AU696936B2 - Support arrangement for an extendible leg rest - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION For A Standard Patent

ORIGINAL

a o Name of Applicant: TEAMCRAFT FURNITURE PTY LTD 0 Actual Inventor: GRAEME ALAN WATSON Address for Service: WRAY ASSOCIATES, Primary Industry House, 239 Adelaide Terrace, Perth, S Western Australia, 6000.

Attorney code: WR Invention Title: "SUPPORT ARRANGEMENT FOR AN EXTENDIBLE LEG REST" Details of Associated Provisional Application: No: PM8730 (11/10/1994) The following statement is a full description of this invention, including the best method of performing it known to me:-

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i The present invention relates to a position control means and in particular such a control means which can be used in the support arrangement for an extendible leg rest of a chair.

Extendible leg rests are generally provided in chairs which are capable of reclining, whereby when the chair is in a reclined position, the leg rest can be extended. The present invention provides a means whereby the leg rest can be controlled in its movement, independent of the position of the chair. This is achieved by the use of a position control means which is not restricted in its application to chairs but can be used in a variety of applications.

Accordingly the invention resides in position control element intended to be oo located between a pair of components which are capable of relative movement with respect to each other between two end positions through at least o)e intermediate position, whereby when positioned at any one of the intermediate positions the position control element cannot be returned to one end position, and when at the other end position the position control element is able to be returned to the one end position without interruption.

0000 0.00 .According to a preferred feature of the invention position control element comprises an elongate first member slidably supported from a second member for .0o.

relative axial movement therewith wherein the first member is to be mounted at one end from one component and wherein the second member is to be mounted at the other end from the other component. According to a further feature the first member can be formed with an axial surface having a recess formed along the axial surface, and a pawl member supported from the second member and biased into engagement with the axial surface, said recess being located at a position at which it is engaged by the pawl member to retain the position control element at the intermediate position. According to a further feature the first member is movable relative to the second member in a first direction towards one end of the position control element on extension of the position control element and in a second direction opposite to the first direction on retraction of the position control g Y IY ~II -~II -3element, the face of the recess proximate the one end being substantially perpendicular to the first direction and the face of the recesses remote from the one end being inclined to the first direction. If desired a plurality of axially spaced recesses can be formed along the axial surface to provide a plurality of intermediate positions.

According to a further preferred feature the second member is provided with two stations for accommodating the pawl member whereby when in the first station the pawl member can be received in the or each recess and when in the second position the pawl member is restrained from entering the or each recess.

According to a further feature the axial surface has provided thereon a first stop remote from the one end and a second stop proximate the one end whereby on the pawl member being engaged by the first stop and with relative movement between the first and second member, the pawl member is moved to the second station from the first station and on movement of the position control element to the retracted position the pawl member is engaged by the second stop to move the pawl member from the second station to the first station. According to a ooe0 further feature the pawl member is received within a "'Ll shaped slot in the second member, the slot being formed from a first arm extending parallel to the axial surface and a second arm extending transversely from the first arm toward the 0 0 axial surface. In one form the first arm comprises the second station and the "second arm comprises the first station.

Accordingly the invention also resides in a support mechanism for a multi-position leg rest of a chair, comprising a mechanism attached to the leg rest, the mechanism being extendible to locate the leg rest in front of the chair and being retractable to locate the leg rest in a position closely adjacent the base of the chair, the mechanism being supported from a shaft pivotally supported from the chair whereby rotation of the shaft causes extension and retraction of the mechanism, a position control element according to any one of the preceding claims extending between the mechanism and the chair frame, the position control element extending and retracting with the extension and retraction of the mechanism the position control element being at the fully extended position when Y II^-PP~S~-~Y -4the leg rest is located in front of the chair at the retracted position when the leg rest is closely adjacent the base of the chair whereby when the position control element is at any one of the intermediate positions the leg rest cannot be returned to the base of the chair, and when the position control element is positioned at the fully extended position the leg rest is able to be returned to the base of the chair without interruption.

According to a preferred feature a spacer element is mounted between the shaft and the chair frame adjacent the mounting of the position control means to the chair frame.

According to a further preferred feature the mechanism comprises a pantograph mechanism. In such an instance the position cor:rol element can be pivotally mounted to an arm of the mechanism, the arm being mounted to the shaft for rotation therewith.

Accordingly the invention also resides in a chair having a multi-position leg rest and a support mechanism for the leg rest of the form as described above S. S The invention will be more fully understood in the light of the following description of one specific embodiment. The description is made with reference to the accompanying drawings of which: Figure 1 is a sectional side view of a chair incorporating a leg-rest extension mechanism according to the embodiment; Figure 2 is an enlarged view of the position control element of the embodiment; and Figure 3 is an enlarged view of the interconnection between the position control element and the pantograph mechanism according to the embodiment.

