IMPROVEMENTS IN THE CONSTRUCTION OF OPERATING CHAIRS MORE ESPECIALLY DESIGNED FOR DENTISTS, PARTS OF SUCH IMPROVEMENTS BEING APPLICABLE FOR OTHER PURPOSES
Year: 1867

page_text: LETTERS PATENT to James Beall Morrison, of St. Louis, Missouri, United
States of America, now of No. 45, Goodge Street, in the County of
Middlesex, Surgeon Dentist, for the Invention of "IMPROVEMENTS IN THE
CONSTRUCTION OF OPERATING CHAIRS MORE ESPECIALLY DESIGNED FOR
DENTISTS, PARTS OF SUCH IMPROVEMENTS BEING APPLICABLE FOR OTHER
PURPOSES."
Sealed the 5th Jane 1868, and dated the 7th December 1867.
PROVISIONAL SPECIFICATION left by the said James Beall Morrison at
the Office of the Commissioners of Patents, with his Petition, on the
7th December 1867.
I, JAMES BEALL MORRISON, of St. Louis, Missouri, United States of
America, now of No. 45; Goodge Street, in the County of Middlesex, Surgeon
Dentist; do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE CONSTRUCTION OF OPERATING CHAIRS MORE ESPECIALLY DESIGNED FOR
DENTISTS, PARTS OF SUCH IMPROVEMENTS BEING APPLICABLE FOR OTHER PURPOSES,'
to be as follows:-
The nature of my said Invention consists chiefly, first, in a novel mode of
raising and lowering a chair or other article; second, in the novel means
employed for adjusting and securing the same at any required angle; third, in
constructing an operating chair with arms adjustable in reference to the seat
of the same; fourth, in a novel mode of adjusting the back and arms in reference
to the seat; fifth, in the novel construction and manner of adjusting the head
rest of an operating chair; and, sixth, in so constructing and combining these

page_text: various parts in a chair as to enable it to be adjusted to adapt it to adults or
children.
The raising and lowering of the chair or other article is effected by means
of three screws extending downward from a universal joint upon which the
seat of the chair rests. To allow the chair to be lowered sufficiently the said
screws are inclined outward at their lower ends, but for other articles may be
arranged in a vertical position. The simultaneous operation of the screws is
effected by means of a bevel wheel which gears into a pinion on the upper end
of each screw.
When the inclined screws are used the teeth of the said wheel
and pinion are curved to allow them to remain properly in gear in whatever
position the chair is adjusted. The universal joint consists of a hemispherical
piece and cup fitted to work together in all directions. A convex piece is
fitted inside the hemispherical piece, and is connected to the cup by a screw.
which when tightened locks the two parts of the joint securely together.
Racks and pinions may also be employed to effect the vertical adjustment of
the chair. The back and arms of the chair are made to adjust independently
of the seat. The back and arms may be fitted to move together on hinges, or
the arms may be made to slide in guideways at the sides of the seat. Screws
or other holding devices are employed to secure the back and arms in any
desired position. A head rest arranged at the back of the chair is supported
upon a universal joint similar to that below the seat of the chair. This joint
is so arranged that by one movement of the pinching screw the two parts of
the joint are locked or unlocked and the rest is secured upon or released from
its support. The screws are fitted to work in nuts attached to three diverging
supports or legs. Each of these supports consists of two parts, one of which
is a frame provided at each end with a bearing for the screw and jointed to
the hollow hemisphere on which the body of the chair rests, while the nut is
formed or fixed in the other part, which is jointed or hinged at its lower end
to a stand or frame preferably of a triangular form. These hinged parts are
so formed and arranged that when the screws are turned in their nuts the
frames will slide over them while the hinges allow them to adapt themselves
to the different angles occasioned by the raising or lowering of the frames.
The upper end of each screw is provided with a bevelled toothed pinion, and
all three of these pinions are geared into a bevelled wheel arranged below the
hemispherical joint or connection. The teeth of the said pinions are made
convex on their surface, and the teeth of the wheel are made correspondingly
concave. By forming the teeth of the wheel and pinions in this manner they
will remain properly in gear throughout all the changes in the angular position
of the legs occasioned by the vertical adjustment of the chair upon the same.

