NZ541379A - Detent device - Google Patents

Abstract

A detent system for adjusting levelling feet of furniture includes first and second relatively movable members 1, 2 which can be releasably retained in any of a number of predetermined positions. The first member 1 includes a series of surface portions 5 to which a projection of a detent element 15 engages as the members 1, 2 move relative to each other. The detent element 15 is connected to the second member 2 by a resilient hinge 16 to bias the detent element 15 toward the first member 1 to hold the projection in engagement with the surface portions 5 as the members 1, 2 move relative to each other, and into receiving engagement with a detent receiving formation 7 to releasably retain the members 1, 2 in one of the predetermined positions. A locking means 4 is also provided to retain the members in position.

Description

Fee No 4: $250.00 James & Wells ref: 43428/57 PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional No: 541379 Dated: 21 July 2005 Detent device We, Vidak Davies Limited, a New Zealand company of PO box 58820, Greenmount, Auckland, New Zealand do hereby declare this invention to be described in the following statement: I Detent device TECHNICAL FIELD The present invention relates generally to detent systems, particularly on height-adjustable levelling feet, and most particularly to levelling feet and systems useable 5 for supporting and levelling furniture.

BACKGROUND ART Detent devices for selectively releasably retaining a pair of relatively movable members in one or more predetermined relative positions commonly employ a detent element such as a hardened steel ball carried in a hole formed in one of the 10 members. Either a leaf spring or a compression coil spring is provided to bias the ball toward engagement with one or more spaced bail-receiving formations provided on the other of the members. Where a compression coil spring has been used to bias the ball, the member in which the ball and the spring are carried must be of relatively substantial thickness in order to define a closed-ended hole of sufficient length to 15 receive the ball and the spring. Providing the mounting member with this substantial thickness often adds undesirably to the cost of the assembly, as does the relatively expensive process of accurately forming the required closed ended hole. Where a leaf spring has been used to bias the ball, some means must be provided for securing the leaf spring to the ball-carrying member. In many instances, the leaf spring has 20 been riveted or welded in place, which procedure complicates assembly and adds to the cost of the system.

Screw threaded levelling feet are known and used widely for supporting and levelling furniture and appliances. The prior art levelling foot generally includes a foot member coupled to a threaded shaft received in a nut or other threaded member which is 25 fastened directly on an underside of the furnishing. Drawbacks with levelling feet of 2 this type are that rotating the foot to provide a large adjustment is time consuming, possibly requiring the use of a tool - especially when the weight of the furniture is resting upon the foot being adjusted. Particularly with modular furniture where modular components may assembled in a number of configurations, there is a need 5 for improved levelling feet which may be readily fixed at discrete heights. This would avoid the necessity for using a measuring instrument to determine the extension of each foot, as is necessary with threaded levelling feet. It would therefore be advantageous to provide levelling feet for furniture which incorporate the operational advantages of a detent device, but which provides a more secure connection.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior 15 art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this 20 specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice. 3 Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION According to one aspect of the present invention there is provided a detent system for 5 releasably retaining relatively movable members in any one of a plurality of predetermined positions, comprising: - first and second members which are relatively movable to successively present a series of surface portions on the first member in spaced, side-by-side relationship to a selected part of the second member; - the selected part having one side which faces toward the surface portions; - a slot formed through the selected part around a section of a detent element, the detent element having a projection projecting from the one side for engaging the surface portions as the members move relative to each other; - a detent-receiving formation provided at a location along the surface portions and being adapted to receive the projection of the detent element when the members are in one of the predetermined positions; and, wherein the detent element is connected by a resilient hinge which extends generally between the ends of the slot, the resilient hinge biasing the detent element toward the first member to hold the projection in engagement with the surface portions as the members move relative to each other; and, biasing the projection into receiving engagement with the detent-receiving formation when the members are in one of the predetermined positions to releasably retain the members, and further including locking means preventing movement of the detent element about the hinge to lock the 4 members in one of the predetermined positions.

Preferably the slot partially circumscribes the detent member, which is formed integrally with the part and connected thereto by the resilient hinge which extends generally between the ends of the slot. The slot may be substantially U-shaped, 5 having opposing parallel sections, but it will be understood that other shapes which partially circumscribe a detent member also be used. Optionally the hinge may be further defined by virtue of having a thickness less than that of the adjacent part, thereby reducing the stiffness or spring rate provided by the resilient hinge.

