Improvements in Dental Engines.
Year: 1898

page_text: Date of Application, 31st May, 1898--Accepted, 30th July, 1898
COMPLETE SPECIFICATION.
Improvements in Dental Engines.
I, ARTHUR JAY MCDONALD, of 3708, Wyandotte Street, in the City of Kansas
City, County of Jackson, and State of Missouri, United States of America, Dentist,
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 fol-
lowing statement:-
My invention relates to improvements in dental engines.
The object of my invention is to provide in a dental engine having a rotatable
driving shaft mounted in a suitable support, a novel construction of clutch by
means of which the direction of rotation of the shaft may be changed, together
with means for stopping the rotation of the said driving shaft without stopping
the motive power.
My invention further provides certain novel peculiarities of construction which
permit the utilizing of various motive devices.
My invention further provides a vertical driving shaft, a tight and a loose
pulley mounted upon the said driving shaft, a support in which the said shaft
is mounted, and means for changing the direction of rotation of the driving shaft,
the two pulleys being adapted to have a frictional contact with each other,
whereby the direction of rotation of the driving shaft is governed by the loose
pulley, all when combined as described, in a dental engine.
My invention consists further in novel features of construction hereinafter fully
described and claimed.
In the accompanying drawings which illustrate my invention, Fig. I represents
an elevation view and shows the engine provided with a foot power driving
mechanism. Fig. 2 represents a vertical sectional view with a portion of the foot
power mechanism removed, and sections of the vertical tube removed. A belt
connected with the loose pulley is shown in this view. Fig. 3 represents a cross
section taken on the dotted line a-b of Fig. 2, the driving shaft and other parts
being removed. Fig. 4 represents an elevation view of the clutch and shaft
elevating mechanism, and some of the parts connected with the driving shaft.
In this view the upper end of the driving shaft is shown in section, as also is a
portion of the vertical supporting tube. Fig. 5 represents a vertical sectional
view of the same parts shown in Fig. 4, the elevating lever being shown in
elevation. Fig. 6 represents an elevation view of the same parts shown in Fig. 4,
the two pulleys being shown in contact with each other. Fig. 7 represents a top
view of the elevating lever, the driving shaft and the supporting tube being
shown in cross section. Fig. 8 represents a perspective view of the elevating
lever. Fig. 9 represents a plan view looking at the under side of the plate in
which is pivoted the driving roller which is acted upon by the loose pulley.
Fig. 10 represents a horizontal sectional view of the elevating lever, tubular sup-
port and driving shaft. Fig. 11 represents an elevation view of the base and the
lower end of the tubular support, some of the parts connected with them being
omitted. In this view, in dotted lines, is shown another position of the collar and
stud on which is mounted the foot power driving wheel.

page_text: Similar numerals of reference indicate similar parts throughout the several
views.
1 indicates the base which is cylindrical in form, closed at the top and pro-
vided at its lower end with three radial feet 2. The base is hollow and has
secured in any suitable manner in its lower end a horizontal plate 3 which is
detachable. In the center of the said plate 3 is a vertical recess in which
is stepped the lower end of the vertical driving shaft 4 the upper end of which is
provided with a vertical opening in which may be secured the inner end of a
Hexible shaft 5, to the outer end of which is adapted to be secured the hand
piece ordinarily used by the operator. Secured in any suitable manner in a
vertical opening in the top of the base is the lower end of a vertical
tube 6, the upper end of which has secured to it a collar 7, in which is secured
the lower end of another vertical tube 8, in the upper end of which is rotatively
fitted a cap 9 in which is rigidly secured the lower end of a laterally curved
tube 10 in which the flexible shaft 5 is revoluble. The cap 9 is provided with a
central vertical opening in which may rotate the rigid spindle attached to the
flexible shaft 5. Within the tubes 6 and 8 at suitable distances apart are located
bearing blocks 11 which are each provided with a central vertical opening in
which is mounted the rotary shaft 4. For the purpose of deadening the noise
caused by the running of the shaft each of the blocks 11 has inserted between
it and the tube, a bushing 12 preferably of a substance similar to soft rubber.
