Improvements in Dental Chairs.
Year: 1896

page_text: Date of Application, 15th Dec., 1896-Accepted, 23rd Jan., 1897
Improvements in Dental Chairs.
I, ARTHUR WILLIAM BROWNE, of Prince's Bay, in the County of Richmond,
and State of New York, United States of America, Manufacturer, do hereby
declare the nature of this invention and in what inanner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
My invention relates to certain improvements, as hereinafter claimed, applicable
to dental chairs of the class in which provision is made for imparting a wide range
of vertical adjustment to the seats and other parts.
In the accompanying drawings, which represent. a suitable embodiment of my
improvements,
Figure 1 is a front and side perspective view, and Fig. 2 a rear and side
perspective view of the complete chair on a smaller scale than the remaining
views.
Fig. 3 is a view partly in plan and partly in horizontal section beneath the top
of the raising and lowering support.
Fig. 4 is a view partly in elevation and partly in vertical central section, omitting
various portions of the chair.
Fig. 5 is a view in perspective, on a smaller scale than that of the preceding
view, of the chair body and its vertically adjustable support.
Fig. 6 is a view on a larger scale partly in plan and partly in horizontal section
on the line 6 of Fig. 7, showing details of the devices for raising and lowering the
chair body support.
Fig. 7 is a view partly in rear elevation and partly in vertical section on the
line 7 of Fig. 4.
Fig. 8 is a view partly in front elevation and partly in vertical section on the
line 8 of Fig. 4, showing details of the pump mechanism.
Fig. 9 is a view in horizontal section, showing details of the back pad tightening
devices.
Fig. 10 is a section on the line 10 of Fig. 4.
Fig. 11 is a view of the pedestal cap inverted.
A hollow pedestal or base A having a detachable cap or dome, constitutes a
reservoir for oil, or other suitable liquid and is provided with four supporting legs
arranged in diverging front and rear pairs, the front legs A¹ A' being longer than
the rear legs A² A². Each leg terminates in a foot a, and the under surfaces of
the legs from their feet to the hollow pedestal are in the horizontal plane of the
bottom of the pedestal and but slightly above the plane of the under or bearing
surfaces of the feet, so that the pedestal and its legs may be brought close to or
caused to bear slightly upon the carpet upon a floor as the feet indent or sink into
the carpet, thus excluding dust, etc., from beneath the pedestal and its legs. Except
that its corners are rounded the pedestal as shown is rectangular in horizontal
section. The hollow cap or pedestal dome is made in two sections B B detachably
secured upon the pedestal by means of a number of screws b passing through a
flange B of the cap and suitably engaging the pedestal, as will be readily
understood. The two sections of the cap are rigidly and strongly detachably
connected with each other by means of clamp bolts 6 6 passing through perforated
lugs B B of the cap sections and secured by uuts 62 b.

page_text: The sectional pedestal cap is provided with suitable guide ways CCC (plainly
shown in Fig. 3) in which a raising and lowering support D is adapted to be
vertically adjusted.
This support partially surrounds a plunger D¹ and its cylinder D2 which
constitute parts of suitable mechanism for raising and lowering the support, the
guide ways C C C for which are at opposite sides of the cylinder and afford a
strong and steady bearing effectually preventing vibration of the support. Upward
movement of the support is limited by contact of a lug d thereon with a shoulder d¹
at the top of a recess 2 in the pedestal cap for this lug to move in. Downward
movement of the support is limited by contact with the pedestal cap of a buffer e
of leather or equivalent material secured to an arm or lateral extension E at the
front side of the top of the support. The buffer comes in contact with the pedestal
cap at e¹ between upwardly projecting portions of the guideways C C in the cap.
The support D terminates at top in the cross arm journal or trunnions E' upon
which is suitably mounted a chair body or frame F so as to be capable of tilting
or vertically rocking. As shown the chair frame is mounted upon the trunnions Ei
by means of bearings formed by blocks F F' detachably secured to the underside
of the body by screwc. The chair body or frame represented comprises the
inclined back frame or upper portion G, and the inclined lower portion G' for
supporting a seat and a foot board or platform. For convenience of manufacture
the parts F and G' are cast together, and the back frame portion G made separate
and rigidly bolted to the part F, so that in operation the entire chair frame is
adapted to tilt, as though in one casing, about its trunnion connection with its
support. The forward tilting movement of the chair body is limited by its contact
with the arm E of the support, and its rearward tilting movement is limited by
its contact with a downwardly and rearwardly extending arm G2 of the support.
A link rod y pivoted to the arm G2, and adjustably engaging a socket gl in the
chair body back and a set screw 92 for clamping the link rod in its socket, provide
for adjusting the inclination of the body in obvious manner.
