CA1049914A - Adjustable height chair - Google Patents
Adjustable height chairInfo
- Publication number
- CA1049914A CA1049914A CA266,822A CA266822A CA1049914A CA 1049914 A CA1049914 A CA 1049914A CA 266822 A CA266822 A CA 266822A CA 1049914 A CA1049914 A CA 1049914A
- Authority
- CA
- Canada
- Prior art keywords
- piston
- bores
- balls
- groove
- chair
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47C—CHAIRS; SOFAS; BEDS
- A47C3/00—Chairs characterised by structural features; Chairs or stools with rotatable or vertically-adjustable seats
- A47C3/20—Chairs or stools with vertically-adjustable seats
- A47C3/34—Chairs or stools with vertically-adjustable seats with pins coacting with holes or bolt-and-nut adjustment
Landscapes
- Chairs Characterized By Structure (AREA)
Abstract
ABSTRACT
An adjustable height chair in which a height adjustment tube slides in a vertical cylindrical post. The post is provided with a plurality of spaced annular grooves and the tube is provided with a plurality of radially extending bores each containing a detent ball.
A piston is provided to releasably lock the balls in the bores in engage-ment with a desired groove. Upon movement of the piston, the balls are released and slide under gravity towards the centre of the tube until they abut a collar on the piston. The bores slope diagonally downward from the periphery to facilitate the movement under gravity and to effect diametrically directed load transfer from the tube to the groove in the post.
An adjustable height chair in which a height adjustment tube slides in a vertical cylindrical post. The post is provided with a plurality of spaced annular grooves and the tube is provided with a plurality of radially extending bores each containing a detent ball.
A piston is provided to releasably lock the balls in the bores in engage-ment with a desired groove. Upon movement of the piston, the balls are released and slide under gravity towards the centre of the tube until they abut a collar on the piston. The bores slope diagonally downward from the periphery to facilitate the movement under gravity and to effect diametrically directed load transfer from the tube to the groove in the post.
Description
1~499~4 Thls il~venLlon r~la~es to an adJusta~le helght cha~r havlng a vertical cylilldrical post and an adj~lstable height slide tube disposed therein. Tlle slide tube carrles detent balls in bore~ annularly dlspo~ed in iLS wall, the balls being slldable radlally outwardly into one of a plurality of vertically arranged annular grooves ln the inner wall surface of the cylindrical post by means of a movable piston arranged within the ; slide tube such that each ball is located in the reces6 with a portion of its body, while the remainder of the body projects through the correspond-ing bore to lock the slide tube relative to the cylindrlcal post at a height defined by the position of the groove.
A chair of this general type is known to the art. In the locked position, the piston pushes the balls outwardly through the action '3', of its wall; the ballg are arranged in bores extending horlzontally, i.e.
perpendlcular to the axis of the sllde tube. Pushing lnto the groove is effected by an oblique surface provided on the piston and the diameter of the balls and the wall thickness of the slide tube are correlated so as to maintain the balls locked in position flush with the wall of the slide tube; the piston, therefore, can slide over the openings of the bores and retain the balls.
This arrangement is disadvantageous ln its transmission of load and release of the balls from the grooves upon release of the lock. The line of action of the force transmitted from the slide tube to the balls , is not in the same plane as the reaction force exerted by the groove on the balls; this results in a higher stress on the transmission elements.
Particularly disadvantageous however is the fact that the balls have to be s displaced horizontally uponreleaseof the lock (inwardly towards the narrow :~ portion of the piston) whereby such forces only can be exerted for such displacement which act in a vertical direction, i.e. push and pull on the slide tube. The balls, accordingly, have to be pulled out of the groove ',.:
,3 30 and pushed back again into the slide tube by a load deflection. This ;3' ~. ~
.. . . .. .
~ '-' ' ' ' ' ~
.,~ ~ , .