One side of the base 1 is provided with an opening. Below this opening a hori-
zontal annular plate 13 is secured within the base in any desirable manner, as by
a screw thread connection therewith. Secured in a vertical central opening in
the plate 13 and extending vertically upward therefrom is a tube 14, the upper
end of which is provided with a lateral flange 15 for preventing vertical move-
ment of the sleeve 16. Rotatable upon the tube 14 between the flange 15 and
the plate 13 is a sleeve 16, to the lower end of which is secured a grooved pulley
wheel 17, adapted to be connected by a belt with the motor used to operate the
engine. Above the pulley 17 is a rubber frictional wheel 19 centrally secured
upon the sleeve 16. The upper end of the sleeve 16 is externally screw threaded
and is provided with a nut 18, the function of which is to secure the rubber
wheel 19 upon the sleeve 16. The lower end of the tube 14 is externally screw
threaded and is provided with a nut 20 located in an annular recess in the under-
side of the plate 13. The tube 14 is shouldered as shown in Fig. 5, at a point
just even with the upper side of the plate 13, thus providing means for rigidly
securing the tube 14 to the plate 13 when the nut 20 is tightened. Upon the
tube 14, between the sleeve 16 and the plate 13 is a washer 21 which serves to
prevent the sleeve or pulley from coming in contact with the plate 13.
shaft 4 is rotatively fitted in the tube 14. The plate 13 is provided with one or
more vertical openings as illustrated in Fig. 9, in which may be inserted one or
more driving rollers 22 the axes of which are horizontal. The roller 22 is pro-
vided with a central shaft 23 having secured to it at one end a plate 24, the other
end of the shaft 23 is screw threaded and has fitted to it a plate 25. The roller 22
is preferably of rubber which is held securely upon the shaft 23 by being com-
pressed between the two plates 24 and 25. Secured upon the shaft 4 below the
plate 13, is a disk 26 which is adapted to have its upper surface come in contact
with the rubber roller 22, when the shaft 4 is elevated in the manner hereinafter
described.
The
Secured upon the driving shaft 4, above the tube 14 is a horizontal disk 27
which is provided with a downwardly extending central tubular projection 28 the
lower end of which is externally screw threaded. A horizontal annular plate 29
is provided with a central opening in which is fitted the screw threaded end of the
projection 28. A rubber disk 30 is clamped between the plate 29 and the disk 27.
A vertical screw 31 extends through the disk 30 and engages a screw threaded
opening in the disk 27 and prevents rotation between the plates 29 and 27 of the
rubber disk 39. The under side of the disk 30 is provided with a recess large

page_text: enough to admit the nut 18. When the shaft 4 is sufficiently lowered the disk 30
will rest upon the disk 19, and the rotation communicated therefrom to the
shaft 4. A set screw 32 is provided in the hub upon the upper side of the disk 27
for the purpose of securing the disk 27 at any point upon the shaft 4 desired.
Secured to the shaft 4 near its upper end is a horizontal disk 33. A friction
roller 34 adapted to have contact with the under side of the disk 33, is pivotally
secured to the inner end of a lever 35 which extends through an opening in the
side of the tube 8. The lever 35 outside the tube 8 is pivoted, by means of a
screw 36 to a projection 37 on the tube 8. Upon the side of the lever opposite to
the projection is secured a flat spring 38 which rests upon the outer end of a
pin 39 carried in an opening in the lever and adapted to have its other end enter
two counter sunk openings in the side of the projection 37. By depressing the
outer end of the lever 35, the shaft 4 may be raised first to the position shown
in Fig. 4 in which the rubber disks are separated, and then to the position shown
in Fig. 5 in which position the disk 26 has forced the roller 22 against the
pulley 17. By releasing the lever 35, the shaft 4 is permitted to drop until the
rubber disk 19 is in contact with the disk 30, as illustrated in Fig. 6. In this
position the roller 22 is out of contact with the plate. When it is desired to
operate the engine by foot power, a vertical wheel 40 is mounted upon a stud 41
on the side of a sleeve 42 fitted upon the exterior of the tube 6. The wheel 40 is
held upon the stud 41 by means of the washer 43 mounted upon the outer end of
the screw 44 which enters a screw threaded opening in the end of the stud.
