Improvements in Electrically Operated Apparatus for Dental Purposes.
Year: 1895

page_text: Date of Application, 10th Dec., 1895-4ccepted, 1st Feb., 1896
COMPLETE SPECIFICATION.
Improvements in Electrically Operated Apparatus for Dental
Purposes.
We, OSCAR HENRY PIEPER, and ALPHONSE FERDINAND PIEPER, both of
the City of San Jose, in the County of Santa Clara, State of California, United
States of America, Engineers, do hereby declare the nature of this invention,
and in what manner the same is to be perforined to be particularly described
and ascertained in and by the following statement:-
This invention relates to improvements in electrically operated apparatus for
dental purposes, especially to a method of mounting for universal adjustment and
convenient use, an electrically driven revolving spindle to receive and operate
rotary dental implements, also relates to apparatus for distributing and controlling
the electric current that impels the spindle and dental implements so as to revolve
the latter either way, at various rates of revolution and degrees of force, also to
start and abruptly stop the revolving spindle when required.
The invention consists in suspending by a rope or cord the electric motor and
the operating spindle, which are by preference enclosed in a spherical case or con-
taining chamber, mounted in a gimbal ring so the whole is free to turn on a horizontal
nxie.
The gimbal ring or frame is suspended by a rope or cord passing over pulleys
and balanced by a counter-weight, so the operating apparatus can be instantly and
easily moved up or down, turned on its vertical axis by torsion of the rope or cord,
or swung to any position to suit the requirements of operating with the spindle,
and a flexible extension thereof that receives and holds the dental implements.
The suspending rope or cord is by preference made to envelop or contain the
electrical conducting wires that connect through the gimbal ring to the electric
motor therein mounted. Another part of this invention essential to, and con-
stituting a part of the same apparatus, consists in an electrical device to control the
current passing to the motor, so as to stop, start, reverse and regulate the same as
to its force and the rate of rotation. This last named device is connected to the
electric motor by means of wires contained in the beforenamed suspending cord, or
in other convenient manner, the operating parts being enclosed in a portable case
that rests on the floor, provided at on side with a pedal that can be moved by the
foot of an operator, forward or back, thereby operating contact apparatus of the
nsual kind for opening and closing the field and armature circuits of the electric
motor, cutting in or out resistance, also short circuiting the armature of the motor
and suddenly stopping the same when required. All as will be hereinafter fully
explained and set forth in the description and drawings.
i
In the drawings:
:
Fig. 1 shows a dental operating apparatus made and arranged according to our
invention.
Fig. 2. is an enlarged partial side view of the motor in a plane opposite to
Fig. 1.
Similar letters of reference are employed to designate like parts in Figures 1
and 2 of the drawings, and also like letters of reference are common to Figures: 3,
4 and 5 of the drawings.
In mounting motors employed for operating dental implements they are commonly
supported on swinging brackets pivoted on a wall, post or other support arranged
to be moved in a horizontal plane, also adjustable radially from the pivotal point

