Improvements in Dental Engines.
Year: 1893

page_text: Date of Application, 17th Jan., 1893
Complete Specification Left, 17th Oct., 1893-Accepted, 18th Nov., 1893
PROVISIONAL SPECIFICATION.
Improvements in Dental Engines.
I, FREDERICK HYMA HALLAM of 117 Lisson Grove in the County of Middlesex,
Dental Instrument Maker, do hereby declare the nature of this invention to be as
follows:-
:-
This invention for improvements in dental engines has for its object to construct
a dental arm for communicating rotary motion from the ordinary driving source to
the drills and other tools used in dental operations, which shall be manipulated
with greater facility and accuracy, and also accommodate itself more readily to the
driving band or cord so as to maintain a more uniform tension than is the case with
dental arms as ordinarily constructed.
A dental arm constructed according to this invention comprises essentially two
tubular arms, a forearm and a back arin, connected together by an universal elbow
joint. Through the forearm passes a long driving spindle whose outer end is
connected to the drill chuck through a flexible connecting piece, while on its inuer
end is mounted a pulley around which passes the driving band from the treadle or
other driving source, the said band being guided on and off the pulley by suitable
guide rollers.
The back arm comprises a vertical pivot post, free to turn about its axis in
suitable bearings or guides, and surmounted by a horizontal tube carrying at its
back end a pair of guide pulleys mounted on bearings forming a part of a sliding
crosshead fitting the tube internally, and being normally pressed by means of a
spring into a backward position, but capable of a limited longitudinal forward
motion.
The forearm is hinged to a plug or spigot inserted into the outer end of the
tubular forearm in which it turns freely, the whole forming an universal elbow
joint.
The driving band is conveyed over the back guide pulleys, through the guide
rollers, and around the forearm spindle pulley, the universal elbow joint allowing
the free movement of the arm, and the back arm guide pulleys keeping the driving
band uniformly tant in all positions of the apparatus.
Dated this 17th day of January 1893.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Dental Engines.
I, FREDERICK HYMA HALLAM, of 117 Lisson Grove, in the County of Middlesex,
Dental Instrument Maker, 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:-
This invention for improvements in dental engines has for its object to construct
a dental arm for communicating rotary motion from the ordinary driving source to
the drills and other tools used in dental operations, which shall be manipulated
with greater facility and accuracy and also accommodate itself more readily to the
driving band or cord so as to maintain a more uniform tension, than is the case with
dental arms as ordinarily constructed.
In the accompanying sheet of illustrative drawings, Fig. 1 represents a sectional.
elevation and Fig. 2 a sectional plan of a dental arm constructed according to this
invention.

page_text: The complete arm comprises essentially two tubular arms, a forearm a and a back
arm, connected together by an elbow joint which permits of considerable independent
motion relatively to one another.
Through the forearm a tubular casing a and working in suitable sleeves, passes
a long driving spindle whose outer end is connected to the drill chuck through a
flexible connecting piece in the ordinary manner, while on its inner end is mounted
a grooved pulley c around which passes the driving band from the treadle wheel or
other driving source, the said band being guided by the guide rollers & mounted
loosely on carrier stud pins e secured to the swivelling bracket f of the elbow
joint.
The back arm comprises a pivot post g free to turn about its axis in a suitable
bearing or guide and surmounted by a horizontal tube in the back end of which
slides a block i to which is secured the bearing stud pins on which are loosely
mounted the guide pulleys m. The sliding block i is normally pressed outwardly
by the spiral spring n its traverse being limited by the slots o in the tube which
also prevent its rotation in the tube. The driving band passes from the driving
source over the guide pulleys m between the guide rollers d and around the pulley c
and is kept taut in all positions of the arm by the spring n as will be readily
understood. The bracket of the forearm is hinged by the pin p to the swivel
plug which rotates freely in the tube hand whose withdrawal is prevented by
the pin feather secured in the tube and working in a groove s in the
said plug.
•
During dental operations it is frequently desirable to relieve the operator of the
weight of the forearm by retaining it in an elevated position at any required angle.
For this purpose the plug 9 is formed with a disc t provided with a projecting
tooth which engages with the ratchet teeth of a disc w mounted loosely upon the
end of the tube and sliding freely thereon, but prevented from turning indepen-
dently of it by means of a pin or feather & working in the slot the said ratchet
dise being normally pressed into engagement with the tooth by a spiral spring a
all as clearly shown.
y
2
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a dental arm: guide pulleys mounted on stud pins secured to a sliding
block encased by the tubular back arm and pressed outwardly by a spring substan-
tially as described, and for the purpose set forth.
2. In a dental arm: connecting the forearm and back arm by means of an elbow
joint comprising a swivel plug, working in the outer end of the back-arm, and a
sleeve bracket connected to the forearm, hinged together, substantially as
described.
3. In a dental arm: a swivel plug rotating in one extremity of the back arm and
forming a part of an elbow joint for connecting the fore-arm and back-arm together,
in combination with a toothed disc sliding on the said backarm and being pressed
into engagement with a corresponding toothed disc on the said plug substantially as
described and for the purpose specified.
4. In a dental arm: the combination of guide pulleys connected to a sliding
block in the back arm pressed outwardly by a spring; of guide rollers mounted on
the sleeve bracket of the forearm ; and of a driving pulley mounted on the driving
spindle passing through the forearm substantially as described.
5. The arrangement and construction of dental arms, substantially as described
with reference to the drawings.
Dated this 17th day of October 1892
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.