Improvements in Dental or Surgical Engines.
Year: 1890

page_text: Date of Application, 11th Nov., 1890-Accepted, 14th Feb., 189;
COMPLETE SPECIFICATION.
Improvements in Dental or Surgical Engines.
I, WILLIAM GIBSON ARLINGTON BONWILL, of 2009, Chestnut Street,
Philadelphia, County of Philadelphia, State of Pennsylvania, United States of
America, Dentist, do hereby declare the nature of my invention for "IMPROVE-
MENTS IN DENTAL OR SURGICAL ENGINES," and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
My invention has reference to dental or surgical engines and consists of certain
improvements, all of which are fully set forth in the following Specification, and
shown in the accompanying drawings, which form a part thereof.
The object of my invention is to provide a simple construction of power tr..ns-
mitting mechanism, whereby the hand piece and connecting flexible arms may be
freely moved in all directions without material variation in the length of the
operating cord. Heretofore the joints in the flexible arm and the joint between
the flexible arm and hand piece have been constructed to compensate for all move-
ments of the said flexible arm with respect to the standard, and the movement
of the hand piece with respect to the flexible arm, the object being to prevent
material variation in the tension upon the operating cord, the latter being kept
under constant and heavy tension, which tension has usually been maintained by
the use of a spring acting upon an extensible joint in the flexible arm, or by a
weight acting upon the driving cord.
This old form of construction of dental engine is illustrated in United States
Letters Patent No. 282,044, granted to me July 31, 1883.
My present improvements are designed to overcome the complication of these old
forms of dental and surgical engines, and at the same time maintain all the
advantageous features thereof, and in addition thereto embody new features of
considerable importance in the use of such machines.
With my improved construction I am enabled to use a very loose driving cord,
and thereby overcome the excessive friction which has heretofore been required
upon the various movable parts of the engine, and by my being able to use such a
loose driving cord I am permitted to simplify the various constructions employed at
the joints and connections in the flexible arm, and between the flexible arm and
hand piece. This looseness in the driving cord also reduces the labour of operating
the engine.
My invention also comprehends certain improvements in the chuck or hand piece,
which improvements are fully referred to hereinafter.
Referring to the drawings
Fig. 1 is an elevation of a dental or surgical engine embodying my improve-
ments;
Fig. 2 is an enlarged view of the hinge joint or elbow connecting the two parts of
the flexible arm, with a portion broken away:
Fig. 3 is a cross section of same on line y. y;
Fig. 4 is an enlarged elevation of the joint between the flexible arm and hand
piece, and shows a portion thereof in section ;
Fig. 5 is a cross section of same on line ...;
Fig. 6 is a sectional elevation of the hand piece:
Fig. 7 is a cross section of Fig. 6 on line;
Fig. 8 is a cross section of the hand piece on line s s of Fig. 6;
Fig. 9 is a cross section of the hand piece on line u u of Fig. 6;
Fig. 10 is a perspective view of the chuck clamps removed from the hand piece
nd slightly separated; and
Fig. 11 illustrates a drill adapted to the hand piece.

page_text: A is the usual standard to which is pivoted the drive wheel B, said wheel being
preferably light in weight and formed with a very deep and sharp V groove in its
periphery. C is a foot treadle and is a connecting arm or pitman for operat.ng
which
the drive wheel B. To the top of the standard A. is hinged the flexible
consists of the parts E and G.
C
arm,
The part E is directly hinged to the top of the standard A, and is provided with
a coiled spring e, which acting upon the pivoted arm E, tends to support the weight
of the hinge arm and keep it raised when the hand piece is being held by the
operator.
Heretofore in many engines it has been customary to make this arm E extensible,
but in my improvement such extensibility is not required, and the primary arm E is
directly hinged to the standard.
The secondary part G of the hinge arm is hinged to a socket piece H at I, and
the socket piece H is provided with a socket H, which fits over the end of the
primary part E and is held thereto by means of a screw fitting in an annular
groove E on the end of the primary part E. This construction allows the part G
and the socket piece H to revolve freely about the part E as an axis. This hinge
joint between the parts G and H is marked !).
The pin is extended upon each side of the hinge joint, and receives the loose
sleeves upon which loosely revolve the two deeply grooved guide wheels J J.
Nuts or washers may be placed upon each end of the pin I to hold the sleeves
and wheels in position. By the employment of the sleeves j, I reduce to a con-
siderable extent the friction and wear which would otherwise exist if the wheels J
ran directly upon the pin 1. The grooves in the wheels are as deep as possible
to make the diameter at the bottom of the grooves as small as possible, so as not to
require a material taking up of the cord for the greatest bending of the joints g.
