Year: 1886

page_text: I, ALEXANDER JAMIESON of 10, Broad Street, Golden Square, in the County
of Middlesex, Manufacturer of Dental Materials, do hereby declare the nature of
invention to be 89 follows:-
My invention relates to an improved construction of dental engine.
The fly-wheel and crank are carried on a suitable pillar springing from a base
upon which the usual pedal is mounted in any well-known way, and fitted with
a proper spring-device for raising the pedal and carrying the crank over the dead
points.
The shape of the base, and nearness of the crank-shaft to the ground, are
regulated by considerations of stability and convenience.
The power is transmitted from the fly-wheel by friction gearing to the top, or
overhead, motion of the engine, at which point a second friction gear is provided to
rotate the horizontal arm.
By this improved method of gearing the engine, my invention does away
with the numerous inconveniences arising from the unprotected position of the
well-known driving cord.
I provide for the even transmission of the power of the engine from the overhead
motion through the indispensable elbow joint to the hand-piece, by an adaptation
of the well-known flexible shaft, which I prefer to make of several, or at least of
more than one, wire coils inside each other. I add side plates, or guards, at
opposite sides, to prevent this flexible shaft from buckling, or assuming any other
position than that of an arc of a circle in one simple plane, when it is required to
transmit the power in any but a right line.
The above mentioned guard may have the individual plates connected so as to
form a circular but flexible guard.
I make use of any suitable hand-piece with the herein described improved
construction of dental engine, the outer covering of the flexible part being according
to my invention made of celuloid, which I prefer as a protective covering for the
various flexible parts of my engine.
DAL: 2 1
T
1000
PHILLIPS & LEIGH,
Agents for the Applicant.

page_text: An Improved Dental Engine.
I, ALEXANDER JAMIESON, of 10, Broad Street, Golden Square, in the County of
Middlesex, Manufacturer of Dental Materials, 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 invention relates to an improved construction of dental engine, and consists
in dispensing with all driving cords, replacing them by simple frictional gearing;
in making the hollow pillar of the engine capable of deflection through a con-
siderable arc, and the horizontal arm capable of a complete revolution; in making
the connection between the first friction pinion and that of the horizontal arm
removeable from the pillar, and capable of automatic compensation for any strain
to which it may be subjected; and in jointing the horizontal arm to the vertical
shaft of the engine releasably, so that it can be put out of gear, and allowed to
hang close to the vertical shaft.
In order that my invention, and the means by which the same may be carried
into practical effect, may be thoroughly understood, I will now describe the same,
referring in so doing to the accompanying drawings which illustrate the mechanisms
by which I attain the aim of my invention. They are to be taken as part of this
< specification and read therewith, like parts being marked throughout with the same
reference letter.
Fig. 1 is a front elevation of the engine, with the frictional pinion of the
horizontal arm out of gear, and the entire arm hanging down by the side of the
hollow pillar.
Fig. 2 is a side elevation shewing the engine in gear, but not in use.
Fig. 3 is a detail drawing, partly in section, of the step bearing of the first
friction pinion, and of the compensation device.
Fig. 4 is a sectional elevation of the spring device for releasing the horizontal
arm to take it out of gear, or to put it into gear.
Fig. 5 is a plan illustrating the construction of the flexible connector.
Fig. 6 is a sectional elevation, on an enlarged scale, through the axis of the
fly-wbeel, illustrating a device for keeping the fly-wheel and its pinion in working
contact.
A is the base of the engine, B the treadle, bits axis, C the connecting rod, a the
crank pin, and D the fly-wheel.
The fly-wheel is carried in a bearing formed in the upper extremity of the
pillar E springing from the centre of the base A.
The bush e and fly-wheel shaft d are continued outwards forming a suitable
support for the upper part of the engine, and one upon which it can oscillate
freely.
The upper part of the engine consists of the piece F, in which the first pinion d'
has its step-bearing; the downward continuation of capable of oscillation upon the
bush e; the vertical hollow pillar G; the connecting rod g from the pinion d' to

