AU738653B2 - Height adjustor means - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: KLASSE PTY LTD Actual Inventor: JUSTIN PETER BROWN Address for Service: MADDERNS, 1st Floor, 64 Hindmarsh Square, Adelaide, South Australia, Australia Invention title: HEIGHT ADJUSTOR MEANS Details of Associated Provisional Application No: PO 3669 filed 18 November 1996 The following statement is a full description of this invention, including the best method of performing it known to us.

y This invention relates to an adjustment means, and although the invention will find many applications, it will be of most use in relation to chairs, and particular adjustment of a chair backrest.

For ease of understanding, the invention will be described in relation to its use in respect of chairs. However, it will be realised that the scope of the invention is not to be restricted to this particular application and that the invention will be equally suited to other uses.

In respect of chairs, it is common to provide various adjustments in respect of the height of the seat for positions of various elements such as seats and backrests. In particular, the height of a backrest needs to be readily adjustable.

Although backrests have been made adjustable, they normally use a clamping system which the backrest support engages adjacent the rear edge of the seat. Such clamping arrangements are not easily operated. They are either difficult to loosen, or i do not hold the backrest support tightly enough.

It is an object of this invention to overcome the abovementioned problems, and in particular to provide a height adjustment means which incorporates a lock that is readily and easily operated.

.In its broadest form the invention is a height adjustment means comprising: a first member having a planar surface with a plurality of recesses in said planar surface spaced along its longitudinal axis, a second member slidably mounted with respect to said first member to allow extension or retraction of said second member with respect to first said member, a locking means connected to said second member comprising a pivotallymounted lever with an actuator mounted on a first side of said pivot and a projection adapted for engagement with said recesses on the other side of said pivot, wherein said pivot mechanism rotates to move the said projection into and out of engagement with said recesses in a direction substantially perpendicular to said planar surface, wherein engagement of said projection with one of said recesses prevents sliding movement of said first member with respect to said second member in at least one direction.

9 9 9 i 99* 9 9 9 9 9 9 o 9 99 9 9 9.

99/ The recesses may comprise apertures within a surface of the first member, or preferably may comprise indentations which have a ledge for engagement of the locking means projection on one side with a ramped surface on the other side. With a number of such ledge and ramp recesses in line, it is possible to extend the second member by pulling in one direction so that the projection rides up each of the ramped surfaces to disengage the locking means from the recess. Upon motion in the opposite direction, the projection abuts against the ledge thereby locking the second member against retraction.

Preferably, the first member comprises a U-shaped channel within which the second i member slidably locates. In this instance, runners need to be located on either side of the channel to hold the second member within the first. Alternatively, the first member may comprise a square or rectangular tube with the necessary cut outs for access to the locking means.

The second member may comprise a flat bar to engage either the U-shaped channel member with runners or the square or rectangular cross section tube.

oo I i Preferably, the lever is housed within a second channel section which is substantially S. U-shaped and is secured to the second member.

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In order to fully understand the invention, a preferred embodiment will now be described. However, it should be realised that the scope of the invention is not to be confined or restricted to the precise details of the embodiment. In this embodiment, the invention is described when used in relation to the backrest support for a chair.

However, it will be realised that this is for the purpose of example only, and that the invention will have other applications.

This embodiment is illustrated in the accompanying representations in which: Fig 1 shows a rear perspective view of a height adjustment means; Fig 2 shows a front perspective view of the height adjustment means of Fig 1; Fig 3 shows an exploded view of the height adjustment means of Fig 1.

Referring to the illustrations, the height adjustment means 10 comprises a first member which in this embodiment is an upright 11, and a second member which in this embodiment is a strut 12.

The upright 11 comprises a U-shaped channel having sides 14 and a base 15. The base 15 has a plurality of recesses 16 formed therein. Each recess 16 has a ledge 17 and a ramped portion 18. The ledge 17 and ramped portion 18 are formed by a pressing operation that makes a U-shaped cut and presses the resulting tongue outwardly.

0 The strut 12 comprises a flat bar that is retained within the upright 11 by rails 20 and a projection in the form of a limit stop screw 21. The rails 20 are each bolted to the sides 14 of the upright 11. They have a flange 22 against which the upper surface of the strut 12 slides.

so Rails 20 are constructed from a polymeric material with a low friction surface.

The base 15 of the upright 11 has a slot 23 within which a projection in the form of the head of the limit stop screw 21 locates. The limit stop screw 21 is threadably engaged into the strut 12, and limits the extent of movement of the strut 12 with respect to the upright 11.

