U.S. patent number 3,870,270 [Application Number 05/411,197] was granted by the patent office on 1975-03-11 for fully enclosed, adjustable, support column for a pivotal chair.
This patent grant is currently assigned to Harter Corporation. Invention is credited to Richard L. Holtz.
United States Patent |
3,870,270 |
Holtz |
March 11, 1975 |
FULLY ENCLOSED, ADJUSTABLE, SUPPORT COLUMN FOR A PIVOTAL CHAIR
Abstract
A support column for a pivotal chair. The support column may be
fully enclosed and yet permit selective adjustability in the height
of the seat section above a base portion merely by rotation of the
seat section. A threaded spindle is nonrotatably secured to, and
extends downwardly from, a seat section and is received within a
hub tube that extends upwardly from the base portion. An adjusting
nut is threaded onto the spindle to control the axial extent to
which the spindle is received within the hub tube and thereby
regulates the height of the seat section above the base portion.
The adjusting nut is normally rotatable with the spindle, and an
arm is secured to the adjusting nut which will engage a lost motion
device after the seat section has been rotated through no more than
a predetermined angular range. After the seat section has been
further rotated through no more than an additionally predetermined
angular range, the lost motion device -- which is mounted to be
freely rotatable with respect to the spindle -- contacts a stop so
that continued rotation of the seat section in the same direction
effects relative movement between the spindle and the adjusting nut
to adjust the height of the seat section. The angular range through
which the seat section is rotated before the stop restrains both
the lost motion device and the arm on the adjusting nut from
rotating with the spindle constitutes the free pivotal range
through which the seat section can be rotated without effecting any
adjustment in the height thereof.
Inventors: |
Holtz; Richard L. (Sturgis,
MI) |
Assignee: |
Harter Corporation (Sturgis,
MI)
|
Family
ID: |
23627978 |
Appl.
No.: |
05/411,197 |
Filed: |
October 31, 1973 |
Current U.S.
Class: |
248/406.1;
297/344.12; 297/344.21 |
Current CPC
Class: |
A47C
3/24 (20130101) |
Current International
Class: |
A47C
3/20 (20060101); A47C 3/24 (20060101); F16m
011/24 () |
Field of
Search: |
;248/405,406,404,161,188.7,188.4 ;297/349 ;108/147 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: McCall; James T.
Attorney, Agent or Firm: Hamilton, Renner & Kenner
Claims
I claim:
1. An adjustable support column for pivotally mounting the seat
section of a chair to a base portion comprising: a hub tube
extending upwardly from the base, a threaded spindle non-rotatably
secured to, and extending downwardly from, the seat section, at
least a portion of said threaded spindle being rotatably and
reciprocatingly received within said hub tube, an adjusting nut
threaded onto said spindle to establish the extent to which said
spindle can extend within said hub tube and thereby control the
height of the seat section, a stop presented from said hub tube, a
first arm means secured to said adjusting nut, and a lost motion
device interposed between said arm and said first stop to permit
relative rotation of said spindle with respect to said adjusting
nut in order to effect adjustment in the height of said seat
section only after the seat section has rotated within a range of
free pivotal movement in either direction, the total range of such
free pivotal movement being at least one full revolution.
2. An adjustable support column, as set forth in claim 1, in which
said lost motion device comprises a second arm means mounted to
rotate about said spindle, said second arm means being engageable
by said first arm means and said stop being sequentially engageable
by said second arm means upon rotation of the seat section beyond a
predetermined free pivotal range.
3. An adjustable support column, as set forth in claim 2, in which
said first arm means is rotatable through a range of up to
approximately 320.degree. before engaging said second arm means,
and said second arm means being rotatable through a range of up to
approximately 320.degree. before engaging said stop.
4. An adjustable support column, as set forth in claim 3, in which
retarding means are operatively interposed between said spindle and
said adjusting nut.