In another aspect, the present invention provides an adjustable furniture foot 10 extension device with the above-described detent system wherein: - the first member includes an elongate foot having a bottom surface for resting on a floor; and - the second member includes a base member having an aperture for receiving the foot, and a surface on which a furniture leg may rest.

In another aspect, the present invention provides an adjustable furniture foot utilising a detent system as hereinbefore described wherein: - the first member includes an elongate foot having a bottom surface for resting on a floor; and the second member is capable of being attached or formed integrally with the 20 furniture and includes a base member having an aperture for receiving the foot.

Preferably the surface portions in the foot are substantially cylindrical surface portions separated by detent-receiving formations provided by longitudinally spaced annular grooves. Optionally the detent-receiving formations may be recesses, apertures or the like.

The locking means is preferably manually operated and in a preferred embodiment includes a locking ring with an internal abutting face, the locking ring being connected to the base member for rotation between a released position for allowing ready 5 extension or retraction of the foot, and a locked position wherein the abutting face presses upon the detent element to lock the detent element in engagement with the foot. Optionally the locking means can be in the form of other known latching devices.

Often furniture legs are short, relative to the height of the furniture itself, and thus a 10 locking means that moves longitudinally with respect to an adjustable leg may abut the floor or furniture base and not effectively operate to release the leg. This problem has prevented many prior art adjustable levelling feet from using typical detent devices and instead predominantly use screw-threaded legs. The present invention overcomes this problem by providing a locking means that is longitudinally rotateable 15 with respect to the leg thus obviating the need for longitudinal linear movement to lock the leg in place.

In a preferred embodiment the base member includes an integrally-formed sleeve for receiving the foot therein and having one end adapted to receive, or be received in the furniture leg and a shoulder upon which the leg may rest.

Preferably a pair of detent elements are provided adjacent the shoulder. The locking ring abuts the shoulder covering both detent elements and, while it may be connected to the base member for rotation in a number of ways, in a preferred embodiment annular recesses are provided in the locking ring and base member and they are joined by a resilient ring received in both recesses.

According to another aspect of the present invention there is provided a method of releasably retaining relatively movable members in a predetermined position by 6 utilising a detent system as described above, including: - moving said first member to present a surface portion of the first member to the selected part of the second member, the projection engaging the surface portion as the members move relative to each other, - the resilient hinge biasing the detent element toward the first member to hold the projection in engagement with the surface portion as the members move relative to each other; the resilient hinge biasing the projection into receiving engagement with the detent-receiving formation to releasably retain the members, and wherein the locking means is rotated to prevent movement of the detent element about the hinge to lock the members in one of the predetermined positions. This invention provides an adjustable furniture foot extension device which is effective and efficient in operational use, and which may be economically constructed. It provides for ready adjustment of levelling feet without the need for tools. The levelling feet 15 may be readily fixed at discrete heights, while they can be securely fixed at any one of a number of predefined positions which is particularly advantageous for use in modular furniture.

BRIEF DESCRIPTION OF DRAWINGS Further aspects of the present invention will become apparent from the following 20 description which is given by way of example only and with reference to the accompanying drawings in which: Figure 1 is an exploded view of an embodiment of the adjustable furniture foot extension device of the present invention; Figure 1 b is an exploded view of an embodiment of the adjustable furniture foot 25 extension device of the present invention for attaching a castor; 7 Figure 2a is a longitudinal cross-section of the device of Fig. 4 in a released position, and Figure 2b is a longitudinal cross-section of the device of Fig. 6 in a released position, and Figure 3a is a pictorial view of a locking ring of the device of Fig. 1; Figure 3b is a pictorial view of a base member of the device of Fig. 1; Figure 4a is a transverse cross-section AA from Fig. 2a; Figure 4b is an enlarged detail F from Fig. 2a; Figure 5a is a transverse cross-section corresponding to Fig.4a showing a locked 10 position, and Figure 5b is an enlarged detail corresponding to Fig.4b showing a locked position.

Figure 6a is a transverse cross-section AA from Fig. 2b; Figure 6b is an enlarged detail F from Fig. 2b; Figure 7a is a transverse cross-section corresponding to Fig.6a showing a locked 15 position, and Figure 7b is an enlarged detail corresponding to Fig.6b showing a locked position.

