Improvements in Dental Chairs.
Year: 1894

page_text: Date of Application, 17th May, 1894-Accepted, 14th July, 1894
UOMPLETE SPECIFICATION.
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 manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:—
My invention relates to certain improvements substantially such as hereinafter
described and claimed in means whereby the bodies of dental chairs may be raised
or lowered, turned horizontally and maintained in any desired position of adjust-
ment, my improvements being especially applicable to the well known "Wilkerson"
dental chair for which Letters Patent of the United States of America were
granted November 20th, 1877, No. 197,441, and Letters Patent in Great Britain,
No. 4662 of the year 1877.
In the accompanying drawings which show all features or a " Wilkerson "
chair needed for proper illustration of a suitable embodiment of my improvements.
Fig. 1, Sheet I, is a view partly in side elevation, partly in vertical section on
the irregular line 1 of Fig. 3, and with the pedestal in central vertical section.
Fig. 2, Sheet 2, is a view partly in side elevation and partly in vertical section
on an enlarged scale, with various parts omitted and broken away.
Fig. 3, Sheet 3, is a view partly in horizontal section on the line 3 of Fig. 1, and
partly in plan.
Fig. 4, Sheet 3, is a view partly in plan and partly in horizontal section on the
line 4 of Fig. 5, showing details of construction.
Fig. 5, Sheet 3, is a view partly in elevation and partly in vertical section on the
line 5 of Fig. 3 representing details of construction.
Fig. 6, Sheet 3, is a view in perspective of the plunger clamping sectional shoe.
Fig. 7, Sheet 2, is a view partly in elevation and partly in vertical section in the
plane of the line 7 of Fig. 3.
Fig. 8, Sheet 1, is a view in perspective showing details of construction.
Fig. 9, Sheet 1, is a view in perspective with parts in section, showing a modifi-
cation of my improvements.
Fig. 10, Sheet 3, is a plan view showing the cylinder projection for engaging the
longitudinal recess of the vertically adjustable support.
Figs. 11 to 15 inclusive, Sheets 4, 5 and 6, show modifications of my
improvements.
Fig. 11, Sheet 4, is a view partly in elevation and partly in vertical section on
the line 1 of Fig. 13.
Fig. 12, Sheet 5, is a view partly in side elevation and partly in vertical section
in different planes, with parts omitted.
Fig. 13, Sheet 6, is a view partly in plan and partly in horizontal section on the
line 3 of Fig. 12.
Fig. 14, Sheet 6, is a view partly in elevation and partly in section on the line 1
of Fig. 13.
Fig. 15 is a view in perspective showing details of construction.
A hollow base or pedestal A provided with supporting legs, has attached to its
lower end a liquid-carrying reservoir A. A hollow cylinder B is fitted to rest
upon and turn within the pedestal. A clamp screw operated by a lever B' serves
to lock the hollow cylinder against turning in the pedestal, and a chain body
support or plunger Cis vertically adjustable in the cylinder. This support C is
formed with a vertical groove or recess provided with a row of rack teeth a.
Suitable packing at the lower end of the support serves to fit it liquid-tight within

page_text: the cylinder B. At its lower end the cylinder is provided with a screw-attached
cap D which has a central opening or liquid passage above which (within the cap)
is a loose or float valve d opening upwardly and hereinafter termed the inlet valve.
A downwardly opening valve d' (hereinafter called the outlet valve) upon which a
spring acts with a tendency to close it or hold it up to its seat, is located in a
chamber D at the side of the cylinder and having communication by way of
a liquid passage e with the cylinder below the chair body support C. The
chamber D also has communication with the liquid reservoir A' when the outlet
valve d is open. The liquid way or passage controlled by the inlet valve is of
much greater area, it will be seen, than the liquid way or passage e through which
liquid is allowed to flow only when the outlet valve is open.
With the exception of modifications, such as will readily be understood, in the
reservoir and the cylinder, and in construction and arrangement of the valve
mechanism, all the parts so far as in detail briefly described above, are the same as
set forth in the before mentioned Patents Nos. 4662 and 197,441 of Great Britain
and the United States; and the modified valve mechanism and other parts perform
the same functions as explained in said Patents.