5. An adjustable support column, as set forth in claim 4, in which
a first cover tube surrounds said hub tube and extends upwardly
from the base portion, and in which a second cover tube surrounds
said spindle and extends downwardly from the seat section, said
first and second cover tubes being telescopically interfitted.
6. An adjustable support column, as set forth in claim 5, in which
the retarding means comprises a J-washer non-rotatably mounted from
said spindle, said J-washer being located in juxtaposition with
said adjusting nut, first means on said J-washer interacting with
second means on said adjusting nut to retard relative rotation
therebetween.
7. A chair having an adjustable support column comprising; a seat
section, a base portion, a hub tube secured to and extending
upwardly from said base portion, a threaded spindle, means
non-rotatably to connect said threaded spindle to said seat
section, an adjusting nut threaded onto said spindle to establish
the height of said seat section above said base portion, a stop
presented from said hub tube, a first arm means presented from said
adjusting nut, and a lost motion device interposed between said
stop and said first arm means.
8. A chair, as set forth in claim 7, in which said lost motion
device comprises a second arm means mounted to rotate about said
spindle, said second arm means being engageable by said first arm
means and said stop being sequentially engageable by said second
arm means upon rotation of the seat section beyond a predetermined
free pivotal range.
9. A chair, as set forth in claim 8, in which said first arm means
is rotatable through a range of up to approximately 320.degree.
before engaging said second arm means, and said second arm means
being rotatable through a range of up to approximately 320.degree.
before engaging said stop.
10. A chair, as set forth in claim 9, in which retarding means are
operatively interposed between said spindle and said adjusting
nut.
11. A chair, as set forth in claim 10, in which a first cover tube
surrounds said hub tube and extends upwardly from the base portion,
and in which a second cover tube surrounds said spindle and extends
downwardly from the seat section, said first and second cover tubes
being telescopically interfitted.
12. A chair, as set forth in claim 10, in which an interconnect
means extends radially inwardly of at least one said arm means, an
annular flange being attached to, and extending outwardly of, said
hub tube, said flange being positioned upwardly of said
interconnect means to preclude inadvertent separation of the seat
section from said base portion, and means radially to withdraw said
interconnect means in order to permit assembly and disassembly of
said seat section with respect to said base portion.
13. A chair, as set forth in claim 12, in which said interconnect
means comprises a screw threadably received through at least one
said arm means and in which a bore is provided through at least one
said cover tube to permit access to said screw.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to an adjustable support
column for pivotally mounting the seat section of a chair to a base
portion.
Historically, adjustment in the height of a seat has been
accomplished by the use of a threaded spindle that becomes
progressively exposed as the seat is raised by threading the
spindle upwardly out of a bell nut and hub tube.
In response to considerations of: improving the operating
efficiency (by shielding the threaded portion of the spindle from
deleterious dust and dirt); providing an aesthetically improved
appearance (by shielding the threaded spindle from view); and,
maintaining cleanliness (by shielding the person using the chair,
and his or her clothes, from the lubricant employed on the threaded
spindle), various types of cover assemblies and concommitant
mechanisms for permitting selective height adjustability have been
provided. However, the prior known configurations have not been
totally acceptable.
One approach has necessitated the incorporation of a special
connection between the seat section of the chair and the threaded
spindle -- often by inserting a pivot therebetween in order to
permit the seat section to be rotated without effecting an
adjustment in the height of the seat.
Another approach has necessitated some physical connection between
the cover assembly and the adjusting mechanism hidden thereby. But
irrespective of the approach, the ability to raise and lower a
pivotally mounted seat section simply by the convenient expedient
of rotating the seat section has not heretofore been accomplished,
and on the basis of the state to which the prior art has advanced,
to provide such a result in conjunction with a cover arrangement
has been considered well nigh impossible.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of the present invention to
provide a support column for pivotally mounting the seat section of
a chair to a base, said support column affording height
adjustability by rotation of the seat section with respect to the
base portion.
It is another object of the present invention to provide a support
column for a chair, as above, which permits the seat section to
rotate through a free pivotal range of approximately one and
three-fourths revolutions without effecting any adjustment in the
height thereof.