page_text: A small shaft or spindle provided with a small bevel pinion geared into the
bevelled wheel is by preference arranged to project at the side of the chair,
and provided with a handle, by turning which the three screws are operated
simultaneously. The screw frames are hinged or jointed at their upper ends
to lugs or wings projecting from the hollow hemispherical piece. Upon this
piece is fitted a cup or socket of similar form, which is secured to the under
side of the chair seat. The said cup is connected by a screw with a convex
piece which fits the interior of the hemispherical piece.. By slackening this
screw the cup will move freely upon the hemisphere and allow the body of the
chair to be adjusted in any desired position. The screw is then tightened
and causes the cup and convex piece to bind closely upon the hemispherical
piece, and thus hold the two parts of the joint securely together. The aperture
in the hemispherical piece through which the screw passes is much larger
than the said screw to allow the required adjustment of the cup upon the
hemisphere. I prefer to form the nut of the tightening screw in the centre of
a bevelled wheel which gears into a small pinion fixed on an axle which projects
from the side or other convenient portion of the chair and is provided with a
suitable handle.
Instead of effecting the vertical and angular adjustment of the chair by
means of the screws and universal joint arranged as above described, one part
of the said joint may be fixed upon the stand or foot of the chair while the
other part is connected with slides which extend upward from the said joint
at the back or other convenient part of the chair. The elevating screw or
screws may be arranged to operate between these slides, or the chair may be
provided with pinions geared into toothed racks attached to the same. The
said pinions are fixed on an axle provided with a handle arranged to turn at
the side of the chair as already described and are secured in any desired
position by an eccentric gripper or other suitable device. The back of the
chair is preferably constructed to. slide up and down at the rear of the seat
and is jointed to the arms which are jointed at the front of the seat.
back is fitted to move between two bars or guides, and is secured to the same
in any desired vertical position by screws, eccentrics, or other suitable means.
The arms may also be formed to move up and down independently of the back
in the following manner-Each arm is formed with a flat piece extending
downward, which fits between two guide pieces on the side of the seat. An
eccentric or other suitable pinching device is fitted in any convenient portion
of the guides which are made of sufficient length and are so arranged that the
arms are supported firmly therein but, will slide freely up and down when
released from the eccentric. When properly adjusted the said eccentric is
The