A foot-actuated elevating lever made in sections jointed together serves to
elevate the chair body support as in the Wilkerson Patents referred to, and in
accordance with my improvements is made to serve, also, as the means through or
by way of which the chair body support may be clamped against lateral movement
in any position to which it may be adjusted, and the outlet valve tripped to permit
of gradual descent of this support, as in turn to be explained. Said elevating lever
is made in two parts or sections-a main or outer part E and a short inner part E'-
which are jointed together by a vertical pivot F passing through lugs or forks fƒ³
of the inner section and through the inner end of the outer section of the lever near
a horizontal pivot g by which the lever is jointed by its inner section to the
cylinder B which is provided with the lugs G G engaged by this pivot g. The
forks of the short arm of the elevating lever embrace the inner end of
the long arm of the lever so as to make a strong connection of the parts. It
will be seen that the lever (both sections thereof) is adapted to rock or swing
vertically, and that the long arm or main section of the lever may be swung
horizontally in opposite directions. Stops hh within the cylinder, and between
which a lug H at the inner extremity of the lever projects, serve to limit the
vertical play of the lever. The inner or short arm of the lever is curved about
the chair body support and provided with a pivoted pawl I for engaging the rack
teeth of the support, and a spring 1' secured at its opposite ends to the pawl heel
and the cylinder, serves to cause engagement of the pawl with the rack teeth when
the main section of the lever is depressed by downward force applied to its foot-
rest J. The pawl is normally held out of engagement with the rack teeth by the
contact of a shoulder onthe pawl with a projection k¹ on the cylinder. This
projection projects into the longitudinal recess of the chair body support.
to keep it from turning in the cylinder. The operation of the spring-actuated
pawl is fully set forth in the above-referred-to Patents, and as explained in said
Patents, when the chair body support is elevated by working the elevating lever
the inlet valve opens automatically so as to allow liquid from the reservoir to
follow the support and uphold it in its position of adjustment, when the outlet
valve is closed, whilst when this outlet valve of the upholding mechanism is tripped
or opened the support is allowed to gradually descend by the flow of the liquid
from beneath the support back to the reservoir as indicated by arrows in Fig. 2.
To clamp the support against lateral movement or vibration in any position to
which it may be elevated, the main arm of the elevating lever is provided at its
inner end with a cam or surface 7 curved eccentrically to the pivot F connecting
the two sections of the lever, which cam when the long arm of the lever is moved
sidewise by the foot in the position in which it is represented by dotted lines Y,
acts upon a sectional clamping shoe to thrust it forcibly against the support to
entirely prevent vibration or lateral movement thereof in the cylinder. The

page_text: clamping shoe is shown as formed in two parts or sections consisting of the thrust
block Land bearing block L' against which the thrust block is forced to bear it
firmly against the support. The thrust block of the clamping shoe is slotted to
embrace the fulcrum pivot g of the lever, and is seated in a guide way in the inner
section or short arm of the lever. When the clamping shoe is actuated by the
elevating lever a lateral lug M of the main arm of the lever rests over or upon a
projection m of the cylinder lug G, thus preventing downward movement of the
lever to actuate the support.
To trip the outlet valve of the mechanism for upholding the support and allow
the support to descend by escape of the liquid from beneath it, the long arm
of the elevating lever is moved by the foot into the position in which it is
represented by dotted lines Z, so that a lateral arm N of the lever presses upon a
push rod n adapted to slide endwise in a guide way or bearing in the cylinder
lug G. This push rod of the valve tripping mechanism actuates a bell-crank
lever O pivoted within the cylinder by pressing against one arm thereof, and thus
rocks downward the other arm of this lever, and forces a thrust rod P downward
upon the stem of the outlet valve, thus tripping or opening the valve against the
pressure of its spring. The valve tripping thrust rod moves at or near its opposite
ends in a guide-way lug P on the cylinder and in a guide-way pin which the
valve stem plays
A spring Q having connection at its opposite ends with the
guide-way lug P and the valve tripping thrust rod, serves to elevate this rod and
hold it in its normal position when not depressed by actuation of the bell-crank
lever, thus leaving the outlet valve free to close and occupy its normal position.