It is a further object of the present invention to provide a column
for a chair, as above, which affords adjustability in the height of
the seat section by rotation thereof beyond the one and
three-fourths revolutions provided for the free pivotal range.
These and other objects, together with the advantages thereof over
existing and prior art forms which will become apparent from the
following specification, are accomplished by means hereinafter
described and claimed.
In general, an adjustable support column embodying the concept of
the present invention incorporates a hub tube that extends upwardly
from a base portion to receive at least a portion of a threaded
spindle that is fixedly secured to, and extends downwardly from, a
seat section. The portion of the spindle received within the hub
tube may rotate and/or reciprocate with respect thereto, and an
adjusting nut assembly is threaded onto the spindle to establish
the extent to which the spindle can be inserted into the hub tube
and thereby adjust the height of the seat section relative to the
base portion.
A first arm means presented from the adjusting nut is indirectly
engeagable with a stop presented from the hub tube. In fact, the
indirect engagement may be affected by a lost motion device
comprising a second arm means that is mounted for free rotation on
the spindle -- said second arm means being engageable by the first
arm means upon no more than a predetermined degree of rotation by
said seat section, and the second arm means, in turn, engaging the
stop upon no more than an additional, predetermined degree of
rotation by said seat section.
As such, the height of the seat section can be adjusted by rotation
of the seat section, but only after the seat section has rotated
through a given range of free pivotal movement.
A telescoping cover arrangement may extend between the seat section
and the base portion to enclose the spindle, hub tube, adjusting
nut and interconnecting mechanism.
One preferred embodiment of an adjusting support column for a
pivotally mounted chair embodying the concept of the present
invention is shown by way of example in the accompanying drawings
without attempting to show all of the various forms and
modifications in which the invention might be embodied; the
invention being measured by the appended claims and not by the
details of the specification.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a frontal-side perspective of a chair embodying the
concept of the present invention, the seat section of the chair
being exploded upwardly to reveal the uniquely adjustable support
column extending upwardly from the base portion and being, in part,
broken away to conserve space;
FIG. 2 is an enlarged, exploded, perspective of a portion of the
internal mechanism incorporated in the adjustable support column
depicted in FIG. 1;
FIG. 3 is an enlarged vertical section taken substantially along
line 3--3 of FIG. 1 and depicting the mechanism interiorly of the
support column, said mechanisms being disposed to permit a range of
free pivotal movement to the seat section without effecting an
adjustment in the height thereof;
FIG. 4 is a horizontal section taken substantially along line 4--4
of FIG. 3 and appearing on the same sheet of drawings as FIGS. 1
and 2;
FIG. 5 is a further horizontal section taken substantially along
line 5--5 of FIG. 3 and appearing on the same sheet of drawings as
FIG. 3;
FIG. 6 is a still further horizontal section taken substantially
along line 6--6 of FIG. 3 and appearing on the same sheet of
drawings as FIGS. 3 and 5;
FIG. 7 is a still further horizontal section taken substantially
along line 7--7 of FIG. 3;
FIG. 7a is a view similar to FIG. 7 but depicting the mechanism
disposed to permit vertically upward adjustment in the height of
the seat section above the base portion;
FIG. 8 is an even further horizontal section taken substantially
along line 8--8 of FIG. 3; and,
FIG. 9 is a vertical section similar to FIG. 3 but depicting the
mechanism interiorly of the support column disposed to permit
vertically upward adjustment in the height of the seat section
above the base portion.
DESCRIPTION OF A PREFERRED EMBODIMENT
A support column embodying the concept of the present invention is
designated generally by the numeral 10 in the appended drawings and
is depicted as providing adjustment in the height of a seat section
11 above a base portion 12 in a chair 13.
The base portion 12 may comprise a plurality of legs 14 that are
conjoined at the nave 15 to support a hub tube 16 that is secured
to, and extends vertically upwardly from, the nave 15. An annular
bushing, or liner, 18 is received within the hub tube 16 and a nib
19 (FIG. 3) on the outer surface thereof may be positioned within a
radial bore 20 in the hub tube 16 to anchor the bushing 18 therein.