A carrier H for a suitable chair seat is adjustable up and down and adapted to
he supported at any desired height upon the lower portion G' of the chair frame
or body in the following way:-The seat carrier has guide way connection with the
chair frame by means of guide ribs h upon the frame engaging with guide
grooves of the carrier so that the carrier may be slid up and down the frame.
Holes in the frame extending in a line longitudinally thereof are adapted to be
engaged by a detent lug at the lower end of a lever H' pivoted at H2 to the
inner surface of the carrier. Above its pivot the detent lever projects forwardly
through an opening in the carrier and in this way there is provided a handle H
by which to rock the detent lever and disengage its lower end or lug from the
frame. The detent handle also serves as a means for supporting the carrier in
raising and lowering it, and is located out of the way beneath the seat, and so
protected against contact with the person or clothing.. The frame is slightly
hollowed out or made of shallow trough shape upon its front surface and the carrier
is also trough shaped upon its rear surface so as to provide ample space for the
rocking movements of the detent lever.
From the above description it will be seen that the seat carrier may quickly be
raised or lowered; that upon the release of the gravitating detent lever, the
carrier becomes automatically locked with the frame; that by providing a long
detent lever pivoted near its upper or handle end the handle is brought to a height
most convenient to reach, and that but slight rocking movement is required to
disengage the detent lug; and that by providing a long carrier a wide range of
adjustment is attained without necessitating the extension of the guide way upon
the frame above the level of the portion F of the frame, thus admitting of this
guide way being terminated in about the horizontal plane of the jointed connection
of the frame with its support.
Downward movement of the seat carrier is limited by contact of the lower end
or lug of the detent lever with a shoulder or stop lug I on the frame, and the

page_text: rocking movement of the lever. is limited by a stop lug I on the carrier, thus
ensuring engagement of the lever with the stop I at the limit of the descent of
the carrier. Upward movement of the carrier is limited by a lug 1' on the inside
of the carrier at its lower end coming in contact with a stop screw 13 on the
frame. See Fig. 4. To provide for securing this stop screw in place and to
permit of its removal for disconnecting the parts, a hole i (Fig. 1) is made in the
carrier through which the screw may be secured in place and detached when this
hole is made to register with the screw hole in the frame.
Any suitable seat frame and seat may be appropriately supported-by and partake
of the movements of the carrier. As shown the construction of parts and their
connection with the carrier are as follows:-A forked bracket J is properly attached-
as by screws to the upper flanged end; of the carrier and the forks of the bracket
are secured to the seat frame bars JJ which are provided with the arms J J
and have secured to them the seat J3 of carpet or other flexible material..
A frame K provided with a foot rest K¹ and foot board or platform K' has
adjustable supporting connection by way of its carrier K with the chair frame
through the medium of the seat carrier H so as to partake of the movements of
this carrier H. The carrier K3 is also adjustable up and down independently of
the adjustments of the seat carrier, and is provided with the child's foot board K'.
The guide-way connection of the foot board carrier K³ with the seat carrier is
substantially the same as the connection between the seat carrier and the chair
frame, the foot board carrier being provided with guide grooves for engaging with
guide ribs kk at the edges of the seat carrier. The range of adjustment of the
foot board carrier on the seat carrier is shorter than that of the letter carrier on
the chair frame, and the detent lever k¹ for engaging and disengaging the two
carriers is shorter than the detent lever for connecting and disconnecting the
seat carrier and frame. The detent lever is pivoted to the foot board carrier k³,
projects through an opening in the carrier, and is provided with a handle at its
outer end and a detent lug at its inuer end. This lug kis adapted to engage
holes in the seat carrier, the operation being essentially similar to that already
described with reference to the operation of adjusting the seat carrier. Stops K³k³
(Fig. 4) limit downward movement of the foot board carrier on the seat carrier.
A suitable back pad is adapted to be adjusted up and down the back portion of
the chair frame and to be clamped in its position of adjustment. As shown the
back pad L consists of a strip of flexible material, such as carpet, fixed to side
bars L' L' which are attached to the arms L2 L2 of a forked carrier adapted to
slide up and down and to be clamped to the upper portion of the chair frame by
the clamp screw 1. To stretch the back pad the connection between one of the
side bars L' and its supporting fork of the carrier is made adjustable in the
following way-Lugs at the outer end of the carrier fork are provided with
slots (see Figs. 2 and 9) and bolts L3 L³ (one for each slot) are each engaged
with a nut secured in the side bar. By loosening the bolts the bar L' may be
given a partial turn to draw taut the back pad and the bolts be then tightened.
