that the first and second pivot shafts41,42are moved along the first and second moving slots31,32in opposite directions, and rotated about their axes to increase the resistance for facilitating movement of the first and second pivot shafts41,42in the first direction (L1) in a synchronous manner.

As illustrated, referring toFIGS. 1 and 5, with the retaining modules61disposed on the pivotal unit4and the retaining plate62, the armrest plate5can be retained by the magnetically attractive force in place at any desired position and orientation relative to the mounting plate3, which renders the adjustment of the armrest assembly free of limitations. Moreover, the armrest assembly of this embodiment is simple in construction with a compact arrangement, and the component parts described above are concealed without affecting the outer appearance of the armrest assembly. Besides, the second pivot shaft42slidably and rotatably extends through the second moving slot32such that the armrest plate5can be moved more freely for changing the position and orientation of the armrest plate5. The rack portions631of the rack plate63are disposed to respectively mesh with the first and second toothed portions411,421of the first and second pivot shafts41,42to permit rotation of the first and second pivot shafts41,42along with the movement thereof in the first direction (L1), thereby facilitating synchronous movement of the first and second pivot shafts41,42in the first direction (L1) without misalignment issue. Alternatively, the rack portions631may be formed on the mounting plate3and respectively extend along the first and second moving slots31,32.

Furthermore, in this embodiment, the retaining plate62is secured on the armrest plate5adjacent to the retaining modules61so as to generate the resistance against the movement of the armrest plate5in the second direction (L2). In this case, the rack portions631are disposed to extend in the first direction (L1) so as to generate the resistance against the movement of the first and second pivot shafts41,42in the first direction (L1). In a variation, the retaining plate62may be secured on the mounting plate3and adjacent to the retaining modules61so as to generate a resistance against the movement of the first and second pivot shafts41,42in the first direction (L1). Also, movements of the first and second pivot shafts41,42relative to the armrest plate5in the second direction (L2) result in rotation of the first and second pivot shafts41,42about their axes so as to rotate the retaining modules61relative to the retaining plate62. Further in this case, as shown inFIG. 13, a rack plate63is disposed on the armrest plate5and has a rack portion631which extends in the second direction (L2) along the sliding slot51and which meshes with the first and second toothed portions411,421so as to generate the resistance against the movement of the pivot shafts41,42in the second direction (L2).

Referring toFIGS. 1 and 5, the retaining members611are annular to respectively surround the first and second pivot shafts41,42so that the magnetically attractive force generated is uniformly and symmetrically distributed, which renders the rotation of the first and second pivot shafts41,42with an increased stability for enhancing operability of the armrest assembly.