Within the tube 6, opposite to the inner end of the screw 44 is a re-enforcing
collar 45.
An ordinary treadle 46 is pivoted at one end to a plate 47 which rests upon the
floor, and the other end is pivoted on a pin 49 secured to the outside of the
wheel 40. A rod 50 connects the plate 47 with one of the feet 2 the upper side
of which is provided with an opening 51 in which is entered the bent end of the
rod 50. The inner side of the wheel 40 is provided with an inwardly extending
peripheral flange adapted to press against the peripheries of the wheels or disks 19
and 30.
My invention is operated as follows. When other than foot power is to be
utilized, the wheel 40 is removed. A belt is then connected at one end with the
motor and at the other end with the pulley 17, thus imparting rotation to the disk 19.
through the intermediacy of the sleeve 16. To rotate the shaft 4 the lever 35 is
released thus permitting the shaft 4 to drop until the rubber disk 30 rests upon
the rubber disk 19 and is rotated thereby. The curved tubular arm 10 having
therein the flexible shaft 5 to which is secured the hand piece to be used, is then
inserted in to the upper end of the tube 8, the inner end of the flexible shaft being
at the same time inserted in the opening provided therefor in the upper end of the
shaft 4. This opening and the rigid spindle at the end of the flexible shaft 5 is other-
wise than round and motion is thus imparted from the shaft 4 to the flexible shaft 5.
To stop rotation of the shaft 4, the lever 35 is depressed at its outer end until the
pin 39 enters the upper depression in the side of the projection 37 on the
tube 8. The disk 30 is thus lifted from contact with the disk 19 and the shaft 4
stops rotating. To reverse direction of rotation of the shaft 4, the lever 35 is still
further depressed until the pin 39 enters the lower opening in the side of the pro-
jection 37, at which time the roller 22 is forced by the plate 26 against the under-
side of the pulley 17, which in rotating rotates the roller 22 and through it the
plate 26 and the shaft 4 in a direction opposite to the former direction of rota-
tion of the shaft 4. In using foot power, the belt is removed from the pulley 17,
and the wheel 40, pedal and pitman are connected to the engine in the manner
already described. Power is then applied to the pedal which through the inter-
mediacy of the pitman and wheel 40 causes a rotation of the rubber disks or
wheels 19 and 30 and the shaft 4.
My invention may be modified in many ways without departing from its spirit.

page_text: 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:-
Claim 1. In a dental engine, the combination with a rotary driving shaft, of a
wheel secured thereto and rotatable therewith, a wheel rotatable around but inde-
pendently of the driving shaft, and means for bringing the two wheels in or out
of engagement with each other, substantially as described.
2. In a dental engine, the combination with a rotary driving shaft, of a wheel
secured thereon and rotatable therewith, a wheel rotatable around but indepen-
dently of the driving shaft, and means for imparting longitudinal motion to the
driving shaft for the purpose of engaging or disengaging the two wheels, substan-
tially as described.
3. In a dental engine, the combination with a driving shaft rotatable in a suit-
able support and longitudinally movable therein, of a Hexible shaft connected to
and rotatable with the driving shaft, a wheel secured upon and rotatable with the
driving shaft, a wheel rotatable independently of the driving shaft, means for
rotating the second wheel, and means for engaging the two wheels with each
other when the driving shaft is moved longitudinally in its support in the proper
direction, substantially as described.
