Improvements in the Construction of Base Castings and Adjustable Spindles of Revoluble Chairs.
Year: 1897

page_text: Date of Application, 25th June, 1897
Complete Specification Left, 17th Mar., 1898-Accepted, 23rd Apr., 1898
Improvements in the Construction of Base Castings and Adjustable
Spindles of Revoluble Chairs.
I, PETER JENSEN, of 77, Chancery Lane, in the County of Middlesex, Chartered
Patent Agent, do hereby declare the nature of this invention, which has been
communicated to me from abroad by the Gilson Manufacturing Company, located
in the City of Port Washington, in the County of Ozaukee and State of Wisconsin,
United States of America, to be as follows:-
This invention has for its object to simplify and cheapen the manufacture of chairs
in which vertically adjustable screw-spindles capable of free rotation on their axes are
held against longitudinal displacement, and to facilitate the taking apart of the said
dovices for shipment and storage without liability of the loss of parts and to these
ends the said invention consists in forming the chair-base casting which receives the
legs of the chair with a vertical longitudinal smooth circular bore, the latter being
for the engagement of a screw-threaded spindle that in practice has connection at
its upper end with a spider to which the seat portion of the chair is made fast. This
screw-spindle is provided with a longitudinal groove, engaged by a spline constitut-
ing an inwardly extending projection of another casting herein termed a cup,
notwithstanding the fact that it has a bottom aperture for the passage of said spindle.
This cup has the underside of its bottom in frictional contact with the base-casting,
but the area of this contact is preferably reduced by beveling said underside of the
cup-bottom in an upward outward direction. The said cup is provided at its lower
end with an exterior annular flange, which is overlapped by a guard of any suitable
construction, preferably a centrally apertured cast-metal plate, said plate and the
base-casting being provided with registering apertures for the passage of leg-holding
screws. The wall of the cup comes within the central apertures of the plate; and
this aperture is properly within the boundary of an annular offset lip that constitutes
part of said plate in opposition to the cup flange above specified. A nut is run upon
the spindle, within the said cup, and an upper annular flange of the nut bears upon
the rim of the cup, but otherwise the two are preferably out of contact with each
other, and this nut may be cast with a hand-wheel, and be provided with an exterior
annular groove for tlic reception of a stop that extends inwardly from the wall of the
cup, this stop being preferably in the form of a set-screw engaging a tapped opening
in the cup-wall. The stop prevents the nut from lifting out of the cup when a
chair is in use, and when the parts of the chair are separated for storage or ship-
ment, the nut may be retained in said cup or be carried by the spindle. Except the
spindle and screw-stop the several parts above specified may be all made by casting,
and no tool or machine work is necessary thereon other than tapping the nut and
cup-wall for engagement of said spindle and screw-stop.
The screw-spindle has a portion of its ordinarily tapered lower end cut away in a
longitudinal direction to form a right-angled notch having the vertical boundary
thereof in line with one side of the described longitudinal groove in said spindle, tho