page_text: by telescopic joints, or other suitable means, but both these movements fail to give
the free adjustment required, also by want of vertical adjustment causing curves in
the flexible transmitting tube hetween the motor and the instrument, which is
avoided by a vertical adjustment.
Referring to Figures 1 and 2 of the drawing, A. is a wall to which the swinging
bracket B is attached by the pivotal bearings CC. A small electric motor is
enclosed in a case D, the latter being preferably of spherical form, as seen in the
drawing, although it may have other form or contour.
This case D and contained electric motor we support in a gimbal frame E, which
is suspended by a cord or cable F passing over pulleys G' G' down along the
wall A, and to a rheostat H, the latter so arranged as to be controlled by the foot
of an operator, and hereafter to be described.
As the electric motor employed consists of the usual elements embraced in such
machines, and as these are well known, we do not give a detail description of the
same, the functions being set forth in a future place in this Specification.
The required wires for conducting the electrical current, and controlling the
movements of the motor in the case D are preferably enclosed in the cord or
rope F, and enter through the gimbal frame E and the axes Q or R, or both, in
the usual manner.
The bracket B when required is made in two parts, having a telescopic section I
that can be moved out or in, and fastened in any required position by means of a
screw J, so the flexible driving shaft K and the implements L can be brought over,
or to either side, of a dental chair M, as seen in Fig. 1.
On the cable or cord F we place a counterweight N that balances the motor and
case D with their fittings, so the latter will remain after adjustment at various
heights from a dental chair M.
When the flexible shaft or transmission tube K is to be led off at an angle, or
horizontally in respect to the motor in the case D, we provide a latch or detent O
that slides on the gimbal frame E, and engages a notched sector P attached to the
motor in the case D, as seen in Fig. 2, so the latter can be fixed in various positions,
or at different angles.
The cord or cable F can be of any flexible material, hollow to contain conducting
wires within, or fibrous and twisted with the conducting wires intervened, or these
wires can be led alongside the cord or cable F, also can be trained to the motor in
the case D independent of the rope or cable F, but the arrangement is more
complete, as shown in the drawings.
Referring next to the electric controlling devices, contained in the case H, Fig. 1,
and shown enlarged in Figures 3, 4 and 5-
Fig. 3 is a central vertical section through a controlling apparatus made according
to our invention.
Fig. 4 is a plan view of Fig. 1 with the top cover removed.
Fig. 5 is an enlarged plan view on the line -y of Fig. 3.
Similar letters of reference are employed to designate like parts in Figures 3, 4
and 5 of the drawing.
The main containing case A is preferably made of metal, with a projecting
base B. adapted to stand on a floor, a mass M being added to the interior or
bottom to increase the weight, and thus resist by friction on the floor the turning
strain of the foot pedal K. This device is portable, and can be set in any
convenient position in respect to the chair or seat M in Fig. 1, to suit the position
of an operator standing thereat, and can be slid about from side to side as occasion
demands.
In the centre is a partially revolving or oscillating spindle F, to the top of which
is attached a lever H, formed integrally with the pedal K, movable to the right or
left through an arc, as indicated at T¹ T in Fig. 4.
When the pedal K and lever H are moved to the right or left the motor Q',
which in this case represents the one contained in the case D, Figures 1 and 2, is,
by reason of electrical functions to be hereinafter explained, started in either

page_text: direction accordingly, and when the pedal K is released the lever H is at once
moved to its central or neutral position by means of the jaws G¹ G³, operated by
the coil spring I, as seen in Fig. 4.
The jaws or levers G1 G2 are pivoted at a a, and rest against stop pins e e, also
against the lever H, as seen in Fig. 4, so that when either of the jaws G or G' are
moved by the lever H the other jaw remains stationary, the spring I acting for
either motion, and returning the lever H when released to its central position.
It will be observed that the movement of this pedal K is in a horizontal plane, so
it can be moved either way by the side of the operator's foot without raising it from
the floor, and while a portion of his weight is resting thereon, thus not disturbing
his position or the free use of his hands.
The lever or pedal K can be provided with stops or locking devices to hold it at
any desired point in its range, but such devices not forming an essential part of the
present invention are not included in the drawings herewith.
On the stem F is fixed a switch bar L provided with brushes m, n and p that
connect with and transfer current to various contact plates in the system
designated "O," with numerals from 1 to 18, connected by means of wires marked
with the letter P, and numerals 1 to 10, as will hereafter appear..
Brush is insulated from switch bar L, and brushes m and p are in direct
contact therewith. V₁ and V' are cells of an electric battery to supply current,
and Q3 the armature or commutator of an electric motor having brushes Q' Q³
and main connecting wires P P³, as seen in Fig. 5.
We will now proceed to describe the course of the electric current when the
bar L is in the position corresponding to that indicated at T in Fig. 4, or an
intermediate position from the centre toward T, and to operate the motor Qin
the direction of the arrow thereon.
In this position of the various elements current from the battery V₁ V' passes
from the positive poles of the battery V1 V2 through the wire P to the main
case A, through the stem F, bar L and brush p to the plate 018, then from the
plate 18 through the wire P to plate O and the binding post S, and through the
wire P to the brush Q' of the armature Q3; then through the armature Q³ to
the brush Q, through the wire P³ to the binding post S', thence to plate O', and
across the brush », which is insulated from bar L, to plate (), thence to the
binding post S, and returns to the negative poles of the battery V₁ V' by the
wire P, thus forming the armature circuit.
Tracing now the field current: Beginning at the battery V1 V2, and following
over the wire P', through the main case A, stem F.and switch bar L and to the
brush m.
From the brush m the current follows to the plates 0 0 0" or ", as the
position of the lever H and consequent position of the bar L and brush m may
determine.
If the brush m rests on plates 0" or 0 then the current passes directly to the
field winding by way of the wire Ps, but if on plates 012 013 014, or corresponding
ones 08 07 06, then the current must pass through varying resistance, shown at V
in Fig. 3, also shown connected between the plates 0° and 08, aud 07 and 0.
This resistance inserted into the field circuit, it will be understood, regulates the
strength of the field magnets, consequently the speed of the armature, the weaker
the field magnets the higher the speed, and rice versa.
After passing through the plates 0" and 0%, or through the whole or some
portion of the resistance coils V, the field circuit then passes over the wire P
to the motor field W, through this field to the wire P, connecting with wire P
at the junction X in Fig. 5, thence by the wire P again to the negative poles of
the battery V V'.
It will be understood without retracing these currents that by moving the
pedal K, lever H and switch bar L to the position indicated by T', in Fig. 4, that
the armature current will be reversed accordingly, the field current remaining in
the direction that has been pointed out.