page_text: the friction wheel H; the stiff horizontal arm I, and the flexible arm J, through
which the power is conveyed from the frictional wheel H by a frictional pinion h
fast on the end of a partly rigid, partly flexible, core passing through the two arms,
and entering the usual hand piece, in which it receives the tool the dentist wishes
to use.
The pinion d is, preferably, made with a collar fitted with a set screw, by means
of which it can be set upon its spindle d' so as to take up wear, as well as to
permit of its easy removal.
This pinion as well as the friction wheel and pinions H, h, are, preferably, made
by gripping a proper number of discs of leather, or similar tough material, between
two discs of metal, and then turning the peripheries up true.
The connection between the pinion and the friction wheel H is not a rigid
one, but consists of three pieces, which are connected in such a way that the
connecting rod is capable of yielding before a sudden twisting strain, and then
recovering itself without suffering permanent distortion, or interfering with the
normal practical continuity of the whole connection.
This part of my invention is carried out as follows.
The upward continuation of the pinion spindle d³ is bored out to receive the
lower end of an intermediate piece g', the upper end, or nose, g₁ of which is made
of an elliptical section in elevation, and connected to the body of the piece by a
neck g. The lower end of the rod g is bored out to receive the nose of the
intermediate piece. Two notches g' are formed diametrically across the end of
the rod to receive two corresponding pins go projecting respectively from opposite
sides of the thick part of the nose g³. A second pair of notches is cut in the end
of the spindle d', and two corresponding pins, projecting laterally from the lower
extremity of the intermediate piece g¹, fit therein. The pins fit into the notches
without play.
When the engine is running without strain, the intermediate piece is in the
position illustrated in Fig. 3, the rod g being down over the nose g², and the
notches gembracing the pins go. But so soon as the rod g is subjected to any
twisting strain, it buckles, in the usual way, against the opposite sides of the
pillar G, its bored out end riding up the nose g, while one of the semi-circular
taces of its extremity, according to the direction of the strain, enters the neck g³.
As the rod g recovers itself, it elongates, and its end rides down the nose g³, the
mechanical connection between the pinion d¹ and the wheel H having been,
throughout, maintained by the pins and notches.
A second advantage of this construction is the facility with which the wheel H
and the rod g as well as the other parts can be taken out for cleaning or repair.
The friction wheel H is, of course, fast upon the upper end of the rod g.
The pinion is fast on the end of the rigid part i of the compound core, the
construction of which is illustrated in Fig. 5. The flexible part of this core is
composed of two spirals ¹, i, respectively right and left handed. The ends are
incorporated with the rigid part i and the tool holder, respectively, in any
suitable way.
The rigid parts I and i are made comparatively short for the sake of compactness,
and may be rotated through an entire circle, from any point of which the length
and flexibility of the arın enable it to be used through a considerable arc and in
various planes.
K is a bracket consisting of two parts hinged together at k. The lower
extremity of the bracket terminates in a socket k¹ which, embracing the top of the
pillar G, rests upon a socket L described further on, and upon which it is, therefore,
capable of an easy rotation.
The opposite extremity of the bracket terminates in a second socket k²,
embracing the arm I with which it is incorporated in any suitable way.
Between the bracket K and a collar g³ formed upon the pillar G, is the device
by means of which the arm I is maintained in the horizontal position illustrated in
Fig. 2, or allowed, to drop down by the side of the pillar G, as illustrated in Fig. 1.

