MECHANISM FOR AN EXTENSION LEAF

Abstract

A mechanism for an extension leaf of an extension table. The mechanism comprises a frame defining a first formation configured for engagement by an end of a first axle of the extension leaf and second formation configured for engagement by an end of a second axle of the extension leaf. The first formation mounts the end of the first axle for rotation about a first axis that is parallel to a hinge axis of the extension leaf, and constrains the first axle against translation in a plane perpendicular to the first axis. In the illustrated embodiment, the first formation is simply an aperture in the frame. The second formation defines an elongate path along the frame, supports the end of the second axle for rotation about a second axis, and guides the second axle along the elongate path from end to end during reconfiguration of the extension leaf between its extended configuration and its collapsed configuration as shown. A force transfer component is hingedly connected to the frame about a third axis and defines an abutment surface extending across the elongate path for engagement by the end of the second axle during the movement of the second axle toward end of the elongate path. Rotation of the lever arm in a first direction about the third axis causes the abutment surface to move toward end of the path and rotation of the lever arm in an opposite, second direction about the third axis causes the abutment surface to move toward end of the path. A damper is connected to the force transfer component to damp force applied to it when it is engaged by the end of the second axle during the movement of the second axle toward end of the elongate path.

Claims

1. A mechanism for an extension leaf, the mechanism comprising: a frame defining: a first formation configured for engagement by an end of a first axle of the extension leaf to mount the end of the first axle for rotation about a first axis and constrain the first axle against translation in a plane perpendicular to the first axis, and a second formation defining an elongate path along the frame, the second formation being configured for engagement by an end of a second axle of the extension leaf to support the end of the second axle for rotation about a second axis and during movement of the second axle along the elongate path, a first end of the path being associated with the position of the end of the second axle when the extension leaf is in an extended configuration and an opposite, second end of the path being associated with the position of the end of the second axle when the extension leaf is in a collapsed configuration; a force transfer component hingedly connected to the frame about a third axis and defining an abutment surface extending across the elongate path in the frame, rotation of the force transfer component in a first direction about the third axis causing the abutment surface to move toward the first end of the path and rotation of the force transfer component in an opposite, second direction about the third axis causing the abutment surface to move toward the second end of the path, the abutment surface being configured for engagement by the end of the second axle during the movement of the second axle toward the second end of the elongate path; and a damper connected to the force transfer component to damp force applied to the force transfer component by the end of the second axle during the movement of the second axle toward the second end of the elongate path.

2. The mechanism of claim 1, wherein the damper is a linear damper having a first end hingedly connected to the frame for rotation about a fourth axis and an opposite, second end connected to the force transfer component.

3. The mechanism of claim 2, wherein the second end of the damper is connected to the force transfer component at a location between the third axis and the abutment surface.

4. The mechanism of claim 2, wherein the second end of the linear damper is hingedly connected to the force transfer component.

5. The mechanism of claim 2, wherein the distance between the fourth axis and the connection between the second end of the damper and the force transfer component gradually reduces or gradually increases during rotation of the force transfer component between a first orientation in which it extends across the elongate path at a first location along the elongate path and a second orientation in which it extends across the elongate path at the second end of the elongate path, the first location along the elongate path being between the midpoint of the elongate path and the second end of the elongate path, the gradual reduction or gradual increase in the distance actuating the linear damper via respective compression or extension thereof.

6. The mechanism of claim 5, wherein the distance between the fourth axis and the connection between the second end of the damper and the force transfer component gradually reduces or gradually increases by less than 80 percent during the rotation of the force transfer component between the first orientation and the second orientation.

7. The mechanism of claim 5, wherein the distance between the fourth axis and the connection between the second end of the damper and the force transfer component gradually reduces or gradually increases by less than 60 percent during the rotation of the force transfer component between the first orientation and the second orientation.

8. The mechanism of claim 5, wherein the distance between the fourth axis and the connection between the second end of the damper and the force transfer component gradually reduces or gradually increases by less than 50 percent during the rotation of the force transfer component between the first orientation and the second orientation.

9. The mechanism of claim 5, wherein the distance between the fourth axis and the connection between the second end of the damper and the force transfer component gradually reduces or gradually increases by less than 60 mm during the rotation of the force transfer component between the first orientation and the second orientation.