The bushing 18 is preferably made of a plastic such as Zytel to
provide a self-lubricating, bearing surface for a spindle 22 that
is secured to, and extends vertically downwardly from, the seat
section 11. The spindle 22 is secured to rotate with the seat
section 11, and this result may be effected by staking, press
fitting or otherwise securing the point 23 of the spindle 22 within
a chair control 24 fastened to the underside of the seat section
11. The threaded portion 25 of the spindle 22 is rotatably and
reciprocatingly received within the bushing 18.
A flange 26 extends radially outwardly from the upper extremity in
the bushing 18 and engages the upper rim 28 of the hub tube 16.
An adjusting nut 30 is threaded onto the threaded portion 25 of
spindle 22 and presents a first arm means 31 that is, upon rotation
through a predetermined range, engageable with a lost motion device
32 which, upon movement to a further predetermined range, is
engageable with a stop 33 presented from the hub tube 16.
Although the foregoing arrangement can be accomplished in a number
of ways, the embodiment depicted works quite well, and in that
construction the arm means 31 is secured to the nut 30 and extends
downwardly therefrom in generally parallel, radially outwardly
spaced, relation to the spindle 22.
The lost motion device 32 may well comprise a washer 34 that is
mounted for free rotation on the spindle 22 medially and adjusting
nut 30 and hub tube 16. As best seen in FIGS. 3 and 9 the washer 34
is sandwiched between the flange 26 on bushing 18 and a J-washer
35, the purpose for which will be more fully hereinafter
described.
A second arm means 36 is secured to, and extends downwardly from,
the washer 34 in generally parallel, radially outwardly spaced,
relation to the spindle 22. The first and second arm means 31 and
36, respectively, are disposed to interengage upon a predetermined
degree of angular movement. At least the second arm means 36 may be
disposed to extend downwardly past the outer surface 38 of the hub
tube 16 in radially outwardly spaced relation with respect thereto
in order to engage the stop 33 which projects radially outwardly
beyond the outer surface 38 of the hub tube 16.
In the embodiment depicted, the stop 33 is represented as being a
bar-like arrangement secured to the outer surface 38 of the hub
tube 16, but the stop 33 could just as well be a projecting pin
received within a bore in the hub tube 16, or, for that matter, an
extension of the nib 19 on bushing 18 which would extend outwardly
through the radial bore 20 in the hub tube 16. Thus, it should be
apparent that any number of configurations would satisfy the
purpose of the present invention.
In order to adjust the height of the seat section, the arm means 31
must engage arm means 36 and the arm means 36 must engage stop 33,
both in the direction the seat section is being rotated (depending
upon whether the seat section is to be raised or lowered). As shown
in FIGS. 7a and 9, one lateral edge 39 on arm means 31 engages the
opposed lateral edge 40 of arm means 36, and the opposite edge 41
of arm means 36 engages one side 42 of stop 33. With the arm means
31 and 36 as well as the stop 33 so juxtaposed, continued
counter-clockwise rotation of the seat section 11 (as viewed from
above) will cause the spindle 22 to turn upwardly out of the
adjusting nut 30 and thereby raise the seat section 11.
Should one elect to rotate the seat section 11 in a clockwise
direction (also as viewed from above) there would be nothing
restraining the free movement of arm means 31, and the nut 30 would
simply rotate with the spindle 22. This restraining result is
assured by the use of the J-washer, or other suitable retarding
means, 35. Specifically, a radially inwardly directed key 46 on
J-washer 35 engages an axial slot 48 in the threaded portion 25 of
spindle 22 so that the J-washer 35 will rotate with, but not with
respect to, the spindle 22. At least one flat surface 49 on the
J-washer 35 is provided with a plurality of radially extending
ridges, or other comparable protuberances, 50 that engage with
grooves, or recesses, 51 in the juxtaposed under surface 52 of nut
30 to urge the nut 30 to rotate with the spindle 22.