~0499~4 ne~ slt~te~ a~l apl)ropriul~ ~oll~L~ur~Llo~ f the ~roove w~ich, ln tlJrn, resulL~ ~n an iml)airm~llt ~-f ~he l~ckin~ ~ctlon; ln addition, a relatively large force is re~uired to pull Lhe balls out o~ the g~oove.
It 19 an ob~ect of the p~e~ent lnvention to elimlnate the above-mentioned disadvatl~ages.
In accordance with the present invention there iB provlded ln an adjustable height chair comprising:
(a) a vertical cylindrical post having a plurality of vertically spaced annular grooves in the inner wall thereof;
(b) a slide tube having a pluralit~ o~ radiall~ extending bores theretrhough and coaxially disposed withln said cylindrlcal post;
(c) a detent ball radially slidable in each of said bores; and ~ (d) a piston movable between a lock position wherein said piston i retains each ~aid ball in engagement with an adjacent said annular groove and its radial bore thereby locking said slide tube relative to said post at a height defined by the position of said groove and a free position wherein each said ball is removed from the adjacent annular groove but i6 retained in said radial bore; the improvement wherein said radially extend-ing bores slope from the periphery diagonally downwardly toward the interior of said tube 80 as to provide a chute for inward movement of said balls towards an abutment when said piston is moved from said lock posi-tion to said free position, the slope of said bores being selected such f that, in the locked position, the balls engaging the groove transmit a load on said slide tube substantially diametrically to a lower portion of said groove.
The invention is lllustrated by way of example in the accompany-ing drawings wherein:
Figure 1 is a simplified cross-section of the adjustment mechanism of a chair according to the invention; and Figure 2 is a sectlon, on an enlarged scale, of Figure 1 illustrating the locking action.
-';~ ' .
10~9914 Th~ vertic:al cylindr~c~l po~t of the c1lalr 1~ de~S~nat~d by tlle reference numeral 1 s~ ported at It8 lower end on a base with or without casters (nt)t shown). IL i8 provlded wi~h a sleeve 2 In i~
interior for slidlng movement. Sleeve 2 ls provlded wlth ~ plurality of an~ular groov~ S 3 ~enerdlly, but not necessarily, ~ml-clrcular in cross-section arranged vertic~lly spaced apart from one another; the number of grooves and their vertical spacing depend upon the amount of desired height adjustability of the chair. A load spring 4 carrles the sleeve 3 and thus the load transmitted from a sllde tube 5 via the lock-ing mechanism, to be described hereinafter, to the sleeve 3. The load spring 4 is suitably supported, for example, by a support member 6 fixed-ly attached to vertical post 1.
Slide tube 5 carrie~ at its upper end the seat and armrests, not shown. It is located within sleeve 3 and is slidable therein; a support member 7 is provided for guiding purposes. Adjacent its lower end the slide tube 5 is provided with bores 8 extending radially through the tube wall. The number of bores 8 depend upon the requirements; four ~ to six bores are preferred and most effective. Bores 8 extend from the i periphery of the tube wall diagonally downwardly to the interior thereof, as is particularly apparent from Figure 2. The diameter of these bores corresponts substantially to the width of groove 3.
A detent ball 9 i8 provided within each bore 8 and is easily slidable therein. The detent balls, in the locked state, rest on the upper oblique, and preferably rounded edge 10~ of a piston 10 movably arranged in the interior of the slide tube 5. Piston 10 is pressed up-$ wardly against the balls 9 by a support spring 11. Balls 9 are, in turn, pressed with at least a portion of the ball body into the selected groove 3. The support spring 11 is disposed on a suitable support member 12.
The piston 10 includes a collar 13 of smaller diameter and i9 attached to ;; 30 a piston rod 14 supported within the slide tube 5 by means of a displace-.,, ~
~i ~0499~
al)le slJ~)port l~e~ )er 15 and movable relative ~o the sllde tube along its longitu~linal axls by a lever 16.