page_text: lower terminus of the said groove being at the horizontal boundary of the notch far
enough from said end of the spindle to insure of at least one full width of the screw-
thread upon said spindle coming into contact with the spline of the described oup
prior to the engagement of said groove and spline when the aforesaid spindle is
engaged with the nut and run down, thus insuring the positive ready engagement
of the spindle-groove and cup-spline, and avoiding binding. When the spindle and
spline have been thus engaged, the former may be held against rotation on its own
axis and the nut rotated to cause a vertical adjustment of said spindle.
adjustment has been accomplished, a rotation of the spindle will also cause a rotation
therewith of the cup and nut on the same axis, and consequently the spindle cannot
work down.
Dated this 25th dar of Inna 1907
When this
Improvements in the Construction of Base Castings and Adjustable
Spindles of Revoluble Chairs.
I, PETER JENSEN, of 77, Chancery Lane, in the County of Middlesex, Chartered
Patent Agent, do hereby declare the nature of this invention which has been
communicated to me from abroad by the Gilson Manufacturing Company,, located
in the City of Port Washington, in the County of Ozaukee and State of Wisconsin,
United States of America, and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:-
The invention has for its object to simplify and cheapen the manufacture of chairs
in which vertically adjustable screw-spindles capable of free rotation on their axes are
held against longitudinal displacement, and to facilitate the taking apart of the said
devices for shipment and storage without liability of the loss of parts, and to these
ends the said invention consists of certain peculiarities in the structural details and
combination of parts of said devices, all as hereinafter set forth with reference to the
accompanying drawings and subsequently claimed.
Description of the drawings:
Figure 1 of the drawings represents a view for the most part in vertical transverse
section on the plane indicated by line 1-1 in Figure 2 and illustrates an improved
longitudinally grooved screw-spindle in connection with other features of said
invention.
Figure 2 represents a plan view, partly in horizontal section, as indicated by 'line
2-2 in Figure 1, a guard-plate constituting an element of the assemblage being
illustrated as having a portion thereof broken away.
Figure 3 represents an elevation of the lower portion of the aforesaid screw-
spindle.
Referring by letter to the drawings, A represents what is commonly termed the
"base-casting" in a chair of the class to which this invention relates, this casting
being herein shown provided with a plurality of leg-sockets and having a smooth
bore, the latter being for the engagement of a screw-threaded spindle B, that in
practice has connection at its upper end with a spider to which the seat portion of
the chair is made fast.
The screw-spindle is provided with a longitudinal groove b, and this groove is
engaged by a spline c, constituting an inwardly-extending projection of another.
casting C, that is herein termed a "cup" notwithstanding the fact that it has a

page_text: bottom aperture for the passage of said spindle. The cup Chas the under side of
its bottom in frictional contact with the base-casting, but the area of this contact is
preferably reduced by beveling said under side of the cup-bottom in an upward
outward direction, as clearly illustrated in Figure 1, it being desirable in practice to
avoid unnecessary friction between said cup and base-casting.
An exterior annular flange d at the lower end of the cup C is overlapped by a
guard that may be of nuy suitable construction and held in place by any suitable
means, but as herein shown, the guard is preferably a centrally-apertured cast-metal
plate D, similar in general contour to the top of the base-casting, said plate and
base-casting being provided with registering apertures for the passage of leg-holding
screws common in the art to which this invention relates.
The wall of the cup
C
comes within the central aperture of plate D, and this aperture is properly within
the boundary of an annular offset lip e, that constitutes part of said plate in
opposition to the cup-flange d, above specified. As herein shown it is preferable.
that the cup and guard-plate have such relative proportions that frictional contact of
the two is avoided except at such time as there may be a lift on the spindle B, above
specified.
A preferable cast-metal nut E, run on spindle B, comes within the cup C, and an
upper annular flange f of the nut bears upon the rim of said cup, but otherwise the
two are preferably made to be out of contact with each other in order to avoid
unnecessary friction. The nut may be cast with a hand-wheel F, as herein shown,
and it is also shown provided with an exterior annular groove g for the reception of
a stop that extends inward from the wall of cup C, this stop being preferably in the
form of a set-screw h, engaging a tapped opening in the cup-wall.
The stop
prevents the nut from lifting out of the cup when a chair is set up, and in knock-
down shipment or storage of the chairs said nut may be retained in said cup or
carried by the spindle.
Except the spindle B and the screw h, the several parts above specified may be
made by casting, and no tool or machine work is necessary thereon other than
tapping the nut and cup-wall for engagement of said spindle and screw.
The screw-spindle is herein shown as having a portion of its ordinarily-tapered
lower end cut away in a longitudinal direction to a form a right-angle notch having
the vertical boundary thereof in line with one side of the groove b, the lower
terminus of the latter being at the horizontal boundary of the notch far enough froin
said end of the spindle to ensure of at least one full width of the screw-thread upon
said spindle coming into contact with spline e of cup C prior to the engagement of said
groove and spline when the aforesaid spindle is engaged with nut E and run down.
By notching the lower end of the spindle; as aforesaid, the positive ready engage-
ment of the spindle-groove and cup-spline is insured and binding avoided.
The spindle and spline having been engaged the former may be held against
rotation on its own axis and the nut rotated to effect a vertical adjustment of said
spindle. This adjustment having been accomplished, a rotation of the spindle will
also cause a rotation therewith of the cup and nut on the same axis. Consequently
said spindle cannot work down.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what I
claim is:-
1. The combination of the base-casting, an independent revoluble open-bottom
cup supported by the same and having an inwardly-extending spline, a longitudin-
ally-grooved screw-spindle extending down through the cup-bottom into said base-
casting but having its groove engaging said spline, and an adjusting-nut for the..
spindle having its bearing on the cup out of contact with the aforesaid base-casting.
2. The combination of the base-casting, an independent open-bottom cup supported
by the same and having an inwardly-extending spline as well as an exterior annular
flange, a guard connected to the base-casting to over-lap the cup-flange, a
longitudinally-grooved screw-spindle extending down through the cup-bottom into