page_text: When the lever H and the switch bar L are suddenly moved to their central or
neutral position, and the armature Q³ is in rapid motion, and would continue to
revolve but for the fact that as soon as the brush p reaches the plates 07 and 016
the armature is placed on short circuit, and the field magnets are at full strength,
consequently it instantly comes to rest.
We e are aware that short circuiting an armature for sudden stop has been done
before, but always in combination with resistance in either the fixed or armature
circuit, and very often in both. In this instance we have so designed the electrical
details that all addition of resistance is unnecessary, and we get the full benefit of
the dynamo effect.
The direction of the current at the time of the short circuit is as follows: When
the brush p has passed the plate 018 or plate O", as the case may be, it bridges
over 1 and O", this making a closed circuit on the armature, and no connection
with the battery V₁ V', as we will now trace.
Commencing at the brush Q', through the wire P' to the binding post S and
plate O, then through the wire P7 to the plate 018, through the brush p to the
plate O, and through the wire P to the plate O¹, then through the binding
post S and the wire P³ back to the armature brush Q' without resistance in the
circuit.
While the brush p is passing over the central plates 01 and O", and thereby
closing the only gap betwis position the field magnets are at full strength until the
between the two armature terminals, the brush m rests on the
plate or
segment 00 is reached when no current flows, and the armature is at rest.
In this manner it will be seen that the armature Q³ will be suddenly stopped
without frictional or brake devices, and the whole apparatus simplified as well as
better adapted to its purposes.
We have thus particularly described the electrical controlling mechanism
employed in our invention, because it is in this part that efficient action and
control of dental implements to a great extent depend, but as will be understood,
modifications of this controlling apparatus can be made with fewer details and less
functions that would operate an electric motor as shown in Figures 1 and 2.
For
example, a simple current reversing apparatus could be employed, and with
clutches to stop and start the electric motor and the dental implements being
operated, but not so effectually as in the manner shown.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed we declare that what we
claim is:
-
1. In dental apparatus, a suspended and adjustable electric motor and spindle
for operating rotary dental implements, counterweighted and arranged for adjust-
iment vertically, axially and in all planes, in the manner substantially as shown in
the drawings.
2. In dental apparatus, an electric motor enclosed in a containing case, having
axes in a gimbal frame, suspended by a rope and counterweight, substantially in
the manner described.
3. In dental apparatus, a suspended electric motor and spindle, adjustable in all
planes, and therewith electric controlling apparatus, suitably connected, portable,
and adapted to stand on the floor, substantially as shown.
4. In dental apparatus, a counterweighted electric motor and operating spindle,
vertically adjustable by means of a suspending rope, the latter containing or
including conducting wires connecting to the electric motor, substantially as shown
and specified.
5. In dental apparatus, an electric impelling apparatus, and controlling
mechanism therefor, the latter contained in a portable case, or adapted to stand on
the floor; a pedal moving in a horizontal plane, that can be moved either way
without the operator raising his foot or removing his weight therefrom.
6. In dental apparatus, an electric controlling device having an oscillating stem,

page_text: pedal and brush bar L, as shown in Figures 3, 4 and 5 of the drawing, provided
with integral brushes m and p and an insulated brush n, controlling the armature
and field circuits and short circuiting the armature Q³, in the manner and for the
purposes substantially as described.
7. In dental apparatus, an electric controlling apparatus having an oscillating
stem, pedal and brushes, in the manner described, the pedal provided with pivoted
levers and stops to determine their inward range, and a spring that acts on both.
levers, in the manner substantially as described.
8. In dental apparatus, a suspended and universally adjustable inpelling motor
and spindle, suspending rope, counterweight and portable electric controlling
apparatus, combined, connected and operating in the manner herein set forth and.
specified.
Date : 10L 1
100-
ALLISON BROS.,
Agents for the Applicants..