10. The mechanism of claim 5, wherein the distance between the fourth axis and the connection between the second end of the damper and the force transfer component gradually reduces or gradually increases by less than 50 mm during the rotation of the force transfer component between the first orientation and the second orientation.

11. The mechanism of claim 5, wherein the distance between the fourth axis and the connection between the second end of the damper and the force transfer component gradually reduces or gradually increases by less than 35 mm during the rotation of the force transfer component between the first orientation and the second orientation.

12. The mechanism of claim 1, wherein the damper is configured to damp the force applied to the force transfer component by the end of the second axle during the movement of the second axle toward the second end of the elongate path from a first location along the elongate path to the second end of the elongate path, the first location along the elongate path being between the midpoint of the elongate path and the second end of the elongate path.

13. The mechanism of claim 5, wherein the damper is configured to apply an assistive force to the force transfer component during the movement of the second axle along the elongate path from the second end to the first location along the elongate path.

14. The mechanism of claim 1, wherein the force transfer component is a lever arm.

15. An extension leaf comprising the mechanism of claim 1.

16. An extension table comprising at least one said extension leaf according to claim 15.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0015] One or more embodiment of principles disclosed herein will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0016] FIG. 1 is an underside, perspective view of an extension table comprising an extension leaf, shown with the extension leaf in an extended configuration;

[0017] FIG. 2 is a top, perspective view of the extension table of FIG. 1, shown with the extension leaf in an extended configuration;

[0018] FIG. 3 is a perspective view of a first side of a mechanism for the extension leaf of the extension table of FIG. 1, shown with a cover of the mechanism removed;

[0019] FIG. 4 is a perspective view of the opposite side of the mechanism of FIG. 2;

[0020] FIGS. 5, 6 and 7 are side views of the mechanism of FIG. 3, shown connected to the extension leaf and with the extension leaf in an extended configuration, a partially collapsed configuration and a collapsed configuration, respectively.

DESCRIPTION OF EMBODIMENTS

[0021] Referring to the drawings, there is shown a mechanism 100 for an extension leaf 200 of an extension table 300. The mechanism 100 comprises a frame 110 defining a first formation 112 configured for engagement by an end of a first axle 202 of the extension leaf 200 and second formation 114 configured for engagement by an end of a second axle 204 of the extension leaf 200. The first formation 112 mounts the end of the first axle 202 for rotation about a first axis 206 that is parallel to a hinge axis 208 of the extension leaf 200, and constrains the first axle 202 against translation in a plane perpendicular to the first axis 206. In the illustrated embodiment, the first formation 112 is simply an aperture in the frame 110. The second formation 114 defines an elongate path 116 along the frame, supports the end of the second axle 204 for rotation about a second axis 210, and guides the second axle 204 along the elongate path 116 from end 116a to end 116b during reconfiguration of the extension leaf 200 between its extended configuration as shown in FIGS. 1, 2 and 5 and its collapsed configuration as shown in FIG. 7. In the illustrated embodiment, the second formation 114 takes the form of a slot in the frame 110. However, in other embodiments, the second formation 114 may, for example, comprise a flange extending from and along the frame 110 or a channel extending along the frame 110.

[0022] A force transfer component, which in the illustrate embodiment takes the form of a lever arm 118, is hingedly connected to the frame 110 about a third axis 120. Lever arm 118 defines an abutment surface 118a extending across the elongate path 116 for engagement by the end of the second axle 204 during the movement of the second axle toward end 116b of the elongate path 116. Rotation of the lever arm 118 in a first direction about the third axis 120 causes the abutment surface 118a to move toward end 116b of the path 116 and rotation of the lever arm 118 in an opposite, second direction about the third axis 120 causes the abutment surface 118a to move toward end 116a of the path.

[0023] A damper 122 is connected to the lever arm 118 to damp force applied to it when it is engaged by the end of the second axle 204 during the movement of the second axle toward end 116b of the elongate path 116.