page_text: turned partially round and binds tightly against the flat pieces of the arms,
thus securing the latter firmly in place. The head rest for my improved
chair is supported upon a universal joint of similar construction to that
employed below the seat. The hemispherical piece of the said joint is arranged
upon the top of a flat bar extending.from the back of the chair. This bar is
formed with a long aperture or slot through which the pinching screw of the
joint extends. The nut being placed below the bar the rest is' attached to
the, cup of the joint. The rest is preferably formed with two cushions for the
bead, one of which is just over the joint while the other projects beyond the
same. By turning the rest round upon the joint either cushion may be used,
each one being especially adapted to support the head during certain particular
operations or a rest of ordinary construction may be employed. When the
screw is slackened the rest can be adjusted into any required angular position,
can be turned round and can also be moved on the slotted bar nearer to or
farther from the back of the chair. The screw is then tightened locking the
two parts of the joint together and also securing the rest upon the bar at one
operation. The part of the said bar which is secured to the back of the chair
is formed with a long aperture or slot and the back of the chair has a curved
transverse slot. A screw passes through these two slots to hold this bar, which
by means of the said slots can be elevated and depressed or adjusted to any
desired angle.
In applying my improvements to camera or telescope stands and other like
purposes, I attach the instrument to the cup of the universal joint as already
described. The other part of the said joint is supported on three screws which
are preferably arranged in a vertical position at a sufficient distance apart to
afford a firm support to the upper part of the apparatus. The nuts may be
secured in hollow columns or in a stand of any convenient construction. The
simultaneous operation of the screws may be effected by means of ordinary
bevel gearing or by other convenient means.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Beall Morrison in the Great Seal Patent Office on the
6th June 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
BEALL MORRISON, of St. Louis, Missouri, United States of America, now of
No. 45, Goodge Street, in the County of Middlesex, Surgeon Dentist, send
greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of December, in the year of our
Lord One thousand eight hundred and sixty-seven, in the thirty-first year
of Iler reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said James Beall Morrison, Her special licence that I, the said James
Beall Morrison, my executors, administrators, and assigns, or such others as
I, the said James Beall Morrison, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "Iм-
PROVEMENTS IN THE CONSTRUCTION OF OPERATING CHAIRS MORE ESPECIALLY DESIGNED
FOR DENTISTS, PARTS OF SUCH IMPROVEMENTS BEING APPLICABLE FOR OTHER.
PURPOSES," upon the condition (amongst others) that I, the said James Beall
Morrison, my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Seal itent
Office within six calendar months next and immediately after the date
said Letters Patent.
the
lare
be-
NOW KNOW YE, that I, the said James Beall Morrison, do hereby
the nature of my said Invention, and in what manner the same is
performed, to be particularly described and ascertained in and by the fol wing
statement, reference being had to the accompanying Drawings forming a part
of this Specification:-
The nature of my said Invention consists chiefly, first, in a novel mode of
raising and lowering a chair or other article; second, in the novel means.
employed for adjusting and securing the same at any required angle; third, in
constructing an operating chair with arms adjustable in reference to the seat.
of the same; fourth, in a novel mode of adjusting the back and arms with
reference to the seat; fifth, in the novel construction and manner of adjusting
the head rest of an operating chair; and sixth, in so constructing and com-
bining these various parts in a chair as to enable it to be adjusted to adapt it
to adults or children.
The raising and lowering of the chair or other article may be effected by
means of three screws extending downward from a universal joint upon
which the seat of the chair rests. To allow the chair to be lowered suffi-
ciently the said screws are inclined outward at their lower ends, but for other
articles may be arranged in a vertical position. The simultaneous operation

page_text: of the screws is effected by means of a bevel wheel which gears into a pinion
on the upper end of each screw. When the inclined screws are used the
teeth of the said wheel and pinions are curved to allow them to remain pro-
perly in gear in whatever position the chair is adjust:d. The chair is adjusted
and secured at any required angle, vertical or horizontal, by means of the
universal joint, which consists of a hollow hemispherical piece and cup fitted
to work together in all directions. A convex piece is fitted inside the hemi-
spherical piece, and is connected to the cup by a screw, which when tightened
locks the two parts of the joint securely together. For raising and lowering
the chair, instead of the inclined screws above described, racks and pinions
may be employed, the said chair being thereby simplified and rendered less
costly in its construction. The back and arms of the chair are made to adjust
independently of the seat; the back and arms may be fitted to move together
on hinges, or the arms may be made to slide independently in guideways
at the sides of the seat; screws or other holding devices are employed to
secure the back and arms in any desired position. A head rest arranged at
the back of the chair is supported upon a universal joint similar to that below
the seat of the chair. This joint is so arranged that by one movement of the
pinching screw, the two parts of the joint are locked or unlocked, and the rest
is secured upon or released from its support, the support having also a vertical
and lateral motion in the back of the chair, and being by one turn of a
clamping screw fixed in any required position.
In order to more fully explain my said Invention I have illustrated the
same by Drawings of a dentist's operating chair, showing the method in which
I prefer to adapt the said Invention to the construction of such chairs,
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation of a dentist's operating chair constructed
according to my Invention; Figure 2 is. a vertical central section of the said
chair; Figure 3 is a back view of the same; Figure 4 is a horizontal section
on the line x, x, Figure 3; Figure 5 shows the back of the chair body
detached; Figure 6 shows another detached portion of the said chair drawn
to an enlarged scale; Figures 7 and 8 are a plan and elevation of the adjust-
ing parts of a chair of modified construction. Like letters indicate the same
parts in all of the Figures.
The stand or foot a is formed of cast-iron or other suitable material, and is
made of the proper size and weight to give a firm and solid support to the
body b of the chair while being used in whatever position the same may be
adjusted. The universal joint c consists of a hollow hemispherical piece c³, a