While the sleeves are desirable, it is evident that they might be dispensed with if
desired.
We will now refer to the joint between the flexible arm and the hand piece,
which joint is best shown in Figs. 4 and 5. K is a rigid elbow picce having upon
one end a socket for receiving the end of the secondary part G of the flexible arm,
and about which as an axis it is free to rotate. The other arm of this elbow piece
is formed with a pink which is received in a socket piece L of the hand piece, and
to which it is secured by means of a screw / working in an annular groove K' in
the pink. To the socket piece L the hand piece M is pivoted, so that the operator
in holding the hand piece may move it freely without reference to the connection
between the parts L and K.
The spindle m of the hand piece is provided upon its upper end with a
wheel N having a deep V shaped groove adapted to bite upon the endless cord.
Through the elbow K is a pin p upon which is loosely secured as before the
sleeves and upon these sleeves are the loosely supported deeply grooved guide
wheels (Fig. 5).
"
The endless cord O is placed about the drive wheel B, then over the guide
wheels D at the top of the standard A, thence over the two guide wheels J of the
flexible arm, thence around the two guide wheels P, and finally passing around the
deeply grooved wheel N of the hand piece. This endless cord O is preferably
loose and well rosined so that it may run in a loose condition, and yet in connection
with the very deeply grooved wheels B and N, is well adapted to transmit all the
power needed under every circumstance.
It is quite evident that the antifriction sleeves ; may be used with the pulleys D
and between the shaft and the drive wheel B.
The pulleys J and P have their grooves preferably rounded so as to reduce as
far as possible any friction due to the pressure of the cord about these wheels. By
making the diameters of the various wheels D and J as small as possible the flexible
arm may be moved to the fullest extent without materially taking up the cord O
and such taking up of the cord as actually does take place has no effect upon
running of the machine in view of the fact that the cord is running very loosely
the

page_text: This has the result of enabling the operator to run his machine uniformly without
excessive exertion and permitting the manipulation of the hand piece to the fullest
extent without increasing or decreasing the power required to operate the said
hand piece.
It is evident that the connection of the hand piece with the flexible arm permits
the said hand piece to be moved with respect to said flexible arm in any necessary
direction, and that too, without materially varying the length of the cord required
to maintain the transmitting connection.
By employing a rigid elbow with the loose grooved pulleys at said elbow, I
greatly simplify the construction, and increase the durability of the device over the
devices which have heretofore been employed for accomplishing the same purpose.
The employment of the rigid elbow and fixedly located pulleys is made possible by
the hingeing of the hand piece on the short arm of the rigid elbow so that it is
capable of rotating thereon, and these two features taken together permit of every
desired movement without the necessity of the complicated devices for compen-
sating for the different lengths of cord required in other makes of dental and
surgical engines. The guide wheels D and J run upon the axis of the hinge
joints, and consequently do not shift their position with respect to the arms E
and G.
As far as possible these various guide wheels J and P are arranged as close
together in pairs as is possible, and particularly so with reference to guide
wheels P P, so as to enable a wheel of as small a diameter as possible to be used
with the grooved wheel N of the hand piece.
Referring more specifically to the hand piece, which is clearly shown in Fig. 6
of the drawings, we have the entire hand piece M loosely journaled upon the
sleeve L' of the part L, and in which it is free to revolve. Journaled in this
sleeve is the tubular bearing A, and journaled within this tubular bearing is the
part A of the spindle for rotating the operating part such as the drill S. The
spindle m is provided with a conical collar m' which fits against the under end of
the tubular bearing A² and has secured to its upper end the deeply grooved driven
weel N which acts as a collar to hold the spindle against longitudinal movement
w.th respect to the bearing A2. Furthermore, the bearing A is provided with a
shoulder on its lower part which fits against the under edge of the sleeve L', and
the wheel N at the top extends slightly over the upper portion of the sleeve L'
and thus holds the tubular bearing A² against longitudinal displacement with
reference to the sleeve L'.
The lower part of the spindle m is provided with a removable head T having a
conical bearing t at its lower end. In this head T are arranged the two chuck
p.rt.ons or sections RR' which are provided with cylindrical holes W for
receiving the shank of the drill S, and have their lower ends made conical as at r,
(see Fig. 10). The conical part of the piece R fits against the conical bearing t
of the head T; and the conical end of the part R' fits into the conical socket
of the upper end of the part R.
A clamping screw R² extending through the spindle m is adapted to press upon
the upper end of the part which is closed, and forces the parts R and R¹
ongitudinally, compressing the split end through the action of the conical portions
using them to clamp the shank of the drill at two places in its length. The
lamping screw R2 extends through the spindle of the hand piece and is provided
with a milled head or finger wheel R³ by which it may be turned to operate the
chuck.