[0024] In the illustrated embodiment the damper 122 is a linear damper, such as a pneumatic or hydraulic strut, having a first end 122a hingedly connected to the frame 110 for rotation about a fourth axis 124 and an opposite, second end 122b hingedly connected to the lever arm 118 at a location between the third axis 120 and the abutment surface 118a. In other embodiments (not shown), the second end 122b of the damper 122 is instead cammingly connected to the lever arm 118. As shown in FIGS. 6 and 7, a distance between the fourth axis 124 and the connection between the second end 122b of the damper 122 and the lever arm 118 gradually reduces during rotation of the lever arm between a first orientation, as shown in FIG. 6, in which it extends across the elongate path at a first location 116c along the elongate path 116 and a second orientation, as shown in FIG. 7, in which it extends across the second end 116b of the elongate path 116. In other embodiments (not shown), the lever arm 118 and damper 122 are instead arranged such that the distance between the fourth axis 124 and the connection between the second end 122b of the damper 122 and the lever arm 118 gradually increases during rotation of the lever arm between a first orientation. In either case, the gradual reduction or gradual increase in the distance between the fourth axis 124 and the connection between the second end 122b of the damper 122 and the lever arm 118 actuates the linear damper via respective compression or extension of the damper 122. Moreover, in either case, the lever arm 118 and damper 122 are ideally arranged such that the distance between the fourth axis 124 and the connection between the second end 122b of the damper 122 and the lever arm 118 gradually reduces or gradually increases by less than a predetermined percentage of the original distance therebetween or a predetermined absolute amount during the rotation of the lever arm 118 between the orientation shown in FIG. 6 and the orientation shown in FIG. 7. For example, in the embodiment illustrated in FIGS. 1-7, the distance between the fourth axis 124 and the connection between the second end 122b of the damper 122 and the lever arm 118 gradually reduces from 70 mm to approximately 40 mm, (i.e., by approximately 30 mm or approximately 43 percent) during the rotation of the lever arm 118 between the orientation shown in FIG. 6 and the orientation shown in FIG. 7.

[0025] The damper 122 may be configured to apply an assistive force to the lever arm 118 during the movement of the second axle 204 along the elongate path 116 from the second end 116b to first location 116c, thereby reducing the manual effort the user needs to apply to reconfigure the extension leaf 200 from the collapsed configuration to the extended configuration.

[0026] In the illustrated embodiment, the first axle 202 extends from an associated bracket 212 via which it is connected to its respective leaf portion 200a, and the second axle 204 extends from an associated bracket 214 via which it is connected to its respective leaf portion 200b. Also, a bearing or roller 204a is provided on the end of the second axle 204 to facilitate smooth movement of the second axle along path 116. Also, as shown in FIG. 1, the mechanism 100 has a removable cover plate 130 that extends over the damper 122 and lever arm 118.

[0027] Whilst only mechanism 100 for one end of the extension leaf 200 has been described, it will be appreciated that mechanism 100 is a mirror image of mechanism 100 and operates in the same manner as mechanism 100.

[0028] It will be appreciated that the mechanism 100 provides a number of advantages. For example, the mechanism 100 controls reconfiguration of the extension leaf 200 between its extended and collapsed configurations, including by causing the end of the second axle 204 to move along path 116 and by damping force applied to the lever arm 118 by the end of the second axle 204 during the movement of the second axle toward the second end 116b of the elongate path 116. Such control avoids the need for the user to manually control movement of the extension leaf 200 between its open and closed configurations, and prevents the extension leaf from slamming open and closed, thereby ameliorating the associated risks of damage and injury. Also, transferring force between the end of the second axle 204 and the damper 122 via the lever arm 118 provides the mechanism 100 with a high degree of reconfigurability. For example, rather than using a different damper 122, the amount of damping, or assistive, force applied to the second axle 204 by the damper 122 can be varied by connecting the second end 122b of the damper 122 to the lever arm 118 at a greater or lesser distance from the third axis 120. Also, the locations of the axes 120, 124, the location of the first formation 112, and the relative configurations of the first and second formations 112, 114, can be adjusted to cater for extension leaves 200 of different sizes. It will also be appreciated that the mechanism 100 has a low profile, projecting only a small distance from the underside of the top of the extension table 100, such that the mechanism 100 is relatively well concealed by the top of the extension table. It will also be appreciated that the mechanism 100 is well suited to being motorised to provide for powered-assisted or fully powered reconfiguration of the extension leaf 200 between the extended and collapsed configurations.

[0029] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.