page_text: cup or socket c³, and a convex piece c'. The part of the said universal
joint is fixed upon the stand or foot a of the chair, while the other part c' of
the said joint is attached to the slides d, which extend upward from the said
joint at the back of the chair. The bolt c✶ connects the socket c² with the
convex piece c³ which fits the interior of the hemispherical piece c¹; the
bolt is jointed to the foot lever c which is formed with the cam or pro-
jection c³.
When this lever is depressed, as shown in Figure 2, this cam
presses on the bottom of the stand, and thereby tightens the bolt. By
slackening the said bolt the hemispherical piece c¹ will be allowed to move
freely in the socket c, and will thus allow the body 6 of the chair to be
adjusted in any desired position. The bolt c* can then be tightened, the
cup cnd convex piece c¹ being thereby made to bind closely upon the hemi-
spherical piece c', and thus hold the parts of the joint securely and immovably
together. The aperture in the hemispherical piece c' through which the
bolt c✶ passes is much larger than the said bolt to allow the required adjust-
ment of the hemispherical piece c¹ within its cup. An elevating screw or
screws may be arranged to operate between these slides, but I prefer that
the chair should be provided with pinions e geared into tooth racks fattached
to the slides d. The pinions e are fixed on an axle g provided with a
handle h arranged at the side of the chair, by turning which handle the entire
body can be conveniently raised or lowered as desired; the shaft or axle g
also carries a ratchet wheel i which is arranged in connection with the pawl i¹
in such a manner as to prevent the lowering of the chair by its own weight
when the handle h is released. The pawl is attached to the lever which
is pivoted at to the sides of the chair. The spring keeps the pawl ¹ in
gear with the ratchet wheel until it is desired to raise or lower the chair, when
the ratchet wheel is released by pulling back the lever which extends
upward for convenience of manipulation. The back of the chair is pre-
ferably constructed to slide independently up and down at the rear of the seat,
and may be jointed to the arms 62; the latter may also be jointed to the front
of the seat b
Figure 6, which is an enlarged section on the line y, y, Figure 3, illus-
trates the arrangement of the slides d and sliding back 6'. Cruciform pieces d'
are attached to the body b of the chair by lugs d³, and are fitted to move up
and down in the slides d, and also form guides for the legs 6s of the adjustable
back . These pieces d' also carry the bearings for the shafts g and z; the
latter is provided with a cam 21 at each end to secure the back b¹ in any
desired position, the shaft being operated by the handle ².
I prefer to adopt the method of construction illustrated in Figures 1, 2,

page_text: and 3, in which the arms are formed and arranged to move up and down
independently of the back in the following manner:-Each arm is formed
with a flat piece b* extending downward, which piece fits between two guide
pieces 65 on the side of the seat 63. A pinching screw 66 passes through the
piece and through the slot 6', which screw serves to lock the arms in any
position into which they may be adjusted. Instead of a screw an excentric
or other suitable pinching device may be fitted in any convenient portion
of the guides 65, which are made of sufficient length and are so arranged that
the arms are supported firmly therein, but will slide freely up and down
when released from the pinching screw or other device. When the arm has
been properly adjusted the screw 66 by means of its handle is turned partially
round and binds the flat piece 6 tightly against the sides of the chair, thus
securing the arm firmly in its place. The head rest k for my improved chair
is supported upon a universal joint 1 of similar construction to that employed
below the seat. The cup or socket A of the said joint is arranged upon the
top of a flat bar m extending from the back b¹ of the chair. The upper
part of this bar is formed with a long aperture or slot m' through which the
pinching screw n of the joint extends, the nut n¹ being placed below the bar
m. The rest k is attached to the hemispherical piece of the joint. The
said rest is preferably formed with two cushions k, k, to support the head,
one of which cushions is just over the joint while the other projects beyond
the same. By turning the rest round upon the joint either cushion may be
used, each one being especially adapted to support the head during certain
particular operations. If preferred, however, a rest of ordinary construction
may be employed. When the screw n is slackened the rest can be adjusted
into any required angular position, can be turned round upon the screw n, and
can also be moved on the slotted bar m nearer to or farther from the back b¹
of the chair. The screw n is then tightened, locking the two parts 1, 2, of
the joint together and also securing the rest upon the bar m at one operation.
The part m² of the said bar which is secured to the back b¹ of the chair is
formed with a long aperture or slot mt, and the back of the chair has a
transverse slot 6. A screw m³ passes through these two slots to hold the
bar m, which by means of the said slots can be elevated and depressed or
moved laterally and adjusted to any desired position. The pin mo serves to
steady the lower end of the bar m. The screws o shown in Figures 7 and 8
are fitted to work in nuts p attached to three supports or legs q. Each of
these supports consists of two detached parts, one of which q¹ is a frame
provided at each end with a bearing for the screw and jointed to the hollow
hemisphere c on which the body b of the chair rests, while the nut p is formed