The plunger D' of the main raising and lowering mechanism has 'thrust bearing
at its upper end at M against the upper end or head of the main support D. The
plunger works as a piston rod in the cylinder D2, being provided at its lower end
with a suitable piston head fitting the cylinder liquid-tight. The cylinder is open
from top to bottom and is supported within the pedestal by being screw-attached at
its lower end in a socket m in a supporting frame M which has detachable
connection with the pedestal, as further on to be explained. The socket into
which the cylinder is screwed is provided with a shoulder m' against which the
lower end of the cylinder seats. In this way the cylinder is closed at bottom with
the exception of a single port m in the supporting frame socket for the flow of
liquid to and from the cylinder, as in turn to be explained. A pump cylinder M
rigid with the supporting frame M' and most conveniently formed by being cast
integral therewith, is located at the side of the plunger cylinder. At and
projecting above the top of the pump cylinder are two tubular lugs m³ m³ (Figs. 4

page_text: and 8) for connecting the supporting frame with the pedestal. These tubular lugs:
are bolted by bolts m m to and beneath two bracket lugs M³ M³ (Fig. 11) on one
section of the pedestal cap, and the supporting frame is further connected with this
cap section by means of a bolt ma engaging a tubular lug M of the frame with a
bracket of the cap at m. See Figs. 4 and 11. A very strong and simple
separable connection is thus made. The bolts m³ m³ m are indicated by dotted
lines in Fig. 3. The pump piston N is pivotally connected with its rod N¹ which
at its upper end is jointed to the outer end of an arm or crank N' which has
detachable connection with a rockshaft N³. This rockshaft is mounted to rock in
bearings n n in the two sections of the pedestal cap. To one end of the rockshaft
is detachably fastened an actuating lever O adapted to be operated by the foot.
The connection between the rockshaft and its crank arm N' is through the medium
of a sleeve O¹ extending between the bearings nn and surrounding the rockshaft to
which the sleeve is detachably secured so as to prevent turning or endwise
movement of it about the rockshaft by means of cross pins, one of which is shown
in dotted lines at O³, Fig. 4. A depending crank arm O2 is also connected with
the rockshaft through the medium of the sleeve O'. The two crank arms N2 O'
are formed with the sleeve at the opposite ends thereof. A spring P has
connection at one end with the lower end of the crank arm 02 and at its opposite
end with a bracket arm P¹ rigid with the supporting frame M¹. This spring serves
to normally hold the outer end of the actuating lever in its most elevated position
and return it to such position after being depressed by the foot. The upward
movement of the outer end of the actuating lever is limited by contact of the upper
end of the piston rod N' with the pedestal cap and downward movement imparted
to the outer end of the lever by the foot is limited by contact of the outer end of
the crank arm N2 with the top of the pump cylinder. The manner of connecting
the spring P with the supporting frame bracket P₁ and crank O2 is such as to
permit of varying the tension of the spring as may be found desirable. Link
plates pp of similar construction are jointed respectively to the bracket P and
crank and the opposite ends of the spring pass through holes or eyes in the
plates. By turning or screwing the spring through the link holes its tension may
be increased or lessened, as will be obvious.
An upwardly opening poppet valve o (Fig. 8) in the bottom of the pump cylinder
admits oil from the pedestal reservoir to the cylinder upon the up stroke of the
pump piston. Upon the down stroke of the piston the valve closes and the oil is
forced from the pump cylinder by way of the port o', passage o² and port m² to the
plunger cylinder D2 beneath the piston therein to impart upward movement to the
main support. See Fig. 6. During the up stroke of the pump piston communication
between the ports of the pump cylinder and plunger cylinder is closed by means of
a valve Q. Fig. 6 shows this valve in position to close the port of. Repeated
operations of the pump piston serve to elevate the main support, and with it the
chair frame, as far as desired by the accumulation of oil beneath the plunger
piston. The valve Q is mounted by its stem g in a plug Q1 screwed into a threaded
socket Q3 of the supporting frame in the pedestal. A spring q' acts upon the
valve stem with a tendency to keep the valve Q in position to close the port o'.
A cap or outer plug R screws into a threaded socket R₁ in the outer end of the
plug Q. A valve chamber is provided by the plug socket R¹, and the valve R² in
this chamber is acted upon by the spring q' with a tendency to hold it to its packed
seat on the cap plug R. The stem S of the valve R2 is longitudinally grooved
and is mounted in a hole s in the cap plug by which oil is allowed to escape when
the valve R is moved from its seat against the force of its spring. An oil
passage T communicates with the chamber of the valve R2 and the passage o².
From the above description it will be seen that when the valve stem Š is moved
inward and the valve R2 unseated, oil is allowed to gradually flow from beneath
the plunger piston to the pedestal reservoir, and the main support and with it the
chair body may thus be lowered.