Figur~ 2 illu~trate~ the manner ln which the load actlng do~war~ly on ~he slide tube acts on the contact zone 17 between each bore 8 and the detent ball 9 located therein, resulting in a correspond-ing force P directed diagonally downwardly. Reaction force R to such -~ force P extends through contact ~one 18 between ball 9 and groove 3. It i~ readily apparent that both forces are diametrically oppo~ed with respect to the ball resulting in a sati~factory positive locking action.
To release the lock, which is generally requlred during height ad~ustment of the chair, a slight displacement of the piston lO downwardly is effected by actuating lever 16 against the action of support spring 11.
Since the edge lO' Aupporting balls 9 has also moved downwardly, balls 9 are free and slide under their own weight in a sliding chute, within bores 8 towards the centre to slide tube 5 to a point where they abut collar 13 of piston 10. With this downward movement they have cleared groove 3, and since they are now located completely within the periphery of slide tube 5, the latter can now be moved relative to vertical post 1.
After such movement, the lever 16 is agaln released such that support spring 11 again acts on piston 10 which exerts a pressure on balls 9 dir-ected diagonally outwardly. As soon a~ the next groove 3 is reached during relative movement of cylindrical post l and slide tube 5, the balls 9, under the action of piston 10, slide into such groove 3 thereby again locking the slide tube in its new position.
Apart from the fact that force P and reaction force R lie in ; one line of action, it is also essential that, as previously mentioned, the weight of the balls 9 themselves i8 utili~ed in releasing the locking action; the balls, therefore, need not be pushed out of groove 3 but, , instead, slide therefrom under their own weight.
$
,.i '~ !
. ,, ,.: .
A chair of this general type is known to the art. In the locked position, the piston pushes the balls outwardly through the action '3', of its wall; the ballg are arranged in bores extending horlzontally, i.e.
perpendlcular to the axis of the sllde tube. Pushing lnto the groove is effected by an oblique surface provided on the piston and the diameter of the balls and the wall thickness of the slide tube are correlated so as to maintain the balls locked in position flush with the wall of the slide tube; the piston, therefore, can slide over the openings of the bores and retain the balls.
This arrangement is disadvantageous ln its transmission of load and release of the balls from the grooves upon release of the lock. The line of action of the force transmitted from the slide tube to the balls , is not in the same plane as the reaction force exerted by the groove on the balls; this results in a higher stress on the transmission elements.
Particularly disadvantageous however is the fact that the balls have to be s displaced horizontally uponreleaseof the lock (inwardly towards the narrow :~ portion of the piston) whereby such forces only can be exerted for such displacement which act in a vertical direction, i.e. push and pull on the slide tube. The balls, accordingly, have to be pulled out of the groove ',.:
,3 30 and pushed back again into the slide tube by a load deflection. This ;3' ~. ~
.. . . .. .
~ '-' ' ' ' ' ~
.,~ ~ , .
~0499~4 ne~ slt~te~ a~l apl)ropriul~ ~oll~L~ur~Llo~ f the ~roove w~ich, ln tlJrn, resulL~ ~n an iml)airm~llt ~-f ~he l~ckin~ ~ctlon; ln addition, a relatively large force is re~uired to pull Lhe balls out o~ the g~oove.
It 19 an ob~ect of the p~e~ent lnvention to elimlnate the above-mentioned disadvatl~ages.
In accordance with the present invention there iB provlded ln an adjustable height chair comprising:
(a) a vertical cylindrical post having a plurality of vertically spaced annular grooves in the inner wall thereof;
(b) a slide tube having a pluralit~ o~ radiall~ extending bores theretrhough and coaxially disposed withln said cylindrlcal post;
(c) a detent ball radially slidable in each of said bores; and ~ (d) a piston movable between a lock position wherein said piston i retains each ~aid ball in engagement with an adjacent said annular groove and its radial bore thereby locking said slide tube relative to said post at a height defined by the position of said groove and a free position wherein each said ball is removed from the adjacent annular groove but i6 retained in said radial bore; the improvement wherein said radially extend-ing bores slope from the periphery diagonally downwardly toward the interior of said tube 80 as to provide a chute for inward movement of said balls towards an abutment when said piston is moved from said lock posi-tion to said free position, the slope of said bores being selected such f that, in the locked position, the balls engaging the groove transmit a load on said slide tube substantially diametrically to a lower portion of said groove.