The embodiment is directed to a support mechanism for a reclining chair having a base 11 from which a chair frame 12 is rockably and reclinably supported. The chair frame 12 is provided with a leg rest 13 which is supported from the chair frame 12 by the support mechanism comprising an extendable pantograph mechanism 14 which is mounted at one end. to the leg rest 13 and at the other end to a shaft 15 rotatably supported from the chair frame 12. A suitable handle (not shown) is provided on an outer end of the shaft 15 to effect rotation of the shaft 15. The handle is preferably located at a side of the chair for operation by a user. The support mechanism further comprises with a position control element 16 between one arm 17 of the pantograph mechanism 14 and a bracket 18 provided on the chair frame 12.

The position control element 16 comprises an elongate first member 20 which is slidably receivable within an elongate hollow second member 21 whereby on rotation of the shaft 15 to cause extension or retraction of the leg rest 13, the first member 20 is caused to be telescopically moved out of and into the second member 21. One end 20a of first member is pivotally supported from an o pae intermediate position on the one arm 17 and one end of the second member is pivotally supported from the bracket 18.

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One edge of the first member 20 is provided with an axial surface 22 which comprises a rebated portion 22a in the edge of the first member 20. The rebated portion 22a is provided with a first stop surface 23 at one end thereof remote from the one end 20a of the first member 20 and a second stop surface 24 at the other end of the rebated portion 22a proximate the free end 20a of the first member The first and second stop surfaces 23 and 24 are generally perpendicular to, the longitudinal axis of the first member 20. In addition, the axial surface 22 is formed with a plurality of axially spaced recesses 25 between the first and second stop surfaces 23 and 24. The recesses 25 are formed with a first face 26 which is perpendicular to the longitudinal axis of the first member 20 and which is proximate to its free end 20a and a second face 27 which is inclined to the longitudinal axis of the first member 20 and is remote from its free end The second member 21 supports a pawl member 28 which comprises a rod element extending transversely through the second member 21 and which is receivable in an L-shaped slot 29 provided in each side of the second member 21. The slot 29 is formed from a first arm 29a and a second arm 29b. The slot 29 is located such that the first arm 29a lies parallel to the longitudinal axis of the first member 20 and is positioned such that when the pawl member 28 is located in the first arm 29a it is held clear of the recesses 25. The second arm 29b extends perpendicularly from the first arm 29a and has an inner end 29c corresponding substantially to the position overlying the recesses 25 as they pass by the slot 29 upon longitudinal movement of the first member 20 with respect to the second member 21. A spring 30 is mounted to each side of the second member with one end of each spring being fixed to the respective end of the pawl member 28. The other end of each spring is fixed to the respective side of the second member 21. The spring 30 serves to bias the pawl member 28 into the respective end of either arm of the slot 29.

On movement of the first member 20 out of the second member 21, the pawl member 28 is caused to be sequentially engaged with each of the recesses The pawl does not inhibit the outward movement of the first member 20 because of the inclined second face 27 of each of the recesses 25. When the pawl member 28 is engaged in any one of the recesses 25 it is readily able to slide over the inclined second face 27. However, the first member 20 cannot move into the second member 21 when the pawl is located in a recess due to the configuration of the first face 26 of each recesses 25 which is generally perpendicular to the longitudinal axis of the first member On passage of the first member 20 out of the second member 21 the pawl member 28 is caused to be sequentially moved into and out of each of the recesses 25. After having passed from the last recess 25 it is engaged by the first stop surface 23 at which position it is held in alignment with the first arm 29a of the slot 29. With further extension of the first member 20, the pawl member 28 II I -7is carried into the end 29d of the first arm 29a to be retained therein. With the pawl member 28 so retained, the first member 20 is then capable of moving freely into the second member 21 until the second stop surface 24 engages the pawl member 28 and carries it into the second arm 29b of the slot 29.

Thus the inner end 29c of the second end 29b comprises a first station and the end 29d of the first arm 29a comprises a second station.

The position control element 16 further comprises a third elongate member extending between the bracket 18 and the shaft 15. The third elongate member serves to maintain the spacing between the shaft 15 and the bracket 18 which is

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fixed to the chair frame and also serves to eliminate unwanted axial movement between the first and second members 21 and 22, of the position control element 16 due to movement of the chair frame 12 when subjected to varying loads and over time In many instances chair frames are formed of wood and over time warping or distortion of the chair frame 12 is possible which can result in undesired axial movement between the first and second members 21, 22 and a variation in the spacing between the shaft and the bracket 18 which can detract from the successful operation of the leg rest extension mechanism..

ei The function of the position control element 16 is such that on extension of the leg rest 13 via the pantograph mechanism 14, the leg rest 13 is moved through a plurality of intermediate positions which correspond to positions at which the pawl member 28 of the position control element 16 becomes engaged in each of the recesses 25 of the axial surface 22. When in each of those intermediate positions, the leg rest 13 cannot be returned to the retracted position and is only capable of being moved to the next outermost intermediate position. Once at the outermost intermediate position, the leg rest 13 can be further extended to a position at which the first stop surface 23 engages the pawl member 28 of the position control element 16 to move the pawl element 28 into the first arm 29a of the slot 29, being the second station, at which position the leg rest can then be freely returned to the retracted position.

