Year: 1888

page_text: Date of Application, 26th Mar., 1888
Complete Left, 30th May, 1888
Complete Accepted, 6th July, 1888
I, JOHN SMALLEY CAMPBELL, dentist of 10 Park Square West, Regents Park,
London N.W. do hereby declare the nature of my invention to be as follows:-
My improvements refer to that class of dental engines which are operated by the
foot of the dentist; the engine to which I refer more particularly, is composed of a
vertical stand or frame onto which is fitted on a horizontal axis, a fly-wheel or
driving wheel operated from a treadle and imparting rotary motion by means of a
cord to a pulley on an axis at the top of the frame, the said axis being connected
in the known manner, to the dental tool, by means of a spiral spring covered by a
flexible sheathing.
My object is to improve this class of dental engines with a view of dissimulating
most of its bulky parts under the foot-board of the dental chair, so as to conceal
them, to a great extent, from the eyes of the patient.
A dental engine, according to my improvements is composed as follows: the fly-
wheel or driving wheel is arranged horizontally in suitable bearings on the flooring,
immediately under the foot-board of the dental chair. Rotary motion is imparted
to the driving wheel by means of a treadle; the latter is fitted on a horizontal
pivotal bar connected loosely with the axis of the driving wheel. The said treadle
is on one side of the dental chair, within reach of the operator's foot and it can be
swung in and out more or less, from under the foot-board and thus be put almost
entirely out of the patient's sight. On the other side of the dental chair, is an
extensible vertical stand, set on feet and carrying at its upper end the usual head
and connextions for the dental tool. The lower end of the stand is pivotally con-
nected by another loose horizontal bar with the axis of the driving wheel, so that the
stand also can be swung or rotated and be placed in the suitable position for the
operator. A cord passing over the driving wheel imparts rotary motion to a pulley
at the bottom of the stand, which motion is transmitted to the dental tool by
means of suitable intermediate devices comprising mainly an axis concealed in the
center of the stand and a coil spring.
The stand is rendered extensible by being formed of two or more pipes capable of
sliding within each other and set by a screw; moreover the stand is fitted in a
socket resting on the flooring, and it can be withdrawn from its socket and replaced
therein at will without requiring any adjustment by screws or otherwise.
Did thi- 0161 Ion of Waal 1000

page_text: I, JOHN SMALLEY CAMPBELL, dentist, of 10 Park Square, West, Regents Park,
London N.W. 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 improvements refer to that class of dental engines which are operated by the
foot of the dentist; the engine to which I refer more particularly is composed of a
vertical stand or frame onto which is fitted on a horizontal crank shaft, a fly wheel or
driving wheel operated from a treadle and imparting rotary motion, by means of a
cord, to a pulley on an axis at the top of the frame. The said axis is connected
to the dental tool by a spiral spring which transmits the rotary motion to the said
tool.
My object is to improve this class of engines, with a view of dissimulating most
of its bulky parts under the foot-board of a dental chair, so as to conceal them, to
a great extent, from the eyes of the patient.
In the accompanying drawing, fig. 1 is an elevation of the improved engine, partly
in section, fig. 2 is a top view and fig. 3, 4, 56 and 7 are detail views.
a is the driving wheel fast on a vertical crank shaft 6 fitted in suitable bearings held
by the framing c. The crank of the shaft is connected by links de to a bell
crank lever fitted onto an axis g secured to an arm h; the bell crank lever fis
connected by a link i to the pedalj pivotted at k.
I is the frame for the stand m; the frame carries a pulley n to which the rotary
motion of the wheel a is imparted by a cord o. Both frames c and are adjustably
connected, as shown, in order to regulate the tension of the driving cord, at will.
The adjustment herein shown is composed of a part p held in a socket by means
of a set screw r, the requisite tightening of the cord o being obtained by a screw s.
The pulley n is fast on an axis t the lower end of which rests in a socket of the
frame, whilst the upper end is held by a bracket u fastened to the said frame l, as
shown in fig. 3, which, together with fig. 4 and 5 are on a larger scale than fig. 1
and 2.
The upper end of the axis t is hollowed out and slotted for receiving the lower end
of the axis v, the top portion of which is tubular and slotted for receiving the end of the
internal rod or shaft w. The connection between the bottom end of the axis & and
the top end of the axis t is effected by means of a cross pin ; the connection
between the lower end of the rod w and the top end of the axis is likewise effected
by means of a cross pin y, fig. 3, 4 & 5, fig. 5 being a cross section of fig. 4 on the
line z z.
;
The internal rod we extends upwards to the spiral spring which is inside an ordinary
sheathing the rod and spring being connected in any known manner. The
rod w is held in a tube 2 the upper end of which terminates in a curved bracket com-
posed of two cheeks 3, 3 united at the top by a set screw or thumb screw 4. The