The invention is lllustrated by way of example in the accompany-ing drawings wherein:
Figure 1 is a simplified cross-section of the adjustment mechanism of a chair according to the invention; and Figure 2 is a sectlon, on an enlarged scale, of Figure 1 illustrating the locking action.
-';~ ' .
10~9914 Th~ vertic:al cylindr~c~l po~t of the c1lalr 1~ de~S~nat~d by tlle reference numeral 1 s~ ported at It8 lower end on a base with or without casters (nt)t shown). IL i8 provlded wi~h a sleeve 2 In i~
interior for slidlng movement. Sleeve 2 ls provlded wlth ~ plurality of an~ular groov~ S 3 ~enerdlly, but not necessarily, ~ml-clrcular in cross-section arranged vertic~lly spaced apart from one another; the number of grooves and their vertical spacing depend upon the amount of desired height adjustability of the chair. A load spring 4 carrles the sleeve 3 and thus the load transmitted from a sllde tube 5 via the lock-ing mechanism, to be described hereinafter, to the sleeve 3. The load spring 4 is suitably supported, for example, by a support member 6 fixed-ly attached to vertical post 1.
Slide tube 5 carrie~ at its upper end the seat and armrests, not shown. It is located within sleeve 3 and is slidable therein; a support member 7 is provided for guiding purposes. Adjacent its lower end the slide tube 5 is provided with bores 8 extending radially through the tube wall. The number of bores 8 depend upon the requirements; four ~ to six bores are preferred and most effective. Bores 8 extend from the i periphery of the tube wall diagonally downwardly to the interior thereof, as is particularly apparent from Figure 2. The diameter of these bores corresponts substantially to the width of groove 3.
A detent ball 9 i8 provided within each bore 8 and is easily slidable therein. The detent balls, in the locked state, rest on the upper oblique, and preferably rounded edge 10~ of a piston 10 movably arranged in the interior of the slide tube 5. Piston 10 is pressed up-$ wardly against the balls 9 by a support spring 11. Balls 9 are, in turn, pressed with at least a portion of the ball body into the selected groove 3. The support spring 11 is disposed on a suitable support member 12.
The piston 10 includes a collar 13 of smaller diameter and i9 attached to ;; 30 a piston rod 14 supported within the slide tube 5 by means of a displace-.,, ~
~i ~0499~
al)le slJ~)port l~e~ )er 15 and movable relative ~o the sllde tube along its longitu~linal axls by a lever 16.
Figur~ 2 illu~trate~ the manner ln which the load actlng do~war~ly on ~he slide tube acts on the contact zone 17 between each bore 8 and the detent ball 9 located therein, resulting in a correspond-ing force P directed diagonally downwardly. Reaction force R to such -~ force P extends through contact ~one 18 between ball 9 and groove 3. It i~ readily apparent that both forces are diametrically oppo~ed with respect to the ball resulting in a sati~factory positive locking action.
To release the lock, which is generally requlred during height ad~ustment of the chair, a slight displacement of the piston lO downwardly is effected by actuating lever 16 against the action of support spring 11.
Since the edge lO' Aupporting balls 9 has also moved downwardly, balls 9 are free and slide under their own weight in a sliding chute, within bores 8 towards the centre to slide tube 5 to a point where they abut collar 13 of piston 10. With this downward movement they have cleared groove 3, and since they are now located completely within the periphery of slide tube 5, the latter can now be moved relative to vertical post 1.
After such movement, the lever 16 is agaln released such that support spring 11 again acts on piston 10 which exerts a pressure on balls 9 dir-ected diagonally outwardly. As soon a~ the next groove 3 is reached during relative movement of cylindrical post l and slide tube 5, the balls 9, under the action of piston 10, slide into such groove 3 thereby again locking the slide tube in its new position.