After approximately 320.degree. counter-clockwise rotation of the
seat section 11 from the FIG. 9 position, the opposite lateral edge
53 on arm means 31 would engage edge 41 of arm means 36. Because
the washer 34 is free to rotate about spindle 22, continued
clockwise rotation of seat section 11 with the edges 53 and 41 of
arm means 31 and 36, respectively, engaged, rotates the lost motion
device 32 with the nut 30. After approximately 320.degree. further
clockwise rotation of the seat section the lateral edge 40 of arm
means 36 will engage the opposite side 54 of stop 33.
Continued clockwise rotation of seat section 11 with the arm means
31 and 36 as well as the stop 33 so juxtaposed will cause the
spindle 22 to be screwed downwardly into the adjusting nut 30,
thereby lowering the seat section 11. However, the approximately
640.degree., or one and three-quarters revolutions, range of
rotation between the juxtapositioning of the stop 33 and arm means
31 and 36 to effect either a raising or lowering of the seat
section comprises the free pivotal range afforded to the seat
section 11 supported by a column embodying the concept of the
present invention.
It must be appreciated that when the adjusting nut 30 is restrained
from rotation by engagement of the juxtaposed arm means 31 and 36
with the stop 33, the ridges 50 on J-washer 35 will slip across the
grooves 51 on the nut 30 to permit rotation of the spindle 22 with
respect to the adjusting nut 30.
As such, the hub tube 16, spindle 22, adjusting nut 30 and the
mechanism interconnecting the adjusting nut 30 with the hub tube 16
may be completely inaccessible without impairing the adjustability
in the height of the seat section 11 above the base portion 12, and
a suitable cover 55 may be employed to conceal those parts.
In the embodiment depicted, an outer hub cover 56 may be positioned
in concentrically spaced relation about the hub tube 16. This
disposition of the outer hub cover 56 is achieved by the
cooperative effect of a spacer 58 which circumscribes the hub tube
16 in proximity to the nave 15, and the crenelated lower edge of
the outer hub cover 56. As best seen in FIGS. 3 and 9, the tines 59
forming the crenelations conform to the legs 14 and present
decorative fillets therebetween.
The inner hub cover 60 is suspended from the seat section 11 and is
telescopically received within the outer hub cover 56. One may
conveniently suspend the inner hub cover 60 by means of an annular
ring 61 that rests on the shoulder 62 formed at the juncture of the
threaded portion 25 and the point 23 of the spindle 22. The ring 61
may be secured to the interior surface 63 of the inner hub cover
60, the upper edge 64 of which engages the under surface 65 of the
chair control 24 on the seat section 11.
In order to preclude inadvertent separation of the seat section 11
from the base portion 12, as by lifting the seat section 11 in an
attempt to lift the entire chair 13, a releasable interconnect is
preferably provided. The interconnect may comprise a screw 68 that
is threadably received within a bore 69 through the first arm means
31. With the screw 68 removed, the arm means 31 may be readily
translated past the flange 26 on bushing 18 to allow the seat
section 11 to be lifted independently of the base portion 12 and
thereby to be physically separated from the base portion, but with
the screw 68 extending radially inwardly of the arm means 31 in its
operative position it will engage the flange 26, thereby serving to
preclude separation of the seat from the base. It should be
appreciated that when a cover arrangement 55 is employed an access
bore 70 should be provided through the appropriate hub cover (the
inner hub cover 60 as depicted in FIG. 3) to permit access to the
screw 68 in order that the chair 13 may be selectively assembled
and disassembled.
It should thus be apparent that a chair embodying the concept of
the present invention: permits the height of the seat section to be
adjusted merely by rotation of the seat section with respect to the
base portion; allows the seat section to be pivotal through a
predetermined angular range with respect to the base portion
without changing the height of the seat section; and, otherwise
accomplishes the objects of the invention.
* * * * *