During the time the elevating lever occupies the position to which it is moved for
operating the tripping mechanism to open the outlet valve, its lateral arm N rests
over or upon a projection R of the cylinder lug G' and thus downward movement
of the lever is guarded against. When the lever is relieved from sidewise
pressure of the foot after actuating the valve tripping devices, it is automatically
returned to its normal position in which it is shown in full lines, by means
as follows: A slide rod S having a flat head s is mounted to reciprocate in a
guide-way or bearing S' in the elevating lever in line with the lower fork f¹ of
the inner section of this lever, and is acted upon by a spring T the tendency of
which is to thrust the slide rod outward and cause its head to bear evenly upon
the end of the fork f', or with the abutting surfaces of the rod head and the lever
fork parallel with each other. As will readily be understood when the lever has
been moved but slightly to one side-say to the position represented by dotted
lines Z-and is relieved from pressure by the foot it will quickly be returned to its
normal position; whereas when moved considerably to one side, as represented by
dotted lines Y to clamp and steady the support in the cylinder, the lever will not
be automatically returned to its normal position when relieved from lateral pressure
but must be moved toward such position far enough to admit of its being actuated
by the headed rod to restore it to its normal position and yieldingly hold it in such
position. It will thus be seen that when the lever has been swung sidewise into
position to actuate the clamping shoe it may be relieved from lateral pressure
without danger of its return to its normal position; and that immediately upon
release of the lever after it has been swung into position to trip the outlet valve
this valve closes and arrests the descent of the support and the chair body which
may be connected with the support in any suitable way.
As will readily be understood from the above description the clamping shoe is
not a means for upholding the support but serves simply to clamp the support in
the cylinder and so prevent any lateral or vibratory motion of the support.
Instead of the described upholding mechanism by which a liquid column is
confined beneath the support to prevent its descent, other suitable upholding
mechanism may be employed, such for instance as shown in United States Letters
Patent No. 413,156, dated October 15, 1889, and such equivalent upholding
mechanism be released or tripped by means actuated by swinging the main section
of the elevating lever sidewise, and so admit of the descent of the support.

page_text: Fig. 9 shows enough of the mechanism set forth in said Patent No. 413,156, to
illustrate how, in accordance with my improvements, a push rod n¹ and bell-crank
lever O' are adapted to be actuated by the swinging main section of the elevating
lever to trip the upholding devices. The knee-jointed rod u is moved upward by
the lower arm of the bell-crank lever, when actuated, to lift the clamp block U and
release the support when it is to be allowed to descend.
Sheets 4, 5 and 6 of the drawings show features in many respects similar to the
parts above described and correspondingly lettered, and only the modifications
shown on these sheets need detailed explanation. The lever (made in jointed
sections E E¹ and adapted to rock or swing vertically, as above described) is
adapted to be swung horizontally to one side only.. When the clamping shoe L' L'
is actuated by the elevating lever the lateral lug M on the main arm of the lever
rests between projections m m of the cylinder lug G, thus preventing movement
of the lever either upwardly or downwardly, and guarding against actuation of
either the support or outlet valve. When the main arm of the elevating lever
occupies its normal position it is prevented from swinging sidewise in one direction!
by a lateral projections at its inner end which comes in contact with a
projection of the inner section of the lever.
Provision is made by the modifications, Sheets 4, 5 and 6, for tripping the
ontlet valve of the mechanism for upholding the support, so as to allow the
support to descend by escape of the liquid from beneath it, in the following
way: A thrust rod N guided in its end wise movements by guide-way lugs n n
on the cylinder, through which lugs it passes, is yieldingly held in its normal
or most elevated position by means of a spring P bearing at one end against a
collar p on the rod and at its opposite end against the lower guide way-lug n¹.
The collar p limits upward movement of the thrust rod by coming in contact
with the upper guide-way lug_n. The thrust rod is adapted to bear at its lower
end upon the stem of the outlet valve so as to depress and open this valve when
the rod is actuated by the elevating lever by pushing upward its outer end by
the foot to forcibly rock the inner end of the lever downward. The thrust rod,
by the action of its spring P, is also made to serve as a stop to limit upward
movement of the main section of the lever until it is pressed upward by the
foot with sufficient force to overcome the force exerted by the thrust rod spring.