To actuate the valve stem S and trip or unseat the valve Ra bell-crank lever U,

page_text: is pivoted at t to the supporting frame M' in the pedestal and the lower arm of this
lever is adapted to be rocked against the valve stem to move it inward. A spring U
has connection at its opposite ends with the upper arm of the lever and with the
supporting frame M', and normally holds the bell crank lever out of action. An
arm V is jointed at its lower end to the upper end of the bell crank lever by a
pivot and at its upper end this arm projects through the pedestal cap in position
to be borne upon a lever V₁ when depressed by the foot. This lever is pivoted
upon a trunnion V provided on the pedestal cap. As will be understood by
reference to Figs. 2, 3 and 4, the lever V acts on the arm V by way of a screw ol
adjustable in a side lug of the lever. A set screw-v' serves to hold the screw o' in
its position of adjustinent. The operation of this valve tripping mechanism will
readily be understood. Obviously the spring U¹ serves to restore the lever to its
normal position when relieved from pressure of the foot.
In order to provide for escape of oil from the plunger cylinder in event of
continued working of the pump after the plunger has reached its highest elevation,
outlet openings W are formed in the cylinder near its top.
It will be seen that with the exception of the rookshaft and its sleeve and arms,
all the parts inside the pedestal are carried upon the single depending supporting
frame, and that this frame being supported wholly by the pedestal cap may
readily be placed in position and removed together with the various parts carried
by it, thus greatly facilitating inspection, fitting and repairing of parts, and
rendering unnecessary the removal of oil from the reservoir.
By constructing the frame with the intermediate portion F, horizontal or
approximately so and the rear and front portions G G projecting, respectively,
upwardly and downwardly from the rear and front of the intermediate portion
and provided with their respective guide-ways, I am enabled in simple and
inexpensive manner to adjustably support the chair seat upon the front or lower
portion G' of the frame by way of a carrier engaging said portion, and to
adjustably support the back pad upon the back or upper portion G of the frame
by way of a carrier engaging it. It will be seen that the narrow or bar-like
portions of the frame are, respectively, centrally arranged relatively to those
portions of the carriers which engage them, and that the carriers are thus adapted
to be extended laterally and forwardly without obstruction as far as required to
best suit them to perform their functions.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination, in a dental chair, of the pedestal provided with the detach-
able cap having the guide-ways, the cylinder, the plunger vertically adjustable
in the cylinder, and the support for the chair frame partially surrounding the
cylinder and adjustable in the guide-ways of the pedestal cap, substantially as
set forth.
2. The combination, of the pedestal, its detachable sectional cap having the
guide-ways, the cylinder, the plunger adjustable in the cylinder, and the support
actuated by the plunger and adjustable in the guide-ways in the pedestal cap upon
opposite sides of the cylinder, substantially as and for the purpose set forth.
3. The combination of the raising and lowering support, means for actuating it,
the chair frame mounted to rock on the support and provided with the seat
supporting portion extending downwardly from about the level of the jointed
connection of the frame with its support, the chair seat, its long carrier having
guide-way connection with said downwardly projecting portion of the frame and
adjustable up and down thereon, and the detent devices for adjustably engaging
the carrier with the frame, substantially as and for the purpose set forth.
4. The combination of the raising and lowering support, the chair frame
partaking of the movements of the support and provided with the downwardly
extending seat-supporting portion, the chair seat, its carrier adjustable up and

page_text: down upon the downwardly extending portion of the frame, means for securing
the seat carrier in its position of adjustment, the foot board provided with the
carrier adjustable up and down the seat carrier, and means for securing the foot
board carrier in its position of adjustment upon the seat carrier, substantially as
-set forth.
5. The combination of the forked back pad carrier, the flexible pad, its side
bars having connection with the carrier forks, the clamp bolts engaging with one
of said side bars, and the slotted Ings by which said bar is adjustably connected
with the carrier fork by the clamp bolts, substantially as set forth.
6. The combination of the pedestal constituting a liquid reservoir and provided
with the detachable cap, the supporting frame within the pedestal and detach-
ably connected with the cap, and the raising and lowering mechanism carried
by said frame within the pedestal and removable therefrom with the pedestal
cap, substantially as set forth.
7. The combination of the chair frame, the pedestal constituting a liquid
reservoir and provided with the detachable cap, the vertically adjustable support
for the chair frame having guide-way connection with the pedestal cap, the
plunger actuating the support, the plunger cylinder, the pump, the valve
mechanism for the pump and cylinder, and the supporting frame within the
pedestal and carried by its cap and serving to support the plunger cylinder, the
pump, and the valve mechanism, substantially as and for the purpose set forth.
8. The combination of the chair frame having the upwardly projecting back
portion, the downwardly projecting front portion and the intermediate portion,
the raising and lowering support upon which the chair frame is mounted by way
of its intermediate portion to rock, the seat, its carrier having engagement
with and vertically adjustable upon the front portion of the frame, the back
pad, and its carrier having engagement with and vertically adjustable upon the
back portion of the frame, substantially as set forth.
Dated this 11th day of November 1896.
ARTHUR WILLIAM BROWNE.