page_text: This device consists of the socket L above mentioned which is free to rotate
around the pillar between the socket kl and the collar g³. One side of this is
extended laterally for a short distance, the outer end of the extremity carrying a
vertical socket in which is fitted a pin capable of being pulled down by the
milled head 3, and raised by the spring . The distance of the axis of the pin
from that of the pillar G is such that the pin can enter a corresponding perforation
in the underside of the outer part of the bracket K, when it is brought thereunder
by rotating the socket L and pulling the milled head down. The spring may,
1"
of course, be replaced by screwing the socket and, the shank of the pin.
When the arm I is raised into a horizontal position and held there by the pin A,
the friction pinion h is in proper working contact with the wheel H.
The circular range of my improved construction of engine, and the advantages
thereof have been already described, but the end of the arm I would always be
confined to the horizontal plane-I, however, increase the adaptability of my
engine to the varying exigencies of the operating room, by making the whole
upper part of the engine capable of oscillating freely upon a fixed axis, produced
by a lateral elongation of the fly-wheel shaft d and bush e, one or both. The
dotted lines of Fig. 2 illustrate this capability of oscillation, which can be given to
the engine in either a forward or backward direction.
For the purpose of keeping the surfaces of the fly-wheel and its pinion in contact,
I provide a cup e¹ bearing against the outer faces of the bush e and of a suitable
extension of the part f, and passing over the projecting end of the shaft d. A
spiral spring is inserted in the annular space within the cup, and its power caused
to exert itself for the purpose of keeping the wheel and pinion in proper working
contact, by compressing it with the head of a suitable screw e entering the end of
the shaft d.
M is a returning spring extending from the lower extremity of the oscillating
part of the engine to the base, its function being to return said oscillating part to
a vertical position and to retain it therein.
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 engine, the combination of the upper part capable of an oscillating
notion upon a lateral extension of the fly-wheel bush or axle, with a device for
keeping the fly-wheel in working contact with its pinion, substantially as described
with reference to the accompanying drawings:
2. In a dental engine, the upper part of which is capable of an oscillating
movement checked by a spring, about the axis of the fly-wheel, a mitre frictional
gearing consisting of a driver and pinion only, the driver of which being the
fly-wheel of the engine is carried by a vertical pillar springing from the base of
the engine, and the pinion working within the aforesaid oscillating part of the
engine, substantially as described with reference to the accompanying drawings.
3. In a dental engine, the combination of a tubular vertical pillar,capable of an
oscillating movement upon the fly-wheel shaft, with a friction pinion driven direct
by the fly wheel and a connecting rod contained within said pillar and connecting
said friction pinion with a friction wheel revolving at the top of said pillar,
substantially as described with reference to the accompanying drawings.
4. In the connecting rod contained within the vertical pillar of a dental engine
and conveying power from a driven friction pinion to the driver of the top gear,
the combination of the extended spindle of the said driven friction pinion with an
elliptically shaped end or nose connected by a neck to the said spindle or to a
detachable continuation thereof, which elliptically shaped end or nose enters
entirely into a corresponding cavity bored axially into the end of the upper part of
the connecting rod, thereby rendering it possible for an edge of the cavity to enter
the said neck when the connecting rod as a whole suffers a torsional strain,
substantially as described with reference to the accompanying drawings.

page_text: 5. In a dental engine, the combination of top friction gear, bottom friction gear,
each one consisting of only one driver and one pinion, with the upper part of the
engine capable of an oscillating movement about the axis of the fly-wheel shaft,
substantially as described with reference to the accompanying drawings.
6. In a dental engine, the combination of the bottom friction gear consisting of
only one driver and one pinion, and the top friction gear consisting of only one
driver and one pinion, with a connecting rod having the pinion of the former gear
and the driver of the latter gear fixed on its respective ends substantially as
described with reference to the accompanying drawings.
7. In a dental engine, the combination of the rigid tubular part of the horizontal
arm fastened to or incorporated with one half of a hinged bracket the other half of
which is capable of rotation around the top of the vertical pillar of the engine,
and a device also capable of rotation around the vertical pillar, and of maintaining
the rigid tubular part in a horizontal position and the top friction gear in working
contact, substantially as described with reference to the accompanying drawings.
8. In a dental engine, the combination of a compound rigid and flexible core of
the arm of the engine with and carrying the pinion of the top friction gear, said
pinion bearing directly upon the friction wheel to which the connecting rod is
rigidly attached, substantially as described with reference to the accompanying
drawings.
9. The generally light and compact construction of dental engine consisting of
base, single central pillar springing therefrom, treadle, connecting rod, fly-wheel
revolving close to said central pillar, light tubular pillar axially in the same plane
as the said central pillar aforesaid, capable of an oscillating motion upon a lateral
extension of the fly-wheel axis by means of a downward solid extension (which
also embraces the first pinion) and containing the connecting rod which takes the
power from said first pinion to the top gear, horizontal arm and flexible power
conveyor capable of being put out of gear so as to hang down parallel with the
light tubular pillar and within the projection of the fly wheel axis, substantially as
described with reference to the accompanying drawings.
PHILLIPS & LEIGH,
Agents for the Applicant.