BEST MODES FOR CARRYING OUT THE INVENTION Referring to Figs 1 and 2, an adjustable furniture foot extension device having a detent system of the present invention generally includes a first member in the form of 20 an elongate foot 1, a second member in the form of a one-piece moulded plastic base member 2 having an aperture 3 for receiving the foot 1, and locking means in the form of a locking ring 4. 8 The foot 1 has a substantially cylindrical outer surface 6 with a plurality of longitudinally adjacent annular grooves 7 therein. The annular grooves 7 located adjacent longitudinally spaced surface portions 5. The foot 1 is generally symmetrical and an end surface 8a or 8b may be used to rest directly on a floor or on an 5 intermediary layer(s) or device(s), for example a furniture guide or castor 44 as shown in figure 1 b attached to the foot with castor stud 46.

The base member 2 is generally in the form of a sleeve in which the foot 1 is received in a sliding fit through aperture 3 and having an upper end 38 adapted to be received in a tubular furniture leg 9. An abutment 33 is positioned on 2 to fit into a 10 corresponding receiving slot 45 (shown only in figure 1 b) on the inner surface of the tubular furniture leg 9. The abutment 33 acts as a locator for ensuring correct positioning of the tubular furniture leg 9 over the upper end 38 of the base member. The upper end 38 includes longitudinally extending ribs 10 for engaging the inner face of the leg 9, the ribs 10 extending from a shoulder 11 having an axially extending face 15 12 upon which the annular end 13 of the leg 9 may rest. In the embodiment shown in figure 1b the furniture leg 9 includes a planar end 47 with screw-holes 48 therein for facilitating attachment to furniture.

As shown in Figs 1 and 3b, detent elements 15 are provided adjacent the shoulder 11. Each detent element 15 is integrally formed with the base member 2 by a 20 generally U-shaped slot 41 which leaves the detent element 15 attached along one edge by a resilient hinge 16. The lower end of the base member 2 has substantially cylindrical coaxial inner and outer surfaces 18 (shown only in Figs 4 and 5) and 19 respectively. The hinge 16 extends generally between the ends 42a and 42b of the slot 41 and has a reduced wall thickness than the adjacent part 43 in which the detent 25 element 15 and hinge 16 are formed. As shown in Figs 4 and 5 each detent element 15 has a projection 17 that is elongated circumferentially and extends inwardly from the inner cylindrical face 18. Adjacent each detent element 15 a stop 20 projects 9 from face 19, as does a tab 21 on each detent element 15. An annular O-ring recess 22 is provided below the shoulder 11 for retaining an elastomeric O-ring 23 by which the locking ring 4 is connected to the base member 2.

As shown in Fig 3a the locking ring 4 has an upper edge 24 below which, a 5 corresponding annular O-ring recess 25 is provided. On the inner side of the locking ring 4 are diametrically opposing abutments 26 and part-cylindrical abutting faces 27, both projecting inwardly of surface 28. In each face 27 is a circumferential tab-receiving channel 32. A stop-receiving recess 29 and a foot-engaging-portion-receiving recess 30 are provided on either side of the abutting face 27 between the 10 respective adjacent abutment 26.

The operation of the device may be best seen in Figs 4a, 4b, 5a and 5b, wherein in the released position (Figs 4a, 4b) the locking ring 4 and base member 2 are connected by the O-ring 23. The projections 17 of both detent elements 15 are held in one of the grooves 7 by the resilient action of the hinge 16 thereby providing a 15 detent action. The detent elements 15 are able to move radially outward into the recess 30, thus allowing ready extension or retraction of the foot 1. Rotation of the locking ring 4 places the detent elements 15 in its locked position (Figs 5a, 5b) wherein the abutting face 27 presses upon each detent element 15 when it is attempted to extend or retract the foot 1. In this way the projections 17 cannot retract 20 clear of the grooves 7 and thus the detent element 15 is locked in engagement with the foot 1. The extent of rotation between the locked and released positions is defined by the stops 20 which abut the abutments 26 in the locked position and in the released position abut surface 31. In the locked position, in addition to the O-ring 23, the locking ring 4 is secured by the tabs 21 which are received in the channels 32.