Apart from the fact that force P and reaction force R lie in ; one line of action, it is also essential that, as previously mentioned, the weight of the balls 9 themselves i8 utili~ed in releasing the locking action; the balls, therefore, need not be pushed out of groove 3 but, , instead, slide therefrom under their own weight.
$
,.i '~ !
. ,, ,.: .
Claims (4)
- THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
I. In an adjustable height chair comprising;
(a) a vertical cylindrical post having a plurality of vertically spaced annular grooves in the inner wall. thereof;
(b) a slide tube having a plurality of radially extending bores therethrough and coaxially disposed within said cylindrical post;
(c) a detent ball radially slidable in each of said bores; and (d) a piston movable between a lock position wherein said piston retains each said ball in engagement with an adjacent said annular groove and its radial bore, thereby locking said slide tube relative to said post at a height defined by the position of said groove and a free position wherein each said ball is removed from the adjacent annular groove but is retained in said radial bore; the improvement wherein said radially extend-ing bores slope from the periphery diagonally downwardly toward the interior of said tube so as to provide a chute for inward movement of said balls towards an abutment when said piston is moved from said lock position to said free position, the slope of said bores being selected such that, in the locked position, the balls engaging the groove transmit a load on said slide tube substantially diametrically to a lower portion of said groove. - 2. A chair as claimed in claim 1 wherein said abutment is formed by a collar on said piston.
- 3. A chair as claimed in claim 1 or 2 wherein said piston is provided with a rounded upper edge which engages the balls.
- 4. A chair as claimed in claim 1 or 2 wherein said grooves are substantially semi-circular in cross-section.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH66976A CH591832A5 (en) | 1976-01-20 | 1976-01-20 | Chair with height adjustable mechanism - has movable tube with detent holes featuring chamfer for ball to facilitate setting |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1049914A true CA1049914A (en) | 1979-03-06 |
Family
ID=4192382
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA266,822A Expired CA1049914A (en) | 1976-01-20 | 1976-11-29 | Adjustable height chair |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS52116362A (en) |
| CA (1) | CA1049914A (en) |
| CH (1) | CH591832A5 (en) |
| ZA (1) | ZA767251B (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2954540C2 (en) * | 1979-05-04 | 1989-11-23 | F. Biedermann Gmbh & Co Kg, 7450 Hechingen, De | |
| DE8627648U1 (en) * | 1986-10-16 | 1988-09-01 | Dauphin F W Buerositzmoebel | Chair, especially office chair, with height-adjustable backrest |
| US5720369A (en) * | 1995-04-19 | 1998-02-24 | Lord Corporation | Adjustable, lockable devices |
| JP4135853B2 (en) * | 2000-05-02 | 2008-08-20 | 株式会社ニチリョク | Presentation device |
| CN102068138B (en) * | 2010-11-19 | 2012-09-05 | 镇江浩博航空铁道设备研发有限公司 | Lifting and swiveling structure |
| CN103511388A (en) * | 2013-09-17 | 2014-01-15 | 兰继红 | Lifting hydraulic cylinder used for electroplating suspension rod |
| CN106555795B (en) * | 2016-11-30 | 2019-06-14 | 中航光电科技股份有限公司 | A kind of telescopic rod |
| US12025177B2 (en) | 2020-10-27 | 2024-07-02 | Robert Varney | Universal coupling for hollow carbon fiber composite structures |
-
1976
- 1976-01-20 CH CH66976A patent/CH591832A5/en not_active IP Right Cessation
- 1976-11-29 CA CA266,822A patent/CA1049914A/en not_active Expired
- 1976-12-06 ZA ZA767251A patent/ZA767251B/en unknown
-
1977
- 1977-01-20 JP JP539477A patent/JPS52116362A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS52116362A (en) | 1977-09-29 |
| CH591832A5 (en) | 1977-09-30 |
| ZA767251B (en) | 1977-10-26 |
| JPS5642921B2 (en) | 1981-10-08 |
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