}}}
Enclosing the lower part of the spindle and the head T is a metallic sleeve Q
which is removable by having a slotted upper end through which a clamping
crew passes to clamp the said sleeve Q to the tubular bearing A².
A hard rubber tubular piece U is arranged upon the outside of the sleeve Q
nd the sleeve L' and is held to the tubular bearing A2 and movable with it
ndependently of the movements of the part L' by means of the clamping screw Q
By loosening the screw the sleeve Q may readily be drawn out, exposing the

page_text: various parts for oiling. The outside diameter of the sleeve Q and the sleeve L'
is preferably the same so that the tubular hard rubber sleeve U may fit over both
of them substantially as shown. By this construction it is seen that the bearing
for the rapidly rotating spindle is arranged at the upper part of the hand piece and
close to the place of application of the power. It will furthermore be observed
that the hand piece may be held firmly in the hand while it is revolved about the
flexible arm as an axis, and while the sleeve L' may be revolved with respect to
the tubular bearing A² as an axis. This permits the chuck while firmly held in
the hand to have all conceivable movements during the operation of the engine,
and at all times the transmitting power connection is maintained and practically no
variation in the length of the cord is required.
This hand piece might be modified as to details without changing its general
construction or the essential features of the invention.
It is evident that while the elbow piece K is a right angled piece, said piece
might have its two arms arranged at a greater or less angle without departing
from the spirit of the invention; and it is also evident that the details may be
modified, if so desired.
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:
1. In a dental or surgical engine the combination of a standard, a deeply and
sharply grooved drive wheel, power mechanism for rotating said drive wheel, a
flexible arm hinged to the standard, guide pulleys at the joints of the flexible arm,
a hand piece flexibly connected with the flexible arm and having a deeply and
sharply grooved wheel for operating the movable part of the hand piece, and a
loose rosined driving endless cord passing about said deeply grooved guide
wheel and deeply grooved wheel of the hand piece and the intermediate guide
wheels of the flexible arm.
2. In a dental or surgical engine the combination of a standard, a drive wheel,
a flexible arm connected to the standard, a hand piece, an elbow part pivoted to
the flexible arm and carrying the hand piece permitting rotation of the hand piece
about said flexible arm as an axis, and a pivoted connection between the elbow part
and hand piece permitting said hand piece to move about an axis arranged at an
angle to said flexible arm, a deeply grooved wheel upon the hand piece, grooved
guide pulleys between the flexible arm and the hand piece and an endless driving
cord arranged between the grooved drive wheel and the grooved wheel of the
hand piece said cord being guided over the guide pulleys between the flexible arm
and hand piece.
3. In a dental or surgical engine the combination of a standard or frame, a
grooved drive pulley pivoted to said frame and adapted to be rotated, a flexible
arm hinged to the standard, a rigid elbow piece carried on the end of the flexible
arm, two deeply grooved guide pulleys carried by said elbow piece, a hand piece
pivoted to said elbow on an axis at right angles to the flexible arm and provided
with a movable part, a deeply grooved pulley secured and operating the movable
part arranged close to the guide pulleys, and an endless cord connecting the drive
wheel with the deeply grooved wheel on the hand piece and guided about the; uide
pulleys on the elbow piece.
4. In a dental or surgical engine the combination of a standard or frame, a
grooved drive pulley pivoted to said frame and adapted to be rotated, a flexible
arm hinged to the standard, a rigid elbow piece carried on the end of the flexible
arm by a loose joint permitting rotation of said elbow piece about the end of said
flexible arm as an axis, two deeply grooved guide pulleys carried by said elbow piece
and adapted to rotate about an axis arranged at an angle to the flexible arm, a sleeve
provided with an angular socket piece adapted to be pivotally secured to the rigid
elbow piece, a hand piece journaled in said sleeve at an angle to its connection
with the elbow piece and provided with a movable part, a deeply grooved pulley

page_text: secured to and operating the movable part arranged close to the guide pulleys on
the elbow piece, and an endless cord connecting the drive wheel with the deeply
grooved wheel on the moving part of the hand piece and guided about the guide
pulleys on the elbow piece.
5. In a dental or surgical engine having a flexible arm, a giving connection
between the flexible arm and hand piece consisting of the combination of the elbow
piece K loosely fitted upon the end of the arm and having a pin k, deeply grooved
pulleys P P arranged upon a common axis p and located upon opposite sides of the
elbow piece, loose anti-friction sleeves ; arranged between said grooved wheels P
and axis p, a socket piece L loosely journaled upon the pin k, a hand piece M
supported by said socket piece L, a spindle mounted in the hand piece and
projecting therefrom, and a grooved pulley N mounted therein and having a
diameter substantially equal to the distance apart of the grooves of the two guide
pulleys P P.