In Figures 6a, 6b, 7a and 7b a similar operation is followed as above, however the O-ring is replaced with a flange 33 to connect the locking ring 4 to the base member 2.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof. 11

Claims (18)

CLAIMS:

1. A detent system for releasably retaining relatively movable members in any one of a plurality of predetermined positions, including: - first and second members which are relatively movable to successively present a series of surface portions on the first member in spaced, side-by-side relationship to a selected part of the second member; said selected part having one side which faces toward the surface portions; - a slot formed through the selected part around a section of a detent element, the detent element having a projection projecting from the one side for engaging the surface portions as the members move relative to each other; - a detent-receiving formation provided at a location along the surface portions and being adapted to receive the projection of the detent element when the members are in one of the predetermined positions; and, wherein the detent element is connected by a resilient hinge which extends generally between the ends of the slot, the resilient hinge biasing the detent element toward the first member to hold the projection in engagement with the surface portions as the members move relative to each other; and, biasing the projection into receiving engagement with the detent-receiving formation when the members are in one of the predetermined positions to releasably retain the members, and further including locking means preventing movement of the detent element about the hinge to lock the members in one of the predetermined positions.

2. A detent system as claimed in claim 1, wherein the locking means includes a 12 locking ring with an internal abutting face, the locking ring being connected to the second member for rotation between a released position for allowing relative movement of the first and second members, and a locked position wherein the abutting face presses against the detent element to lock the detent element in engagement with the surface portions.

3. A detent system as claimed in claim 1 or claim 2, wherein the slot partially circumscribes the detent element, which is formed integrally with the selected part and connected thereto by the resilient hinge which extends generally between the ends of the slot.

4. A detent system as claimed in any of the preceding claims, wherein the slot is substantially U-shaped, having opposing parallel sections.

5. A detent system as claimed in any of the preceding claims, wherein the hinge is defined by virtue of having a thickness less than that of the adjacent part.

6. An adjustable furniture foot utilising a detent system as claimed in any of claims 1-5 wherein: - the first member includes an elongate foot having a bottom surface for resting on a floor; - the second member is capable of being attached or formed integrally with the furniture and includes a base member having an aperture for receiving the foot.

7. An adjustable furniture foot as claimed in claim 6, wherein the surface portions in the foot are substantially cylindrical surface portions separated by detent-receiving formations provided by longitudinally spaced annular grooves.

8. An adjustable furniture foot as claimed in claim 6 or claim 7, wherein the base 13 member includes an integrally-formed sleeve for receiving the foot therein and having one end adapted to be attached to the furniture.

9. Furniture including an adjustable furniture foot as claimed in any one of claims 6-9.

10. An adjustable furniture foot extension device utilising a detent system as claimed in any one of claims 1-5 wherein: - the first member includes an elongate foot having a bottom surface for resting on a floor; - the second member includes a base member having an aperture for receiving the foot, and a surface on which a furniture leg may rest.

11. An adjustable furniture foot extension device as claimed in claim 10, wherein the surface portions in the foot are substantially cylindrical surface portions separated by detent-receiving formations provided by longitudinally spaced annular grooves.

12. An adjustable furniture foot extension device as claimed in claim 10 or claim 11, wherein the base member includes an integrally-formed sleeve for receiving the foot therein and having one end adapted to receive, or be received in the furniture leg, and a shoulder upon which the leg may rest.

13. An adjustable furniture foot extension device as claimed in any one of claims 10-12 wherein the locking means includes a locking ring with an internal abutting face, the locking ring being connected to the base member for rotation between a released position for allowing ready extension or retraction of the foot, and a locked position wherein the abutting face presses upon the detent element to lock the detent element in engagement with the foot. 14

14. An adjustable furniture foot extension device as claimed in claim 13 further including a pair of detent elements provided adjacent the shoulder and wherein the locking ring abuts the shoulder and covers both detent elements

15. An adjustable furniture foot extension device as claimed in claim 14, further including annular recesses provided in the locking ring and base member and wherein the locking ring and base member are joined by a resilient ring received in the recesses.

16. A method of releasably retaining relatively movable members in a predetermined position by utilising a detent system as claimed in any one of claims 1-5, including: - moving said first member to present a surface portion of the first member to the selected part of the second member, the projection engaging the surface portion as the members move relative to each other, - the resilient hinge biasing the detent element toward the first member to hold the projection in engagement with the surface portion as the members move relative to each other; the resilient hinge biasing the projection into receiving engagement with the detent-receiving formation to releasably retain the members, and - wherein the locking means is rotated to prevent movement of the detent element about the hinge to lock the members in one of the predetermined positions.

17. A detent system substantially as hereinbefore described, with respect to, and as shown in the drawings.

18. An adjustable furniture foot extension device substantially as hereinbefore described, with respect to, and as shown in figures 1 and 2. 15 Vidak Davies Limited by their authorised agents JAMES & WELLS