-8engages the pawl member 28 of the position control element 16 to move the pawl element 28 into the first arm 2a f the slot 29, being the second station, at which position the leg rest can then be freely returned to the retracted position.

On movement of the leg rest 13 to the retracted position, the second stop surface 24 will engage the pawl member 28 to carry it from the first arm 29a of the slot 29 and move it into the second arm 29b of the slot 29, being the first station, at which position the pawl member will again engage with the recesses 25 upon axial movement of the first member 21.

The embodiment provides a support mechanism for an extendible leg rest whereby the leg rest is capable of being positively retained in a number of intermediate positions and yet when extended can be readily retracted lae Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

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It should be appreciated that the scope of the present invention need not be limited to the particular scope of the embodiment described above and in particular need not be restricted to the particular application of the embodiment.

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Claims (16)

1. A position control element intended for an extendible leg rest of a chair to be located between a pair of components which are capable of relative movement with respect to each other between a first end position and a second end position through at least one intermediate position, whereby when positioned at any one of the intermediate positions the position control element cannot be returned to the first end position and when the position control element is at the second end position, the position control element is able to be returned to the first end position without interruption.

2. A position control element as claimed at claim 1, wherein the position control element comprises an elongate first member slidably supported from a second member for relative axial movement therewith and wherein the b elongate first member is to be mounted to a first component and the second b member is to be mounted to a second component. So S.0

3. A position control means as claimed at claim 2 wherein the first member is formed with an axial surface having a recess formed along the axial surface, and a pawl member supported from the second member and biased into engagement with the axial surface, said recess being located at a position at which it is engaged by the pawl member to retain the pair of components at an intermediate position.

4. A position control element as claimed at claim 3, wherein the elongate first member is movable relative to the second member in a first direction towards a first end of the position control element on extension of the position control element and in a second direction opposite to the first direction on retraction of the position control element towards a second end of the position control element, the face of the recess proximate the first end being substantially perpendicular to the first direction and the face of the recesses proximate the -ST Rsecond end being inclined to the first direction.

I A position control element as claimed at claim 3 or 4, wherein a plurality of axially spaced recesses are formed along the axial surface to provide a plurality of intermediate positions.

6. A position control element as claimed at any one of claims 3 to 5, wherein the second member is provided with a first station and a second station for accommodating the pawl member whereby when in the first station the pawl member can be received in the or each recess and when in the second station the pawl member is restrained from entering the or each recess.

7. A position control element as claimed at claim 6, wherein the axial surface has provided thereon a first stop proximate the second end and a second stop proximate the first end whereby on the pawl member being engaged by the first stop and with relative movement between the first and second member, the pawl member is moved to the second station from the first station and on movement of the position control element to the first end position the pawl member is engaged by the second stop to move the pawl member from the second station to the first station. 00

8. A position control element as claimed at any one of claims 3 to 7, wherein the pawl member is received within a shaped slot in the second member, the slot being formed from a first arm extending parallel to the axial surface and a second arm extending transversely from the first arm toward the axial surface.

9. A position control element as claimed at claim 8 as dependent upon claim 6 wherein the first arm comprises the second station and the second arm comprises the first station.

A position control element for an extendible leg rest of a chair substantially as herein described.

11. A support for a multi-position leg rest of a chair comprising a mechanism attached to the leg rest, the mechanism being extendible to locate the leg -11 rest in front of the chair and being retractable to locate the leg rest in a position closely adjacent the base of the chair, the mechanism being supported from a shaft pivotally supported from the chair whereby rotation of the shaft causes extension and retraction of the mechanism, a position control element according to any one of the preceding claims extending between the mechanism and the chair frame, the position control element extending and retracting with the extension and retraction of the mechanism the position control element being at the fully extended position when the leg res,: o located in front of the chair at the retracted position when the leg rest is closely adjacent the base of the chair whereby when the position control element is at any one of the intermediate positions the leg rest cannot be returned to the base of the chair, and when the position control element is positioned at the fully extended position the leg rest is able to be returned to .the base of the chair without interruption.

12. A support as claimed at claim 11 wherein a spacer element is mounted between the shaft and the chair frame adjacent the mounting of the position control means to the chair frame.

13, A support as claimed at claim 10 or 11 wherein the mechanism comprises a 99° 'pantograph mechanism.

14. A support as claimed at claim 13, wherein the position control element is pivotally mounted to an arm of the pantograph mechanism, the arm being 4mounted to the shaft for rotation therew;th.

A support for a multi-position leg rest of a chair substantially as herein described. -12-

16. A chair having a multi-position leg rest and a support mechanism for the leg rest as claimed in any one of claims 11 to Dated this Twenty-Second day of January 1998. TEAMORAFT FURNITURE PTY LTD Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant V. 6 I -13- Abstract A position control element intended to be located between a pair of components which are capable of relative movement with respect to each other between two end positions through at least one intermediate position, whereby when positioned at any one of the intermediate positions the position control element cannot be returned to one end position, and when at the other end position the position control element is able to be returned to the one end position without interruption. oe A save 4 *0 o S p a o a 4 00 g 0 09 4 6 0 0s, p -u