page_text: space between the two cheeks 3, 3 is for allowing the free passage of a slide piece 5
provided with a central hole for the sheathing 1. The spiral spring, shown at 6,
fig. 1 & 6 is connected by an ordinary hand piece 7, to a dental tool 8.
By means of this stand, the operator is enabled to set the sheathing in the most
convenient position for his work, by simply slackening the thumb screw 4, setting
the slide-piece 5 and then tightening the said screw; moreover, this construction
enables the sheathing 1 to be set almost parallel to the stand, see fig. 6, thus affording
every facility for folding the engine, in case it requires to be carried.
The stand can be set at any suitable height for the operator, by raising the tube 2
and parts thereto attached and then setting by means of a screw 9; in rising, the
tube 2 carries with it the rod w which then slides, at its lower end, out of the tubular
portion of the axis v, without however being put out of gear therewith. Moreover,
the entire stand may be taken out of its socket in the frame l, by simply raising it
by hand the connection between the lower end of the axis v and the axis t being such
as to enable this motion to take place.
The most important feature of this dental engine resides, however, in this, that the
pedal is fitted on a bar 10 connected by a pivot 11 to a second bar 12 connected, in
its turn, with the frame c by another pivot, which, in this case, is the lower end of
the crank shaft b. On the other hand, the frame with its stand, is likewise pivotally
connected to the remainder of the engine, by means of the frame c, as shown."
By this means, the engine is composed of three elements which are pivotally con-
nected to each other, and can be made to assume angular positions to each other, as
shown in dotted lines in fig. 2.
In practice, the whole engine forms one whole device, of which the driving wheel a
and attached parts are entirely concealed under the foot-board of a dental chair; and
as to the frames c and they are mostly concealed at one side of the chair, and the
treadle mostly at the other side.
Having now described my improvements, I wish it to be clearly understood that the
stand m which is new in itself and which is claimed hereafter, can be replaced by any
other stand known, without otherwise taking away any of the characteristics of the
dental engine. I wish it also to be understood that if it is not desired to have a stand
being adjustable in height, the ordinary stand 8 of the well known Shaw and
S. S. White engines can be substituted, in this case, the driving cord would reach up
to the top of the stand and pass over a pulley, after first passing over a couple of
pullies placed in the same horizontal plane as the driving wheel a.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
First. Connecting a treadle j with the driving wheel a of a dental engine by means
of bars 10, 12 pivotted together at 11, the latter bar 12 being connected to the
axis of the said driving wheel, substantially as described and shown and for the
purpose set forth.
Second. A dental engine having a horizontal driving wheel a fitted in a frame c, the
said frame being adjustably connected on one side with a pivotted frame / carrying
any suitable stand and on the other side with a treadle j, pivotted bars 10 and 12 and
intermediate gearing i, f, e and d, substantially as described and shown.
Third. Concealing the driving wheel a of a dental engine under the foot-board
of a dental chair, the said wheel being operated by a treadle connected by pivotted
bars 10 and 12 to the axis of the driving wheel a, substantially as described and
shown.
Fourth. The combination, in a dental engine, of two adjustable frames and c
with any suitable stand, a treadle j and driving wheel a, substantially as described and
shown.
Fifth. The combination of an extensible stand consisting of an adjustable frame 1,
pulley n, axis t, axis v, rod w, tube m, sliding tube 2, cheeks 3, 3, set screw q,
spring 6 and sheathing 1, with an adjustable frame c, driving wheel a, treadle j,

page_text: driving gear i, f, e, d and b, and pivotted bars 10 and 12, substantially as described
and shown.
Sixth. A stand in which the spring carrying sheathing 1 can be adjusted at any
desired angle between two cheeks 3, 3 and set by means of a screw 4 substantially as
described and shown.
Seventh. An extensible dental engine stand composed of a main tube m, rod w,
axis v, tube 2 and set screw 7, substantially as described and shown.
not 1
30
1000
For J. S. CAMPBELL,
Brandon & Son,
Agents.