page_text: or fixed in the other part 93 which is jointed or hinged at its lower end to the
stand or foot a which is preferably of a triangular form. These hinged parts
are so formed and arranged that when the screws o are turned in their nuts p
the frames q' will slide over them while the hinges allow them to adapt
themselves to the different angles occasioned by the raising or lowering of the
frames q. The upper end of each screw o is provided with a bevelled toothed
pinion r and all three of these pinions are geared into a bevelled wheels arranged
below the hemispherical joint or connection c. The teeth of the pinions r are
made convex' on their surface and the teeth of the wheels are made corre-
spondingly concave as shown in Figure 8. By forming the teeth of the wheel
and pinions in this manner they will. remain properly in gear throughout
all the changes in the angular position of the legs 9 caused by the vertical
adjustment of the body 6 of the chair upon the same. A small shaft or
spindle t provided with a small bevel pinion u geared into the bevelled wheels,
is by preference arranged to project at the side of the chair,, and is provided
with a bandle by turning which the three screws o are operated
simultaneously. The screw frames q' are hinged or jointed at their upper
ends to lugs or wings c projecting from the hollow hemispherical piece c¹ of
the joint c which is substantially of the same construction as that illustrated
in Figures 1, 2, and 3. Upon this piece c¹ is fitted the cup or socket c² of
similar form which is secured to the under side of the chair seat 63. The said
cup is connected by the screw c with the convex piece which fits the
interior of the hemispherical piece. I prefer to form the nut of this tightening
serew in the centre of a bevelled wheel v which gears into a small pinion w
fixed on an axle y which projects from the side or other convenient portion
of the chair and is provided with a suitable handle y².
In applying my improvements to camera or telescope stands and other like
apparatus I attach the instrument to the cup of the universal joint as already
described. The other part of the said joint is supported on three screws
which are preferably arranged in a vertical position at a sufficient distance
apart to afford a firm support to the upper part of the apparatus. The nuts
may be secured in hollow columns or in a stand of any convenient
construction. The simultaneous operation of the screws may be effected by
means of ordinary bevel gearing or by other convenient means.
Having thus fully described my said Invention and shown how the same
may be conveniently and advantageously carried into practice, I claim
generally the modes of constructing an operating chair herein-before described,
and I claim in particular,-

page_text: First. The application of a universal joint constructed in manner herein-
before described to the body of an operating chair.
Second. The application of a universal joint constructed in manner herein-
before described to the head rest of an operating chair.
Third. The arrangement herein-before described and illustrated in Figures
1, 2 and 3, for elevating and depressing the body of the chair.
Fourth. The arrangement shown in Figures 7 and 8 for elevating and
depressing a chair or any other article.
In witness whereof, I, the said James Beall Morrison, have hereunto
set my hand and seal, this Sixth day of June, in the year of our Lord
One thousand eight hundred and sixty-eight.
JAMES BEALL MORRISON. (L.S.)
Witness,
THO. N. PALMER,
8, Southampton Buildings, W.C.