IMPROVEMENTS IN ELECTRIC DRILLS
Year: 1880

page_text: LETTERS PATENT to Sydney Pitt, of Sutton, in the County of Surrey, for an
Invention of "IMPROVEMENTS IN ELECTRIC DRILLS." A communication from
abroad by Charles E. Ball, of the City and County of Philadelphia, State of
Pennsylvania, United States of America.
COMPLETE SPECIFICATION filed by the said Sydney Pitt at the Office of
the Commissioners of Patents on the 9th December 1880.
"IMPROVEMENTS IN
SYDNEY PITT, of Sutton, in the County of Surrey.
ELECTRIC DRILLS." A communication from abroad by Charles E. Ball, of the
City and County of Philadelphia, State of Pennsylvania, United States of
America.
This Invention relates to drills of the class reciprocated by electro-magnetism.
Its object is to secure a simple, efficient, and durable machine, to which end the
Invention broadly stated consists in a novel organization of mechanism, whereby
the drill is positively actuated in both directions by the direct action of the electric
current.
The subject-matter of the Invention is set forth in the claims at the end of
this Specification.
The essential elements of the improved organization are, a suitable generator of
electricity, a voltaic circuit, a series of helices, a core common to the helices
reciprocating axially therethrough, a drilling tool connected with the core, and a
rheotome or circuit breaker for reversing, changing, or switching the currents at
the proper time to impart the desired motion to the tool.
The accompanying Drawing represents a longitudinal central section through so
much of an apparatus embodying all the improvements as is necessary to illustrate
the subject-matter herein claimed in the best way known to me at the date of
filing this application.
The details of construction of the apparatus being well known need not be

page_text: particularly described herein, especially as such details constitute no part of the
subject-matter herein claimed, and may be greatly varied without departing from
the spirit of the Invention.
The Drawing shows a frame or yoke A mounted in usual well known ways upon
a tripod, the legs a of which are variable in length so as to adjust the drilling tool
properly relatively to the substance to be operated upon. A stock or cylinder B
slides freely endwise in the frame, its movement being controlled by an adjusting
screw b. Coils or helices C, D, of insulated wire wound in a way usual with
electro-magnets are secured in the stock B, end to end in the same axial plane, but
with a space between them. An ordinary soft iron core D' common to both these
helices has the capacity of sliding freely endwise axially therethrough, the core it
will be observed being about one-third longer than either coil, so as to always leave
it within their magnetic field. The upper end of the cylinder D terminates in a
small chamber in which the core D¹ plays on its back stroke; the confined air in
this chamber is thus compressed at each back stroke, and acts as a buffer to prevent
shocks or jars.
A tool-stock or drill-holder E constituting a prolongation of this core carries the
drilling-tool in usual well-known ways. The conductor from a suitable dynamo or
magneto-electric machine or generator (not shown in the Drawing) is divided, each
branch being connected with its respective coil, so that the circuit may pass
alternately through each one as it is shunted by the action of the rheotome or
circuit-changer hereinafter described.
One terminal of the coil C leads to contact g, and a terminal of the coil D
likewise connects with another contact g¹, both of said contacts being insulated
from each other, but secured to the same pendant or bracket H of the stock B.
The return-wire F' to the generator is secured to a T shaped bar I located
between the drill-stock E and pendant H above mentioned.
With the parts in the position shown in the Drawing, one coil C is is circuit while
the other one D is inactive. The operative force of the coil C draws the core D¹
into it and retracts the drill, at the same time moving the bar I out of contact with
the contact g, and into contact with the contact g', this bar being moved at the
proper time by the tappets or wipers e, e¹, on the drill-stock E.
As the core D₁ reaches the limit of its back stroke the bar I comes in contact
with the contact g', thus changing the current from the back coil C to the front
one D, causing the core to be drawn forcibly into said coil, thus producing the
necessary stroke of the drill. When the forward stroke of the drill is completed,
the stud e strikes the plate I and forees it against the contact g, thus again
throwing the coil C into circuit, and the coil D out of circuit, and retracting the
drill. These operations being repeated at every stroke of the drill produce a very
rapid and effective reciprocation thereof.
I claim,-
First. The combination, substantially as herein set forth, of a series of helices,
a core reciprocating axially therethrough, and actuated positively thereby in both
directions, and a drilling tool connected with the core.
Second. The combination, substantially as herein set forth, of a series of helices,
a core reciprocating axially therethrough, a drilling-tool connected with the core,
and a commutator or circuit-breaker alternating the currents through the helices.
Third. The combination, substantially as herein set forth, of a series of helices,
a core reciprocating axially therethrough, a drilling-tool connected with the core,
circuit-connections, and a circuit-breaker actuated by the drill-stock.
Fourth. The combination, substantially as herein set forth, of the yoke or frame,
the stock, the mechanism for adjusting the stock in the frame, the coils mounted in
the stock, the core reciprocating through the coils, and the drilling-tool connected with
the core, whereby all the mechanism may be adjusted by a single instrumentality.
Fifth. The combination, substantially as herein set forth, of the yoke or frame,
its adjustable supports, the stock, the mechanism for adjusting it in the frame, the

page_text: coils and circuit-breaking mechanism mounted on the stock, the core reciprocating
axially through the coils, and the drilling tool connected with the core, whereby
the double adjustability of the drilling tool is secured.
In witness whereof, I, the said Sydney Pitt, have hereunto set my hand
and seal, this Sixth day of December, in the year of our Lord One thousand
eight hundred and eighty.