The height adjustment means 10 is provided with a bracket 25 that enables attachment of the upright 11 to the base of a chair. The strut 12 is provided with connection means 26 which enables attachment of the upper portion of the strut 12 to the backrest of a chair.

The locking means 28 is a manually operated pivoting lever with an actuator in the form of a button 31 and a projection 35 (shown in Fig 3) that engages a recess 16. The strut 12 has an aperture 34 through which the projection locates to engage the recess 16. A housing in the form of a cover 29 is attached to the strut 12, and the locking means 28 has a lever 30 that is located within the cover 29. The lever 30 has a pair of spigots 36 that extend sideways towards the sides 14 which are located within cut outs or apertures in the cover 29. The spigots are held captive between the cover 29 and the strut 12. This enables the lever 30 to pivot to enable the projection to engage or disengage the recess 16. A spring 37 is located beneath the actuating button 31 i: which pushes the lever so that the actuator button 31 is at its outermost position. At the same time, the projection at the other end of the lever 30 is located and held within a recess 16.

If the strut 12 is pulled upwardly (as seen in the illustrations), then the projection will abut against and ride up the ramped portion 18. This will result in rotation of the lever 30 against the spring, until the projection engages with the next recess 16. This will enable the strut 12 to be lifted without having to manually depress actuator button 31.

In order to lower the strut 12, the button 31 is depressed to rotate the projection from the recess 16 and its engagement with the ledge 17 whereupon the strut 12 is free to drop until the button 31 is released. Once released, the spring will rotate the lever so that the projection will engage the next recess 16.

As will be seen from the above description, the height adjustment means 10 provides a convenient and easy means of adjusting the height of a backrest of a chair. It would also be equally suited to height adjustment for an armrest or any other application requiring ease of height adjustment between two sliding members.

Claims (14)

1. A height adjustment means comprising: a first member having a planar surface with a plurality of recesses in said planar surface spaced along its longitudinal axis, a second member slidably mounted with respect to said first member to allow extension or retraction of said second member with respect to first said member, a locking means connected to said second member comprising a pivotally- mounted lever with an actuator mounted on a first side of said pivot and a projection adapted for engagement with said recesses on the other side of said pivot, wherein said pivot mechanism rotates to move the said projection into and out of engagement with said recesses in a direction substantially perpendicular to said planar surface, 15 wherein engagement of said projection with one of said recesses prevents sliding movement of said first member with respect to said second member in at least one direction. 0..:I

2. A height adjustment means according to claim 1 further comprising a spring acting on said lever to bias said projection into engagement with said recesses. S..

3. A height adjustment means according to claim 2 wherein said spring is a S..S.compression spring located on said first side of said pivot. o•

4. A height adjustment means according to any of the preceding claims wherein said projection is manually disengageable from said recesses by depression of said actuator to thereby allow said retraction.

A height adjustment means according to claim 4 wherein said recesses are ramp-shaped on one side to thereby allow said extension without said manual znagement.

6. A height adjustment means according to any of the preceding c1ain-~ wherein said projection extends through an aperture within said second member to engage with said recesses. S S S *.SS S. S S S.. S. S SS S

7. A height adjustment means according to any one of the preceding claims wherein said first member further comprises a slot, within which a second projection attached to said second member is captive, thereby limiting said extension.

8. A height adjustment means according to any one of the preceding claims wherein said first member is a U-shaped channel partially enclosing said second member.

9. A height adjustment means according to claim 8 wherein said second member is captive between: at least one pair of rails, which are secured to the inner sides of said U-shaped channel; and the base of said U-shaped channel.

10. A height adjustment means according to claim 9 wherein said rails have a low-friction surface.

11. A height adjustment means according to claim 10 wherein said rails are constructed from a polymeric material.

12. A height adjustment means according to any of the preceding claims wherein said lever is housed within a second channel section which is substantially U-shaped and is secured to said second member.

13. A height adjustment means according to claim 12 wherein said pivot is supported by said second channel section.

14. A height adjustment means according to any one of the preceding claims in combination with a chair wherein one of said first member and said second member is attached to the base of said chair and the other is attached to the backrest of said chair. A height adjustment means as hereinbefore described with reference to and as illustrated in the accompanying drawings. DATED this 1811 day of November 1997 KLASSE PTY LTD By their Patent Attorneys MADDERNS I8