4. In a dental engine, the combination with a driving shaft rotatable in a suit-
able support and longitudinally movable therein, of a flexible shaft connected to
and rotatable with the driving shaft, a wheel secured upon and rotatable with
the driving shaft, a second wheel rotatable independently of the driving shaft,
means for imparting rotation to the second wheel, means for imparting
rotation in the same direction to the driving shaft when it is moved
longitudinally in one direction, and means for reversing the direction of
rotation of the driving shaft when it is moved in the opposite direction longi-
tudinally, substantially as described.
5. In a dental engine, the combination with a rotary driving shaft of a wheel
secured thereon and rotatable therewith, a wheel rotatable independently of the driv-
ing shaft, a plate rotatable with the driving shaft, a roller located between the inde-
pendent wheel and the plate, means for moving the driving shaft in one direction
for the purpose of engaging the two wheels together, and means for moving
the driving shaft in the opposite direction for the purpose of engaging the roller
with the independent wheel and the said plate, substantially as described.
6. In a dental engine, the combination with a rotary driving shaft, of a wheel
secured to and rotatable with the driving shaft, a plate secured to and rotatable
with the driving shaft, a wheel rotatable independently of the driving shaft and
located between the said plate and the first wheel, a roller located between the
independent wheel and the said plate and adapted to have a rolling connection
between the two, a lever for controlling the lengthwise movement of the driving
shaft in opposite directions, whereby when moved in one direction the roller may
be brought into engagement with the independent wheel and the plate, and when
moved in the opposite direction the independent wheel may be brought into en-
gagement with the wheel secured to the driving shaft, substantially as described.
7. In a dental engine, the combination with a longitudinally movable rotary
driving shaft provided with a suitable support, of a driving pulley mounted upon
said support and rotatable about and independently of said shaft, a friction wheel
secured to the shaft at one end of the said pulley and rotatable with the driving
shaft, a plate on said shaft at the other end of said pulley also rotatable with the
driving shaft, a roller interposed between the driving pulley and said plate, and
means whereby the shaft may be longitudinally shifted to alternately bring the
friction wheel and roller in contact with the driving pulley for reversing the
rotary movement of the shaft, substantially as described.
8. In a dental engine, the combination with a rotary driving shaft, of a plate
secured to and rotatable therewith, a driving wheel rotatable independently of the
driving shaft, a roller between the plate and driving wheel, and means for bring

page_text: ing the plate and driving wheel in and out of revolving contact with the roller,
substantially as described.
9. In a dental engine, the combination with a rotary driving shaft, of a driving
wheel rotatable independently of the driving shaft, a plate secured to and rota-
table with the driving shaft, a roller located between the plate and driving wheel,
and a lever pivoted to a suitable support and adapted to engage the driving shaft
for the purpose of moving the said shaft lengthwise whereby the roller is made
to have a rolling contact with the plate and the driving wheel, substantially as
described.
10. In a dental engine, the combination with a rotary driving shaft, of a wheel
rotatable therewith, a wheel rotatable around but independently of the driving
shaft, means for preventing longitudinal movement of the independent wheel,
and means for bringing the two wheels into or out of engagement with each other,
substantially as described.
11. In a dental engine, the combination with a rotary driving shaft, of a driv-
ing wheel rotatable around the driving shaft, two devices rotatable with the
driving shaft, means for engaging the driving wheel with one of the said devices
for rotating the driving shaft in one direction, and means for engaging the driv-
ing wheel with the other device for rotating the driving shaft in the opposite
direction, substantially as described.
:
12. In a dental engine, the combination with a rotary driving shaft, of a flex-
ible shaft rotatable therewith and connected thereto, a driving wheel rotatable in
a fixed plane independently of the driving shaft, means for imparting rotation
from the driving wheel to the driving shaft in one direction when the driving
shaft is moved in one direction, and means for imparting rotation to the driving
shaft in the opposite direction when the driving shaft is moved lengthwise in the
opposite direction, substantially as described.
Dated this 2nd day of May 1898.
ARTHUR JAY MCDONALD,
Haseltine, Lake, & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.