page_text: said base-casting but having its groove engaging said spline, and an adjusting-nut
for the spindle having its bearing on the cup out of contact with the aforesaid base-
casting.
3. The combination of the base-casting, an open-bottom cup supported by the
same and having an inwardly extending spline as well as an exterior annular Hange,
a plate made fust to said base-casting and provided with an annular offset lip in
opposition to the cup-flange, a longitudinally-grooved screw-spindle extending down
through the cup-bottom into said base-casting but having its groove engaging said
spline, and an adjusting-nut for the spindle, having a supporting-flange at rest on
the cup-rim.
n
4. The combination of the base-casting, an independent revoluble open-bottom
cup supported by the same and having an inwardly-extending spline,
longitudinally-grooved screw-spindle extending down through the cup-bottom into
said base-casting but having its groove engaging said spline, an adjusting-nut for
the spindle having its bearing on the cup out of contact with the aforesaid base-
casting, and suitable means for preventing loss of the nut from the cup.
5. The combination of the base-casting, an independent revoluble open-bottom
cup supported by the same and having an inwardly-extending spline, a
longitudinally-grooved screw-spindle extending down through the cup-bottom into
the base-casting but having its groove engaging said spline, an exteriorly-grooved
spindle-adjusting nut having its bearing on the cup out of contact with the afore-
said base-casting, and a screw adjustable in the cup-wall to come within the nut-
groove.
6. The combination of the base-casting, an open-bottom cup supported by the
same and having an inwardly-extending spline as well as an exterior annular flange,
a plate made fast to said base-casting and provided with an offset annular lip in
opposition to the cup-flange, a longitudinally-grooved screw-spindle extending down
through the cup-bottom into said base-casting but having its groove engaging said
spline, an adjusting-nut for the spline having a supporting-flange at rest on the
cup-rim as well as an exterior annular groove that comes within the cup, and a set-
screw engaging the cup-wall to come within the nut-groove.
7. The combination of the base-casting, an independent open-bottom cup having a
beveled under side in contact with said casting, and provided with an inwardly-
extending spline, a longitudinally-grooved screw-spindle extending down through
the cup-bottom into the aforesaid casting but having its groove engaging said spline,
and a spindle-adjusting nut having its hearing on the cup out of contact with the
base-casting.
8. The longitudinally-grooved screw-spindle having its lower end cut away in a
longitudinal direction to form a right-angled notch having the vertical boundary
thereof on a line with a side of the groove and a depth sufficient to insure of a full
width of screw-thread coming into contact with a guide-spline when said spindle is
run down through a nut above said spline, whereby the latter is caused' to have a
positive automatic engagement with said groove.
9. The combination of a base-casting, an independent open-bottom cup supported
by the same and having an inwardly-extending spline as well as an exterior annular
flange, a guard connected to the base-casting to overlap the cup-flange, a
longitudinally-grooved screw-spindle extending down through the cap-bottom into
said base-casting and having a right-angled notch at its lower end, the vertical
boundary of the notch being in line with one side of the spindle-groove that has its
lower terminus on the horizontal boundary of said notch at a point that will insure
of at least one full width of the spindle-thread coming into contact with the afore-
said spline prior to engagement of the latter with said groove; and a spindle-adjust-
ing nut having its bearing on the cup out of contact with the aforesaid base-casting.
10: The combination of the base-casting, an independent revoluble open-bottom
cup supported by the same and having an inwardly-extending spline, a
longitudinally-grooved screw-spindle extending down through the cup-bottom into
said base-casting but having its groove engaging said spline, and a spindle-adjusting

page_text: nut having free rotation in the cup as well as bearing thereon out of contact with the
aforesaid base-casting.
Dated this 17th day of March 1898.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.