6. In a dental or surgical engine, the combination of a flexible arm, a hand piece
having a movable part, a rigid elbow piece having one arm connected to the end of
the flexible arm and the other or free arm arranged at an angle to the hand piece,
an intermediate sleeve piece pivoted to the free arm of the elbow piece on one end
and at the other end sleeved upon the hand piece whereby the hand piece may
rotate in the sleeve and also about the elbow piece, and flexible power transmitting
devices for operating the movable part of the hand piece.
7. In a dental or surgical engine, the combination of a flexible arm, a universal
joint between the flexible arm and hand piece consisting of a rigid elbow piece
pivoted upon the end of the flexible arm and at right angles to the hand piece and
connected therewith by a hinge or pivot joint whereby the hand piece may
revolve freely about the flexible arm and also about the rigid elbow piece, and
guide wheels carried by the elbow piece for guiding the cord to the hand
piece.
8. In a dental or surgical engine, a giving connection between the flexible arm
and hand piece consisting of the elbow piece K loosely fitted upon the end of the
flexible arm and having a pin k, deeply grooved guide wheels P P arranged upon a
common axis and located upon opposite sides of the elbow piece, a socket piece L
loosely journaled upon the pink, a hand piece M loosely journaled in the socket
piece L and adapted to rotate in said socket piece upon an axis lying in a direction
corresponding to the flexible arm to which the elbow piece is secured, a rotating
spindle for holding the operating part carried by said hand piece, and a grooved
pulley for the hand piece having a diameter substantially equal to the distance apart
of the grooves of the two guide pulleys P P.
9. In a dental or surgical engine the combination of a flexible arm, with a rigid
elbow at its free end, guide pulleys at said elbow, a hand piece connected to said
elbow and journaled on an axis arranged in a plane parallel or substantially parallel
to the end of the flexible arm to which the elbow is secured, a grooved pulley
arranged upon the hand piece at an angle to the pulleys upon the elbow, and a
power transmitting band passing about the guide pulleys and pulley upon the hand
piece.
10. In a dental or surgical engine the combination of a flexible arm, a hand piece
journaled at its upper end upon a sleeve and provided with a deeply grooved wheel
for rotating the spindle of the hand piece, a joint between the journal of the hand
piece and the flexible arm whereby the hand piece is held at a substantially fixed
distance from the end of the flexible arm and movable about an axis arranged
transversely to the said arm and directed toward the hand piece, and guide pulleys
for guiding the driving cord from said flexible arm around the deeply grooved wheel
of the hand piece.
11. In a hand piece for dental or surgical engines the combination of a tubular
bearing, a spindle journaled in said bearing and having a grooved wheel upon its
free end, two tubular clamping portions RR' arranged in the lower part of the
spindle and having their lower ends made conical and split and respectively adapted

page_text: to conical sockets t and ² arranged respectively on the spindle and the part R,
and a clamping screw for forcing said parts R R toward the conical socket t.
12. In a hand piece for dental or surgical engines the combination of a tubular
bearing, a spindle journaled in said bearing and having a grooved wheel upon its
free end, two tubular clamping portions R R arranged in the lower part of the
spindle and having their lower ends made conical and split and respectively adapted
to conical sockets & and 2 arranged respectively on the spindle and the part R, a
clamping screw for forcing said parts R R' toward the conical socket t, a supporting
sleeve portion L L' in which the tubular bearing is journaled, a sleeve Q detachably
connected to the tubular bearing and enclosing the lower part of the spindle, and a
tubular sleeve to be grasped by the hand secured to the tubular bearing and
extending over the parts Q and L'.
13. A chuck for a hand piece consisting of a rotating spindle having a conical
socket upon its lower end, combined with two tubular or clamping sections R R'
having their lower ends made conical and split and having the upper end of the
part R made with a conical socket for the reception of the conical end of the
part R', and a clamping screw carried by the spindle adapted to force said
clamping sections R R longitudinally with respect to each other and the spindle.
14. A chuck for a hand piece consisting of a rotating spindle having a conical
socket upon its lower end, combined with two tubular clamping sections R R¹ the
part R having an aperture entirely through it and the part R' having an aperture
only part way through it and also having their lower ends made conical and split
and having the upper end of the part R made with a conical socket for the reception
of the conical end of the part R', and a clamping screw carried by the spindle
adapted to force said clamping sections R R' longitudinally with respect to each
other and the spindle.
1
A D 1000
Date US Un ay
WM. G. A. BONWILL.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.