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 vertically adjustable support, the
cylinder in which it is mounted, the elevating lever pivoted to the cylinder,
composed of jointed sections and provided with the cam, and the clamping shoe
for locking the support against lateral movement acted upon by said cam when
the main section of the lever is swung sidewise in one direction, substantially as
set forth.
2. The combination, in a dental chair, of the vertically adjustable support, the
cylinder in which it is mounted, the elevating lever pivoted to lugs of the
cylinder, composed of jointed sections and provided with the cam and lateral lug,
and the clamping shoe for locking the support against lateral movement, acted
upon by said cam when the main section of the lever is swung sidewise in one
direction to bring its lateral lug above a projection of one of the lugs of the
cylinder to which the lever is pivoted, substantially as set forth.
3. The combination, in a dental chair, of the cylinder, the vertically adjustable
support mounted in the cylinder, the elevating lever pivoted to the cylinder and
composed of jointed sections, mechanism serving to uphold the support, and tripping
mechanism actuated by the main section of the lever when swung sidewise to throw
the upholding mechanism out of action and allow the support to descend,
substantially as set forth.
4. The combination, in a dental chair, of the cylinder, the liquid-carrying

page_text: reservoir, the vertically adjustable support mounted in the cylinder, the inlet and
outlet valves by which liquid is allowed to pass from the reservoir to the cylinder
beneath the support and from the cylinder to the reservoir, the elevating lever
pivoted to the cylinder and composed of jointed sections, and the tripping
mechanisin of the outlet valve actuated by swinging the main section of the lever
sidewise, substantially as set forth.
5. The combination, in a dental chair, of the cylinder, the liquid-carrying
reservoir, the vertically adjustable support mounted in the cylinder, the outlet.
valve by which liquid is allowed to pass from the cylinder beneath the support to
the reservoir, the elevating lever pivoted to the cylinder, composed of jointed
sections and provided with the lateral arm, the push rod against which said arm is.
made to bear by swinging the main section of the lever sidewise, the bell-crank.
lever acted upon by the push rod, and the thrust rod acted upon by the bell-crank
lever to trip the outlet valve, substantially as set forth.
6. The combination of the vertically adjustable chair body support, its carrying
cylinder, the elevating lever composed of the inner section pivoted to the cylinder
and the main section pivoted to the inner section to swing horizontally, and the
spring-actuated slide rod mounted in one section of the lever and acting against the
other section thereof to yieldingly hold the main section of the lever in its normal
position and
restore it thereto from a position slightly to one side thereof,.
substantially as set forth.
7. The combination of the vertically adjustable chair body support, its carrying
cylinder, the vertically rocking elevating lever pivoted to the cylinder and
composed of two sections jointed together with the main section capable of
swinging sidewise in opposite directions, the clamp for locking the support against
lateral movement acted upon by the swinging section of the lever when moved.
sidewise in one direction, mechanism for upholding the support, and its tripping
mechanism acted upon by the swinging section of the lever when moved sidewise in
a direction opposite to that in which it is moved to actuate the clamp, substantially
as set forth.
8. The combination, in a dental chair, of the vertically adjustable support, the
cylinder having the lever pivoting lugs one of which is provided with two
projections, the elevating lever pivoted to said lugs, composed of jointed sections
and provided with the cam and lateral lug, and the clamping shoe for locking the
support against lateral movement, acted upon by said cam when the main section
of the lever is swung sidewise to bring its lateral lug between said projections of
one of the lever pivoting lugs, substantially as set forth.
9. The combination, in a dental chair, of the horizontally rotating cylinder, the
liquid-carrying reservoir, the vertically adjustable support mounted in the cylinder
and provided with the rack teeth, the vertically rocking sectional elevating lever
pivoted by its inner section to the cylinder, the pawl carried by said section and
adapted to engage the rack teeth of the support upon downward movement of the
outer section of the lever, the outlet valve by which liquid is allowed to pass from
the cylinder beneath the support to the reservoir, the thrust rod actuated by the
lever upon forcible upward movement of the outer section thereof to trip the
outlet valve, and the spring acting upon the thrust rod to hold it up when not
forcibly depressed by the action of the lever, substantially as and for the purpose
set forth.
Dated this 27th day of April 1801